Dataset Information

NLRP7 variants in spontaneous abortions with multilocus imprinting disturbances from women with recurrent pregnancy loss.

ABSTRACT:

Purpose

Comparative analysis of multilocus imprinting disturbances (MLIDs) in miscarriages from women with sporadic (SPL) and recurrent pregnancy loss (RPL) and identification of variants in the imprinting control gene NLRP7 that may lead to MLIDs.

Methods

Chorionic cytotrophoblast and extraembryonic mesoderm samples from first-trimester miscarriages were evaluated in 120 women with RPL and 134 women with SPL; 100 induced abortions were analyzed as a control group. All miscarriages had a normal karyotype. Epimutations in 7 imprinted genes were detected using methyl-specific PCR and confirmed with DNA pyrosequencing. Sequencing of all 13 exons and adjusted intron regions of the NLRP7 gene was performed.

Results

Epimutations in imprinted genes were more frequently detected (p < 0.01) in the placental tissues of miscarriages from women with RPL (7.1%) than in those of women with SPL (2.7%). The predominant epimutation was postzygotic hypomethylation of maternal alleles of imprinted genes (RPL, 5.0%; SPL, 2.1%; p < 0.01). The frequency of MLID was higher among miscarriages from women with RPL than among miscarriages from women with SPL (1.7% and 0.4%, respectively, p < 0.01). Variants in NLRP7 were detected only in miscarriages from women with RPL. An analysis of the parental origin of NLRP7 variants revealed heterozygous carriers in families with RPL who exhibited spontaneous abortions with MLIDs and compound heterozygosity for NLRP7 variants.

Conclusion

RPL is associated with NLRP7 variants that lead to germinal and postzygotic MLIDs that are incompatible with normal embryo development.

Trial registration

Not applicable.

SUBMITTER: Sazhenova EA

PROVIDER: S-EPMC8608992 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature

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Publications

NLRP7 variants in spontaneous abortions with multilocus imprinting disturbances from women with recurrent pregnancy loss.

Sazhenova Elena A EA Nikitina Tatyana V TV Vasilyev Stanislav A SA Tolmacheva Ekaterina N EN Vasilyeva Oksana Yu OY Markov Anton V AV Yuryev Sergey Yu SY Skryabin Nikolay A NA Zarubin Alexey A AA Kolesnikov Nikita A NA Stepanov Vadim A VA Lebedev Igor N IN

Journal of assisted reproduction and genetics 20210923 11

<h4>Purpose</h4>Comparative analysis of multilocus imprinting disturbances (MLIDs) in miscarriages from women with sporadic (SPL) and recurrent pregnancy loss (RPL) and identification of variants in the imprinting control gene NLRP7 that may lead to MLIDs.<h4>Methods</h4>Chorionic cytotrophoblast and extraembryonic mesoderm samples from first-trimester miscarriages were evaluated in 120 women with RPL and 134 women with SPL; 100 induced abortions were analyzed as a control group. All miscarriage ...[more]

PMID: 34554362

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Project description:Miscarriage is the most common complication of pregnancy. Approximately 1% of couples trying to conceive will experience recurrent miscarriages, defined as three or more consecutive pregnancy losses and many of these cases remain idiopathic. Complement is implicated both in the physiology and pathology of pregnancy. Therefore, we hypothesized that alterations in the C3 gene could potentially predispose to this disorder. We performed full Sanger sequencing of all exons of C3, in 192 childless women, with at least two miscarriages and without any known risk factors. All exons carrying non-synonymous alterations found in the patients were then sequenced in a control group of 192 women. None of the identified alterations were significantly associated with the disorder. Thirteen identified non-synonymous alterations (R102G, K155Q, L302P, P314L, Y325H, V326A, S327P, V330I, K633R, R735W, R1591G, G1606D, and S1619R) were expressed recombinantly, upon which C3 expression and secretion were determined. The L302P and S327P were not secreted from the cells, likely due to misfolding and intracellular degradation. Y325H, V326A, V3301I, R1591G, and G1606D yielded approximately half C3 concentration in the cell media compared with wild type (WT). We analyzed the hemolytic activity of the secreted C3 variants by reconstituting C3-depleted serum. In this assay, R1591G had impaired hemolytic activity while majority of remaining mutants instead had increased activity. R1591G also yielded more factor B activation in solution compared with WT. R1591G and G1606D showed impaired degradation by factor I, irrespectively if factor H, CD46, or C4b-binding protein were used as cofactors. These two C3 mutants showed impaired binding of the cofactors and/or factor I. Taken together, several alterations in C3 were identified and some of these affected the secretion and/or the function of the protein, which might contribute to the disorder but the degree of association must be evaluated in larger cohorts.

Project description:Study questionAre mutations in NLRP2/7 (NACHT, LRR and PYD domains-containing protein 2/7) or KHDC3L (KH Domain Containing 3 Like) associated with recurrent pregnancy loss (RPL) or infertility?Summary answerWe found no evidence for mutations in NLRP2/7 or KHDC3L in unexplained RPL or infertility.What is known alreadyMutations in NLRP7 and KHDC3L are known to cause biparental hydatidiform moles (BiHMs), a rare form of pregnancy loss. NLRP2, while not associated with the BiHM pathology, is known to cause recurrent Beckwith Weidemann Syndrome (BWS).Study design, size, and durationNinety-four patients with well characterized, unexplained infertility were recruited over a 9-year period from three IVF clinics in Sweden. Blood samples from 24 patients with 3 or more consecutive miscarriages of unknown etiology were provided by the Recurrent Miscarriage Clinic at St Mary's Hospital, London, UK.Participants/materials, setting, methodsPatients were recruited into both cohorts following extensive clinical studies. Genomic DNA was isolated from peripheral blood and subject to Sanger sequencing of NLRP2, NLRP7 and KHDC3L. Sequence electropherograms were analyzed by Sequencher v5.0 software and variants compared with those observed in the 1000 Genomes, single nucleotide polymorphism database (dbSNP) and HapMap databases. Functional effects of non-synonymous variants were predicted using Polyphen-2 and sorting intolerant from tolerant (SIFT).Main results and the role of chanceNo disease-causing mutations were identified in NLRP2, NLRP7 and KHDC3L in our cohorts of unexplained infertility and RPL.Limitations, reasons for cautionDue to the limited patient size, it is difficult to conclude if the low frequency single nucleotide polymorphisms observed in the present study are causative of the phenotype. The design of the present study therefore is only capable of detecting highly penetrant mutations.Wider implications of the findingsThe present study supports the hypothesis that mutations in NLRP7 and KHDC3L are specific for the BiHM phenotype and do not play a role in other adverse reproductive outcomes. Furthermore, to date, mutations in NLRP2 have only been associated with the imprinting disorder BWS in offspring and there is no evidence for a role in molar pregnancies, RPL or unexplained infertility.Study funding/competing interestsThis study was funded by the following sources: Estonian Ministry of Education and Research (Grant SF0180044s09), Enterprise Estonia (Grant EU30020); Mentored Resident research project (Department of Obstetrics and Gynecology, Baylor College of Medicine); Imperial NIHR Biomedical Research Centre; Grant Number C06RR029965 from the National Center for Research Resources (NCCR; NIH). No competing interests declared.

Dataset Information

NLRP7 variants in spontaneous abortions with multilocus imprinting disturbances from women with recurrent pregnancy loss.

Purpose

Methods

Results

Conclusion

Trial registration

Publications

NLRP7 variants in spontaneous abortions with multilocus imprinting disturbances from women with recurrent pregnancy loss.

Similar Datasets

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