Clinicopathologic characteristics and subsequent pregnancy outcome in 139 complete hydatidiform moles

Perinatal outcomes of first pregnancy after chemotherapy for gestational trophoblastic neoplasia: a systematic review of observational studies and meta-analysis

OBJECTIVE

To assess perinatal outcomes of first pregnancy after remission from gestational trophoblastic neoplasia and the impact of the time between the end of chemotherapy and the subsequent pregnancy.

DATA SOURCES

The Medical Subject Headings related to perinatal outcomes, chemotherapy, and gestational trophoblastic neoplasia were used alone or in combination to retrieve relevant articles. We searched all references registered until April, 2019 in Embase, LILACS, MEDLINE, the Cochrane Central Register of Controlled Trials, and Web of Science.

STUDY ELIGIBILITY CRITERIA

We included any observational or interventional studies that evaluated perinatal outcomes of first pregnancy after chemotherapy for gestational trophoblastic neoplasia. Animal studies, narrative reviews, expert opinions, and previous treatments with potential risks for future perinatal outcomes which may introduce confounding bias were excluded.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two reviewers independently screened all identified references for eligibility and data extraction. Methodological quality and bias of included studies were assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from the National Institutes of Health. For the meta-analysis, the measures of association were calculated using bivariate random-effects models. Statistical heterogeneity was evaluated with I² statistics and explored through sensitivity analysis. Publication bias was assessed by visual inspection of the funnel plot or Egger's test, according to the number of articles included. For all analyses, a P value of <.05 indicated statistical significance. This study was registered on PROSPERO (CRD42018116513).

RESULTS

A total of 763 studies were identified after literature search and 23 original studies were included in the systematic review and in the meta-analysis. The combined data from the subgroup meta-analysis (outcome vs time after chemotherapy) showed an incidence of spontaneous abortion of 15.28% (95% confidence interval, 12.37-18.74; I²=73%), 3.30% of malformation (95% confidence interval, 2.27-4.79; I²=31%), 6.19% of prematurity (95% confidence interval, 5.03-7.59; I²=0), and 1.73% of stillbirth (95% confidence interval, 1.17-2.55; I²=0%). These results were not influenced by the time between the end of chemotherapy and the subsequent pregnancy in most of the studied outcomes, including malformation (P=.14, I²=31%), prematurity (P=.46, I²=0), and stillbirth (P=.66, I²=0). However, there was a higher occurrence of spontaneous abortion (P<.01, I²=73%) in pregnancies that occurred ≤6 months after chemotherapy.

CONCLUSION

Chemotherapy for gestational trophoblastic neoplasia does not appear to increase the chance of unfavorable perinatal outcomes, except for the higher occurrence of spontaneous abortion in pregnancies occurring ≤6 months after chemotherapy.

Obstetrics outcomes after complete and partial molar pregnancy: Review of the literature and meta-analysis

The hydatidiform mole is a rare gynecological disease rising from the trophoblastic. Post-molar pregnancies have an extremely variable course, varying from repeated abortions, stillbirths, preterm births, live births, or recurring in further molar pregnancies. Literature on obstetric outcomes following molar pregnancy is poor, often including monocentric studies, and with data collected from national databases. This review and meta-analysis aim to analyze the obstetric outcomes after conservative management of complete (CHM) and partial (PHM) molar pregnancies. The meta-analysis was performed following the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) and the preferred reporting items for systematic reviews and meta-analyses statement (PRISMA). Six studies met the inclusion. Of the total 25,222 patients, 13,129 complete (52.1 %) and 12,093 partial (47.9 %) molar pregnancies were included. Live births rate after CHM was statistically higher (p = 0.002) compared to the live births after PHM (53.6 % vs. 51.0 %, 3266 vs. 1807 cases, respectively). Studies showed heterogeneity I² = 57.7 %, pooled proportion = 0.2 %, and 95 % Confidence Interval (CI) 0.6 to 0.9. No statistically significant difference was demonstrated for ectopic pregnancies (p = 0.633), miscarriage (p = 0.637), preterm birth (p = 0.865), stillbirth (p = 0.911), termination of pregnancy (p = 0.572), and complete molar recurrence (p = 0.580) after CHM and PHM. Partial molar recurrence occurred more frequently after PHM than CHM (0.4 % vs. 0.3 %, 52 vs. 37 cases, respectively, p = 0.002). Careful counseling on the obstetric subsequent pregnancies outcomes should be provided to patients eager for further pregnancy and further studies are needed to confirm these results.

Molar pregnancy after in vitro fertilization with euploid single embryo transfer

Objective

To describe a case of molar pregnancy after in vitro fertilization (IVF) resulting from the transfer of a euploid embryo derived from a monopronuclear zygote.

Design

Case report and review of the literature.

Setting

Private practice IVF center.

Patients

A 42-year-old woman, gravida 3 para 0, with advanced maternal age and infertility who underwent IVF.

Interventions

Preimplantation genetic testing for aneuploidy using next-generation sequencing, single frozen euploid blastocyst transfer, and medical management of suspected missed abortion.

Main Outcome Measures

Genetic examination of products of conception and correlation with embryonic preimplantation genetic testing for aneuploidy results.

Results

Transfer of the euploid embryo derived from an abnormally fertilized oocyte (monopronuclear zygote) resulted in a clinical pregnancy suspected to be a missed abortion. Products of conception collected after medical management of the suspected missed abortion were analyzed using next-generation sequencing with the report "46,XX complete molar pregnancy".

Conclusions

To our knowledge, this is the first account of a complete molar pregnancy resulting from the transfer of a reported euploid embryo, highlighting the importance of understanding the limitations of genetic testing platforms in the setting of abnormally fertilized oocyte-derived embryos.

The management of hydatidiform mole using prophylactic chemotherapy and hysterectomy for high-risk patients decreased the incidence of gestational trophoblastic neoplasia in Vietnam: a retrospective observational study

The management of hydatidiform mole (HM) and the incidence of post-molar gestational trophoblastic neoplasia (GTN) in Vietnam has not been reported to date. This study aimed to study the incidence of HM and post-molar GTN and identify factors associated with post-molar GTN at a tertiary hospital in Vietnam. Five hundred and eighty-four patients who were treated for HM at Tu Du Hospital between January and December 2010 were included in this study. The mean age and gestational age at the first evacuation were 28.8 years old and 11.0 weeks, respectively. After the initial evacuation and pathological examination, 87 patients who were older than 40 or did not wish to have children underwent a hysterectomy, while the others underwent second curettage. All 472 patients who had human chorionic gonadotropin (hCG) ≥ 100,000 IU/L before treatment received one cycle of methotrexate with folinic acid as prophylactic chemotherapy. The incidence of HM was 11.1 per 1,000 deliveries; 47 patients (8.0%) developed post-molar GTN. Gestational week, hCG level at one week after the first evacuation, and pathological remnants were significantly associated with the development of post-molar GTN. The results of this study suggest that prophylactic chemotherapy and hysterectomy may be useful for high-risk HM patients to reduce post-molar GTN in settings in which the risk of post-molar GTN and loss to follow-up after HM are greater and hCG measurements and appropriate GTN treatments are unavailable. However, future studies on the long-term outcomes and side effects of prophylactic therapies on HM are required.

Evaluation of a routine second curettage for hydatidiform mole: a cohort study

OBJECTIVE

The aim of this study was to evaluate routine second curettage for hydatidiform mole (HM) by comparing the characteristics and outcomes of developing gestational trophoblastic neoplasia (GTN).

STUDY DESIGN

This was a cohort study including 173 patients diagnosed with HM between January 2002 and August 2019 who were followed up at Nagoya University Hospital, Japan. After an evacuation, 105 and 68 patients were managed with the routine method (routine group) and elective method (elective group) for a second curettage, respectively. The routine second curettage was performed around 7 days after the first evacuation. Patients in the elective group underwent a second curettage if there was ultrasonographic evidence of molar remnants in the uterine cavity. Socio-clinical factors were retrospectively compared between the routine and elective groups, and between patients showing regression and those who developed GTN.

RESULTS

The incidence of GTN was 15.2% in the routine group and 20.6% in the elective group, and the difference was not significant (P = 0.364). The median GTN risk score was significantly higher in the routine group than in the elective group (P = 0.033). Presence of a complete HM, gestational age, and a pre-treatment human chorionic gonadotropin level of ≥ 200,000 mIU/mL were independent risk factors for GTN in molar patients.

CONCLUSION

The incidence of GTN was unchanged but the risk score of GTN was higher in the routine group than in the elective group. Routine second curettage may not be necessary, but further study will be needed to confirm this.

Gestational Trophoblastic Neoplasia After Human Chorionic Gonadotropin Normalization Following Molar Pregnancy

OBJECTIVE

To estimate the incidence of gestational trophoblastic neoplasia following complete and partial molar pregnancy after reaching normal human chorionic gonadotropin (hCG) levels to guide evidence-based follow-up recommendations.

DATA SOURCES

MEDLINE, EMBASE, Web of Science, POPLINE, Cochrane, and ClinicalTrials.gov were searched from inception to November 2018, using the intersection of "gestational trophoblastic disease," "molar pregnancy," and "human chorionic gonadotropin" themes.

METHODS OF STUDY SELECTION

Search results were screened to identify cohort studies of molar pregnancy reporting gestational trophoblastic neoplasia development, with at least 6 months of intended normal hCG follow-up.

TABULATION, INTEGRATION, AND RESULTS

Two reviewers independently identified articles for inclusion. Data were extracted using a standardized form. For meta-analysis, cumulative incidence of gestational trophoblastic neoplasia, with CIs by the Agresti-Coull method, and pooled risk ratios (RRs) comparing complete and partial mole were calculated. Among the 19 eligible studies that reported adequate data for inclusion in the primary meta-analysis, we found low incidence of gestational trophoblastic neoplasia after normal hCG level following both complete mole (64/18,357, 0.35%, 95% CI 0.27-0.45%), and partial mole (5/14,864, 0.03%, 95% CI 0.01-0.08%). There was a significantly higher risk of gestational trophoblastic neoplasia after complete compared with partial molar pregnancy (RR 4.72, 95% CI 1.81-12.3, P=.002). Among gestational trophoblastic neoplasia cases after normal hCG level following complete mole, 89.6% occurred when the time from evacuation to normalization was 56 days or longer, and 60.7% were diagnosed beyond the commonly recommended 6-month surveillance interval. Sensitivity analyses, including those limiting to studies at low risk of bias, did not significantly affect results. We found an overall incidence of gestational trophoblastic neoplasia of 15.7% for complete mole (1,354/8,611, 95% CI 15.0-16.5%) and 3.95% for partial mole (221/5,593, 95% CI 3.47-4.50%).

CONCLUSION

Gestational trophoblastic neoplasia development after normal hCG level following molar pregnancy is rare. Recommendations for frequency and duration of hCG follow-up can be minimized to lessen burden on patients and informed by the type of molar pregnancy and time interval from uterine evacuation to hCG normalization.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42019116414.

Gestational Trophoblastic Neoplasia From Genetically Confirmed Hydatidiform Moles: Prospective Observational Cohort Study

OBJECTIVE

The aim of this study was to evaluate the incidence and risk factors of gestational trophoblastic neoplasia (GTN) from hydatidiform moles (HMs) cytogenetically diagnosed in a prospective cohort setting.

METHODS

The prospective observational cohort study included cases of cytogenetically defined molar pregnancies, which were diagnosed by a multiplex short tandem repeat polymorphism analysis. Cases were classified as androgenetic complete HMs (CHMs), diandric monogynic triploid partial HMs (PHMs), or biparental abortion. Gestational trophoblastic neoplasia was diagnosed according to the International Federation of Gynecology and Obstetrics 2000 criteria. Incidences for each category, that is, CHM, PHMs, and biparental abortion, were calculated. Clinical variables (age, partner age, gravidity, parity, height, weight, BMI, and gestational age) and laboratory data (serum human chorionic gonadotropin [hCG], white blood cell count, hemoglobin, and platelet count) were compared between spontaneous remission cases and GTN cases in androgenetic CHMs.

RESULTS

Among 401 cases, 380 were classified as follows: 232 androgenetic CHMs, 60 diandric monogynic PHMs, and 88 biparental abortions. A total of 35 cases (15.1%) of CHMs, but only 1 case of PHM (1.7%) and no biparental abortions, exhibited progression to GTN. The hCG value before evacuation was significantly higher in GTN cases than in spontaneous remission cases (P = 0.001, Kruskal-Wallis test). Patient age was also significantly higher in GTN cases than in spontaneous remission cases (P = 0.002, Student t test).

CONCLUSIONS

Under the cohort cytogenetic diagnosis setting, the traditional risk factors for GTN after molar pregnancy, hCG value before evacuation and age, were confirmed in androgenetic CHMs. The risk of GTN was lower for PHMs than for CHMs. However, 1 patient with cytogenetic PHMs developed into GTN.

Causative Mutations and Mechanism of Androgenetic Hydatidiform Moles

Androgenetic complete hydatidiform moles are human pregnancies with no embryos and affect 1 in every 1,400 pregnancies. They have mostly androgenetic monospermic genomes with all the chromosomes originating from a haploid sperm and no maternal chromosomes. Androgenetic complete hydatidiform moles were described in 1977, but how they occur has remained an open question. We identified bi-allelic deleterious mutations in MEI1, TOP6BL/C11orf80, and REC114, with roles in meiotic double-strand breaks formation in women with recurrent androgenetic complete hydatidiform moles. We investigated the occurrence of androgenesis in Mei1-deficient female mice and discovered that 8% of their oocytes lose all their chromosomes by extruding them with the spindles into the first polar body. We demonstrate that Mei1^-/- oocytes are capable of fertilization and 5% produce androgenetic zygotes. Thus, we uncover a meiotic abnormality in mammals and a mechanism for the genesis of androgenetic zygotes that is the extrusion of all maternal chromosomes and their spindles into the first polar body.

The genetics of recurrent hydatidiform moles: new insights and lessons from a comprehensive analysis of 113 patients

Hydatidiform mole is an aberrant human pregnancy characterized by early embryonic arrest and excessive trophoblastic proliferation. Recurrent hydatidiform moles are defined by the occurrence of at least two hydatidiform moles in the same patient. Fifty to eighty percent of patients with recurrent hydatidiform moles have biallelic pathogenic variants in NLRP7 or KHDC3L. However, in the remaining patients, the genotypic types of the moles are unknown. We characterized 80 new hydatidiform mole tissues, 57 of which were from patients with no mutations in the known genes, and we reviewed the genotypes of a total of 123 molar tissues. We also reviewed mutation analysis in 113 patients with recurrent hydatidiform moles. While all hydatidiform moles from patients with biallelic NLRP7 or KHDC3L mutations are diploid biparental, we demonstrate that those from patients without mutations are highly heterogeneous and only a small minority of them are diploid biparental (8%). The other mechanisms that were found to recur in patients without mutations are diploid androgenetic monospermic (24%) and triploid dispermic (32%); the remaining hydatidiform moles were misdiagnosed as moles due to errors in the analyses and/or their unusual mechanisms. We compared three parameters of genetic susceptibility in patients with and without mutations and show that patients without mutations are mostly from non-familial cases, have fewer reproductive losses, and more live births. Our data demonstrate that patients with recurrent hydatidiform moles and no mutations in the known genes are, in general, different from those with mutations; they have a milder genetic susceptibility and/or a multifactorial etiology underlying their recurrent hydatidiform moles. Categorizing these patients according to the genotypic types of their recurrent hydatidiform moles may facilitate the identification of novel genes for this entity.

Early Pregnancy Losses: Review of Nomenclature, Histopathology, and Possible Etiologies

Miscarriage is a frequent complication of human pregnancy: ∼50% to 70% of spontaneous conceptions are lost prior to the second trimester. Etiology of miscarriage includes genetic abnormalities, infections, immunological and implantation disorders, uterine and endocrine abnormalities, and lifestyle factors. Given such variability, knowledge regarding causes, pathophysiological mechanisms, and morphologies of primary early pregnancy loss has significant gaps; often, pregnancy losses remain unexplained. Pathologic evaluation of miscarriage tissue is an untapped source of knowledge. Although miscarriage specimens comprise a significant part of pathologists' workload, information reported from these specimens is typically of minimal clinical utility for delineating etiology or predicting recurrence risk. Standardized terminology is available, though not universally used. We reintroduce the terminology and review new information about early pregnancy losses and their morphologies. Current clinical terminology is inconsistent, hampering research progress. This review is a resource for diagnostic pathologists studying this complex problem.

Implementation and Monitoring of a Gestational Trophoblastic Disease Management Program in a Tertiary Hospital in Morocco: Opportunities and Challenges

Objective. Gestational Trophoblastic Disease (GTD) management requires clear guidelines for diagnosis, treatment, and follow-up. Unequal management skills among practitioners, inadequate treatment, irregular surveillance, and drop-out are common in resource-limited settings and can lead to life-threatening complications and morbidities. To address these challenges, we implemented a GTD Management Program at the National Center for Reproductive Health in Rabat, Morocco. Methods and Program Description. In-depth review of management protocols was carried out, and concise guidelines were developed, with targeted training for physicians. A physical space and a weekly fixed GTD consultation were set, and personalized follow-up was established for each patient. An electronic database documenting patients' surveillance was created, allowing immediate outreach in case of irregularities. Results. During the period from October 2013 to June 2016, 50 patients were included in this program. Patients' mean age was 33 years; 92% were illiterate and 82% had a low socioeconomic status. 68% had a positive evolution, while 32% developed gestational trophoblastic neoplasia, requiring 2 to 6 chemotherapy sessions. An average of 2.8 outreach reminders were necessary for each patient. 94% fully adhered to the program of care and completed properly their follow-up. Conclusion. Implementation and thorough monitoring of this program helped optimize patients' care, avoiding drop-outs and delays in diagnosing and treating complications.

The genomic architecture of NLRP7 is Alu rich and predisposes to disease-associated large deletions

NLRP7 is a major gene responsible for recurrent hydatidiform moles. Here, we report 11 novel NLRP7 protein truncating variants, of which five deletions of more than 1-kb. We analyzed the transcriptional consequences of four variants. We demonstrate that one large homozygous deletion removes NLRP7 transcription start site and results in the complete absence of its transcripts in a patient in good health besides her reproductive problem. This observation strengthens existing data on the requirement of NLRP7 only for female reproduction. We show that two other variants affecting the splice acceptor of exon 6 lead to its in-frame skipping while another variant affecting the splice donor site of exon 9 leads to an in-frame insertion of 54 amino acids. Our characterization of the deletion breakpoints demonstrated that most of the breakpoints occurred within Alu repeats and the deletions were most likely mediated by microhomology events. Our data define a hotspot of Alu instability and deletions in intron 5 with six different breakpoints and rearrangements. Analysis of NLRP7 genomic sequences for repetitive elements demonstrated that Alu repeats represent 48% of its intronic sequences and these repeats seem to have been inserted into the common NLRP2/7 primate ancestor before its duplication into two genes.

Comprehensive genotype-phenotype correlations between NLRP7 mutations and the balance between embryonic tissue differentiation and trophoblastic proliferation

BACKGROUND

Hydatidiform mole (HM) is a human pregnancy with excessive trophoblastic proliferation and abnormal embryonic development that may be sporadic or recurrent. In the sporadic form, the HM phenotype is driven by an abnormal ratio of paternal to maternal genomes, whereas in the recurrent form, the HM phenotype is caused by maternal-recessive mutations, mostly in NLRP7, despite the diploid biparental origin of the HM tissues. In this study, we characterised the expression of the imprinted, maternally expressed gene, CDKN1C (p57(KIP2)), the genotype, and the histopathology of 36 products of conception (POC) from patients with two defective alleles in NLRP7 and looked for potential correlations between the nature of the mutations in the patients and the various HM features.

METHODS/RESULTS

We found that all the 36 POCs are diploid biparental and have the same parental contribution to their genomes. However, some of them expressed variable levels of p57(KIP2) and this expression was strongly associated with the presence of embryonic tissues of inner cell mass origin and mild trophoblastic proliferation, which are features of triploid partial HMs, and were associated with missense mutations. Negative p57(KIP2) expression was associated with the absence of embryonic tissues and excessive trophoblastic proliferation, which are features of androgenetic complete HMs and were associated with protein-truncating mutations.

CONCLUSIONS

Our data suggest that NLRP7, depending on the severity of its mutations, regulates the imprinted expression of p57(KIP2) and consequently the balance between tissue differentiation and proliferation during early human development. This role is novel and could not have been revealed by any other approach on somatic cells.

NLRP7 and the Genetics of Hydatidiform Moles: Recent Advances and New Challenges

NOD-like receptor proteins (NLRPs) are emerging key players in several inflammatory pathways in Mammals. The first identified gene coding for a protein from this family is Nlrp5 and was originally called Mater for “Maternal Antigen That Mouse Embryos Require” for normal development beyond the two-cell stage. This important discovery was followed by the identification of other NLRPs playing roles in inflammatory disorders and of the first maternal-effect gene in humans, NLRP7, which is responsible for an aberrant form of human pregnancy called hydatidiform mole (HM). In this review, we recapitulate the various aspects of the pathology of HM, highlight recent advances regarding NLRP7 and its role in HM and related forms of reproductive losses, and expand our discussion to other NLRPs with a special emphasis on those with known roles in mammalian reproduction. Our aim is to facilitate the genetic complexity of recurrent fetal loss in humans and encourage interdisciplinary collaborations in the fields of NLRPs and reproductive loss.

Report of four new patients with protein-truncating mutations in C6orf221/KHDC3L and colocalization with NLRP7

To date, two maternal-effect genes have been shown to have causative roles in recurrent hydatidiform moles (RHMs); NLRP7 that is mutated in 48-60% of patients with RHMs and C6orf221 (HUGO-approved nomenclature is now KHDC3L), a recently identified gene, that is mutated in 14% of patients with RHMs who are negative for NLRP7 mutations. We sequenced KHDC3L in 97 patients with RHMs and reproductive loss who are mostly negative for NLRP7 mutations. We identified three unrelated patients, each homozygous for one of the two protein-truncating mutations, a novel 4-bp deletion resulting in a frameshift, c.299_302delTCAA, p.Ile100Argfs*2, and a previously described 4-bp deletion, c.322_325delGACT, p.Asp108Ilefs*30, transmitted on a shared haplotype to three patients from different populations. We show that five HM tissues from one of these patients are diploid and biparental similar to HMs from patients with two defective NLRP7 mutations. Using immunofluorescence, we show that KHDC3L protein displays a juxta perinuclear signal and colocalizes with NLRP7 in lymphoblastoid cell lines from normal subjects. Using cell lines from patients, we demonstrate that the KHDC3L mutations do not change the subcellular localization of the protein in hematopoietic cells. Our data highlight the similarities between the two causative genes for RHMs, KHDC3L and NLRP7, in their subcellular localization, the parental contribution to the HM tissues caused by them, and the presence of several founder mutations and variants in both of them indicating positive selection and adaptation.

Hydatidiform mole mimicking an enlarged uterine fibromyoma four months after ART

Hydatidiform mole is a pregnancy disorder, of a benign nature. We present a case of molar tissue within a uterine myoma, the first such entity reported in the literature. In May 2006, a thirty-eight year old infertility patient was admitted for myomectomy. She had anamnesis for chronic pelvic inflammatory disease and surgeries performed for tubal pregnancies. After the sixth intracytoplasmal spermatozoa injection procedure performed in January 2006, she conceived, but curettage was performed in March 2006 for a missed abortion. Following the routine preoperative evaluation in May 2006, four months after the last artificial reproductive technology procedure, myomectomy was performed as uneventful operation, but the histological report appeared unusual, showing degenerated chorionic villi within the uterine myoma. Molar tissue within uterine myoma might evolve even after artificial reproductive procedures. Furthermore, this finding might be misinterpreted as a fibromyoma degeneration. This is the first, and a unique case, of molar tissue within uterine myoma reported in the literature.

NLRP7 mutations in women with diploid androgenetic and triploid moles: a proposed mechanism for mole formation

Hydatidiform mole is an aberrant pregnancy with abnormal embryonic development and hydropic placental villi. Common moles are sporadic, not recurrent and affect one in every 1500 pregnancies in Western societies. Approximately, half of common moles are complete and mostly diploid androgenetic, whereas the remaining are partial and mostly triploid diandric. NLRP7 has been found to be responsible for a recurrent form of molar pregnancies. Recently, we showed that patients with NLRP7 mutations have an impaired inflammatory response to various stimuli. To date, molar tissues analyzed from patients with NLRP7 mutations have been found to be diploid and biparental. In this study, we report 10 new non-synonymous variants and one stop codon found in patients and not in controls. We demonstrate the presence of different types of moles, diploid biparental, diploid androgenetic, triploid and tetraploid conceptions, in patients with NLRP7 variants. We document in vitro and in vivo early embryo cleavage abnormalities in three patients. We propose a two-hit mechanism at the origin of androgenetic moles. This mechanism consists of variable degrees of early embryo cleavage abnormalities leading to chaotic mosaic aneuploidies, with haploid, diploid, triploid and tetraploid blastomeres. Surviving embryonic cells that reach implantation are then subject to the maternal immune response. Because of the patients' impaired inflammatory response, androgenetic cells, which are complete allograft, are able to grow and proliferate. In women with normal immune system, chaotic mosaic aneuploidies may also occur during early cleavage, however, androgenetic cells would die after implantation or stay undetected, confined to a small portion of the placenta.