Prenatal Ultrasound Interpretation and Genetic Testing ... · •Fetal imaging with ultrasound...

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Prenatal Ultrasound

Interpretation and

Genetic Testing

WorkshopNovember 1st, 2018

Esther Friedrich, MDSouthern California Permanente Medical

Group

Department of Obstetrics & Gynecology

Maternal Fetal Medicine & Genetics

Esther Friedrich, MD – November 2018 – Interregional Symposium

Disclosures

• NONE


Objectives

▪ Understand the genetic basis and evolution of

current genetic screening and testing methods

commonly used in OB & Gyn including obstetric ultrasound

▪ Be able to counsel particularly obstetric patients

accurately about their choices of genetic

screening and testing before, during and after pregnancy

▪ Learn about newly developing methods of

genetic screening and testing applicable to an

OB & Gyn population

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On May 21, 2014, The American Board of Medical Genetics changed its name to the

American Board of Medical Genetics andGenomics [ABMGG]

In 2011, The American College of Medical

Genetics changed its name to American College of Medical Genetics and Genomics

[ACMG]

Background


Genetics:The study of heredity and the variation of

inherited characteristics

ge·net·ics [/jəˈnediks/]

Genomics:

The branch of molecular biology concerned with the structure, function, evolution and

mapping of genomes

ge·no·mics [/jēˈnōmiks,-ˈnäm-/]

Definition


▪ 1/30 (3-4%) of all neonates have clinically significant recognized anomaly

▪ 1/12 (5-8%) of children recognized to have a clinically significant anomaly by age 5

▪ Each of us carry 5 – 10 abnormal recessive genes

▪ Up to 50%+ of birth defects/mental

retardation have genetic basis

Background

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Overview

• Diagnosis vs Screening

• Genetic Basics,Terminology & Disease

• Genetic Counseling

• Prenatal Screening & Diagnosis– Serum Screening and Blood tests

– Genetic Ultrasound

– Invasive Diagnosis

– Preconception

• Future direction


Overview







– Preconception



Screening vs. diagnostic

testing

Relevant

Populations

Type of

Assessment

Type of Test

Entire Population(e.g., all people should

have their cholesterol

checked every two

years)

At-risk(e.g., a cardiac

stress

test to evaluate

heart damage)

Risk Assessment(e.g., you are at a higher

risk for cancer)

Definitive Answer(e.g., you have cancer)

ScreeningDiagnostic

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• Genetic testing:Utilizing specific assay or DNA test to evaluate genetic status of individual at high risk for particular inherited condition

• Genetic screening:Utilizing various genetic tests to evaluate populations or groups of individuals independent of family history or clinical symptoms

Screening vs. diagnostic

testing


Genetic Screening

• DNA testing – E.g. Cystic Fibrosis

• Chromosome Analysis

• Evaluating a gene product– E.g. thyroid hormones, hemoglobin

• Measuring a metabolite– E.g. PKU, Tay Sachs

• Fetal imaging with ultrasound

• Serum screening and variants


Overview







– Preconception


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Basic Molecular &

Cytogenetics

• Chromosome

– Strand of DNA, divided

into two arms by a

centromere

– Normal human cells

have 46 (23 pairs)

• Short arm – p

• Long arm – q


• Karyotype

– Chromosomal constitution of an individual

Basic Molecular &

Cytogenetics

Liken to “books” containing recipes

Contain coding and

non-coding regions (“ads”)


• Non-disjunction

• Robertsonian translocation

• Reciprocal translocation

• Deletion/Duplication

• Insertion

Basic Molecular &

Cytogenetics

Basic Chromosomal Errors

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• DNA - Genes• contains within it the information of all aspects of embryogenesis,

development, growth, metabolism and reproduction

• each cell: full genome• ~25,000 genes encode proteins

• ~2 meters of DNA coiled in

nucleus

• 4 base pairs = 6 billion nucleotides

Basic Molecular &

Cytogenetics


FISH

• FISH

– Fluorescence in situ hybridization

– Probes specific to chromosome or gene locus; can find specified areas, e.g. microdeletion DiGeorge


FISH

FISH

Used for whole chromosome paint probes (marker), as unique sequence probes or to perform subtelomericanalysis

FISH can find the “recipes” in a book

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Basic Genetics

Microdeletion syndromes

• 22q11.2 deletion

[DiGeorge, VCFS etc]

• 17p11.2 deletion [Smith-

Magenis]

• 15q11-q13 deletion [Prader-Willi, Angelman]

• 7q11.23 deletion [Williams]

Deletions of < 3-5Mb, not usually seen on microscopy


Basic Genetics

Uniparental disomy

• individual has two copies

of allele but both come

from one parent

– Loss of maternal allele –

Angelman

– Loss of paternal allele –

Prader Willi

– Known clinically

significant on

chromosomes 6, 7, 11, 14, 15

• If gene is imprinted,

normal development

requires presence of both maternally and

paternally derived gene copy


Array CGH

[Comparative genomic hybridization]

• Chip = FISH x thousands

• tests for thousands of genes

at the same time

• No culture (uses DNA)

Patient DNA is compared to normal reference DNA on glass

slide

Fluorescent tags are use to

hybridize to specific regions, read by laser scanners

But: also identifies benign changes

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• Green = added material

= duplication

• Red = deleted

material = deletion

• Yellow = c/w

reference DNA

= no change in CNVs

(copy number variants)

• Balanced translocations

cannot be detected!

• Finds chunks of pages

extra or missing

in all books!

Genetic Microarray


Genetic Microarray

Different types of probes commonly utilized:

BAC clones: 0.5-1 Mb

detection

Oligo-array: 50-500 Kb

detection

SNP-array: 3-10 Kb

If a new change is identified, parental blood is obtained to

identify the change as

significant, the majority are benign polymorphisms

Targeted vs Whole Genome


Genetic Microarray - SNP

SNP’s are single nucleotide polymorphisms, the smallest detectable

changes. Graduated to clinical use.

Medi-Cal approved use of micro-array

analysis 2009

Detects ~ 5-20% genetic causes in previously unexplained MR

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Basic Genetics

Single Gene Disorders

• Result of mutations in genes in the nuclear genome

• Usually follow mendelian inheritance

• Listed in OMIM

• > 3917 diseases logged

• E.g. NF1, DMD (2.2Mb)

• Different mutations in the

same gene can cause

different disease


DNA Sequencing

Method of determining the nucleotide sequence of adenine, guanine,

thymine and cytosine within a gene

Today sequencing is an automated

process

Detects mutations on a single nucleotide base

Detects “spelling errors”


Basic Genetics

Inheritance patterns

• Autosomal dominant – e.g. Achondroplasia,

Marfan’s

• Autosomal recessive – e.g. CF, sickle cell

• X-linked recessive – e.g. Duchenne Muscular

Dystrophy

• X-linked dominant – e.g. incontinentia pigmenti

• Multifactorial inheritance – e.g. NTD’s, heart defects, cleft lip/palate, DM, autism

• Mitochondiral inheritance – e.g. Myoclonic epilepsy

with ragged red fibers (MERRF)

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Overview







– Preconception



Genetic Counseling

Providing individuals with information on nature, inheritance and implications of genetic disorders to enable them to make informed medical and personal decisions

Organized initially as a subgroup in the ASHG, now individually active

Masters training programs throughout the US, board certification through ABGC/ABMG.


Genetic Counseling

- Indications

• Previous affected child

• Family history of hereditary condition or birth defect

• Advanced maternal age or positive screening

• Consanguinity

• Ethnicity associated with increased risk

• Infertility, recurrent miscarriage

• Maternal disease

• Known carrier of genetic disease

• Fetal anomaly on ultrasound

• Positive newborn screening

• Familial cancer syndrome

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Who to Refer to Genetics

(counseling vs clinical)

• Ultrasound abnormalities (excluding single

soft sign)

• California Prenatal Screen positive results

• Family history of a possible genetic condition

• Prior pregnancy with a chromosome

condition

• Carrier of a genetic condition

• Members who are interested in

CVS/amniocentesis

• Members with more extensive questions


Overview







– Preconception



Overview







– Preconception


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Prenatal Diagnosis

• Serum Screening – California Prenatal Screening Program

• Non-Invasive Prenatal Screening

• Other important Blood tests

• Genetic Ultrasound– First Trimester

– Second Trimester

– Prenatal Dysmorphology, MRI, 3D and 4D US

• Invasive Diagnosis– Amnio, CVS, PUBS

– Karyotyping, FISH, PGD

– Single Genes

– Metabolic Disease

– Microarray, Gene Sequencing


Who should be offered prenatal screening and diagnostic testing?

➢ Screening:➢ All patients: offer screening through the

California Prenatal Screening Program (CPSP).➢ Advanced maternal age patients: also offer

Non Invasive Prenatal Testing (NIPT).

➢ Diagnostic testing (CVS or amniocentesis):

➢ AMA patients➢ Patients whose fetus is at risk for conditions that

can be diagnosed through these procedures (e.g., cystic fibrosis, Tay Sachs, Sickle Cell

disease)

➢ All patients


Aneuploidy Screening

• What it USED TO BE:

• State of California expanded

AFP program – Quad screening• What

– Maternal serum alpha feto protein (MSAFP)

– Human chorionic gonatotropin (hCG)

– Unconjugated estriol (uE3)

– Inhibin –A (Inh)

• When

– 15 – 20 (22) weeks, most accurate at 16 – 18

weeks

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• What it IS NOW:

• State of California Prenatal

Screening Program (CPSP)• What

– Quad marker screening

– Serum Integrated Screening

(combines 1st & 2nd trimester blood results)

– Sequential Integrated Screening

(combines NT, 1st & 2nd trimester blood results)

- NIPT & 2nd trimester blood results

• When: 10 – 20 (24) weeks of gestation



CA Prenatal Screening

What it IS NOW:

First trimester blood

10 0/7 – 13 6/7 wks

PAPP-A

hCG

Nuchal translucency (11 2/7 – 14 2/7)

If CVS or NIPT done, serum screening for NTD

and SLOS only in the second trimester.

State covers both blood, US and follow up studies – unless

NIPT done outside of CPSP - NEW 11/2013

Sign Consent or Decline.


• State of California Prenatal Screening

Program – it still screens for:– Neural tube/abdomen wall defects

– Trisomy 21

– Trisomy 18 (risk not assessed for twins)

– SLOS – Smith-Lemli-Opitz Syndrome

– SCD = SLOS, Congenital anomalies and fetal demise

Autosomal recessive, incidence 1 : 60,000-100,000

Defect in cholesterol metabolism (7DHC is increased)

Microcephaly, cleft lip, MR, dysmorphic features


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Down syndrome detection rates for

various screening tests

• Maternal age ≥ 35 at delivery ~20% [2% PPV]

• Midtrimester triple screen overall 60% [2% PPV]

– Maternal age < 35 50%

– Maternal age ≥ 35 70%

• Midtrimester quad screen 80% [2% PPV]

• Midtrimester “genetic ultrasound” 25-85%

• First trimester screen 80-85% [3% PPV]

• Serum Integrated screen 80%

• Sequential Integrated screen ~90% [5% PPV]

• NIPT ~99% [60-90% PPV]

Malone, 2005; Cuckle 2008 - FASTER


Prenatal Diagnosis









– Single Genes




NIPT is a Quantitative Analysis

Image taken from Illumina website: Patient Counseling Guide for Reproductive Genetics

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Non-invasive prenatal

diagnosis

• Fetal Rh determination

• Fetal sex determination

• Fetal aneuploidy detection

• Targeted fetal mutation analysis?

Genet Med. 2013 May;15(5):395-8. doi: 10.1038/gim.2013.29. Epub 2013 Apr 4.

ACMG statement on noninvasive prenatal screening for fetal aneuploidy.

ACOG Committee Opinion # 545, December 2012:

“Noninvasive Prenatal Testing for Fetal Aneuploidy”



diagnosis


NIPS/NIPT

• Pursued for > 4 decades

• Desai and Cregel showed 1963:

• Cells pass between mother and fetus

• Fetal cells can be extracted, quantified,

molecularly analyzed

• Presence of fetal DNA in maternal plasma and serum

• Lo, YM et al 1997 Lancet, 350:845-7

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• ffDNA/ffRNA results from placental apoptosis

• Present in early gestation ~5-7 wks GA

• Cleared within hours of placental removal

• Shows specificity for placental gene

expression

• Levels are altered by GA, BMI, aneuploidy

• Levels are not altered by race, parity, smoking, age, mode of conception,

placental volume

• Fetal genes distinguished as different by SRY presence, paternal genes

NIPS/NIPT


Possible by next generation sequencing

Massively parallel genomic sequencing

Identifier codes

added for

multiplexing (12-96)

10s of millions DNA

fragments sequenced at

the same time

First 36 bases are

sequencedRossa W. K. Chiu, 20458–20463, doi: 10.1073/pnas.0810641105

NIPS/NIPT


Each chromosome holds a reference % of genome

Chromosome 1

~8.5% genome

Chromosome 18

~2.8%

Chromosome 21 ~1.3%

Z score represents

sample standard deviations from

the reference%

Rossa W. K. Chiu, 20458–20463, doi: 10.1073/pnas.0810641105

NIPS/NIPT

Massively parallel genomic sequencing

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A Quick Statistics Review

• False Positive = The screening test is positive, but the

baby does NOT have the condition

• True Positive = The test is screen positive, and the baby HAS the condition.

Positive Predictive Value (PPV) = IF a result is screen positive, how often is it a TRUE positive?


A Quick Statistics Review

• Sensitivity = Ability of

a test to correctly identify those with

the disease [true

positive rate]

• Specificity = Ability of a test to correctly

identify those without the disease

[true negative rate]


Sensitivity Specificity

Chiu, BMJ,

2011

824 women

(86 trisomy

21)

2 plex

8 plex

100%

79.1%

97.9%

98.9%

Ehrich,

AJOG, 2011

449 women

(39 trisomy

21)

4 plex 100% 99.7%

Palomaki,

Gen in Med,

2011

1471 women

(212 trisomy

21)

4 plex 98.6% 99.8%

NIPS/NIPT

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MELISSA study (Maternal Blood is Source to Accurately

Diagnose Fetal Aneuploidy)

2,882 women at 60 U.S sites

Prospective, blinded study

All abnormal karyotypes and random euploidkaryotypes

Known karyotype and MPS results were compared

Bianchi et al Obstet Gynecol. 2012 May;119(5):890-901

NIPS/NIPT


Sensitivity Specificity

Bianchi, OB-Gyn,

2012

2,882 women

89 T21

36 T18

14 T13

16 Mononsomy X

100%

97.2%

78.6%

93.8%

100% (CI 98.5-100)

100*

100*

99.8%

Palomaki,

Genetics in Med,

2012

1,971 women

212 T21

59 T18

12 T13

All three (21, 18,

13)

98.6%

100%

98.2%

98.9%

99.8%

99/7%

99.0%

99.9%

* No false positives for autosomal aneuploidies

NIPS/NIPT


Test clinically marketed as “advanced prenatal

screening”:

• screens for T21, 18, 13, X, Y

• still validated ONLY in a high risk population, no multiples:

• AMA > age 35 at time of delivery

• positive prenatal screening

• US anomalies

• prior affected pregnancy

NIPS/NIPT

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NIPS/NIPT


Company Detection Rate (%)

T21 T18 T13

False Positive

Rate (%)

Failure Rate (%)1

Sequenom 99% 99% 92% 0.2-1.3% 0.9%

Verinata >99% 97% 87% 0.1-0.4% <3%

Ariosa >99% 98% 80% unreported 1%

Natera >99% >99% >99% <0.1% 2.9%

1Failed; uninformative; “no call” (e.g., low fetal fraction,

failed QC, failed sequencing)

J Canick, Prenat Diag 2013 Jul;33(7):667-74

NIPS/NIPT


Combined 1st

Trimester

Sequential

Screening

cfFetal DNA

Detection of T21

(>35 y/o)

92% 92% >99%

Timing 1st trimester 1st & 2nd

trimester

1st trimester

Complexity Coordinated

US & blood

Coordinated

US & blood x 2

Blood

Screen positive 22% 4% <1%

PPV 3% 5% 60-90%

NIPS/NIPT

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• Can ffDNA analysis be used in ALL women?

• ffDNA concentration independent of age

• Technology not altered by maternal age

• Sensitivities/Specificities same, PPV will

change

• Estimates:

• High risk population: 50-90%

• All risk population: 20-60%

• Still improved over 2-4% PPV of serum screening

NIPS/NIPT


Screen

positive

Sensitivity Specificity PPV

NIPT 0.68% 100%

(11/11)

99.4%

(172/173)

91.67%

Triple

Screen

14% 54.5%

(6/11)

85%

(148/173)

2.4%

2000 women – NIPT vs triple marker screening

20-34 years old

N = 1916 women in China, 1741 samples analyzed

Song Y et al Prenat Diagn. 2013 Jul;33(7):700-6

NIPS/NIPT


Screen

positive

Sensitivity Specificity PPV

NIPT 0.3% T21

0.2% T18

100%

(8/8)

99.7% 45.5%T21

40% T18

Serum

Screen

(1st or 2nd)

3.6% T21

0.6% T18100%

(8/8)96.4% 4.2% T21

8.3% T18

Almost 2000 women – NIPT vs serum marker

screening

All risk population, average age 29.6 years old

N = 1914 women, CARE study group

Bianchi et al N Engl J Med. 2014 Feb 27;370(9):799-808

NIPS/NIPT

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Prenatal Screening Options and

Detection Rates

NIPT STATE

Timing 10-24 weeks 10-20 weeks

Specimen Maternal Blood Maternal Blood

Risk to Fetus None None

Trisomy 21 99% 80-90%

Trisomy 18 97% 67-81%

Trisomy 13 87% Not Targeted

Sex Chromosome

Abnormalities

90-93% Not Targeted

NTD/AWD Not screened. Screened for

by fetal anatomy ultrasound

or MSAFP

80% NTD/85%AWD


How can false positives be explained?

• Other sources of chromosome specific cfDNA

• Placenta [CPM], multiple reports of discordance for T13, 18 (Futch, 2012, Hall 2013, Pan 2013)

• Vanishing twin, multiple reports of discordance for T13 (Futch 2013; McAdoo 2013 –

ASHG)

• Maternal

• chaotic results – cancer (Osborne, 2013)

• 45,X0 mosaicism, 47,XXX (Nicolaides, 2013; Lau,

2013; Wang, 2014)

NIPS/NIPT


How can false negatives be explained?

• Low fetal fraction

• High BMI

• Dilutional effect

• Increased maternal inflammation(Palomaki, 2011; Canick, 2013; Lapiere, 2013)

• Mosaicism in surviving T13 & T18 pregnancies (Pergament, 2014)

NIPS/NIPT

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NIPT results

• Possible NIPT results:

– NIPT results can also be reported as:

– Aneuploidy Detected

– Aneuploidy Suspected

– No Aneuploidy Detected

– No result

• NIPT does not have 100% accuracy

• Diagnostic testing recommended for

Aneuploidy Detected or Aneuploidy suspected results

– Amniocentesis or CVS are offered


No Screening is Perfect

Neither screening test detects

– Single gene disorders (e.g. cystic fibrosis,

SMA)

– Multifactorial conditions (e.g. diabetes,

bipolar)

– Unknown etiology conditions (e.g. autism, SIDS)

– Physical abnormalities (e.g. cardiac, limb, etc.)


Common Question #1

Patient: “If my NIPT is normal, will my baby be born healthy?”

Provider: “A normal NIPT result is good news. It’s not one-hundred percent and doesn’t look for

everything, but the chance for some common conditions like Down syndrome becomes much

lower.”

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Common Question #2

Patient: “If my NIPT comes back abnormal do I have

to do a CVS or amniocentesis?”

Provider: “No, you don’t have to. If your NIPT comes back abnormal it is VERY IMPORTANT that you have a

consultation with a genetic counselor to discuss your

results in detail and find out what other tests can be done that you are comfortable with. It is important to

remember---never make a decision about your

pregnancy based on the NIPT test result alone—it is a screening test, not diagnostic.”


Common question #3

Patient: “I want the test that will tell me if it’s a

boy or girl…”

Provider: “This test is a screening test for Trisomy

21, 13, 18 and sex chromosome abnormalities.

The purpose of the test is not to tell you the sex of the baby, you will get that information if you

want it. However, it’s not 100% accurate.”


Common Question #4

Patient: “My friend had NIPT and she said it is better than the State blood test. I want that

test.”

Provider: “Let’s see, you will be 30 years old at

delivery, at your age you are considered to

have a low risk for chromosome problems. At Kaiser Permanente in Southern California we

don’t currently offer NIPT to low risk women, but are constantly evaluating the technology and

may offer it to all women in the future.”

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Common question #5

Patient: “I’m so confused! I don’t know what to do!”

Provider: “We have many resources to help you make your decision. If after reviewing them you need more information, I can also refer you to our local genetics department for a consultation.”

• EMMI module sent to all pregnant women• Decision Tree, Choices Booklet, KP NCAL video on

prenatal testing, other video options.• Genetics website : http://kp.org/scal/genetics


Decision Tree for Prenatal TestingDo I want to know if my baby has a birth defect?*


Fetal RHD determination:

• Most rh negative women: deletion of RHD gene on

chromosome 1

• NIPD avoids invasive procedures potentially leading to isoimmunization

• RHD gene absent in rh negative women; any

detection of gene in cffDNA means: fetus is Rh pos.

• Automated robotic system: sensitivities up to

99% @ 28 wks

(van der Schoot, 2004; Geifman-Holtzman, 2006)


diagnosis

http://kp.org/scal/genetics

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Fetal sex determination:

• Indicated in women at risk for x-linked genetic disorder, or

CAH [potential development ambiguus genitalia] e.g.

Duchenne muscular dystrophy

• Advantage: early determination, option of termination of affected fetus, or avoidance of invasive procedure in

female fetus

• Best results: real time PCR for fetal SRY or DYS14 areas in cffDNA; NIPT

• Multiple studies show accuracy up to 99% after 7-10 wks

Moise et al, Prenat Diagn. 2013 Jan; 33(1):95-101


diagnosis


Prenatal Diagnosis









– Single Genes




Other blood test/screening

opportunities

• CF

• SMA

• Ashkenazi Jewish Screening

• Fragile X

• Blood disorders

(thalassemia, hemophilia, sickle cell etc)

• Metabolic disorders

• Neonatal screening,

(standard versus expanded)

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Cystic Fibrosis

– Carrier frequency 1:29

(North American Caucasians, Ashkenazi Jewish: 1:24, 94%)

– Testing sensitivity • in Caucasians 88% Carrier 1:25

• In Hispanics 72% Carrier 1:58

• In African American 64% Carrier 1:61

• In Asians 49% Carrier 1:94

– NIH recommended screening in 1997

– ACOG and ACMG recommended screening in

Oct 2001; common panel includes 23-84 mutations,

over 2000 are known


SMA

(Spinal Muscular Atrophy)

– Affects ~ 1:10,000 newborns, progressive

muscle weakness and early death

• Caused by a mutation in the SMN1 gene, types 1 and 2 are known

• Recessive inheritance pattern

• Carrier frequency 1:40 – 1:60 in all

populations

• Reliable DNA testing is available, only ~10%

of carriers will be missed

• ACMG recommends population screening as of 11/2008; ACOG does as of 2017


Carrier screening for Spinal muscular

atrophy

• Carrier screening for spinal muscular atrophy can now be ordered within HC (as of 9/20/18)

– Autosomal recessive disorder

– Carrier frequency (most populations): 1/40 – 1/60– Incidence: ~1/6,000 -1/10,000 live births

• SMA carrier screening should be offered to all prenatal patients at prenatal registration and to pts considering future pregnancies

• HealthConnect order: SPINAL MUSCULAR ATROPHY, SMN1 AND SMN2, CARRIER TESTING, 81401L

• OB providers’ SmartPhrases have been updated to include SMA:

– GENETICOBETHNICITYSCREENING and GENETICOBETHNICITYSCREENINGCLINICIANFOLLOWUP

• Member education handouts available in KP Clinical Library October 2018

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Hemoglobinopathies

• Hemoglobinopathies Carrier Frequency

Sickle cell 1:10 – 1:12 in AA

Hgb C 1:40 in AA

B Thalassemia 1:50 AA; 1:30 med.

α Thalassemia 1:25 in SEA

• Hemoglobin electrophoresis recommended for

prenatal screening in individuals of high risk ethnic background

• Electrophoresis if MCV < 80 in lower risk group


Ashkenazi Jewish

screening

• Screening Panels for the most common disorders

are available, e.g. Quest laboratories, Genzyme:

• Bloom Syndrome

• Canavan disease

• Cystic Fibrosis

• Familial Dysautonomia

• Fanconi anemia group C

• Gaucher Disease

• Niemann-Pick disease A and B

• Tay-Sachs disease

An expanded Ashkenazi Jewish carrier screening

panel (10 conditions)

available when bothmembers of a couple are

AJ➢ Not orderable within

HealthConnect➢ Samples are sent out to

GeneDx

➢ Refer AJ/AJ couples to

Genetics or OB providers can fill out GeneDx lab

form


Fragile-X syndrome

• Most common cause of mental retardation

in males. (< in females). Carrier ~1:130-250

• Phenotypic features

– Males: mental retardation, coarse facial

features, macroorchidism

– Females: no distinctive phenotype, variable

mental retardation; premutation: 25% POF

– Later life: fragile x tremor/ataxia syndrome

• Inheritance ~ X linked “dominant”, FMR1 gene (Xq27.3), expansion syndrome, no new mutations, all affected

individuals inherit gene from carrier parent

• ACOG CO #469 10/2010

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Member Education

• Member education handouts pre-test and post-test screen positive

– English can be ordered and Spanish print on demand (will

be in Clinical Library as well).

• New “infographic style” for general carrier screening

pamphlet pending

– English expected 10/2018, Spanish coming soon


Expanded Carrier Screening

• Laboratories such as Counsyl and Natera offer

expanded carrier screening for 100s of genetic disorders

• Most of these disorders are very rare

• Offered for consanguineous couples, as previously noted

• Testing of partners can be expensive if the patient tests

positive for one or more conditions

• Expanded carrier screening is not recommended for the general population at this time and is not covered by KP

• If testing is requested, patients should be directed to

seek testing outside KP at their own expense


Overview







– Preconception


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BREAK


Prenatal Diagnosis









– Single Genes




Guidelines

ACOG, ACR, AIUM, NICHD, SRU, SMFM

Reaffirmed 2018

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Equipment and

Documentation

Equipment– Abdominal

3 or 5 MHz Transducer

- Abdominal

2 or 2.25 MHz in obese patients

– Vaginal

5 - 10 MHz Transducer

Documentation– Permanent record

– Image retention

– Appropriate labeling

– Written Report

AIUM= American Institute for Ultrasound in Medicine


Ultrasound Types

What Are They?

First Trimester Ultrasound

Basic = Standard Second- or Third Trimester Ultrasound

Limited = Performed in certain, defined circumstances

Comprehensive = Specialized “Indicated for a patient suspected of carrying an abnormal fetus by: history, clinical evaluation, or prior ultrasound exam”


WHO DOES THE EXAM?

Basic - “Peformed or reviewed by appropriately trained operator”

Limited - “Performed by ultrasonographer or specially trained personal”

Comprehensive - “Performed by an operator with experience and expertise in such scanning”

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Ultrasonographic

Visualization of Pregnancy

Part I


First-Trimester Exam

Abdominal or vaginal US

Gestational sacYolk Sac

Embryo

Crown-Rump-LengthPresence or absence of cardiac activity Fetal number

Amnionicity, ChorionicityUterus, cervix, adnexal structures, cul-de-sac

YS

First Trimester Ultrasound ~8 weeks

CRL

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Cardiac Activity

Measure by M-mode at < 8 weeks

Measure by Doppler at > 8 weeks

Doppler = Heat


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First Trimester Guidelines

Multiple Pregnancies

– Report only when multiple embryos

seen

– Report chorionicity and amnionicity• More reliable than at any other time in pregnancy

– # yolk sacs “sometimes” = # amniotic sacs

Crown-rump more reliable gestational age predictor than sac

size


Triplets

Monochorionic,

diamniotic

Dichorionic,

diamniotic

1

2

3

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Monoamniotic, monochorionic twins, 7 weeks

Dichorionic, diamniotic twins, 7 weeks, 3D US

What exactly is a nuchal translucency?Nicolaides

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Nicolaides

Esther Friedrich, MD – November 2018 – Interregional SymposiumTris. 13

Midline facial defect

Hygroma

Omphalocele


Genetic syndromes

with enlarged nuchal fold

Jarcho-Levine syndrome

Joubert syndrome

Nance-Sweeney syndrome

Noonan syndrome

Smith-Lemli-Opitz syndrome

Spinal muscular dystrophy

Thanatophoric dysplasia

Trigonocephaly ̀ C´ syndrome

VATER association

Achondrogenesis

Achondroplasia

Beckwith-Wiedemann syndrome

Camptomelic dysplasia

EEsC yndrome

Fryns` syndrome

GM1 gangliosidosis

Hydrolethalus syndrome

Meckel-Gruber syndrome

Roberts syndrome

Zellweger syndrome

Fetal Akinesia Deformation

Sequence

Osteogenesis imperfecta

Asphyxiating thoracic dystrophy

Blomstrand osteochondrodysplasia

Short rib-polydactyly syndrome

type I

Short rib-polydactyly syndrome

type IV

Diatomatomelia

Di George syndrome

Perlman syndrome

Alpha-thalassaemia

Spondylocostal dysostosis

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Early hydrops

CRL


First trimester ultrasound

Total of 200,868 pregnancies, 871 trisomy 21:

Increased NT 76.8% T21 detection; 4.2% false positive


NT + serum markers 87% T21 detection, 5% false positive


NT + nasal bone 69% T21 detection, 1.4% false positive

“Nuchal translucency and other first trimester sonographic markers of chromosomal

abnormalities” Nicolaides, K; Am J Obstet Gynecol (2004) 191, 45-67


“First Trimester Screening for Chromosomal Abnormalities” Nicolaides, K; Seminars Perinat (2005) 29:190-194

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Tricuspid

Regurgitation

Assessment:

Population 77 T21, 232

normal fetuses:TR in 57 = 74% T21; 16 =

6.9% normals

No significant

differences in maternal serum levels

in pregnancies with or

without T21 and evidence of TR

“Screening for trisomy 21 by fetal tricuspid regurgitation, NT and

maternal serum f-β HCG and PAPP-A at 11+0 to 13+6 weeks”

Falcon, O; Nicolaides, K et al; Ultrasound Obstet Gynecol 2006; 27: 151-155.

Faiola et al, 2005



Abnormal Ductus Venosus Flow Assessment:

Found in ~80% of T21 fetuses, 5% chromosomally

normal

“First Trimester Screening for Chromosomal Abnormalities” Nicolaides, K; Seminars

Perinat (2005) 29:190-194



Relative risk of a congenital heart defect in relation

to first trimester nuchal fold thickness:

3 mm 5 / 1000

4 mm 27 / 1000

5 mm 54 / 1000

6 mm 266 / 1000Nicolaides, Snijders


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Ultrasonographic

Visualization of Pregnancy

Part II


What are Indications for a Standard

Second or Third -Trimester Exam ?

ACOG has a list of at 29 indications, initially adapted from the NIH in 1984, since then steadily increased:


What Is a Standard Second- or Third-

Trimester Exam ?

Amniotic Fluid Volume Assessment

Fetal PresentationCardiac Activity

Fetal biometry

Fetal weight estimationAnatomic Survey

Placental Localization Maternal cervix and adnexa if technically feasible

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When Is a Limited Exam

Appropriate?


Amniocentesis Guidance

External Cephalic Version

Presentation

Confirmation of IUFD

Placental Localization (if bleeding)


When Is a Specialized Exam

Appropriate?

Suspected fetal anomaly (clinical, biochemical, based on history or

results of prior exam)

Fetal Doppler

Fetal Echocardiogram

Biophysical Profile

Additional biometric studies


What do we want to see?

• Chromosomal malformations

• Structural malformations

• Fetal disease

• Feto-maternal disease

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What are we unable to see?

•Mental retardation

•Most metabolic disorders

•Most single gene defects

•Ca. 20-25% of chromosomal malformations



Trimester Exam ?



Fetal biometry




Fetal Biometry

Second Trimester

Biparietal Diameter

Head Circumference

Abdominal Circumference

Femur Length

Humerus Length

Cerebellar Diameter

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Biparietal Diameter

Landmarks– Midline Falx

– Thalamic symmetry on either side of falx

– Cavum Septum pellucidum

Measure leading edge to leading edge– “Outer edge to inner edge”

No cerebellum or orbits visualized


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Cerebellar Diameter

Obtained by starting with BPD view, then

visualizing posterior fossa

Requires maintaining visualization of thalami

Tends to be “spared” as a predictor of gestational age in the presence of IUGR

Between 14 - 20 weeks, measurement in

mm = GA in weeks


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Femur/Humerus Length

Measure perpendicular to ultrasound beam (femur ends at

03:00 and 09:00)

Third trimester: distal femoral

epiphysis visible

Humerus equally so


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Abdominal Circumference

Landmarks

– Circular circumference

– 90° transverse image of spine

– Stomach in left abdomen

– Umbilical portion of left portal vein:• equidistant from lateral sides of body

• not contiguous with anterior abdominal wall

• Spine cannot be at 12:00 position

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Trimester Exam ?



Fetal biometry



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ANATOMIC SURVEY:

What Must It Include?

Cerebral Ventricles

Four Chamber Cardiac View, Cardiac Position

Spine

Stomach

Bladder

Kidneys

Anterior Abdominal Wall

Umbilical Cord Insertion

Posterior Fossa

Nuchal Fold

Extremities

if technically feasible,

cardiac outflow tracts should be visualized


ANATOMIC SURVEY:

What Must It Include?


•Thickened nuchal fold RR x 18,6

•Severe structural heart defects

•Duodenal stenosis RR x 25

•Hydrocephalus

•Omphalocele

Due to high specificity and low false positive rate, those markers have a high positive predictive value – even within

the low risk population Benacerraf et al, ´00,

Second trimester

ultrasound

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Likelihood Ratios and Soft Markers –Nicolaides 2003

5.20.7932.9661/9384(0.65%)

75/350(21.4%)

Major Defect

3.00.8721.1758/9227(0.6%)

39/293(13.3%)

Echogenic bowel

1.10.756.41401/9199(4.4%)

75/266(28.2%)

Echogenic focus

1.00.856.77242/9331(2.6%)

56/319(17.6%)

Hydronephrosis

1.60.627.94486/9331(5.2%)

132/319(41.4%)

Short Femur

4.10.6822.76136/9254(1.5%)

102/305(33.4%)

Short humerus

9.80.6753.0559/9331(0.6%)

107/319(33.5%)

Nuchal fold

LR for isolated marker

Negative LRPositive LRNormalTrisomy 21Sonographic Marker


Down syndrome

• Down Syndrome – Trisomy 21– 1:700 newborns

– Moderate mental retardation,

congenital cardiac defects (40%),

GI obstruction, typical facies,

median survival 50 years

– 95% non-disjunction

(95% maternal, usually meiosis I)

– 3% translocation (half are de novo)

– 2% mosaic (may modify phenotype

but not reliable for counseling)


•Nuchal thickening 38 % (80%)

•Cardiac defect 26% (40%)

•Mild hydronephrosis 30%

•short femur 28%

•Abnormal hands and feet 25% (60%)

•SGA 20%

•Hydrops 20%

•Ventriculomegaly 16%

•Brachycephaly 15%

•Duodenal stenosis 8%

US findings in Trisomy 21

n= 155 (Nicolaides FMF)

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stomach

Dilated

duodenum

Trisomy 21

Classic „Double Bubble“ with duodenal stenosis


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Perinatology.com


Edwards syndrome

• Edwards Syndrome -

Trisomy 18

– 1:6,000 newborns, 80% female

– Multiple anomalies,

especially cardiac, renal,

hand posturing

– Death

• 30% by 1st month, 50%

by 2nd month, 90% by 12th month

– 85-90% non-disjunction

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•SGA 74% (>50%)

•Abnormal hands and feet 72% (>50%)

•Heart defects 52% (>50%)

•Micrognathia 53% (>50%)

•Abnormally shaped head 54% (>50%)

•Choroid plexus cysts 47% (<10%)

•Omphalocele 31% (10-50%)

•Talipes 30% (10-50%)

•Brachycephalus 29% (>50%)

•Mild Hydronephrosis 16% (10-50%)

US findings in trisomy 18


Tris. 18

Complete cystic choroid plexus

Tris. 18

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Chrom. normal

Large omphalocele containing liver

Omphalocele


Tris. 18

Persistently overlapping fingers

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Overlapping fingers


Pätau syndrome

• Pätau syndrome –

Trisomy 13

– 1:12,000 newborns

– Multiple anomalies, clefts polydactyly,

microophthalmia,

omphalocele, holoprosencephaly, NTDs

– Death

• 45% 1st month, 90% by 6th month

– 80% non-disjunction

Zafira – 6 months old

www.livingwithtrisomy13.or

g


•SGA 61% (<50%)

•Abnormal hands and feet 52% (>50%)

•Cardiac defects 43% (>80%)

•Holoprosencephaly 39% (>50%)

•Facial clefts 39% (60-80%)

•Mild hydronephrosis 37% (<50%)

•enlarged cisterna magna 25% (<50%)

•Microcephaly 24% (>50%)

•Brachycephalus 26% (>50%)

•Nuchal thickening 22% (>50%)

postpartum

US findings in trisomy 13


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Tris. 13

singular ventricle

Ethmocephaly

Cebocephaly


4-chamber-view:

40 % of CHD

Outflow-tract of the large vessels:

additional 20-30 % of CHD

Second trimester

ultrasound

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Jeanty, et al

Association of cardiac defects

with genetic disease


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Neural Tube Defects

• Etiology:

– Multifactorial Origin

– Syndromes – single gene

• Meckel-Gruber, chromosome 17, autosomal-recessive

– Chromosomal disorders

• T13, T18, ring chromosomes, triploidy

– Teratogens

• Valproic Acid, Thalidomide, MTX, increased core temp?

– Metabolic deficiencies in Mom

• Diabetes mellitus

• Folic acid deficiency

– Others (eg Amnion Band Syndrome)


Ultrasound vs

Amniocentesis

Norem, C.T. et al. ObGyn 106(4):747-752, 2005

• N = 130 cases with no MSAFP available at time of

scan

• Detection rate 96%

– Included all gestational ages

– Only 1/3 of cases done at tertiary centre

• N = 189 total cases at N. Cal. Kaiser during 7 year

period

– 38% of cases of spina bifida occurred in

women with negative MSAFP screening


Anencephaly

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Intact facial

bones,

„frog face“


Fetal Dysmorphology

• Attempted visualization soft tissue

structures prenatally:

– Chin

– Tongue

– Ears

– Epicanthal eyefolds

– Hands (creases)

• Few published case reports of

successful use [Mangione Prenat Diagn. 2003 Oct;23(10):810-8.]

• Currently not standard of care


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BREAK

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59


Overview







– Preconception



Prenatal Diagnosis









– Single Genes




Prenatal Diagnosis

ACOG Practice Bulletin 2007: option of invasive testing

should be available to

ALL

women, regardless of age

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Amniocentesis

• Done @ 15 wks – term

• Amniotic fluid – Enzymes

– Proteins

– Hormones

– culture, PCR (infections)

– Delta OD 450 (rh-disease)

– Lung maturity

– Genetic (cell culture)

• Procedure risk ~ 1/3-500 loss (twins are different)

• Early amnio has higher risk (13-15 wks)


Chorion Villous Sampling

• Done @ 11wks-13wks

• Chorionic villi– Karyotype only

– Higher incidence of mosaicism

• Confined placental mosaicism

– Vaginal or abdominal procedure

• Procedure risk ~ 1/200 loss

• Early procedure associated with limb defects


Periumbilical Blood

Sampling

Done after 18-20 weeks

• Rarely done for genetic

purposes

• does not require cell culture,

fast!

• Procedure risk ~ 1-2/100 loss

• Usually with therapeutic

intent

(transfusion,

medication application)

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Regional Amniocentesis Trends2010 – 2018 YTD*

18361710

1506

1025

597522

442 452354

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2010 2011 2012 2013 2014 2015 2016 2017 2018*

*2018 YTD: Jan – Sept 2018


Regional CVS Trends2010 - 2018 YTD*

370 364 370

291

196

244 251

283

193

0

50

100

150

200

250

300

350

400

2010 2011 2012 2013 2014 2015 2016 2017 2018**2018 YTD: Jan – Sept 2018


Trends in Abnormal Diagnostic

Testing Results

2012 (pre-NIPT) to 2017:

62% fewer diagnostic tests detected a

greater number of abnormal karyotypes.

# Abnormal

karyotypes T21 T18 #diagnostic procedures

2012 120 63 29 1936

2017 154 78 31 738

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Overview







– Preconception



Preimplantation Genetic

Screening and Diagnosis

• Utilizes a single cell, 8-cell stage or blastomere biopsy

• Only with IVF; impact on pregnancy outcome controversial

• Selective karyotype or array CGH

• Able to detect ~ 40% single gene disorders testable

(know what to look for; choose which test to use!)

• High misdiagnosis rate (> 3%) with PCR

• Allele dropout and postzygotic events;

even trisomies can occur post PGD,

trisomic rescue

• Mosaicism stays undetected by FISH

• May have new utility with use of sequencing technologies

• ACOG CO #430, 3/2009Fiorentino et al, Hum Reprod. 2014 Oct

21. pii: deu277. [Epub ahead of print]


Present day challenges

• Personalized

medicine

• Patient expectations

• Screening and diagnostic test

marketed by commercial

companies

• Rapidly evolving new

technologies

• Ethical concerns www.genomemag.com

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Genetic Microarray

• Increasingly used prenatally

• population selection bias: referral for postnatal array-CGH mostly due to dysmorphic features,

behavioral abnormalities or DD, not available to the

prenatal population

• Indicated for unexplained US anomalies, stillbirth,

miscarriage [?], routine [?]

Shaffer et al, “Comparison of microarray-based detection rates for

cytogenetic abnormalities in prenatal and neonatal specimens ”, Prenatal

Diagnosis 2008

Wapner et al: N Engl J Med. 2012 Dec 6;367(23):2175-84. doi:

10.1056/NEJMoa1203382.

Chromosomal microarray versus karyotyping for prenatal diagnosis.


• Targeted versus SNP array

• Targeted: company specific “chip” of probes specific to disease causing mutations

• Advantage: less CNV’s of unknown significance

• Diagnosis can be limited to desired location

• Prenatal targeted arrays widely available, eg

GeneDx with ~150 common or novel microdeletions and –duplications

• Disadvantage: not usually detecting uniparental disomy, imprinting and methylation disorders unless

specified

• SNP/Genome wide: fills the gaps above

Genetic Microarray


Cytogenomic Microarray Analysis

(CMA)CMA: Cytogenomic Microarray Analysis detects DNA copy number gains and losses associated with unbalanced

chromosomal aberrations

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Cytogenomic Microarray Analysis to replace Standard Karyotyping following prenatal diagnostic

procedures as standard of care?

• In December 2012, Ronald Wapner, MD published an article in the NEJM showing that in the context of prenatal diagnosis, CMA identified additional, clinically significant cytogenetic results as compared to standard karyotyping

• In 2013, the ACMG revised their Standards and Guidelines for constitutional cytogenomic microarray analysis, including postnatal and prenatal applications. They listed the advantages and limitations of CMAs

• In 2013, ACOG published Committee Opinion Number 581 on the Use of Chromosomal Microarray Analysis in Prenatal Diagnosis, which included the information to share with patients before prenatal CMA

California Department of Public Health


Indications for MA as a “Soft” Authorized Follow-up Service through the CA PNS Program

• The woman must be seen at a PDC in the Second Trimester (between 15 and 24 weeks gestation), receive Genetic

Counseling, an Ultrasound performed by an approved

Consultative Sonologist and consent to have an Amniocentesis provided by an approved Amniocentesis

Practitioner

• The Second Trimester Ultrasound must find a designated

fetal structural anomaly

• The woman must consent to Microarray in lieu of Standard

Karyotyping



Second Trimester Ultrasound Anomalies where MA is Authorized as an Option in Lieu of Standard Karyotyping

Central Nervous System

Agenesis/Hypoplasia of Corpus Callosum

Arnold Chiari Malformation

Cerebellar Hypoplasia

Dandy WalkerEncephalocele

Holoprosencephaly

Hydrocephalus NOT with spina bifida (unknown

etiology)

Meckel Gruber

Mega Cisterna MagnaPentalogy of Cantrell

Porencephaly

Ventriculomegaly

Face

Absent Nasal BoneCleft Lip

Cleft Lip & Palate

Cleft Palate

Micrognathia

NeckCystic Hygroma

Nuchal Fold (> 5 mm)

Heart/Lung

Cardiac Defect- Abnormal Outflow Tracts

Cardiac Defect- Aortic Valve Stenosis

Cardiac Defect- Atrial Septal Defect (ASD)

Cardiac Defect- CardiomegalyCardiac Defect- Coarctation of Aorta

Cardiac Defect- Truncus Arteriosus

Cardiac Defect- Dextrocardia/Heart on right

side

Cardiac Defect- Endocardial Cushion Defect/

A-V canalCardiac Defect- Ebstein Anomaly

Cardiac Defect- Enlarged Atrium

Cardiac Defect- Hypoplastic Left Heart

Cardiac Defect- Hypoplastic Right Ventricle

Cardiac Defect- Pericardial Effusion

Cardiac Defect- Pulmonary Valve Atresia/Stenosis

Cardiac Defect- Tetralogy of Fallot

Cardiac Defect- Total Anomalous Pulmonary

Venous Return

Cardiac Defect- Transposition of the Great VesselsCardiac Finding- Tricuspid Regurgitation (TR)

Cardiac Defect- Tricuspid Valve Atresia/Stenosis

Cardiac Defect- Ventricular Septal Defect (VSD)

Pleural Effusion

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Second Trimester Ultrasound Anomalies where MA is Authorized as an Option in Lieu of Standard Karyotyping

Abdomen

Absent Stomach

Ascites/Anasarca/Edema

Diaphragmatic Hernia

Double BubbleDuodenal Obstruction

Omphalocele

Small Stomach

Skeletal System

Skeletal DysplasiaSevere Scoliosis Lower extremity- Abnormal in position or number

of

bones

Lower extremity- Unilateral Clubfoot

Lower extremity- Bilateral ClubfeetUpper extremity- Abnormal in position or

number of

bones

Upper extremity- Absent bones

Upper extremity- Arthrogryposis Multiplex

CongenitaUpper extremity- Clenched hands

Upper extremity- Polydactyly

Kidney/Urinary Bladder/Pelvis

Absent Bladder

Absent Kidney-Unilateral

Absent Kidneys-Bilateral

Dilated Urinary BladderEchogenic kidneys

Empty Urinary Bladder

Enlarged kidneys

Hydronephrosis

Multicystic Dysplastic kidneys

Pelvic cystsPotter syndrome

Pyelectasis

Renal cysts

Size/Growth/Overall Appearance

Generalized EdemaHydrops Fetalis

Intrauterine Growth Retardation (IUGR)

Amniotic Fluid Volume

Severe Oligohydramnios

Severe Polyhydramnios

Umbilical Cord

2 Vessel Cord/Single Umbilical Artery


Targeted Mutation

analysis

• Suspected specific disorder based on prenatal US findings and normal karyptype

• Select cases may warrant additional prenatal testing, eg

• Noonan Syndrome (8 genes: BRAF, HRAS, KRAS,

MAP2K2, PTPN11, RAF1, SOS1)

• Holoprosencephaly (SHH, SIX3, TGIF, ZIC2)

• Hydrocephalus (L1CAM)

• Skeletal dysplasias (some labs offer panels)

• Cardiomyopathy (>50 genes and counting)

• Prenatal mutation panels are available, eg GeneDx, with summary of US and prenatal findings

• COST?


• Multiple labs and companies developed “exome

sequencing”, clinically available

• Only sequences short, functionally important

sequences of DNA (Exons) representing regions in

genes translated into proteins

• Human genome: ~180,000 exons (50 million DNA

bases), ~1.5% of the human genome; protein coding regions are estimated as ~85% of disease

causing mutations.

• Multiple companies offer exome sequencing at $699-$999 in addition to clinical labs

Sequencing

Yang et al, N Engl J Med 10/17/2013, Vol 369(16):1502-1511

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Overview







– Preconception



• 2007 the internet –based company 23andme

offers gene analysis & risk assessment for everyone

• First: $999 + $45 S&H, now $99: DNA kit for saliva

samples

• Using SNP-based technology for ~ 1.8 million data points, not full sequencing

• Allows comparison of DNA to family & friends, provides maps of genetic ancestry

• Google is one of the main investors

• 2013 the FDA temporarily forced discontinuation of

personal genome service for regulatory reasons

• www.23andme.com

Science Fiction?

http://www.23andme.com/

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67

The future


Science Fiction?

• Gene

pioneer Craig

Venter published his

own entire genome in

full sequence

on the internet in

9/2007


• Since: J.Craig Venter Institute

• First synthetic genome

• High throughput Sequencing (first: shotgun

sequencing) in Human Genome Project Race

• Massively parallel genomic sequencing

• Race/Competition for first commercially available

“$1000 genome” lead by Complete Genomics, Knome, Beckman Coulter, (IBM, Google, Apple etc.)

• Competition lead to $100 Genome – single molecule, electrical real-time analysis without need

for complicated optics [“GENIA”/”IMEC/Panasonic”]

Science Fiction?

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68


• PGD can now screen for >150 diseases prior to

implantation; many adult onset

• Major contributing genes for diabetes, heart disease,

cancer, mental illness, Parkinson’s, stroke, asthma are

being identified or already known

• Embryos selected by gender, eye, hair color and

“traits” – polymorphisms thought to be associated with athletic talent, musical talent etc

• Ethicists raise concerns:

• Eugenics

• Inequality

• Control

Reality


• February 2014: Natera expanded Panorama NIPT

to include clinically significant microdeletions

• 22q11.2 deletion syndrome

• Angelman syndrome

• Cri-du-chat syndrome

• 1p36 deletion syndrome

• Prader-Willi syndrome

• Marketed as an “opt-out” addition

• Based on a small trial; all conditions with incidences of 1:1-2000 or less

Reality


Kitzman et al

Sci Transl Med. Jun 6, 2012; 4(137): 137re76

Maternal plasma DNA sequencing reveals the

genome-wide genetic and mutational profile

of the fetus.

Reality

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• May 21st, 2008:

Genetic Information Non-Discrimination Act (GINA)

• It is illegal for employers or insurances to discriminate

based on genetic information

= insurance or employment cannot be denied due to genetic

information (e.g. Carriers of cancer predisposing mutations

(HNPCC, BRCA, etc))

• Also 2008: first child born in UK selected NOT to

carry the BRCA mutation by PGD

• In utero gene therapy works in animal models

(eg Pompe’s disease, hemophilia B) but has not been

translated into clinical practice (Nature, 2005, 2010)

Reality

Reality?


Take Home Message

• Prenatal genetic diagnosis AND screening:

increasingly complicated processes; multitude of

different strategies available to both MD and patient

• Genetic counselor = your best friend ! family history; testing and screening options; results

• The future moves rapid: Do NOT start ordering NIPT, array-CGH or targeted mutation analysis

without a geneticist or counselor involved

• Be prepared: your patient will ask about sequencing and cfDNA; both are commercially

available

• Next year: this talk will be entirely different

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70


30 years ago

High risk patient and

pregnancy

Invasive Diagnostics


Prenatal diagnostics today

High- and low-risk-patient

Path.Path.

PAPP-A,

ß-HCG

First-Trimester-Screening

WNL

WNL

WNL

Serum-

AFP

Quad-

Test

Path.

AC CVS

Path.

kayotype FISH array

sequence

Serum-ScreeningFirst-Trimester-Scan Second-Trimester-Scan

genetic Ultrasound

Invasive Diagnostics

Non-invasive TestingNIPT Genetic counseling

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71


Select References

• NSGC practice guideline: prenatal screening and diagnostic testing options for chromosome aneuploidy. Wilson KL,

Czerwinski JL, Hoskovec JM, Noblin SJ, Sullivan CM, Harbison A, Campion MW, Devary K, Devers P, Singletary CN. J Genet

Couns. 2013 Feb;22(1):4-15. doi: 10.1007/s10897-012-9545-3. Epub 2012 Nov 22.

• Effects of changes in prenatal aneuploidy screening policies in an integrated health care system. Norton ME, Nakagawa S,

Norem C, Gregorich SE, Kuppermann M. Obstet Gynecol. 2013 Feb;121(2 Pt 1):265-71. doi:

http://10.1097/AOG.0b013e31827e5c85.

• Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Bianchi DW, Platt LD, Goldberg JD,

Abuhamad AZ, Sehnert AJ, Rava RP; MatErnal BLood IS Source to Accurately diagnose fetal aneuploidy (MELISSA) Study

Group. Obstet Gynecol. 2012 May;119(5):890-901. doi: 10.1097/AOG.0b013e31824fb482. Erratum in: Obstet Gynecol. 2012

Oct;120(4):957.

• Early anatomy ultrasound in women at increased risk of fetal anomalies. Lim J, Whittle WL, Lee YM, Ryan G, Van Mieghem T.

Prenat Diagn. 2013 May 9:1-6. doi: 10.1002/pd.4145.

• Chromosomal microarray versus karyotyping for prenatal diagnosis. Wapner RJ, Martin CL, Levy B, Ballif BC, Eng CM,

Zachary JM, Savage M, Platt LD, Saltzman D, Grobman WA, Klugman S, Scholl T, Simpson JL, McCall K, Aggarwal VS, Bunke

B, Nahum O, Patel A, Lamb AN, Thom EA, Beaudet AL, Ledbetter DH, Shaffer LG, Jackson L. N Engl J Med. 2012 Dec

6;367(23):2175-84. doi: 10.1056/NEJMoa1203382.

• CA State Screening program: http://www.cdph.ca.gov/programs/gdsp/pages/default.aspx

• http://www.acog.org/Resources_And_Publications/Practice_Bulletins/Committee_on_Practice_Bulletins_--

_Obstetrics/Invasive_Prenatal_Testing_for_Aneuploidy #88, 2009

• http://www.acog.org/Resources_And_Publications/Practice_Bulletins/Committee_on_Practice_Bulletins_--

_Obstetrics/Screening_for_Fetal_Chromosomal_Abnormalities #77, 2011

•http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Genetics/Noninvasive_Prenatal_Testi

ng_for_Fetal_Aneuploidy # 545 12/2012

• Thompson & Thompson “Genetics in Medicine”, 7th Edition, 2007

• Women’s Health Review – A clinical update in Obstetric & Gynecology1st Edition, 2012

• Additional sources as marked in the presentation

•BUN trial Wapner et al, NEJM, 2003, multiple publications

•SURUSS trial Wald et al, BJOG, 2004, multiple publications

•FASTER trial Malone et al, NEJM, 2005, multiple publications


Genetics

is available in your area

http://www.ncbi.nlm.nih.gov/pubmed/23179172

http://www.ncbi.nlm.nih.gov/pubmed/22362253

http://www.acog.org/Resources_And_Publications/Practice_Bulletins/Committee_on_Practice_Bulletins_--_Obstetrics/Invasive_Prenatal_Testing_for_Aneuploidy

http://www.acog.org/Resources_And_Publications/Practice_Bulletins/Committee_on_Practice_Bulletins_--_Obstetrics/Screening_for_Fetal_Chromosomal_Abnormalities

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CA STATE PRENATAL SCREENING PROGRAM INFORMATION

PSR Contacts and Special Authorizations:

Jacqueline Avila (510) 412-6205

Cheryl Ikeda (510) 412-1475Bret Hutchinson (510) 412-3939

PDC Invoicing:

Nympha Valdezotto (510) 412-1479



Regional NIPT statistics

• Total number of specimens drawn in 2017: 10,040 (9,885

resulted)

– 91% AMA indication

– 8.6% increase over 2016

– 30 failed lab tests, increased from 7 in 2016. Likely caused by algorithm adjustments 6/2017

• Total number of abnormal NIPT results: 222 (2.2% abnormal results)

– decrease of 1% from prior year—likely due to elimination of “suspected” abnormality category


Exercise 1

24 year old G1P0 presents with 29 year old husband for PNV.

Both are Caucasion.

She has bipolar disorder and mild

learning disabilities, he is healthy.

They wonder about prenatal screening

options.

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Exercise 1

They choose sequential integrated screening.

During their NT ultrasound an NT of 4.5 mm is noted.

How do you counsel the patient?


Exercise 1

They undergo genetic counseling and choose to continue the pregnancy.

Anatomic US at 20 weeks shows bilateral EIF, mild pyelectasis and an AV canal

defect.

How do you counsel them?


Exercise 1

They undergo genetic amniocentesis and the karyotype returns 47,XX+21.

They choose to continue the pregnancy and deliver an otherwise healthy baby

with classic features of Down syndrome at term.

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Exercise 2

4 years later they return with another pregnancy.

She is now 28 years old, G2P1 and reports a young half sibling with a

cardiac defect; he is 33 years old and has developed diabetes.

They wonder again about their prenatal screening options.



Exercise 2

They choose NIPT, which returns with a low risk.

They undergo detailed anatomy screening and fetal screening

echocardiogram and fetal Tetralogy of Fallot is suspected.



Exercise 2

They undergo genetic amniocentesis and the karyotype returns 46,XY.

Array CGH reveals a deletion 22q11.2

The couple decides to terminate the

pregnancy.

Maternal FISH reveals the same 22q11.2

deletion.

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Exercise 3

The patient returns to your office 10 years later.

She, 38 years old, G2P1, presents with a new partner, who is 49 years old and

healthy.

They underwent IVF with PGD for the

22q11.2 deletion.

They are10 weeks pregnant with twins.



Exercise 3

They decline prenatal screening, but desire anatomy US screening.

Twin A appears healthy, twin B is noted to have an omphalocele on screening US.

She declines amniocentesis.

The pregnancy progresses, but twin B

shows accelerated growth and polyhydramnios and they are born at 33

weeks.


Exercise 3

Twin B is diagnosed with Beckwith Wiedeman Syndrome after birth

The couple returns 5 years later for preconception counseling.

She is now 43 years old, he 52, and they are wondering about their reproductive

options.


Prenatal Ultrasound Interpretation and Genetic Testing ... · •Fetal imaging with ultrasound...

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