Hippocrates(460-360 B.C.)

Dropsy of the Uterus, mola hydatidosa

FMFSAID, Rome 2008

NLRP7 and Hydatidiform Moles

Clinical Manifestation of HMs

May include one or several of the followings:

-vaginal bleeding in the 1st trimester (in 84% of the cases),-larger than normal growth of the uterus (28%),-excessive nausea and vomiting (8%),-anaemia (4%),-hyperthyroidism,-toxaemia of pregnancy (sepsis),-and passage of grape-like tissues from the vagina.

Ultrasound and Gross Morphology of aComplete Hydatidiform Mole

Histopathology

CHM PHM

Several Forms of HMs

Familial recurrent

Not recurrent (1/1000 pregnanciesin Western societies, but 2-10 higher elsewhere).Complex etiology

1-6% recurrent moles10-25% a 2nd reproductive wastage

Sporadic Recurrent

Rare

Karyotype and Genotype Data of CommonSporadic HMs

CHMs Diploid PHMs Triploid

80% Androgenetic 20% Biparental

monospermic dispermic

60% 20%

Karyotype and Genotype Data of RHMs

All biparental

Mostly biparental, some androgenetic

RHMs

p13.2

p13.3

q13.3

q13.4

p13.1

p13.2

p13.3

p12

p11

q11

q12

q13.1

q13.2

q13.3

q13.4

A Maternal Recessive Locus Responsible forRHMs

~ 4.8 MbHM candidate region

Moglabey et al., Hum Mol Genet, 1999

Hypotheses: Immunological Defect

Before 1977:

-Medawar’s hypothesis: “fetus is a semi-allograft”Consensus: Immunostimulation / immunosuppressionConsensus: Maternal immunity is down regulated during pregnancy.

-Abnormal immune relationship between the motherand her fetus may underlie pathologic pregnanciesincluding androgenetic HMs - complete allograft.

After 1977:CHMs Normal zygote

Androgenetic (2n) Biparental (2n)Kaji & Ohama, Nature 1977

Supported by the work of Surani and Solter ( 1980s)

Hypotheses: Imprinting Defect

Abnormal Methylation of Imprinted Genes in BiHMs

Maternally methylated 1 BiHM 2 BiHM in sisters

PEG3 --- ---

PEG1 --- KCNQ1OT1 ---

SNRPN --- - to -- GNAS -AS ---

GNAS -XL! s normal

GNAS -1A ---

Paternally methylated

GNAS -NES P55 +++ +++ H19 normal + to ++

Ju

dson

et

al, 2

002

El-M

aarri

et a

l, 20

03

Abnormal Methylation at Imprinted Genes is Restricted to their DMRs

Djuric et al., Hum Genet, 2006

Normal Postzygotic DNA Methylation at Repetitive Elements

Djuric et al., Hum Genet, 2006

Normal Methylation at Inactive and Active X Genes

Djuric et al., Hum Genet, 2006

Sequencing a Total of 80 Genes to IdentifyNLRP7

Moglabey et al.,1999

D19

S924

1151

5-31

D19

S418

NA

LP5

AA

AT

1113

8

D19

S890

Sensi et al., 2000

4.8 Mb

Hodges et al., 2003

3.5 Mb

1.1 Mb

0.65 MbMurdoch et al., 2006

NLR

P7

Size

54 genes

26 genes

Reported Mutations in NLRP7

1 93 172 491 614 957

PYD

NACHT

LRR

R693PG118X

N913S

L825X

D657V

R693W

980

L750V

E710Dfs7X

c.2810+2T>G

G99X

4

3

32

3

2

Reported women with RHMs have 2 defective alleles

Conditions Associated with familial RHMs

-Spontaneous abortions (in most families)

-Stillbirths (in half of the families)

-Preeclampsia (in some of their pregnancies)

-Early neonatal deaths (in 2 families)

-Normal pregnancies with or without severe intra uterine growth restriction (NPs in several cases).

Interobserver & Intraobserver Variations

C: Complete, P: partial, A: abortion

Family ProteinHeterozygous women

MoPa61 L825X 4 NP, 1 SA

MoGe2 R693W 6 NP, 1 SA

MoCh76 Glu99X 3 NP, 1 SB

Reproductive Outcomes

One Mutation in NLRP7 is a Risk Factorfor Reproductive Wastage

Role of NLRP7 in RHMs?

What causes RHMs????-Defective oocytes???-Defective maternal reproductive tract???-or both???

NLRP7 transcripts in unfertilized denudedoocytes, endometrium, & Fallopian tubes.

NLRP7, in vitro, inhibits IL-1β secretion.

Roles of Interleukin-1β

- In rabbit and mares, intrafollicular injection ofIL-1β induces ovulation, but embryos

arrest during early cleavage (Takehara, 1994; Caillaud, 2005).

- IL-1β is involved in embryo-maternal signalling, trophoblast invasion, and proliferation (several studies).

-Cause: Inflammatory and Immunological defects

-Consequence: Abnormal methylation, when & where???

In the oocytes before fertilization?Between fertilization and implantation?Post implantation and proliferation of HMs?

Revisiting the Pathology of HMs: Old andNew Schools

Imprinting Hypothesis???Major Risk Factors for Common HMs

Environmental/physiological:

-Maternal age

Genetic:

-Maternal history of spontaneous abortions

-Maternal ethnicity

Areas of low incidence

Areas of high incidence

*

* **

*

*

**

*

**

*

**

**

*

*

*

*

Reported families with RHMs

*

*

*

*

*

*** *

*

*

Acknowledgments

Muhieddine Seoud (Lebanon)Laila Zahed (Lebanon)Batool Mazher (Pakistan)Rashmi Bagga (India)Renate Kircheisen (Germany)Philippe Coullin (France)Jianhua Qian & Xing Xie (China)

Guy Rouleau (Canada)Asangla Ao (Canada)Amira Mehio (Canada)

Rork Kuick &Samir Hanash (USA)Osman El-Maarri &Johannes Oldenburg(Germany)

Sharlene MurdochUgljesa DjuricRabia KhanCatherine DeveaultMoglabey YollaHelwani Mazen

CIHR, FRSQ, MISRI

The patients and their families

Paternally expressed SNRPN

BiC

HM

16

Abnormal Unmethylation of the Maternal SNRPN Allele in one BiHM

Nor

mal

P

M

P

M

El-Maarri et al.Hum Mol Genet, 2003

Maternally expressed NESP55

BiC

HM

9

Maternally expressed H19

Abnormal Gain of Methylation at theMaternal Alleles in BiCHMs

M

P

P

M

BiC

HM

16

P

MN

orm

alBi

CH

M 9

P

M

P

M

Nor

mal

El-Maarri et al.Hum Mol Genet, 2003

Abnormal Methylation of Imprinted Genes in BiHMsMaternally methylated 1 BiHM 2 BiHM

in sisters 2 BiHM

unrelated PEG3 --- --- ---

PEG1 --- KCNQ1OT1 ---

SNRPN --- - to -- --- GNAS -AS --- normal to +++

GNAS -XL! s normal normal

GNAS -1A --- --- to --

Paternally methyla ted

GNAS -NESP55 +++ +++ +++ in normal TP

H19 normal + to ++ normal

Juds

on e

t

al,

2002

El-

Maa

rri

et a

l, 20

03

Kou

et a

l.

2008

Age-related incidence of HMs

15-1920-24

25-2930-34

35-3940-44

>45