Pregnancy after oocyte donation in a patient with NLRP7 gene mutations and recurrent molar hydatidiform pregnancies

Human Reproduction and Disturbed Genomic Imprinting

Genomic imprinting is a specific mode of gene regulation which particularly accounts for the factors involved in development. Its disturbance affects the fetus, the course of pregnancy and even the health of the mother. In children, aberrant imprinting signatures are associated with imprinting disorders (ImpDis). These alterations also affect the function of the placenta, which has consequences for the course of the pregnancy. The molecular causes of ImpDis comprise changes at the DNA level and methylation disturbances (imprinting defects/ImpDefs), and there is an increasing number of reports of both pathogenic fetal and maternal DNA variants causing ImpDefs. These ImpDefs can be inherited, but prediction of the pregnancy complications caused is difficult, as they can cause miscarriages, aneuploidies, health issues for the mother and ImpDis in the child. Due to the complexity of imprinting regulation, each pregnancy or patient with suspected altered genomic imprinting requires a specific workup to identify the precise molecular cause and also careful clinical documentation. This review will cover the current knowledge on the molecular causes of aberrant imprinting signatures and illustrate the need to identify this basis as the prerequisite for personalized genetic and reproductive counselling of families.

Decoding the Genetics of Recurrent Molar Pregnancy

Hydatidiform mole is a condition characterised by abnormal trophoblastic hyperplasia and failure of embryonic tissue development. The risk of recurrence is seen to be associated with biallelic maternal mutations in NLRP7, KHDC3 L and PAD16 genes. Women with such mutations have a major risk of reproductive failure and normal pregnancy is seen in only 1.8%. We report the case of a 31-year-old woman with previous three molar pregnancies who on genetic testing was found to be compound heterozygous for pathogenic variants in the NLRP7 gene (c.2738A>G and c.2078G>C). Accordingly, the woman was counselled regarding assisted reproduction with oocyte donation for a normal pregnancy outcome. At present, the patient has an ongoing 5-month pregnancy through oocyte donation.

Recurrent Hydatidiform Moles: A Clinical Challenge-A Case Report and an Update on Management and Therapeutical Strategies

Hydatidiform mole, complete or partial (CHM/PHM), is the most common type of gestational trophoblastic disease (GTD), which is characterized by excessive trophoblastic proliferation and abnormal embryonic development. Some patients present with sporadic or familiar recurrent hydatidiform moles (RHMs), which are characterized by two or more episodes of the disease. A healthy 36-year-old woman was admitted to the Obstetrics and Gynecology Unit of Santa Maria Goretti Hospital, Latina, because of RHMs at 6 weeks of amenorrhea, with an obstetrical anamnesis of RHMs. We performed uterine dilatation and curettage with suction evacuation. The histological examination confirmed the diagnosis of PHM. The clinical follow-up was conducted according to recent guidelines on the diagnosis and management of GTD. After the return to the baseline values of the beta-human chorionic gonadotropin hormone, a combined oral contraceptive therapy was proposed, and the patient was invited to undergo in vitro fertilization (IVF) techniques, specifically oocyte donation, to reduce the possibility of similar future cases of RHMs. Although some etiopathogenetic mechanisms involved in RHMs are still unknown, all patients of childbearing age who are affected by this syndrome should be properly treated and directed towards a correct clinical path as IVF, to have a successful and safe pregnancy.

Biallelic NLRP7 variants in patients with recurrent hydatidiform mole: A review and expert consensus

Hydatidiform mole (HM) is an abnormal human pregnancy characterized by excessive growth of placental trophoblasts and abnormal early embryonic development. Following a first such abnormal pregnancy, the risk for women of successive molar pregnancies significantly increases. To date variants in seven maternal-effect genes have been shown to cause recurrent HMs (RHM). NLRP7 is the major causative gene for RHM and codes for NOD-like receptor (NLR) family pyrin domain containing 7, which belongs to a family of proteins involved in inflammatory disorders. Since its identification, all NLRP7 variants have been recorded in Infevers, an online registry dedicated to autoinflammatory diseases (https://infevers.umai-montpellier.fr/web/). Here, we reviewed published and unpublished recessive NLRP7 variants associated with RHM, scored their pathogenicity according to the American College of Medical Genetics classification, and recapitulated all functional studies at the level of both the patients and the conceptions. We also provided data on further variant analyses of 32 patients and genotypes of 36 additional molar pregnancies. This comprehensive review integrates published and unpublished data on NLRP7 and aims at guiding geneticists and clinicians in variant interpretation, genetic counseling, and management of patients with this rare condition.

Maternal genetic factors in the development of congenital heart defects

Congenital heart defects (CHDs) are among the most common, serious birth defects. However, the cause of CHDs is unknown for approximately half of affected individuals and there are few prevention strategies. Although not extensively investigated, maternal genes may contribute to CHD etiology by modifying the effects of maternal exposures (e.g. medications, nutrients), contributing to maternal phenotypes that are associated with an increased risk of CHDs in offspring (e.g. diabetes), or acting as maternal effect genes. Since maternal genes could serve as a target for the primary prevention of CHDs, efforts to further define the contribution of the maternal genome to CHD etiology are warranted.

Maternal effect genes: Update and review of evidence for a link with birth defects

Maternal effect genes (MEGs) encode factors (e.g., RNA) that are present in the oocyte and required for early embryonic development. Hence, while these genes and gene products are of maternal origin, their phenotypic consequences result from effects on the embryo. The first mammalian MEGs were identified in the mouse in 2000 and were associated with early embryonic loss in the offspring of homozygous null females. In humans, the first MEG was identified in 2006, in women who had experienced a range of adverse reproductive outcomes, including hydatidiform moles, spontaneous abortions, and stillbirths. Over 80 mammalian MEGs have subsequently been identified, including several that have been associated with phenotypes in humans. In general, pathogenic variants in MEGs or the absence of MEG products are associated with a spectrum of adverse outcomes, which in humans range from zygotic cleavage failure to offspring with multi-locus imprinting disorders. Although less established, there is also evidence that MEGs are associated with structural birth defects (e.g., craniofacial malformations, congenital heart defects). This review provides an updated summary of mammalian MEGs reported in the literature through early 2021, as well as an overview of the evidence for a link between MEGs and structural birth defects.

Recurrent Androgenetic Complete Hydatidiform Moles with p57KIP2-Positive in a Chinese Family

Androgenetic complete hydatidiform moles (CHMs) are associated with an increased risk of gestational trophoblastic neoplasia. P57^KIP2 expression in hydatidiform moles is thought to be a powerful marker for differentiating CHMs from partial hydatidiform moles (PHMs). However, since there are so few such families clinically, very few studies have addressed the importance of p57^KIP2-positive in the diagnosis and prognosis of CHM. This study aimed to emphasize the significance of the accurate diagnosis of rare CHM and careful follow-up. The classification of the hydatidiform mole was based on morphologic examination and p57^KIP2 expression was determined by p57^KIP2 immunohistochemical staining. Copy number variation sequencing was used to determine the genetic make-up of the mole tissues. In addition, the short tandem repeat polymorphism analysis was used to establish the parental origin of the moles. Finally, whole-exome sequencing was performed to identify the causal genetic variants associated with this case. In one Chinese family, the proband had numerous miscarriages throughout her two marriages. Morphologic evaluation and molecular genotyping accurately sub-classified two molar specimens as uniparental disomy CHM of androgenetic origin. Furthermore, p57^KIP2 expression was found in cytotrophoblasts and villous stromal cells. In the tissue, there were hyperplasia trophoblastic cells and heteromorphic nuclei. In this family, no deleterious variant genes associated with recurrent CHM were detected. It is important to evaluate the prognostic value of p57^KIP2 expression in androgenetic recurrent CHM. This knowledge may help to minimize erroneous diagnosis of CHMs as PHMs, as well as making us aware of the need to manage potential gestational trophoblastic neoplasia.

High-Risk Gestational Trophoblastic Neoplasia from a Homozygous NLRP7 Mutation

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NLRP7 germline mutation can result in high risk gestational trophoblastic neoplasia.

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No successful reproductive outcomes have been reported with homozygous NLRP7 mutation.

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Germline testing should be considered for patients presenting with recurrent gestational trophoblastic disease.

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Once an NLRP7 mutation is diagnosed, consultation with reproductive endocrinology is necessary to discuss future fertility.

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Further research is needed in rare cases regarding gestational trophoblastic neoplasia recurrence and reproductive outcomes.

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.