Review Article The G Allele of CaSR R990G Polymorphism...

13
Review Article The G Allele of CaSR R990G Polymorphism Increases Susceptibility to Urolithiasis and Hypercalciuria: Evidences from a Comprehensive Meta-Analysis Kang Liu, Xiaolan Wang, Jiaxin Ye, Chao Qin, Pengfei Shao, Wei Zhang, Jie Li, and Changjun Yin Department of Urology, e First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China Correspondence should be addressed to Jie Li; lijie [email protected] Received 8 August 2014; Revised 4 October 2014; Accepted 6 October 2014 Academic Editor: Mohammad I. Kamboh Copyright © 2015 Kang Liu et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. e calcium-sensing receptor gene (CaSR) is a candidate to explain urolithiasis. A number of case-control studies were conducted to investigate associations between CaSR polymorphisms with risks of hypercalciuria and urolithiasis in humans. But the results were still inconsistent. Methods. A meta-analysis was performed to address this issue. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of associations between CaSR polymorphisms and the risk of urolithiasis. e pooled standardized mean difference (SMD) with 95% CI was used for the meta-analysis of CaSR polymorphisms and urine calcium concentration. Results. For urolithiasis association, the SS genotype of A986S polymorphism was a risk factor for urolithiasis in Asians and PHPT patients, but a protective factor in Caucasians. e GG genotype of R990 polymorphism was associated with an increased risk of urolithiasis, especially in Caucasians and healthy population. Regarding urine calcium concentration association, individuals with the G allele had a higher level of urine calcium than the noncarriers. Conclusions. is meta-analysis revealed that the G allele of CaSR R990G polymorphism increases susceptibility to urolithiasis and hypercalciuria. e A986S and Q1011E polymorphisms were associated with urolithiasis and hypercalciuria in specific populations. 1. Introduction Urolithiasis is a condition that has been recognized for centuries and is the third most common cause of urinary tract disease [1]. Nearly 5% of females and 12% of males are likely to develop urolithiasis during their lifetime [2]. Urolithiasis is a global health problem with a 40 to 50% recurrence rate within five years [3]. In recent years, many studies have made utmost efforts to investigate the pathogenesis of urolithiasis. However, the detailed pathogenic mechanism for the occurrence and recurrence of urolithiasis remains unknown. Urolithiasis is a multifactorial disease which is consid- ered to be associated with the effects of multiple genes in combination with lifestyles and environmental influences [4]. Although no specific gene has been declared to be the underlying cause of urolithiasis, many functional genes such as urokinase, vitamin D receptor gene (VDR), and calcium- sensing receptor gene (CaSR) have been verified to be related to urolithiasis [5–7]. e CaSR gene, located on chromosome 3q13.3-21, spans 103 kb and encodes for a protein of 1078 amino acids present in the plasma membrane. CaSR is a member of the G-protein coupled receptors and its structure has 3 different domains [8, 9]. It is widely accepted that CaSR may be connected with urolithiasis, since it decreases calcium reabsorption in thick ascending limbs and distal convo- luted tubules, increases phosphate reabsorption in proximal tubules, and decreases water and proton reabsorption in collecting ducts [10]. As a consequence, the CaSR gene is a candidate to explain the susceptibility to urolithiasis. e CaSR gene is composed of seven exons, the first six coding for the extracellular domain of the CaSR protein and exon 7 coding for the transmembrane and the intracel- lular domains [11]. ree single-nucleotide polymorphisms Hindawi Publishing Corporation BioMed Research International Volume 2015, Article ID 958207, 12 pages http://dx.doi.org/10.1155/2015/958207

Transcript of Review Article The G Allele of CaSR R990G Polymorphism...

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Review ArticleThe G Allele of CaSR R990G Polymorphism IncreasesSusceptibility to Urolithiasis and Hypercalciuria Evidences froma Comprehensive Meta-Analysis

Kang Liu Xiaolan Wang Jiaxin Ye Chao Qin Pengfei Shao Wei ZhangJie Li and Changjun Yin

Department of Urology The First Affiliated Hospital of Nanjing Medical University Nanjing 210029 China

Correspondence should be addressed to Jie Li lijie urology163com

Received 8 August 2014 Revised 4 October 2014 Accepted 6 October 2014

Academic Editor Mohammad I Kamboh

Copyright copy 2015 Kang Liu et alThis is an open access article distributed under the Creative CommonsAttribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

BackgroundThe calcium-sensing receptor gene (CaSR) is a candidate to explain urolithiasis A number of case-control studies wereconducted to investigate associations between CaSR polymorphisms with risks of hypercalciuria and urolithiasis in humans Butthe results were still inconsistentMethods A meta-analysis was performed to address this issue Crude odds ratios (ORs) with 95confidence intervals (CIs) were calculated to estimate the strength of associations between CaSR polymorphisms and the risk ofurolithiasis The pooled standardized mean difference (SMD) with 95 CI was used for the meta-analysis of CaSR polymorphismsand urine calcium concentration Results For urolithiasis association the SS genotype of A986S polymorphism was a risk factorfor urolithiasis in Asians and PHPT patients but a protective factor in Caucasians The GG genotype of R990 polymorphismwas associated with an increased risk of urolithiasis especially in Caucasians and healthy population Regarding urine calciumconcentration association individuals with the G allele had a higher level of urine calcium than the noncarriers Conclusions Thismeta-analysis revealed that the G allele of CaSR R990G polymorphism increases susceptibility to urolithiasis and hypercalciuriaThe A986S and Q1011E polymorphisms were associated with urolithiasis and hypercalciuria in specific populations

1 Introduction

Urolithiasis is a condition that has been recognized forcenturies and is the thirdmost common cause of urinary tractdisease [1] Nearly 5 of females and 12 of males are likelyto develop urolithiasis during their lifetime [2] Urolithiasisis a global health problem with a 40 to 50 recurrencerate within five years [3] In recent years many studieshave made utmost efforts to investigate the pathogenesis ofurolithiasis However the detailed pathogenic mechanismfor the occurrence and recurrence of urolithiasis remainsunknown

Urolithiasis is a multifactorial disease which is consid-ered to be associated with the effects of multiple genes incombination with lifestyles and environmental influences[4] Although no specific gene has been declared to be theunderlying cause of urolithiasis many functional genes such

as urokinase vitamin D receptor gene (VDR) and calcium-sensing receptor gene (CaSR) have been verified to be relatedto urolithiasis [5ndash7]The CaSR gene located on chromosome3q133-21 spans 103 kb and encodes for a protein of 1078amino acids present in the plasma membrane CaSR is amember of the G-protein coupled receptors and its structurehas 3 different domains [8 9] It is widely accepted that CaSRmay be connectedwith urolithiasis since it decreases calciumreabsorption in thick ascending limbs and distal convo-luted tubules increases phosphate reabsorption in proximaltubules and decreases water and proton reabsorption incollecting ducts [10] As a consequence the CaSR gene is acandidate to explain the susceptibility to urolithiasis

The CaSR gene is composed of seven exons the firstsix coding for the extracellular domain of the CaSR proteinand exon 7 coding for the transmembrane and the intracel-lular domains [11] Three single-nucleotide polymorphisms

Hindawi Publishing CorporationBioMed Research InternationalVolume 2015 Article ID 958207 12 pageshttpdxdoiorg1011552015958207

2 BioMed Research International

(SNPs) A986S (rs1801725 G gt T) R990G (rs1042636 Agt G) and Q1011E (rs1801726 C gt G) located on exon 7are extensively studied [12] Shakhssalim and his colleaguesobserved a significantly higher frequency of the 986S 990Gand 1011Q alleles in stone formers [13] Another Italianstudy puts forward similar conclusions [14] These findingsconfirm that CaSR gene polymorphisms may be involved inurolithiasis but the impact of these amino acid changes onthe function of CASR is not well defined Unfortunately wehave no sufficient knowledge to resolve these puzzles

At present several studies have attempted to investigateassociations between CaSR gene variants with urolithiasisand urinary calcium concentration However the resultswere inconsistent or even contradictory To date no one hasconducted a meta-analysis to further probe the associationsTo fill this gap we performed a meta-analysis of all eligiblestudies to derive more reliable estimation of associationsbetween calcium-sensing receptor gene polymorphisms withurolithiasis and urinary calcium concentration

2 Materials and Methods

21 Identification of Eligible Studies A comprehensive liter-ature search was performed through the PubMed MedlineEmbase and Web of Science databases for relevant articlespublished (the last search update was June 30 2014) with thefollowing key words ldquoCaSRrdquo ldquopolymorphismrdquo ldquovariationrdquo orldquomutationrdquo and ldquourolithiasisrdquo or ldquocalculirdquo and in combina-tion with ldquourine calcium excretionrdquo Additional studies wereidentified by hand searching references in original articlesand review articles

22 Inclusion and Exclusion Criteria The included studiesneeded to meet the following criteria (1) The study exam-ined the associations between CaSR polymorphisms andurinary calcium concentration andor urolithiasis risk (2)For urolithiasis association the study must be case-controlstudy and must have clear original data of genotypic andallelic frequencies (3) For urinary calcium concentrationassociation the study must have clear original data ofthe mean of urinary calcium concentration and standarddeviations (SD) by genotypes In addition the number ofeach genotype must be clear Major reasons for exclusionof studies were as follows (1) not for urolithiasis or urinarycalcium concentration research (2) review articles (3) onlycase population and (4) duplicate of previous publication

23 Data Extraction Information was carefully extractedfrom all eligible studies independently by two investigatorsaccording to the inclusion criteria listed above For conflict-ing evaluation a consensus was reached by discussion Thefollowing information was collected from each study thefirst authorrsquos name the year of publication ethnicity countryof origin genotyping method source of control groups(population- or hospital-based controls) subjects numbersof cases and controls frequency of CaSR polymorphisms incases and controls the mean of urinary calcium concentra-tion and SD by genotypes Meanwhile the corresponding

and first authors of the published studies were contacted bysending e-mails if they did not provide their original data

24 Statistical Analysis Crude odds ratios (ORs) with theircorresponding 95 CIs were used to assess the strength ofassociations between CaSR polymorphisms and urolithia-sis risk The pooled ORs were performed for homozygotemodel (MMversusWW) heterozygotemodel (WMversusWW) dominant model (WM + MM versus WW) andrecessive model (MM versus WW + WM) respectivelyBetween-study heterogeneity was checked by the chi-square-based 119876 test (heterogeneity was considered statistically sig-nificant if 119875 lt 010) [24] Pooled OR estimate of eachstudy was calculated by both the fixed-effects model (theMantel-Haenszel method) and the random-effects model(the DerSimonian and Laird methods) The fixed-effectsmodel would be adopted when the studies were found to behomogeneous (with 119875 gt 010 for the 119876 test) Otherwisethe random-effects model would be applied To better inves-tigate the possible sources of between-study heterogeneitymeta-regression analysis was performed In addition to thecomparison among all subjects we also conducted stratifi-cation analyses by ethnicity subjects and source of controlsSensitivity analyses were performed to assess the stability ofthe results namely a single study in the meta-analysis wasdeleted each time to reflect the influence of the individualdata set to the pooled OR The pooled standardized meandifference (SMD) with 95CI was used for themeta-analysisof CaSR polymorphisms and urinary calcium concentrationBeggrsquos funnel plot and Eggerrsquos linear regression test wereused to assess publication bias Moreover departure fromHardy-Weinberg equilibrium (HWE) in controls was testedby the chi-square test for goodness of fit and a 119875 lt 005was considered as a significant disequilibrium All statisticalanalyses were performedwith the Stata software (version 121StataCorp LP College Station TX USA) using two-sided 119875values

3 Results

31 Characteristics of Studies There were 43 articles relevantto the search words of which 34 articles were excluded Ofthe 34 excluded studies 11 articles were not related to A986SR990G and Q1011E polymorphisms 8 studies were reviewarticles and 15 papers were not case-control studies Besides3 additional articles [17 20 21] were identified by handTwelve papers were finally included in this meta-analysis

For the associations between CaSR polymorphisms andurolithiasis a total of seven papers which included 10 case-control studies [5 13ndash18] for the A986S polymorphism 9case-control studies [13ndash18] for the R990G polymorphismand 4 case-control [13 14 17] studies for the Q1011E poly-morphism were involved in this meta-analysis Figure 1graphically illustrates the trial flow chart All studies usedblood samples for DNA extraction while polymerase chainreaction method TaqMan or DNA sequencing methodswere used for genotyping Controls were mainly matched onsex and age In addition the distribution of genotypes in

BioMed Research International 3

For urolithiasis riskA986S 10 case-control studies A986S 9 case-control studiesR990G 9 case-control studies R990G 6 case-control studiesQ1011E 4 case-control studies Q1011E 5 case-control studies

For urine calcium concentration

Citations identified and screened (n = 43)

Review (n = 8)Not case-control study (n = 15)Not CaSR polymorphism (n = 11)

Eligible articles (n = 9)

hand (n = 3)Articles searched by

Figure 1 Studies identified with criteria for inclusion and exclusion

the controls of all studies was consistent with Hardy-Weinberg equilibrium Main characteristics for all case-control studies were listed in Table 1

For the associations between CaSR polymorphisms andurinary calcium concentration ten papers [5 13ndash15 18ndash23] were retrieved according to the inclusion criteria Theprocess of study selection is also shown in Figure 1 Here-into nine (1670 individuals) six (1049 individuals) andfive (964 individuals) studies were included in the meta-analysis for the association between A986S R990G andQ1011E polymorphisms and urinary calcium concentra-tion respectively Table 2 listed the characteristics of thesestudies

32 Association between CaSR Polymorphisms and Urolithi-asis Risk Table 3(a) lists the main results of the meta-analysis of the associations between A986S polymorphismand urolithiasis risk Overall no obvious association wasobserved in all the genetic models (Figure 2(a)) Howeverthere was noteworthy heterogeneity between studies Hencewe then performed subgroup analysis Through stratifiedanalyses the heterogeneity of the subgroup notably reducedIn the subgroup analysis on ethnicity we discovered that theA986S polymorphism was significantly associated with anincreased urolithiasis risk in Asians under the heterozygotemodel (OR = 164 95 CI = 104ndash256) and the dominantmodel (OR = 178 95 CI = 113ndash289 Figure 3(a)) Inter-estingly a conflicting association was found in Caucasiansunder the dominant model (OR = 078 95 CI = 062ndash099)Stratified analysis was also performed by subjectsThe resultsindicated that primary hyperparathyroidism (PHPT) patientswith the AA genotypes had a significantly lower urolithiasisrisk in the dominant model (OR = 062 95CI = 040ndash096)In the stratified analysis by source of controls significantassociations were found in hospital-based group (dominantmodel OR = 067 95 CI = 046ndash096)We next conducted aleave-one-out sensitivity analysis to determinewhether a par-ticular study or studies would result in heterogeneity Finallythe omission of individual studies did not materially alter theresults (Figure 4(a)) The sensitivity analysis thus confirmedthat the results were statistically robust In addition as shown

in Figure 5(a) no possibility of publication bias for this testwas observed

The relationship between the R990G polymorphism andthe risk of urolithiasis is summarized in Table 3(b) Signif-icant associations were observed in the dominant geneticmodel (OR = 210 95 CI = 123ndash358 Figure 2(b)) Inthe stratified analysis by ethnicity the positive results werefound only in the Caucasian subgroups but not in the Asianpopulations The pooled OR was 217 (95 CI = 150ndash491)in Caucasian subgroups for the dominant model When thestudies were stratified by subjects healthy individuals withthe RR genotypes were related to a significantly decreasedrisk of urolithiasis (dominant model OR = 336 95 CI= 100ndash1128 Figure 3(b)) Moreover we failed to find anyeffects on urolithiasis risk in all genetic models testedwhen restricting the analysis to the source of controls Itis worth noting that the heterogeneity remained significantafter subgroup analysis Therefore we used meta-regressionanalysis to explore the source of heterogeneity by ethnicitysubjects source of controls and year of publicationWe foundthat only the year of publication contributed to substantialaltered heterogeneity which could account for 100 sourceof heterogeneity Moreover the sensitivity analysis was alsoconducted (Figure 4(b)) After individual study omissionthe corresponding pooled OR was not altered significantlyBeggrsquos funnel plot and Eggerrsquos test did not suggest evidence ofpublication bias (Figure 5(b))

As shown in Table 3(c) we did not observe any significantassociations between the Q1011E polymorphism and urolithi-asis risk in all the genetic models (Figure 2(c)) The Q1011Evariant has been reported to be much less frequent than theother two SNPs Given heterogeneity was not remarkablein all the genetic models and only four case-control studieswere finally included we did not conduct subgroup analysisThe sensitivity analysis showed that results were reliableand stable Besides Beggrsquos funnel plot and Eggerrsquos test wereperformed to evaluate the publication bias of the literaturesSimilarly no publication bias was detected for association ofQ1011E polymorphism with urolithiasis

33 Association between CaSR Polymorphisms and UrinaryCalcium Concentration The results of the overall meta-analysis provided a strong evidence of the associationbetween urinary calcium concentration and the CaSR R990Gpolymorphism (SMD = 252 95 CI 012ndash492 and 119875 =0039 Figure 2(d)) but not the A986S polymorphism (SMD= 025 95 CI minus059ndash110 and 119875 = 056) and theQ1011E polymorphism (SMD=minus119 95CIminus252ndash015 and119875 = 0081) Furthermore we performed subgroup analysis(Table 4)The stratified analysis only showed that Caucasianswith the Q1011E polymorphism ancestral genotype had sig-nificantly higher urinary calcium concentration than thosewith the minor allele (SMD = minus199 95 CI minus374 to minus024and 119875 = 0026) Unfortunately we did not obtain otherpositive findings

There was heterogeneity among studies in overall com-parisons To explore the sources of heterogeneity we con-ducted subgroup analyses by ethnicity and subjects However

4 BioMed Research International

Table1Ch

aracteris

ticso

fstudies

inclu

dedin

them

eta-analysisfora

ssociatio

nsbetweenCa

SRpo

lymorph

ismsa

ndurolith

iasis

risk

CaSR

A986S

polymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

AA

AS

SS

AA

AS

SS

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

645

1215

150

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

645

188

60

Y2011

Kim

etal[5]

Asian

Korea

PCR

PBHealth

ypo

pulatio

n415

180

191

60

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n71

262

9314

0Y

2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

157

5610

469

191

16Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

7836

7282

130

20Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

7836

752

3814

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

3012

191

424

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

3012

124

146

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

157

7457

44

CaSR

R990Gpo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

RR

RG

GG

RR

RG

GG

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

2040

1050

11961

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

2040

1024

5317

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n87

102

105

20

Y2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

171

3814

568

102

6Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

105

160

391

410

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

105

160

102

20

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

349

128

9

2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

349

431

2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

216

15100

1

CaSR

Q1011Epo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

QQ

QE

EE

QQ

QE

EE

2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n94

50

107

00

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

113

80

402

300

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

113

80

102

20

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulatio

n222

90

983

0Y

PBPop

ulation-basedstu

dyH

Bho

spita

l-based

studyand

HWE

Hardy-W

einb

ergequilib

rium

BioMed Research International 5

Table2Ch

aracteris

ticso

find

ividualstudies

inclu

dedin

them

eta-analysisof

CaSR

polymorph

ismsa

ndurinec

alcium

concentration

CaSR

A986S

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

AA

Mean

SDAS+SS

Mean

SDHan

etal[15]

2013

Asian

China

164

PHPT

patie

nts

151

41347

20496

1350605

1805

Kim

etal[5]

2011

Asian

Korea

433

urolith

iasis

patie

nts

415

1903

112

181386

84Ferreira

etal[19]

2010

Mixed

Brazil

187

urolith

iasis

patie

nts

177

239

100

10280

86Ve

zzolietal[20]

2007

Caucasian

Italy

243

Females

168

601

0233

75572

0323

Perez-Ca

strillon

etal[21]

2006

Caucasian

Spain

48osteop

oroticwom

en33

219

124

15175

175

Corbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

51676

393

2876

1427

Harding

etal[22]

2006

Caucasian

England

188

dizygotic

femaletwin

pairs

141

044

015

47046

018

Kelly

etal[23]

2006

Caucasian

England

121

Health

ypo

pulations

9002

009

31019

01

Vezzolietal[14

]2002

Caucasian

Italy

207

urolith

iasis

patie

nts

133

691

026

7479

6046

CaSR

R990Gpo

lymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

RRMean

SDRG

+GG

Mean

SDCorbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

69677

431

1090

5205

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

167

045

017

2104

042

Vezzolietal[14

]2002

Caucasian

Italy

148

Urolithiasispatie

nts

133

691

026

1596

8087

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

192

1870

69975

1421443

9923

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

8283

112

Vezzolietal[20]

2007

Caucasian

Italy

243

Females

220

582

0196

23759

063

CaSR

Q1011E

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

QQ

Mean

SDQE+EE

Mean

SDVe

zzolietal[20]

2007

Caucasian

Italy

243

Females

230

603

0193

1352

0966

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

172

045

014

16037

062

Vezzolietal[14

]2002

Caucasian

Italy

142

Urolithiasispatie

nts

133

691

026

96

091

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

201

2336

1399

51878

19873

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

4287

80

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

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Page 2: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

2 BioMed Research International

(SNPs) A986S (rs1801725 G gt T) R990G (rs1042636 Agt G) and Q1011E (rs1801726 C gt G) located on exon 7are extensively studied [12] Shakhssalim and his colleaguesobserved a significantly higher frequency of the 986S 990Gand 1011Q alleles in stone formers [13] Another Italianstudy puts forward similar conclusions [14] These findingsconfirm that CaSR gene polymorphisms may be involved inurolithiasis but the impact of these amino acid changes onthe function of CASR is not well defined Unfortunately wehave no sufficient knowledge to resolve these puzzles

At present several studies have attempted to investigateassociations between CaSR gene variants with urolithiasisand urinary calcium concentration However the resultswere inconsistent or even contradictory To date no one hasconducted a meta-analysis to further probe the associationsTo fill this gap we performed a meta-analysis of all eligiblestudies to derive more reliable estimation of associationsbetween calcium-sensing receptor gene polymorphisms withurolithiasis and urinary calcium concentration

2 Materials and Methods

21 Identification of Eligible Studies A comprehensive liter-ature search was performed through the PubMed MedlineEmbase and Web of Science databases for relevant articlespublished (the last search update was June 30 2014) with thefollowing key words ldquoCaSRrdquo ldquopolymorphismrdquo ldquovariationrdquo orldquomutationrdquo and ldquourolithiasisrdquo or ldquocalculirdquo and in combina-tion with ldquourine calcium excretionrdquo Additional studies wereidentified by hand searching references in original articlesand review articles

22 Inclusion and Exclusion Criteria The included studiesneeded to meet the following criteria (1) The study exam-ined the associations between CaSR polymorphisms andurinary calcium concentration andor urolithiasis risk (2)For urolithiasis association the study must be case-controlstudy and must have clear original data of genotypic andallelic frequencies (3) For urinary calcium concentrationassociation the study must have clear original data ofthe mean of urinary calcium concentration and standarddeviations (SD) by genotypes In addition the number ofeach genotype must be clear Major reasons for exclusionof studies were as follows (1) not for urolithiasis or urinarycalcium concentration research (2) review articles (3) onlycase population and (4) duplicate of previous publication

23 Data Extraction Information was carefully extractedfrom all eligible studies independently by two investigatorsaccording to the inclusion criteria listed above For conflict-ing evaluation a consensus was reached by discussion Thefollowing information was collected from each study thefirst authorrsquos name the year of publication ethnicity countryof origin genotyping method source of control groups(population- or hospital-based controls) subjects numbersof cases and controls frequency of CaSR polymorphisms incases and controls the mean of urinary calcium concentra-tion and SD by genotypes Meanwhile the corresponding

and first authors of the published studies were contacted bysending e-mails if they did not provide their original data

24 Statistical Analysis Crude odds ratios (ORs) with theircorresponding 95 CIs were used to assess the strength ofassociations between CaSR polymorphisms and urolithia-sis risk The pooled ORs were performed for homozygotemodel (MMversusWW) heterozygotemodel (WMversusWW) dominant model (WM + MM versus WW) andrecessive model (MM versus WW + WM) respectivelyBetween-study heterogeneity was checked by the chi-square-based 119876 test (heterogeneity was considered statistically sig-nificant if 119875 lt 010) [24] Pooled OR estimate of eachstudy was calculated by both the fixed-effects model (theMantel-Haenszel method) and the random-effects model(the DerSimonian and Laird methods) The fixed-effectsmodel would be adopted when the studies were found to behomogeneous (with 119875 gt 010 for the 119876 test) Otherwisethe random-effects model would be applied To better inves-tigate the possible sources of between-study heterogeneitymeta-regression analysis was performed In addition to thecomparison among all subjects we also conducted stratifi-cation analyses by ethnicity subjects and source of controlsSensitivity analyses were performed to assess the stability ofthe results namely a single study in the meta-analysis wasdeleted each time to reflect the influence of the individualdata set to the pooled OR The pooled standardized meandifference (SMD) with 95CI was used for themeta-analysisof CaSR polymorphisms and urinary calcium concentrationBeggrsquos funnel plot and Eggerrsquos linear regression test wereused to assess publication bias Moreover departure fromHardy-Weinberg equilibrium (HWE) in controls was testedby the chi-square test for goodness of fit and a 119875 lt 005was considered as a significant disequilibrium All statisticalanalyses were performedwith the Stata software (version 121StataCorp LP College Station TX USA) using two-sided 119875values

3 Results

31 Characteristics of Studies There were 43 articles relevantto the search words of which 34 articles were excluded Ofthe 34 excluded studies 11 articles were not related to A986SR990G and Q1011E polymorphisms 8 studies were reviewarticles and 15 papers were not case-control studies Besides3 additional articles [17 20 21] were identified by handTwelve papers were finally included in this meta-analysis

For the associations between CaSR polymorphisms andurolithiasis a total of seven papers which included 10 case-control studies [5 13ndash18] for the A986S polymorphism 9case-control studies [13ndash18] for the R990G polymorphismand 4 case-control [13 14 17] studies for the Q1011E poly-morphism were involved in this meta-analysis Figure 1graphically illustrates the trial flow chart All studies usedblood samples for DNA extraction while polymerase chainreaction method TaqMan or DNA sequencing methodswere used for genotyping Controls were mainly matched onsex and age In addition the distribution of genotypes in

BioMed Research International 3

For urolithiasis riskA986S 10 case-control studies A986S 9 case-control studiesR990G 9 case-control studies R990G 6 case-control studiesQ1011E 4 case-control studies Q1011E 5 case-control studies

For urine calcium concentration

Citations identified and screened (n = 43)

Review (n = 8)Not case-control study (n = 15)Not CaSR polymorphism (n = 11)

Eligible articles (n = 9)

hand (n = 3)Articles searched by

Figure 1 Studies identified with criteria for inclusion and exclusion

the controls of all studies was consistent with Hardy-Weinberg equilibrium Main characteristics for all case-control studies were listed in Table 1

For the associations between CaSR polymorphisms andurinary calcium concentration ten papers [5 13ndash15 18ndash23] were retrieved according to the inclusion criteria Theprocess of study selection is also shown in Figure 1 Here-into nine (1670 individuals) six (1049 individuals) andfive (964 individuals) studies were included in the meta-analysis for the association between A986S R990G andQ1011E polymorphisms and urinary calcium concentra-tion respectively Table 2 listed the characteristics of thesestudies

32 Association between CaSR Polymorphisms and Urolithi-asis Risk Table 3(a) lists the main results of the meta-analysis of the associations between A986S polymorphismand urolithiasis risk Overall no obvious association wasobserved in all the genetic models (Figure 2(a)) Howeverthere was noteworthy heterogeneity between studies Hencewe then performed subgroup analysis Through stratifiedanalyses the heterogeneity of the subgroup notably reducedIn the subgroup analysis on ethnicity we discovered that theA986S polymorphism was significantly associated with anincreased urolithiasis risk in Asians under the heterozygotemodel (OR = 164 95 CI = 104ndash256) and the dominantmodel (OR = 178 95 CI = 113ndash289 Figure 3(a)) Inter-estingly a conflicting association was found in Caucasiansunder the dominant model (OR = 078 95 CI = 062ndash099)Stratified analysis was also performed by subjectsThe resultsindicated that primary hyperparathyroidism (PHPT) patientswith the AA genotypes had a significantly lower urolithiasisrisk in the dominant model (OR = 062 95CI = 040ndash096)In the stratified analysis by source of controls significantassociations were found in hospital-based group (dominantmodel OR = 067 95 CI = 046ndash096)We next conducted aleave-one-out sensitivity analysis to determinewhether a par-ticular study or studies would result in heterogeneity Finallythe omission of individual studies did not materially alter theresults (Figure 4(a)) The sensitivity analysis thus confirmedthat the results were statistically robust In addition as shown

in Figure 5(a) no possibility of publication bias for this testwas observed

The relationship between the R990G polymorphism andthe risk of urolithiasis is summarized in Table 3(b) Signif-icant associations were observed in the dominant geneticmodel (OR = 210 95 CI = 123ndash358 Figure 2(b)) Inthe stratified analysis by ethnicity the positive results werefound only in the Caucasian subgroups but not in the Asianpopulations The pooled OR was 217 (95 CI = 150ndash491)in Caucasian subgroups for the dominant model When thestudies were stratified by subjects healthy individuals withthe RR genotypes were related to a significantly decreasedrisk of urolithiasis (dominant model OR = 336 95 CI= 100ndash1128 Figure 3(b)) Moreover we failed to find anyeffects on urolithiasis risk in all genetic models testedwhen restricting the analysis to the source of controls Itis worth noting that the heterogeneity remained significantafter subgroup analysis Therefore we used meta-regressionanalysis to explore the source of heterogeneity by ethnicitysubjects source of controls and year of publicationWe foundthat only the year of publication contributed to substantialaltered heterogeneity which could account for 100 sourceof heterogeneity Moreover the sensitivity analysis was alsoconducted (Figure 4(b)) After individual study omissionthe corresponding pooled OR was not altered significantlyBeggrsquos funnel plot and Eggerrsquos test did not suggest evidence ofpublication bias (Figure 5(b))

As shown in Table 3(c) we did not observe any significantassociations between the Q1011E polymorphism and urolithi-asis risk in all the genetic models (Figure 2(c)) The Q1011Evariant has been reported to be much less frequent than theother two SNPs Given heterogeneity was not remarkablein all the genetic models and only four case-control studieswere finally included we did not conduct subgroup analysisThe sensitivity analysis showed that results were reliableand stable Besides Beggrsquos funnel plot and Eggerrsquos test wereperformed to evaluate the publication bias of the literaturesSimilarly no publication bias was detected for association ofQ1011E polymorphism with urolithiasis

33 Association between CaSR Polymorphisms and UrinaryCalcium Concentration The results of the overall meta-analysis provided a strong evidence of the associationbetween urinary calcium concentration and the CaSR R990Gpolymorphism (SMD = 252 95 CI 012ndash492 and 119875 =0039 Figure 2(d)) but not the A986S polymorphism (SMD= 025 95 CI minus059ndash110 and 119875 = 056) and theQ1011E polymorphism (SMD=minus119 95CIminus252ndash015 and119875 = 0081) Furthermore we performed subgroup analysis(Table 4)The stratified analysis only showed that Caucasianswith the Q1011E polymorphism ancestral genotype had sig-nificantly higher urinary calcium concentration than thosewith the minor allele (SMD = minus199 95 CI minus374 to minus024and 119875 = 0026) Unfortunately we did not obtain otherpositive findings

There was heterogeneity among studies in overall com-parisons To explore the sources of heterogeneity we con-ducted subgroup analyses by ethnicity and subjects However

4 BioMed Research International

Table1Ch

aracteris

ticso

fstudies

inclu

dedin

them

eta-analysisfora

ssociatio

nsbetweenCa

SRpo

lymorph

ismsa

ndurolith

iasis

risk

CaSR

A986S

polymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

AA

AS

SS

AA

AS

SS

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

645

1215

150

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

645

188

60

Y2011

Kim

etal[5]

Asian

Korea

PCR

PBHealth

ypo

pulatio

n415

180

191

60

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n71

262

9314

0Y

2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

157

5610

469

191

16Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

7836

7282

130

20Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

7836

752

3814

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

3012

191

424

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

3012

124

146

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

157

7457

44

CaSR

R990Gpo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

RR

RG

GG

RR

RG

GG

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

2040

1050

11961

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

2040

1024

5317

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n87

102

105

20

Y2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

171

3814

568

102

6Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

105

160

391

410

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

105

160

102

20

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

349

128

9

2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

349

431

2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

216

15100

1

CaSR

Q1011Epo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

QQ

QE

EE

QQ

QE

EE

2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n94

50

107

00

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

113

80

402

300

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

113

80

102

20

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulatio

n222

90

983

0Y

PBPop

ulation-basedstu

dyH

Bho

spita

l-based

studyand

HWE

Hardy-W

einb

ergequilib

rium

BioMed Research International 5

Table2Ch

aracteris

ticso

find

ividualstudies

inclu

dedin

them

eta-analysisof

CaSR

polymorph

ismsa

ndurinec

alcium

concentration

CaSR

A986S

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

AA

Mean

SDAS+SS

Mean

SDHan

etal[15]

2013

Asian

China

164

PHPT

patie

nts

151

41347

20496

1350605

1805

Kim

etal[5]

2011

Asian

Korea

433

urolith

iasis

patie

nts

415

1903

112

181386

84Ferreira

etal[19]

2010

Mixed

Brazil

187

urolith

iasis

patie

nts

177

239

100

10280

86Ve

zzolietal[20]

2007

Caucasian

Italy

243

Females

168

601

0233

75572

0323

Perez-Ca

strillon

etal[21]

2006

Caucasian

Spain

48osteop

oroticwom

en33

219

124

15175

175

Corbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

51676

393

2876

1427

Harding

etal[22]

2006

Caucasian

England

188

dizygotic

femaletwin

pairs

141

044

015

47046

018

Kelly

etal[23]

2006

Caucasian

England

121

Health

ypo

pulations

9002

009

31019

01

Vezzolietal[14

]2002

Caucasian

Italy

207

urolith

iasis

patie

nts

133

691

026

7479

6046

CaSR

R990Gpo

lymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

RRMean

SDRG

+GG

Mean

SDCorbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

69677

431

1090

5205

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

167

045

017

2104

042

Vezzolietal[14

]2002

Caucasian

Italy

148

Urolithiasispatie

nts

133

691

026

1596

8087

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

192

1870

69975

1421443

9923

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

8283

112

Vezzolietal[20]

2007

Caucasian

Italy

243

Females

220

582

0196

23759

063

CaSR

Q1011E

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

QQ

Mean

SDQE+EE

Mean

SDVe

zzolietal[20]

2007

Caucasian

Italy

243

Females

230

603

0193

1352

0966

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

172

045

014

16037

062

Vezzolietal[14

]2002

Caucasian

Italy

142

Urolithiasispatie

nts

133

691

026

96

091

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

201

2336

1399

51878

19873

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

4287

80

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

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BioMed Research International

OncologyJournal of

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Oxidative Medicine and Cellular Longevity

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PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Research and TreatmentAIDS

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Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 3: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

BioMed Research International 3

For urolithiasis riskA986S 10 case-control studies A986S 9 case-control studiesR990G 9 case-control studies R990G 6 case-control studiesQ1011E 4 case-control studies Q1011E 5 case-control studies

For urine calcium concentration

Citations identified and screened (n = 43)

Review (n = 8)Not case-control study (n = 15)Not CaSR polymorphism (n = 11)

Eligible articles (n = 9)

hand (n = 3)Articles searched by

Figure 1 Studies identified with criteria for inclusion and exclusion

the controls of all studies was consistent with Hardy-Weinberg equilibrium Main characteristics for all case-control studies were listed in Table 1

For the associations between CaSR polymorphisms andurinary calcium concentration ten papers [5 13ndash15 18ndash23] were retrieved according to the inclusion criteria Theprocess of study selection is also shown in Figure 1 Here-into nine (1670 individuals) six (1049 individuals) andfive (964 individuals) studies were included in the meta-analysis for the association between A986S R990G andQ1011E polymorphisms and urinary calcium concentra-tion respectively Table 2 listed the characteristics of thesestudies

32 Association between CaSR Polymorphisms and Urolithi-asis Risk Table 3(a) lists the main results of the meta-analysis of the associations between A986S polymorphismand urolithiasis risk Overall no obvious association wasobserved in all the genetic models (Figure 2(a)) Howeverthere was noteworthy heterogeneity between studies Hencewe then performed subgroup analysis Through stratifiedanalyses the heterogeneity of the subgroup notably reducedIn the subgroup analysis on ethnicity we discovered that theA986S polymorphism was significantly associated with anincreased urolithiasis risk in Asians under the heterozygotemodel (OR = 164 95 CI = 104ndash256) and the dominantmodel (OR = 178 95 CI = 113ndash289 Figure 3(a)) Inter-estingly a conflicting association was found in Caucasiansunder the dominant model (OR = 078 95 CI = 062ndash099)Stratified analysis was also performed by subjectsThe resultsindicated that primary hyperparathyroidism (PHPT) patientswith the AA genotypes had a significantly lower urolithiasisrisk in the dominant model (OR = 062 95CI = 040ndash096)In the stratified analysis by source of controls significantassociations were found in hospital-based group (dominantmodel OR = 067 95 CI = 046ndash096)We next conducted aleave-one-out sensitivity analysis to determinewhether a par-ticular study or studies would result in heterogeneity Finallythe omission of individual studies did not materially alter theresults (Figure 4(a)) The sensitivity analysis thus confirmedthat the results were statistically robust In addition as shown

in Figure 5(a) no possibility of publication bias for this testwas observed

The relationship between the R990G polymorphism andthe risk of urolithiasis is summarized in Table 3(b) Signif-icant associations were observed in the dominant geneticmodel (OR = 210 95 CI = 123ndash358 Figure 2(b)) Inthe stratified analysis by ethnicity the positive results werefound only in the Caucasian subgroups but not in the Asianpopulations The pooled OR was 217 (95 CI = 150ndash491)in Caucasian subgroups for the dominant model When thestudies were stratified by subjects healthy individuals withthe RR genotypes were related to a significantly decreasedrisk of urolithiasis (dominant model OR = 336 95 CI= 100ndash1128 Figure 3(b)) Moreover we failed to find anyeffects on urolithiasis risk in all genetic models testedwhen restricting the analysis to the source of controls Itis worth noting that the heterogeneity remained significantafter subgroup analysis Therefore we used meta-regressionanalysis to explore the source of heterogeneity by ethnicitysubjects source of controls and year of publicationWe foundthat only the year of publication contributed to substantialaltered heterogeneity which could account for 100 sourceof heterogeneity Moreover the sensitivity analysis was alsoconducted (Figure 4(b)) After individual study omissionthe corresponding pooled OR was not altered significantlyBeggrsquos funnel plot and Eggerrsquos test did not suggest evidence ofpublication bias (Figure 5(b))

As shown in Table 3(c) we did not observe any significantassociations between the Q1011E polymorphism and urolithi-asis risk in all the genetic models (Figure 2(c)) The Q1011Evariant has been reported to be much less frequent than theother two SNPs Given heterogeneity was not remarkablein all the genetic models and only four case-control studieswere finally included we did not conduct subgroup analysisThe sensitivity analysis showed that results were reliableand stable Besides Beggrsquos funnel plot and Eggerrsquos test wereperformed to evaluate the publication bias of the literaturesSimilarly no publication bias was detected for association ofQ1011E polymorphism with urolithiasis

33 Association between CaSR Polymorphisms and UrinaryCalcium Concentration The results of the overall meta-analysis provided a strong evidence of the associationbetween urinary calcium concentration and the CaSR R990Gpolymorphism (SMD = 252 95 CI 012ndash492 and 119875 =0039 Figure 2(d)) but not the A986S polymorphism (SMD= 025 95 CI minus059ndash110 and 119875 = 056) and theQ1011E polymorphism (SMD=minus119 95CIminus252ndash015 and119875 = 0081) Furthermore we performed subgroup analysis(Table 4)The stratified analysis only showed that Caucasianswith the Q1011E polymorphism ancestral genotype had sig-nificantly higher urinary calcium concentration than thosewith the minor allele (SMD = minus199 95 CI minus374 to minus024and 119875 = 0026) Unfortunately we did not obtain otherpositive findings

There was heterogeneity among studies in overall com-parisons To explore the sources of heterogeneity we con-ducted subgroup analyses by ethnicity and subjects However

4 BioMed Research International

Table1Ch

aracteris

ticso

fstudies

inclu

dedin

them

eta-analysisfora

ssociatio

nsbetweenCa

SRpo

lymorph

ismsa

ndurolith

iasis

risk

CaSR

A986S

polymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

AA

AS

SS

AA

AS

SS

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

645

1215

150

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

645

188

60

Y2011

Kim

etal[5]

Asian

Korea

PCR

PBHealth

ypo

pulatio

n415

180

191

60

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n71

262

9314

0Y

2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

157

5610

469

191

16Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

7836

7282

130

20Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

7836

752

3814

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

3012

191

424

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

3012

124

146

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

157

7457

44

CaSR

R990Gpo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

RR

RG

GG

RR

RG

GG

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

2040

1050

11961

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

2040

1024

5317

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n87

102

105

20

Y2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

171

3814

568

102

6Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

105

160

391

410

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

105

160

102

20

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

349

128

9

2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

349

431

2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

216

15100

1

CaSR

Q1011Epo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

QQ

QE

EE

QQ

QE

EE

2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n94

50

107

00

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

113

80

402

300

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

113

80

102

20

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulatio

n222

90

983

0Y

PBPop

ulation-basedstu

dyH

Bho

spita

l-based

studyand

HWE

Hardy-W

einb

ergequilib

rium

BioMed Research International 5

Table2Ch

aracteris

ticso

find

ividualstudies

inclu

dedin

them

eta-analysisof

CaSR

polymorph

ismsa

ndurinec

alcium

concentration

CaSR

A986S

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

AA

Mean

SDAS+SS

Mean

SDHan

etal[15]

2013

Asian

China

164

PHPT

patie

nts

151

41347

20496

1350605

1805

Kim

etal[5]

2011

Asian

Korea

433

urolith

iasis

patie

nts

415

1903

112

181386

84Ferreira

etal[19]

2010

Mixed

Brazil

187

urolith

iasis

patie

nts

177

239

100

10280

86Ve

zzolietal[20]

2007

Caucasian

Italy

243

Females

168

601

0233

75572

0323

Perez-Ca

strillon

etal[21]

2006

Caucasian

Spain

48osteop

oroticwom

en33

219

124

15175

175

Corbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

51676

393

2876

1427

Harding

etal[22]

2006

Caucasian

England

188

dizygotic

femaletwin

pairs

141

044

015

47046

018

Kelly

etal[23]

2006

Caucasian

England

121

Health

ypo

pulations

9002

009

31019

01

Vezzolietal[14

]2002

Caucasian

Italy

207

urolith

iasis

patie

nts

133

691

026

7479

6046

CaSR

R990Gpo

lymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

RRMean

SDRG

+GG

Mean

SDCorbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

69677

431

1090

5205

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

167

045

017

2104

042

Vezzolietal[14

]2002

Caucasian

Italy

148

Urolithiasispatie

nts

133

691

026

1596

8087

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

192

1870

69975

1421443

9923

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

8283

112

Vezzolietal[20]

2007

Caucasian

Italy

243

Females

220

582

0196

23759

063

CaSR

Q1011E

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

QQ

Mean

SDQE+EE

Mean

SDVe

zzolietal[20]

2007

Caucasian

Italy

243

Females

230

603

0193

1352

0966

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

172

045

014

16037

062

Vezzolietal[14

]2002

Caucasian

Italy

142

Urolithiasispatie

nts

133

691

026

96

091

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

201

2336

1399

51878

19873

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

4287

80

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 4: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

4 BioMed Research International

Table1Ch

aracteris

ticso

fstudies

inclu

dedin

them

eta-analysisfora

ssociatio

nsbetweenCa

SRpo

lymorph

ismsa

ndurolith

iasis

risk

CaSR

A986S

polymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

AA

AS

SS

AA

AS

SS

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

645

1215

150

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

645

188

60

Y2011

Kim

etal[5]

Asian

Korea

PCR

PBHealth

ypo

pulatio

n415

180

191

60

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n71

262

9314

0Y

2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

157

5610

469

191

16Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

7836

7282

130

20Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

7836

752

3814

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

3012

191

424

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

3012

124

146

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

157

7457

44

CaSR

R990Gpo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

RR

RG

GG

RR

RG

GG

2013

Han

etal[15]

Asian

China

Sequ

encing

PBPH

PTandhealthy

2040

1050

11961

Y2013

Han

etal[15]

Asian

China

Sequ

encing

HB

PHPT

patie

nts

2040

1024

5317

Y2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n87

102

105

20

Y2009

Ham

ilton

etal[16]

Caucasian

Canada

Sequ

encing

PBHealth

ypo

pulation

171

3814

568

102

6Y

2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

105

160

391

410

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

105

160

102

20

Y2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

andhealthy

349

128

9

2006

Corbetta

etal[18]

Caucasian

Italy

Taqm

anHB

PHPT

patie

nts

349

431

2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulation

216

15100

1

CaSR

Q1011Epo

lymorph

ismCa

se(119873

)Con

trol(119873)

HWE

Year

Author

Ethn

icity

Cou

ntry

Genotyping

SOC

Subjects

QQ

QE

EE

QQ

QE

EE

2010

Shakhssalim

etal[13]

Asian

Iran

Sequ

encing

PBHealth

ypo

pulatio

n94

50

107

00

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

PBPH

PTandhealthy

113

80

402

300

Y2007

Scillitani

etal[17]

Caucasian

Canada

Sequ

encing

HB

PHPT

patie

nts

113

80

102

20

Y2002

Vezzolietal[14

]Ca

ucasian

Italy

Sequ

encing

PBHealth

ypo

pulatio

n222

90

983

0Y

PBPop

ulation-basedstu

dyH

Bho

spita

l-based

studyand

HWE

Hardy-W

einb

ergequilib

rium

BioMed Research International 5

Table2Ch

aracteris

ticso

find

ividualstudies

inclu

dedin

them

eta-analysisof

CaSR

polymorph

ismsa

ndurinec

alcium

concentration

CaSR

A986S

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

AA

Mean

SDAS+SS

Mean

SDHan

etal[15]

2013

Asian

China

164

PHPT

patie

nts

151

41347

20496

1350605

1805

Kim

etal[5]

2011

Asian

Korea

433

urolith

iasis

patie

nts

415

1903

112

181386

84Ferreira

etal[19]

2010

Mixed

Brazil

187

urolith

iasis

patie

nts

177

239

100

10280

86Ve

zzolietal[20]

2007

Caucasian

Italy

243

Females

168

601

0233

75572

0323

Perez-Ca

strillon

etal[21]

2006

Caucasian

Spain

48osteop

oroticwom

en33

219

124

15175

175

Corbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

51676

393

2876

1427

Harding

etal[22]

2006

Caucasian

England

188

dizygotic

femaletwin

pairs

141

044

015

47046

018

Kelly

etal[23]

2006

Caucasian

England

121

Health

ypo

pulations

9002

009

31019

01

Vezzolietal[14

]2002

Caucasian

Italy

207

urolith

iasis

patie

nts

133

691

026

7479

6046

CaSR

R990Gpo

lymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

RRMean

SDRG

+GG

Mean

SDCorbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

69677

431

1090

5205

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

167

045

017

2104

042

Vezzolietal[14

]2002

Caucasian

Italy

148

Urolithiasispatie

nts

133

691

026

1596

8087

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

192

1870

69975

1421443

9923

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

8283

112

Vezzolietal[20]

2007

Caucasian

Italy

243

Females

220

582

0196

23759

063

CaSR

Q1011E

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

QQ

Mean

SDQE+EE

Mean

SDVe

zzolietal[20]

2007

Caucasian

Italy

243

Females

230

603

0193

1352

0966

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

172

045

014

16037

062

Vezzolietal[14

]2002

Caucasian

Italy

142

Urolithiasispatie

nts

133

691

026

96

091

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

201

2336

1399

51878

19873

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

4287

80

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

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OncologyJournal of

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Oxidative Medicine and Cellular Longevity

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PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Computational and Mathematical Methods in Medicine

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Research and TreatmentAIDS

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Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 5: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

BioMed Research International 5

Table2Ch

aracteris

ticso

find

ividualstudies

inclu

dedin

them

eta-analysisof

CaSR

polymorph

ismsa

ndurinec

alcium

concentration

CaSR

A986S

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

AA

Mean

SDAS+SS

Mean

SDHan

etal[15]

2013

Asian

China

164

PHPT

patie

nts

151

41347

20496

1350605

1805

Kim

etal[5]

2011

Asian

Korea

433

urolith

iasis

patie

nts

415

1903

112

181386

84Ferreira

etal[19]

2010

Mixed

Brazil

187

urolith

iasis

patie

nts

177

239

100

10280

86Ve

zzolietal[20]

2007

Caucasian

Italy

243

Females

168

601

0233

75572

0323

Perez-Ca

strillon

etal[21]

2006

Caucasian

Spain

48osteop

oroticwom

en33

219

124

15175

175

Corbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

51676

393

2876

1427

Harding

etal[22]

2006

Caucasian

England

188

dizygotic

femaletwin

pairs

141

044

015

47046

018

Kelly

etal[23]

2006

Caucasian

England

121

Health

ypo

pulations

9002

009

31019

01

Vezzolietal[14

]2002

Caucasian

Italy

207

urolith

iasis

patie

nts

133

691

026

7479

6046

CaSR

R990Gpo

lymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

RRMean

SDRG

+GG

Mean

SDCorbetta

etal[18]

2006

Caucasian

Italy

79PH

PTpatie

nts

69677

431

1090

5205

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

167

045

017

2104

042

Vezzolietal[14

]2002

Caucasian

Italy

148

Urolithiasispatie

nts

133

691

026

1596

8087

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

192

1870

69975

1421443

9923

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

8283

112

Vezzolietal[20]

2007

Caucasian

Italy

243

Females

220

582

0196

23759

063

CaSR

Q1011E

polymorph

ismAu

thor

Year

Ethn

icity

Cou

ntry

Samples

ize

Subjects

QQ

Mean

SDQE+EE

Mean

SDVe

zzolietal[20]

2007

Caucasian

Italy

243

Females

230

603

0193

1352

0966

Harding

etal[22]

2006

Caucasian

England

188

Dizygoticfemaletwin

pairs

172

045

014

16037

062

Vezzolietal[14

]2002

Caucasian

Italy

142

Urolithiasispatie

nts

133

691

026

96

091

Shakhssalim

etal[13]

2010

Asian

Iran

206

Urolithiasisandhealthy

201

2336

1399

51878

19873

Ferreira

etal[19]

2010

Mixed

Brazil

185

Urolithiasispatie

nts

177

239

100

4287

80

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Disease Markers

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Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 6: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

6 BioMed Research International

Table3SummaryORand95CI

oftheC

aSRpo

lymorph

ismsa

ndurolith

iasis

risk

(a)A986S

119873a

ASversus

AA

119875b

SSversus

AA

119875b

SSversus

AAA

S119875b

119873a

ASSS

versus

AA

119875b

Total

9097

(079ndash

119)

0261

104(048ndash225)

006

010

8(053

ndash219

)0099

10094

(071ndash12

5)0031

Ethn

icity

Asian

416

4(104ndash

259

)0549

418

(084ndash

2086)

0770

397

(080ndash

1976

)0782

417

8(113

ndash280)

0591

Caucasian

5085

(067ndash10

7)0778

074

(031ndash180)

0029

081

(035

ndash185)

0047

6078

(062ndash

099

)0257

Subjects

PHPT

andhealthy

3098

(048ndash14

1)0918

135(060ndash

302)

0412

135(061ndash300)

0421

310

3(073ndash14

5)0773

PHPT

patie

nts

3070

(044ndash

110)

0690

038

(010

ndash142)

0221

044

(012

ndash144)

0248

3062

(040ndash

096

)0351

Health

ypo

pulation

3110(082ndash14

7)0038

195(091ndash418)

0667

207

(095ndash452)

0512

4113(065ndash19

6)000

9SO

C PB5

107(084ndash

136)

0156

172(097ndash305)

064

1174(099ndash

306)

066

46

110(077ndash15

7)0035

HB

4074

(050ndash

110)

0809

040

(016

ndash102)

0330

044

(019

ndash100)

0376

4067

(046ndash

096

)044

2(b)R9

90G

119873a

RGversus

RR119875b

GGversus

RR119875b

GGversus

RRRG

119875b

119873a

RGG

Gversus

RR119875b

Total

614

5(090ndash

234)

0029

190(049ndash

730)

000

018

4(053

ndash643)

000

09

210

(123ndash358

)0001

Ethn

icity

Asian

312

7(054ndash

296)

0059

063

(026ndash

151)

0213

065

(032

ndash133

)0246

312

6(047ndash340

)0017

Caucasian

3174(088ndash342)

0063

701(285ndash172

7)0745

673

(274

ndash1653)

0717

6271

(150ndash

491)

004

4Subjects

PHPT

andhealthy

2111(065ndash190)

0223

107(007ndash1553

)0105

107(009ndash

1275)

0123

314

5(061ndash341)

0014

PHPT

patie

nts

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035

ndash181)

064

63

361

(055ndash2384)

000

4Health

ypo

pulation

2228

(050ndash

1045)

0051

757(300ndash

1911)

0877

727(289ndash

1831

)0851

3336

(100ndash

1128)

006

4SO

C PB4

131(083ndash208)

0123

287

(037

ndash2243)

000

0283

(039

ndash2063)

000

05

164(090ndash

301)

0013

HB

2240

(028ndash2065)

000

9076

(030ndash

196)

0575

079

(035ndash18

1)064

64

340

(097ndash1185)

000

4(c)Q1011E

119873a

QEversus

QQ

119875b

EEversus

QQ

119875b

EEversus

QQQ

E119875b

119873a

QEEE

versus

QQ

119875b

Total

415

9(091ndash281)

0201

220

(040ndash

1207)

0863

214

(039

ndash117

5)0859

415

9(091ndash281)

0201

a Num

bero

fstudies

b 119875valueo

f119876testforh

eterogeneity

SOC

Source

ofcontrols

HB

hospita

l-based

controlgroup

and

PBpop

ulation-basedcontrolgroup

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

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Diabetes ResearchJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 7: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

BioMed Research International 7

Vezzoli G (2002)Corbetta S (2006)Corbetta S (2006)Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Note weights are from random effects

061 (038 099)086 (041 180)052 (022 125)104 (068 158)055 (032 094)095 (068 133)

1352883708

148412381697926647603462

10000

262 (129 534)138 (054 353)134 (050 361)138 (042 446)094 (071 125)

Study ID OR (95 CI) Weight ()

0187 1 534

analysis

Overall (I2 = 509 P = 0031)

(a)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

694 (090 5330)

376 (139 1022)

1138 (137 9430)

145 (078 269)

777 (174 3466)

160 (110 232)

724 (158 3323)

069 (038 127)

086 (043 172)

210 (123 358) 10000

1459

1551

756

1768

773

1540

483

1158

510

Study ID OR (95 CI) Weight ()

00106 1 943

Note weights are from random effectsanalysis

Overall (I2 = 703 P = 0001)

(b)Study ID OR (95 CI) Weight ()

Vezzoli G (2002)

Scillitani A (2007)

Scillitani A (2007)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

000436 1 229

132 (035 500) 2670

4403

2134

792

10000169 (071 403)

1251 (068 22929)

361 (075 1740)

095 (042 213)

Overall (I2 = 352 P = 0201)

(c)

Study ID SMD (95 CI) Weight ()

Vezzoli G (2002)

Vezzoli G (2007)

Corbetta S (2006)

Harding B (2006)

Shakhssalim N (2010)

Note weights are from random effectsanalysis

Ferreira LG (2010)

860minus86

1641

1669

1681

1665

1677

1667

10000252 (012 492)

664 (590 737)

758 (656 860)

055 (minus011 122)

minus024 (minus069 022)

044 (minus027 115)

027 (minus027 082)

Overall (I2 = 988 P = 0000)

(d)

Figure 2 (a) Forest plot of urolithiasis risk associated with the CaSR A986S polymorphism under the dominant model (b) Forest plot ofurolithiasis risk associated with the CaSR R990G polymorphism under the dominant model (c) Forest plot of urolithiasis risk associatedwith the CaSR Q1011E polymorphism under the dominant model (d) Forest plot of urine calcium concentration associated with the CaSRR990G polymorphism under the dominant model

the heterogeneity remained significant Eggerrsquos test andBeggrsquosfunnel plot were applied for comparison to assess the publi-cation bias of the literature and no possibility of publicationbias for this test was observed (A986S Begg 119875 = 0466 Egger119875 = 0493 Figure 5(c) R990 Begg119875 = 006 Egger119875 = 0066Figure 5(d) Q1011E Begg 119875 = 0806 Egger 119875 = 0066)

4 Discussion

Prevalence of urolithiasis is epidemic in many regions of theworld It is acknowledged that urolithiasis is a major healthproblem with a significant proportion of patients requiringextensive surgical procedure However it is still puzzlingwhether the increased risk of urolithiasis is attributable togenetic factors environmental exposure or some combina-tion [4 25] In recent years single nucleotide polymorphisms(SNP) have been identified as a powerful tool for predictingcomplex diseases [26] As a candidate gene calcium-sensingreceptor gene has been widely noticed Three missense poly-morphisms of the CaSR gene (A986S R990G and Q1011E)have a significant frequency in general population [27] Sev-eral investigators tried to examine associations betweenCaSRpolymorphisms and urolithiasis risk but the conclusionswere conflicting Meta-analysis is a powerful tool which canprovide more reliable results than a single study and explain

controversial conclusions [28] To our best knowledge noone has conducted ameta-analysis to confirm the associationbetween CaSR polymorphisms and urolithiasis To fill thisgap we performed a meta-analysis of all eligible studies toderive more precise estimation Finally our meta-analysisindicated that the S allele of A986S polymorphism mightbe a risk factor for urolithiasis in Asians but be a protectivefactor in Caucasians Besides the G allele of R990G poly-morphism might contribute a significant increased overallrisk of urolithiasis particularly in Caucasians and healthypopulations No significant associations were discovered inthe Q1011E polymorphism

A growing body of evidence shows that the CaSR mightplay a crucial role in the pathogenesis of urolithiasis CaSR is acommon protein which usually expressed in the parathyroidglands renal tubules and distal tubules [29] CaSR is animportant regulator of PTH secretion according to bloodcalcium concentrations [30] In the kidney the CaSR hasdifferent functions based on the tubular segments where itis located [31] In brief it is mainly involved in regulatingthe function of different tubular segments through mod-ulating electrolyte and water excretion Particularly CaSRrestrains passive and active reabsorption of calcium in distaltubules and enhances reabsorption of phosphate in proximaltubules [3] Simultaneously CaSR can increase excretion of

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

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PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

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Diabetes ResearchJournal of

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Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

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Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 8: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

8 BioMed Research International

1Shakhssalim N (2010)Kim JY (2011)Han G (2013)Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)Corbetta S (2006)

Scillitani A (2007)Scillitani A (2007)Hamilton DC (2009)

262 (129 534)138 (054 353)134 (050 361)138 (042 446)178 (113 280)

9266476034622638

13528837081484123816977362

10000094 (071 125)

078 (062 099)095 (068 133)055 (032 094)104 (068 158)052 (022 125)086 (041 180)061 (038 099)

53410187

Study ID OR (95 CI) Weight ()

2

Overall (I2 = 509 P = 0031)

Subtotal (I2 = 235 P = 0257)

Subtotal (I2 = 00 P = 0591)

Note weights are from random effectsanalysis

(a)

1

Shakhssalim N (2010)

Han G (2013)

Han G (2013)

Vezzoli G (2002)

Corbetta S (2006)

Corbetta S (2006)

Scillitani A (2007)

Scillitani A (2007)

Hamilton DC (2009)

2

3

10000

30357561768510

27161459773483

4249155115401158376 (139 1022)

145 (078 269)069 (038 127)145 (061 341)

1138 (137 9430)777 (174 3466)086 (043 172)361 (055 2384)

694 (090 5330)160 (110 232)724 (158 3323)336 (100 1128)

210 (123 358)

943100106

Study ID OR (95 CI) Weight ()

Overall (I2 = 703 P = 0001)

Subtotal (I2 = 635 P = 0064)

Subtotal (I2 = 823 P = 0004)

Subtotal (I2 = 766 P = 0014)

Note weights are from random effectsanalysis

(b)

Figure 3 (a) Forest plot of the CaSR A986S polymorphism associated with urolithiasis risk stratified by ethnicity (AS + SS versus AA) (b)Forest plot of the CaSR R990G polymorphism associated with urolithiasis risk stratified by subjects (RG + GG versus RR)

Vezzoli G

Corbetta SCorbetta S

Scillitani AScillitani A

Hamilton DCKim JY

Han GHan G

Shakhssalim N

minus040

minus035

minus006

022

031

Meta-analysis random-effects estimates (linear form)Study omitted

(a)

Vezzoli G

Corbetta S

Corbetta S

Scillitani A

Scillitani A

Hamilton DC

Han G

Han G

Shakhssalim N

008

020

074

127

160

Meta-analysis random-effects estimates (linear form)Study omitted

(b)

Figure 4 (a) Sensitivity analysis of urolithiasis risk associatedwith the CaSRA986S polymorphismunder the dominantmodel (b) Sensitivityanalysis of urolithiasis risk associated with the CaSR R990G polymorphism under the dominant model

proton and water in collecting ducts [27] It is reported thatthe process of urolithiasis partly starts with an imbalancebetween excretion of water and insoluble stone-forming saltsleading to high concentrations that supersaturate urine andinner medullary collecting duct fluid [32] Hence CaSRplays an important role in urolithiasis and it is rational tohypothesize that its gene polymorphisms may be relatedto urolithiasis risk An initial contribution was given by astudy in knockout mice for the calcium channel TRPV5 [33]Renkema and his colleagues found that transient receptorpotential vanilloid 5 knockout (TPRV5minusminus) mice lackedkidney stones despite urinary calcium (Ca2+) wasting andhyperphosphaturia and it perhaps resulted from their sig-nificant polyuria and urinary acidification Activation of therenal CaSR promoted H+-ATPase-mediated H+ excretionand downregulation of aquaporin 2 (AQP 2) leading tourinary acidification and polyuria respectively The mice

developed calcium-phosphate precipitate in collecting ductsonly after inhibition of H+-ATPase activity that hampersurine acidification Thus we thought that CaSR polymor-phisms might be involved in urolithiasis via influencingactivities of CaSR gene and H-pump

The incidence of gene polymorphisms can vary sub-stantially among different racial populations We there-fore performed stratified analysis by ethnicity Interestinglycontradictory associations were found in the A986S andR990G polymorphisms For the A986S polymorphism theSS genotype was associated with an increased urolithiasisrisk in Asians but a decreased risk in Caucasians Regardingthe R990G polymorphism the association between GGgenotype and an increased risk of urolithiasis was only foundin Caucasians Even though the exact mechanism for theresults was not well known some concerns may accountfor it Firstly we presumed that the difference among ethnic

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 9: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

BioMed Research International 9

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of logor

1

0

minus1

minus2

Logo

r

(a)

Beggrsquos funnel plot with pseudo 95 confidence limits

0

0 05 1se of logor1

minus2

2

4

Logo

r1

(b)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04se of SMD

1

0

minus1

2

3

SMD

(c)

Beggrsquos funnel plot with pseudo 95 confidence limits

0 02 04 06se of SMD

0

2

4

6

8

SMD

(d)

Figure 5 (a) Beggrsquos funnel plot for publication bias test of urolithiasis risk associated with the CaSR A986S polymorphism (b) Beggrsquos funnelplot for publication bias test of urolithiasis risk associated with the CaSR R990G polymorphism (c) Beggrsquos funnel plot for publication biastest of urine calcium concentration associated with the CaSR A986S polymorphism (d) Beggrsquos funnel plot for publication bias test of urinecalcium concentration associated with the CaSR R990G polymorphism

groups might be a reflection of different genetic backgroundsand environmental context Secondly the sample size wasrelatively small not having enough statistical power toexplore the real association Moreover in view of diversity ofpossible comparisons and unavoidable flexibility of definingthe correlations associationsmay not necessarily reliable Forinstance selection bias different matching criteria may playa role

Different research objects may have an influence on theconclusionsWe also conducted stratified analysis by subjectsDifferent subjects were categorized as PHPT patients healthypopulation and mixed population Primary hyperparathy-roidism is a disease characterized by excessive parathyroidcell proliferation and PTH secretion and occurs frequentlyin postmenopausal women [34 35] Kidney stones that aregenerally related to hypercalciuria are a common compli-cation in PHPT patients [36] Both Corbetta and Scillitanirevealed that PHPT patients with the AGQ haplotype weresusceptible to risk of urolithiasis [17 18] In ourmeta-analysiswe also found that PHPT patients who carried AA genotype

were liable to stone formation The calcium-sensing receptor(CaSR) regulates calcium homeostasis within a narrow phys-iological range by sensing extracellular calcium concentra-tions and bymediating alterations in PTH secretion and renalcalcium reabsorption [37] We speculated that the A986Spolymorphism with a G-to-T mutation changed the activityof CaSR gene which might further adjust PTH secretionincrease calcium clearance and affect calcium homeostasisAs a consequence the risk of urolithiasis reduced Neverthe-less regarding the R990G polymorphism the results showedthat there was no significant association between the G alleleand urolithiasis risk in PHPT patients which were not inaccordance with the results from Corbetta and ScillitaniIt was regrettable that we did not have adequate data andrelevant studies to explain the inconformity but relativelysmall sample size selection bias and ethnic difference couldnot be ignored

It is worth noting that hypercalciuria a disorder predis-posing to calcium kidney stones is vital in the mechanism ofurolithiasis therefore we performed the first meta-analysis

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 10: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

10 BioMed Research International

Table 4 Summary of SMD and 95 CI for associations between urine calcium concentration and CaSR polymorphisms

Polymorphism Subgroup 119873a Sample size SMD (95 CI) 119875 value 119875 heterogeneity

A986S

All 9 1670 025 (minus059ndash110) 056 lt00001Caucasian populations 6 886 031 (minus087ndash149) 0605 lt00001Asian populations 2 597 minus002 (minus092ndash088) 0967 0015Urolithiasis patients 3 827 100 (minus132ndash332) 0397 lt00001Healthy populations 4 600 minus035 (minus100ndash029) 0282 lt00001PHPT patients 2 243 031 (minus005ndash067) 0093 0511

R990G

All 6 1049 252 (012ndash492) 0039 lt00001Caucasian populations 4 658 362 (minus018ndash742) 0062 lt00001Urolithiasis patients 2 333 400 (minus300ndash1099) 0263 lt00001Healthy populations 2 431 319 (minus354ndash993) 0353 lt00001

Q1011E

All 5 964 minus119 (minus252ndash015) 0081 lt00001Caucasian populations 3 573 minus199 (minus374 to minus024) 0026 lt00001Urolithiasis patients 2 327 minus114 (minus429ndash201) 0477 lt00001Healthy populations 2 431 minus163 (minus411ndash086) 0201 lt00001

aThe number of studies

to evaluate the relationships between three CaSR poly-morphisms and urine calcium concentration The calcium-sensing receptor is the key controller of extracellular calciumhomeostasis via its effects on regulation of parathyroidhormone secretion and renal calcium reabsorption [38]Hypercalciuria is the most common abnormality identifiedin calcium stone formers seen in up to 40 of the stoneformers [39] So far the associations between CaSR poly-morphisms and urine calcium concentration were unclear Inour meta-analysis we demonstrated the strong associationbetween urine calcium concentration and the CaSR R990Gpolymorphism A study from Vezzoli revealed that the extra-cellular calcium concentration producing the half-maximalintracellular calcium response was lower in HEK-293 cellstransfectedwith the 990Gallele than in those transfectedwiththe wild-type allele The G allele was recognized to cause again of CaSR function and increased susceptibility to hyper-calciuria [20] In the subgroup analysis wemerely discoveredthe Q1011E polymorphism had a linkage with low urine cal-cium concentration However we mentioned that there washeterogeneity among studies in overall comparisons and evensubgroup analyses We speculated that different methods toassess urine calcium could substantially influence the initialheterogeneity We classified all eligible articles accordingto methods of measuring urine calcium and conducted asubgroup analysis Heterogeneity was decreased after sub-group analysis which confirmed our speculation In themeanwhile we noted that two studies from Vezzoli G mightbe the sources of heterogeneity The degree of heterogeneitydramatically decreased after we dropped these two studiesWe proposed some explanations although the exact reasonswere not well known Individuals included in this study haddifferent genetic background and environmental factors Thesample size of each study varied and was relatively smallBesides there were some other factors whichmight influencethe urine calcium concentration such as PH phosphate andPTH level

Furthermore despite the overall robust statistical evi-dence generated through this analysis some limitations havebeen identified Firstly our results were based on unadjustedestimates while a more precise analysis should be conductedif all individual rawdatawere available whichwould allow forthe adjustment by other covariates including age sex familyhistory and lifestyle Secondly only published studies whichwere retrievable in the selected databases were includedin this meta-analysis and some unpublished studies weremissed Thirdly urolithiasis is a multifactorial disease thatresults from complex interactions between many genetic andenvironmental factors It suggests that there will not be singlegene or single environmental factor that has large effects onurolithiasis susceptibility Fourth heterogeneity could not beomitted because of methodological diversities between stud-ies Last but not least this is the first meta-analysis regardingthe comprehensive assessment of the relationship betweenCaSRpolymorphismswith urolithiasis risk andurine calciumconcentration So numbers of published studies were notsufficiently large for a comprehensive analysis The popula-tions only come from Asians and Caucasians Other ethnicpopulations should be involved in the future studies suchas Africans Only four papers evaluated associations betweenthe Q1011E polymorphism and urolithiasis risk more studiesshould be conducted

5 Conclusion Future and Recommendations

Despite these limitations the results of the present meta-analysis suggest that the G allele of CaSR R990G polymor-phism increases susceptibility to urolithiasis and hypercal-ciuria In other words individuals that carry GG genotypehave a higher risk of urolithiasis than those who carryRR genotype The A986S and Q1011E polymorphisms wereassociated with urolithiasis and hypercalciuria in specificpopulations

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 11: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

BioMed Research International 11

The identification of urolithiasis susceptible variants canprovide new insight into its etiology Moreover it is animportant step to individualize treatment and preventionprograms A well-established genetic marker surely wouldhave a profound influence in screening and prediction ofurolithiasis To advance an understanding of the relationshipsbetween CaSR polymorphisms with urolithiasis risk andhypercalciuria the following recommendations have beenmade Firstly try to decrease false positive and negativeresults by conducting the studies in a large sample withstratification by age sex food habit lifestyle and ethnic-ity Secondly more case-control studies or updated meta-analyses should be conducted to clarify the possible rolesof CaSR polymorphisms in the etiology of urolithiasis Inaddition because the genetic background of stone formationis a complicated issue including single-candidate genes aswellas epigenetic process it is not simple to identify a single geneas an independent factor for urolithiasis Combined effects ofdifferent gene polymorphisms need to be further analyzed

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Kang Liu XiaolanWang and Jiaxin Ye contributed equally tothis work

References

[1] P C Damasio C R Amaro C R Padovani et al ldquoInfluence ofclinical therapy and nutritional counseling on the recurrence ofurolithiasisrdquo Acta Cirurgica Brasileira vol 29 no 6 pp 400ndash404 2014

[2] D Li J Liu J Ren L Yan H Liu and Z Xu ldquoMeta-analysis of the urokinase gene 31015840-UTR TC polymorphism andsusceptibility to urolithiasisrdquo Bioscience Reports vol 1 no 3 pp369ndash374 2013

[3] E M Worcester and F L Coe ldquoCalcium kidney stonesrdquo TheNew England Journal of Medicine vol 363 no 10 pp 954ndash9632010

[4] C J Danpure and C J Danpure ldquoGenetic disorders andurolithiasisrdquoUrologic Clinics of North America vol 27 no 2 pp287ndash299 2000

[5] J-Y Kim Y-S Kim I-H Jang J-D Jung T-H Kim andH-RKim ldquoInterleukin-1120573 calcium-Sensing receptor and urokinasegene polymorphisms in Korean patients with urolithiasisrdquoKorean Journal of Urology vol 52 no 5 pp 340ndash344 2011

[6] S Wang X Wang J Wu et al ldquoAssociation of vitamin Dreceptor gene polymorphism and calcium urolithiasis in theChinese Han populationrdquoUrological Research vol 40 no 4 pp277ndash284 2012

[7] Y-H Chou P Y Woon W-C Chen et al ldquoA geneticpolymorphism (rs17251221) in the calcium-sensing receptorgene (CASR) is associated with stone multiplicity in calciumnephrolithiasisrdquo PLoSONE vol 6 no 9 Article ID e25227 2011

[8] E M Brown and R J Macleod ldquoExtracellular calcium sensingand extracellular calcium signalingrdquo Physiological Reviews vol81 no 1 pp 239ndash297 2001

[9] S PidashevaMGrant L Canaff O Ercan U Kumar andGNHendy ldquoCalcium-sensing receptor dimerizes in the endoplas-mic reticulum biochemical and biophysical characterizationof CASR mutants retained intracellularlyrdquo Human MolecularGenetics vol 15 no 14 pp 2200ndash2209 2006

[10] G Vezzoli A Terranegra and L Soldati ldquoCalcium-sensing receptor gene polymorphisms in patients withcalcium nephrolithiasisrdquo Current Opinion in Nephrology andHypertension vol 21 no 4 pp 355ndash361 2012

[11] G Vezzoli A Terranegra T Arcidiacono et al ldquoCalciumkidney stones are associated with a haplotype of the calcium-sensing receptor gene regulatory regionrdquo Nephrology DialysisTransplantation vol 25 no 7 pp 2245ndash2252 2010

[12] A Scillitani V Guarnieri S De Geronimo et al ldquoBlood ionizedcalcium is associated with clustered polymorphisms in thecarboxyl-terminal tail of the calcium-sensing receptorrdquo Journalof Clinical Endocrinology and Metabolism vol 89 no 11 pp5634ndash5638 2004

[13] N Shakhssalim B Kazemi A Basiri et al ldquoAssociation betweencalcium-sensing receptor gene polymorphisms and recurrentcalcium kidney stone disease a comprehensive gene analysisrdquoScandinavian Journal of Urology and Nephrology vol 44 no 6pp 406ndash412 2010

[14] G Vezzoli A Tanini L Ferrucci et al ldquoInfluence of calcium-sensing receptor gene on urinary calcium excretion in stone-forming patientsrdquo Journal of the American Society of Nephrologyvol 13 no 10 pp 2517ndash2523 2002

[15] G Han O Wang M Nie et al ldquoClinical phenotypes ofChinese primary hyperparathyroidism patients are associatedwith the calcium-sensing receptor gene R990G polymorphismrdquoEuropean Journal of Endocrinology vol 169 no 5 pp 629ndash6382013

[16] D C Hamilton V K Grover C A Smith and D E CCole ldquoHeterogeneous disease modeling for Hardy-Weinbergdisequilibrium in case-control studies application to renalstones and calcium-sensing receptor polymorphismsrdquo Annalsof Human Genetics vol 73 no 2 pp 176ndash183 2009

[17] A Scillitani V Guarnieri C Battista et al ldquoPrimary hyper-parathyroidism and the presence of kidney stones are associatedwith different haplotypes of the calcium-sensing receptorrdquoJournal of Clinical Endocrinology and Metabolism vol 92 no1 pp 277ndash283 2007

[18] S Corbetta C Eller-Vainicher M Filopanti et al ldquoR990Gpolymorphism of the calcium-sensing receptor and renal cal-cium excretion in patients with primary hyperparathyroidismrdquoEuropean Journal of Endocrinology vol 155 no 5 pp 687ndash6922006

[19] L G Ferreira A C Pereira and I P Heilberg ldquoVitamin Dreceptor and calcium-sensing receptor gene polymorphismsin hypercalciuric stone-forming patientsrdquo Nephron ClinicalPractice vol 114 no 2 pp c135ndashc144 2010

[20] G Vezzoli A Terranegra T Arcidiacono et al ldquoR990G poly-morphism of calcium-sensing receptor does produce a gain-of-function and predispose to primary hypercalciuriardquo KidneyInternational vol 71 no 11 pp 1155ndash1162 2007

[21] J L Perez-Castrillon A Sanz J Silva I Justo E Velasco andADuenas ldquoCalcium-sensing receptor gene A986S polymorphismand bone mass in hypertensive womenrdquo Archives of MedicalResearch vol 37 no 5 pp 607ndash611 2006

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 12: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

12 BioMed Research International

[22] B Harding A J Curley F M Hannan et al ldquoFunctionalcharacterization of calcium sensing receptor polymorphismsand absence of association with indices of calcium homeostasisand bonemineral densityrdquoClinical Endocrinology vol 65 no 5pp 598ndash605 2006

[23] C Kelly I R Gunn D Gaffney and M S Devgun ldquoSerumcalcium urine calcium and polymorphisms of the calciumsensing receptor generdquo Annals of Clinical Biochemistry vol 43no 6 pp 503ndash506 2006

[24] H S Sacks J Berrier D Reitman V A Ancona-Berk and TC Chalmers ldquoMeta-analyses of randomized controlled trialsrdquoNew England Journal of Medicine vol 316 no 8 pp 450ndash4551987

[25] R D Mittal H K Bid P K Manchanda and R KapoorldquoPredisposition of genetic polymorphism with the risk ofurolithiasisrdquo Indian Journal of Clinical Biochemistry vol 23 no2 pp 106ndash116 2008

[26] T Arcidiacono A Terranegra R Biasion L Soldati and GVezzoli ldquoCalcium kidney stones Diagnostic and preventiveprospectsrdquo Giornale Italiano di Nefrologia Organo UfficialeDella Societa Italiana di Nefrologia vol 24 no 6 pp 535ndash5462007

[27] G Vezzoli A Terranegra F Rainone et al ldquoCalcium-sensingreceptor and calcium kidney stonesrdquo Journal of TranslationalMedicine vol 9 no 1 article 201 2011

[28] M R Munafo and J Flint ldquoMeta-analysis of genetic associationstudiesrdquo Trends in Genetics vol 20 no 9 pp 439ndash444 2004

[29] D Riccardi A E Hall N Chattopadhyay et al ldquoLocalization ofthe extracellular Ca2+polyvalent cation -sensing protein in ratkidneyrdquo The American Journal of Physiology-Renal Physiologyvol 274 no 3 pp F611ndashF622 1998

[30] O Devuyst and Y Pirson ldquoGenetics of hypercalciuric stoneforming diseasesrdquo Kidney International vol 72 no 9 pp 1065ndash1072 2007

[31] G Vezzoli L Soldati and G Gambaro ldquoRoles of calcium-sensing receptor (CaSR) in renalmineral ion transportrdquoCurrentPharmaceutical Biotechnology vol 10 no 3 pp 302ndash310 2009

[32] A P Evan J E Lingeman F L Coe et al ldquoCrystal-associatednephropathy in patients with brushite nephrolithiasisrdquo KidneyInternational vol 67 no 2 pp 576ndash591 2005

[33] K Y Renkema A Velic H B Dijkman et al ldquoThe calcium-sensing receptor promotes urinary acidification to preventnephrolithiasisrdquo Journal of the American Society of Nephrologyvol 20 no 8 pp 1705ndash1713 2009

[34] F Cetani S Borsari E Vignali et al ldquoCalcium-sensing receptorgene polymorphisms in primary hyperparathyroidismrdquo Journalof Endocrinological Investigation vol 25 no 7 pp 614ndash619 2002

[35] T Carling J Rastad A Kindmark E Lundgren S Ljunghalland G Akerstrom ldquoEstrogen receptor gene polymorphism inpostmenopausal primary hyperparathyroidismrdquo Surgery vol122 no 6 pp 1101ndash1106 1997

[36] C V Odvina K Sakhaee H J Heller et al ldquoBiochemicalcharacterization of primary hyperparathyroidism with andwithout kidney stonesrdquo Urological Research vol 35 no 3 pp123ndash128 2007

[37] D E C Cole V D Peltekova L A Rubin et al ldquoA986Spolymorphism of the calcium-sensing receptor and circulatingcalcium concentrationsrdquoThe Lancet vol 353 no 9147 pp 112ndash115 1999

[38] J Tfelt-Hansen andEM Brown ldquoThe calcium-sensing receptorin normal physiology and pathophysiology a reviewrdquo Critical

Reviews in Clinical Laboratory Sciences vol 42 no 1 pp 35ndash702005

[39] C Y C Pak ldquoMedical management of nephrolithiasisrdquo Journalof Urology vol 128 no 6 pp 1157ndash1164 1982

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom

Page 13: Review Article The G Allele of CaSR R990G Polymorphism ...downloads.hindawi.com/journals/bmri/2015/958207.pdf · meta-analysis revealed that the G allele of CaSR R G polymorphism

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Behavioural Neurology

EndocrinologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Disease Markers

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

OncologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Oxidative Medicine and Cellular Longevity

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Computational and Mathematical Methods in Medicine

OphthalmologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Diabetes ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Research and TreatmentAIDS

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Gastroenterology Research and Practice

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


CASR 145 Rev 1

CASR 145 Rev 1

Current transducer CASR/SP6 series I 6 15 25 50 A …Ref CASR 6-NP/SP6 CASR 15-NP/SP6 CASR 25-NP/SP6 CASR 50-NP/SP6 For the electronic measurement of currents DC AC pulsed ith galvanic

Current transducer CASR/SP6 series I 6 15 25 50 A …Ref CASR 6-NP/SP6 CASR 15-NP/SP6 CASR 25-NP/SP6 CASR 50-NP/SP6 For the electronic measurement of currents DC AC pulsed ith galvanic

Rear End Crashes (CASR) 2005

Rear End Crashes (CASR) 2005

CASR Part 142

CASR Part 142

Casr part 25 rev 5

Casr part 25 rev 5

SCIENCE CHINA Life Sciences - Springer · using single nucleotide polymorphism ... calculating fetal DNA fraction using the formula: ... for the allele count of the special base of

SCIENCE CHINA Life Sciences - Springer · using single nucleotide polymorphism ... calculating fetal DNA fraction using the formula: ... for the allele count of the special base of

CONCISE REPORT Ankylosing spondylitis is associated with ......2014/08/28  · HLA, human leukocyte antigen; MAF, minor allele frequency; SNP, single nucleotide polymorphism. Table

CONCISE REPORT Ankylosing spondylitis is associated with ......2014/08/28  · HLA, human leukocyte antigen; MAF, minor allele frequency; SNP, single nucleotide polymorphism. Table

Part 91 CASR Dictionary - Draft consultation

Part 91 CASR Dictionary - Draft consultation

Compliance CASR Part 142

Compliance CASR Part 142

CASR 183 Rev 1

CASR 183 Rev 1

Selectionist view: allele substitution and polymorphism are determined by different, selective processes. Mutation yields advantageous alleles that are.

Selectionist view: allele substitution and polymorphism are determined by different, selective processes. Mutation yields advantageous alleles that are.

Conformational Polymorphism Analysis Polymorphism Detection

Conformational Polymorphism Analysis Polymorphism Detection

Casr Otech2012 Easy Insites Cint Presentation Final

Casr Otech2012 Easy Insites Cint Presentation Final

GENETICS VOCABULARY QUIZ 2 · GENETICS VOCABULARY QUIZ 2 Allele Dominant Allele Recessive Allele Phenotype Genotype Heterozygous/Hybrid Homozygous/Purbred 1. 2 Allele Allele- one

GENETICS VOCABULARY QUIZ 2 · GENETICS VOCABULARY QUIZ 2 Allele Dominant Allele Recessive Allele Phenotype Genotype Heterozygous/Hybrid Homozygous/Purbred 1. 2 Allele Allele- one

Safety Regulations CASR 1998

Safety Regulations CASR 1998

CASR-Pt.66-AMC and GM

CASR-Pt.66-AMC and GM

PATHWAYS CONTROLLING METABOLIC AND HYPERTROPHIC … · R577X polymorphism on metabolic disease was evaluated. A higher proportion of T2D patients with the homozygous null allele (577XX)

PATHWAYS CONTROLLING METABOLIC AND HYPERTROPHIC … · R577X polymorphism on metabolic disease was evaluated. A higher proportion of T2D patients with the homozygous null allele (577XX)

Casr Part 21 Amdt. 1

Casr Part 21 Amdt. 1

CASR 61 Amdt3

CASR 61 Amdt3

MAJOR DEPRESSIVE DISORDER - turkpsikiyatri.org · Glutamatergic genes (eg, GRIK4) citalopram response and adverse effects Met allele of the functional Val/Met polymorphism (rs6265)

MAJOR DEPRESSIVE DISORDER - turkpsikiyatri.org · Glutamatergic genes (eg, GRIK4) citalopram response and adverse effects Met allele of the functional Val/Met polymorphism (rs6265)