Familial Recurrent Hydatidiform Mole Research Articles

High Risk of Gestational Trophoblastic Neoplasia Development in Recurrent Hydatidiform Moles with NLRP7 Pathogenic Variations.

Pathogenic variations of the NLRP7 and KHDC3L genes are responsible for familial recurrent hydatidiform moles, a rare autosomal recessive phenomenon that can lead to severe comorbidities. Little is known about the diversity of genetic defects or the natural course of disease progression among recurrent hydatidiform mole cases from distinct ethnicities. In this study, we aimed to investigate the mutation profile and pregnancy outcomes in patients with multiple molar pregnancies. Three unrelated cases with recurrent molar pregnancies are included in this study. None of the patients had a known family history of molar pregnancy. Clinical findings and follow-up results are documented. Sanger sequencing is used to reveal genetic defects in exons and exon-intron boundaries of NLRP7 and KHDC3L genes. NLRP7 pathogenic variants were found in all three cases. In two cases, homozygous, c.2471+1G>A canonical splice cite variant was identified and in one case a homozygous, c.2571dupC (p.Ile858HisfsTer11) frameshift variant was identified. No variant in the KHDC3L gene was found in any case. In all cases, the development of gestational trophoblastic neoplasia complicated the clinical course and the treatment plans. We found that defects of the NLRP7 gene are principally responsible for etiology in our region, and the mutation profile suggests a founder effect in the Turkish population. We suggest early genetic diagnosis and counseling in molar pregnancies and recommend close follow-up in terms of conversion to gestational trophoblastic neoplasia.

Recurrent GTD and GTD coexisting with normal twin pregnancy

Hydatidiform mole (HM) affects around 1/1000 pregnancies, and in such cases the recurrence risk is around 1%, being greater for those with complete HM (CHM). Whilst most cases appear sporadic with unknown mechanisms, there is a distinct subgroup of patients who suffer recurrent pregnancy loss, including multiple recurrent CHM (familial recurrent biparental HM syndrome). The majority of these cases are related to maternal genetic mutations in genes related to the control of imprinting, specifically NALP7 and KHDC3L. Oocyte donation is an effective treatment allowing these patients to have successful pregnancies. Approximately 1 in 50,000 pregnancies are complicated by twin pregnancy comprising normal foetus and HM, the majority of reported cases being CHM. Such pregnancies are at significantly increased risk of complications, including pregnancy loss, early-onset preeclampsia and severe preterm delivery, but when managed conservatively the delivery of a liveborn healthy infant occurs in around one-third of cases. Regardless of management, the risk of persistent GTD in such cases appears similar to that following singleton CHM. Rarely, other conditions mimic prenatal ultrasound appearances of twin pregnancy with HM, CHM mosaicism and placental mesenchymal dysplasia, both of which have distinctive histological and genetic features.

Recurrent hydatidiform mole: when to stop?

Recurrent hydatidiform mole (RHM) is defined as two or more repeated molar pregnancies in the same patient. Familial recurrent hydatidiform mole (FRHM) is a rare condition in which the patient has relatives with the same condition and mutations. Maternal mutations in the NLRP7 gene are mostly observed in RHM. The authors report a patient from Turkey with a history of seven molar pregnancies who had an aunt with similar obstetric history and NLRP7 mutations.

Absence of Maternal Methylation in Biparental Hydatidiform Moles from Women with NLRP7 Maternal-Effect Mutations Reveals Widespread Placenta-Specific Imprinting.

Familial recurrent hydatidiform mole (RHM) is a maternal-effect autosomal recessive disorder usually associated with mutations of the NLRP7 gene. It is characterized by HM with excessive trophoblastic proliferation, which mimics the appearance of androgenetic molar conceptuses despite their diploid biparental constitution. It has been proposed that the phenotypes of both types of mole are associated with aberrant genomic imprinting. However no systematic analyses for imprinting defects have been reported. Here, we present the genome-wide methylation profiles of both spontaneous androgenetic and biparental NLRP7 defective molar tissues. We observe total paternalization of all ubiquitous and placenta-specific differentially methylated regions (DMRs) in four androgenetic moles; namely gain of methylation at paternally methylated loci and absence of methylation at maternally methylated regions. The methylation defects observed in five RHM biopsies from NLRP7 defective patients are restricted to lack-of-methylation at maternal DMRs. Surprisingly RHMs from two sisters with the same missense mutations, as well as consecutive RHMs from one affected female show subtle allelic methylation differences, suggesting inter-RHM variation. These epigenotypes are consistent with NLRP7 being a maternal-effect gene and involved in imprint acquisition in the oocyte. In addition, bioinformatic screening of the resulting methylation datasets identified over sixty loci with methylation profiles consistent with imprinting in the placenta, of which we confirm 22 as novel maternally methylated loci. These observations strongly suggest that the molar phenotypes are due to defective placenta-specific imprinting and over-expression of paternally expressed transcripts, highlighting that maternal-effect mutations of NLRP7 are associated with the most severe form of multi-locus imprinting defects in humans.

Risk of recurrent molar pregnancies following complete and partial hydatidiform moles.

What is the risk of further molar pregnancies for women with one or more hydatidiform moles (HM) in relation to molar subtype. Women with a complete hydatidiform mole (CM) have a 1 in 100 and 1 in 4 risk of further CM after one or two consecutive CM, respectively, while women with a partial hydatidiform mole (PM) have only a small increase in risk for further molar pregnancies. Women with a molar pregnancy have an increased risk of further HM. A small subgroup of women with recurrent HM has an autosomal recessive condition, familial recurrent hydatidiform moles (FRHM), that predisposes them to molar pregnancies. A retrospective study of subsequent pregnancies in 16 000 women registered at a centralized referral centre, with a CM or PM, between 1990 and 2009. One hundred and sixty-six women with two or more molar pregnancies were identified from electronic records and patient notes. Histopathological features of all molar tissue were reviewed in these cases and genotyping performed where diagnosis was not possible on the basis of histopathological features alone. In addition, genotyping of molar tissue was performed in all cases of women with three or more CM to establish whether the tissue was diploid and biparental or androgenetic. This study confirms an increased recurrence risk of ∼1% for a second molar pregnancy and in addition that this risk is associated with CM rather than PM. The data further indicate that the risk of a third HM is associated almost exclusively with CM and enabled an estimate that 1 in 640 women registered with a CM has the rare condition FRHM. The study also found that there was no significant difference between the risk of developing gestational trophoblastic neoplasia (GTN) for typical sporadic CM and the diploid biparental CM associated with FRHM (GTN; proportion difference 0.05, Z = 0.87, P = 0.29). While pathology was reviewed for all women with two or more molar pregnancies, not all cases registered underwent central review particularly those women registered in the early 1990s. It is therefore possible that the total number of CM and PM may differ slightly from that stated. While women were followed for a minimum of 5 years, it is possible that some women may subsequently have further molar pregnancies that will not have been included in the present study. This is the largest study to date on recurrence for molar pregnancies, and as such provides the most detailed information so far regarding the risk of further molar pregnancies for women with a PM or CM. Furthermore, the data provide new insights into the incidence of the rare autosomal recessive condition, FRHM, important information for counselling women with molar pregnancies. No competing interests declared. No funding was obtained for this study.

Novel NLRP7 mutations in familial recurrent hydatidiform mole: are NLRP7 mutations a risk for recurrent reproductive wastage?

ObjectiveFamilial recurrent hydatidiform mole is an exceedingly rare clinical condition. Affected women are predisposed to molar pregnancies of diploid, biparental origin rather than androgenetic origin. At present, NLRP7 and KHDC3L (C6orf221) are the only genes known to be associated with familial recurrent hydatidiform mole. This study investigated the genetic dispositions in two large Turkish families with recurring molar conceptuses. Study designCopy number variation analysis was performed followed by NLRP7 gene sequencing. The finding of a mono-allelic condition in one family led to investigation of the adjacent NLRP2 gene and recently associated KHDC3L gene. Sampled molar tissues were genotyped using microsatellite markers. ResultsIn one family, a homozygous single nucleotide insertion that caused a frameshift leading to an early stop codon, c.2940_2941insC (p.Glu981ArgfsX13), was identified in the affected sisters. In the other family, a heterozygous 60-kb deletion eliminating substantial portions of the NLRP2 and NLRP7 genes on one allele was found. Screening of NLRP2 and KHDC3L genes revealed no alterations that were considered to be pathological. Genotyping of six independent molar conceptions revealed that five were of diploid, biparental origin and one was of diandric, triploid origin. ConclusionsTwo novel protein-truncating mutations in the NLRP7 gene were found to be associated with familial recurrent hydatidiform mole. Mutations in the NLRP7 gene causing recurrent biparental hydatidiform mole may also be associated with other forms of recurrent reproductive wastage.

Recurrent familial hydatidiform mole - a rare clinical problem

Familial recurrent hydatidiform mole is a rare event; here we report an unusual case of a gravida 5 aged 29 years, with five recurrent hydatidiform moles and no normal pregnancy. After the fourth molar pregnancy, she developed persistent trophoblastic disease that required 7 cycles of single agent chemotherapy. Two years after the treatment, she presented with her fifth molar pregnancy. Her elder sister had seven hydatidiform moles from two different unrelated male partners. As this is familial, and recurrent, with no viable conceptions in both the sisters, it is likely to be biparental in origin. Unlike androgenetic moles, biparental moles arise due to a global inherited failure of maternal imprinting. It is an autosomal recessive defect in the female germ line. Genetic analysis is essential, although it is not available in all centers. Donor Oocyte IVF is the only option for women with biparental moles to have normal offspring.

Histopathological features of biparental complete hydatidiform moles in women with NLRP7 mutations

ObjectivesMolar pregnancies, characterized by hydropic change and trophoblast hyperplasia of chorionic villi, are usually sporadic. Second and third molar pregnancies can occur by chance but may be associated with a rare autosomal recessive condition, familial recurrent hydatidiform mole (FRHM). This condition, in which affected women have a predisposition to complete hydatidiform moles (CHM), is not usually diagnosed until women have experienced several CHM when a differential diagnosis is made by demonstrating the CHM are diploid and biparental (BiCHM) in contrast to sporadic CHM which are androgenetic (AnCHM). Our objective was to investigate whether these genetic differences might be reflected in identifiable phenotypic differences between BiCHM and AnCHM that could enable earlier diagnosis of FRHM. Study designHistopathological features were compared between 27 AnCHM from 17 individuals and 51 BiCHM from 20 families in whom a diagnosis of FRHM was confirmed by the presence of biallelic NLRP7 mutations or pathological variants. ResultsA spectrum of morphological features was observed in BiCHM. As a group they show subtle, but consistent, histological differences from typical sporadic AnCHM, with less marked villous trophoblast hyperplasia, extravillous trophoblast fragments, stromal apoptotic debris, budding architecture, cisterns and trophoblastic inclusions. While there are some BiCHM that individually show atypical histological features, the majority are indistinguishable from typical sporadic AnCHM. ConclusionThe majority of cases of FRHM cannot be distinguished from sporadic AnCHM on the basis of histopathological features alone. In a minority of cases CHM may demonstrate ‘atypical’ features that raise the possibility of underlying BiCHM requiring further investigation.

Mutations inNLRP7 andKHDC3LConfer a Complete Hydatidiform Mole Phenotype on Digynic Triploid Conceptions

Digynic triploidy is classically associated with a severely growth restricted fetus and a small nonmolar placenta. However, in genotyping hydatidiform moles as part of clinical practice, we identified two digynic triploid conceptions presenting with histopathological features of classical complete hydatidiform mole (CHM). Both cases occurred in women with a history of previous molar pregnancies and no normal pregnancies. Pathological review and genotyping of other molar pregnancies in these cases showed them to be typical CHM with negative p57(KIP2) immunostaining of the cytotrophoblast cells and villous stroma and to be diploid but biparental, confirming a diagnosis of familial recurrent hydatidiform mole (FRHM). Mutation screening of NLRP7 had identified a homozygous duplication, leading to a truncated protein, in case 1 whereas mutation screening of KHDC3L (C6orf221) in case 2 showed both the proband and her sister to be compound heterozygotes for mutations in KHDC3L. The observation of a single digynic, triploid conception presenting as a CHM in women with FRHM, where other pregnancies are diploid and biparental, supports the hypothesis that the role of both NLRP7 and KHDC3L in pregnancy is in setting and/or maintaining the maternal imprint. Clinically, a diagnosis of FRHM should be considered in women with genetically unusual conceptions that are phenotypically CHM.

Mosaic moles and non-familial biparental moles are not caused by mutations in NLRP7, NLRP2 or C6orf221

Hydatidiform moles (HMs) most often occur sporadically and are either diploid androgenetic or triploid. The very rare familial recurrent HMs (FRHMs) have been related to NLRP7 and C6orf221 mutations in the mother. FRHMs are most often diploid with both maternal and paternal origin of the molar genome. We have screened a cohort of 11 women with diploid HMs with biparental contributions to the molar genome with regard to mutations in NLRP7, NLRP2, the NLRP gene most homologous to NLRP7, and C6orf221. This was done in order to reveal if mutations in the mentioned genes play a major role in development of non-recurrent biparental moles. Recently, we have shown that eight of these diploid moles consist of two different cell lines. Only one woman had a mutation in the coding DNA sequence of NLRP7, which most likely contributed to HM development. This woman had non-mosaic repeated moles, and she was the only woman in our cohort with FRHM. We found no unequivocal pathogenic mutations in NLRP2 or C6orf221. Our observations suggest that although NLRP7 and C6orf221 mutations are related to diploid biparental FRHMs, neither of these genes, nor NLRP2, are related to diploid HMs with biparental contributions to the molar genome, in general.

Screening for NLRP7 Mutations in Familial and Sporadic Recurrent Hydatidiform Moles

A familial or sporadic recurrent hydatidiform mole is a rare autosomal recessive condition that has been associated with biallelic mutations in the nucleotide-binding, leucine-rich repeat, pyrin domain 7 (NLRP7) gene (19q13.42). Cases from different ethnic origins have been reported earlier. Here we report the first Tunisian patients: 2 sisters with homozygous NLRP7 mutations (p.E570X) and 1 sporadic case with no mutation in NLRP7. Our results extend the number of familial recurrent reproductive wastages due to mutations in NLRP7. We suggest that mutations screening of NLRP7 could be proposed more systematically in women with recurrent pathologic pregnancy outcomes of unknown origin. The rare cases with a typical clinical picture, which were not related to NLRP7 mutation as in our sporadic case, should be investigated more to identify the causative gene.

Identification of 13 novel NLRP7 mutations in 20 families with recurrent hydatidiform mole; missense mutations cluster in the leucine-rich region

Background:NLRP7 (NALP7) has recently been identified as the causative gene for familial recurrent hydatidiform mole (FRHM), a rare autosomal recessive condition in which affected women have recurrent molar pregnancies of...

Women heterozygous forNALP7/NLRP7 mutations are at risk for reproductive wastage: report of two novel mutations

Familial recurrent hydatidiform moles are a rare recessive condition in which molar tissues have biparental contribution to their genome. One maternal locus responsible for this condition has been mapped to 19q13.4 and the causative gene, NALP7, identified (HUGO-approved nomenclature is now NLRP7). Here we report a first stop codon, c.295G>T (p.Glu99X) and a missense mutation, c.1970A>T (p.Asp657Val) in NLRP7 in two sisters with RHMs. We found these two mutations and a previously reported one, c.2078G>C (p.Arg693Pro) in a homozygous state, in males with normal reproductive outcomes. This suggests that NLRP7 is not required for normal spermatogenesis. The mother of the patients is heterozygous for Glu99X and had one stillbirth and three normal pregnancies. Our data on this new family and on heterozygous women from previously reported families indicate that women heterozygous for NLRP7 mutations are at risk for reproductive wastage without the manifestation of molar phenotype.

Analysis of the chromosomal region 19q13.4 in two Chinese families with recurrent hydatidiform mole

Familial recurrent hydatidiform mole is an extremely rare autosomal recessive condition in which affected individuals have a predisposition to molar pregnancies that are diploid but biparental, rather than androgenetic, in origin. A gene for this condition has been previously mapped to a 1.1 Mb region of chromosome 19q13.4. However, investigation of further families is needed to refine the location of the specific gene(s) involved. We have recently identified two novel Chinese families in which four affected women had recurrent pregnancy loss including 14 complete hydatidiform moles (CHM). Fluorescent microsatellite genotyping was used to determine the origin of CHM in both families. Using a panel of polymorphic microsatellite markers, genotyping and haplotype analysis of the 19q13.4 chromosomal region was performed in both families. Genotyping of CHM from affected individuals confirmed their biparental origin and diagnosis of familial recurrent hydatidiform mole in both families. However, no significant homozygosity for the 19q13.4 candidate region was found in affected members of either family. Genotyping and haplotype analysis has shown that a mutation in 19q13.4 is unlikely to be responsible for recurrent CHM in the two Chinese families investigated and provides further evidence to support the hypothesis that, although extremely rare, this condition shows genetic heterogeneity.

The human homologue (PEG3) of the mouse paternally expressed gene 3 (Peg3) is maternally imprinted but not mutated in women with familial recurrent hydatidiform molar pregnancies.

We mapped a locus for autosomal recessive molar pregnancies with biparental genomic contribution to chromosome 19q13.4 between D19S924 and D19S890. This 5-Mb region is homologous to proximal mouse chromosome 7 and contains a cluster of Krüppel-type zinc finger genes, including the human homologue of the mouse imprinted genes: the paternally expressed gene 3 (PEG3) and the maternally expressed Zim1 genes. We analyzed the PEG3 gene for mutations in women with familial recurrent hydatidiform moles and to determine its imprinting status in humans. We used database searches and screened cDNA libraries to find the complete genomic structure of PEG3. Polymerase chain reaction (PCR) amplification and direct sequencing of coding exons and flanking introns were performed on genomic DNA from the affected women. Allele-specific methylation and expression were studied by methylation-sensitive Southern analysis of a 5' located CpG island and by reverse-transcription PCR of total lymphoblast-derived RNA of normal individuals who were informative for two expressed polymorphisms. We did not detect any mutations in the coding region of PEG3 in the affected women. We observed allele-specific methylation of the CpG island and expression from the paternal allele in two independent informative pedigrees. Consistent with the findings in the mouse, the human PEG3 gene is expressed from the paternal allele. Our data support that PEG3 is not mutated in women with familial recurrent hydatidiform moles, although mutations in the regulatory regions that might affect imprinting or transcriptional level of the gene could not be evaluated.

Mole maker phenotype: possible narrowing of the candidate region.

Recent data has suggested that familial recurrent hydatidiform mole is a rare autosomal recessive trait in women experiencing this gestational disease (MIM 231090). Here we provide molecular data on an additional family confirming that recurrent familial hydatidiform moles are diploid, biparental and arise from independent conceptions. A narrowing of the gene interval on chromosome 19q13.3-13.4 is suggested by haplotype analysis in two sisters.