Genetic landscape of a large cohort of Primary Ovarian Insufficiency: New genes and pathways and implications for personalized medicine.

BACKGROUND: Primary Ovarian Insufficiency (POI), a public health problem, affects 1-3.7% of women under 40 yielding infertility and a shorter lifespan. Most causes are unknown. Recently, genetic causes were identified, mostly in single families. We studied an unprecedented large cohort of POI to unravel its molecular pathophysiology. METHODS: 375 patients with 70 families were studied using targeted (88 genes) or whole exome sequencing with pathogenic/likely-pathogenic variant selection. Mitomycin-induced chromosome breakages were studied in patients' lymphocytes if necessary. FINDINGS: A high-yield of 29.3% supports a clinical genetic diagnosis of POI. In addition, we found strong evidence of pathogenicity for nine genes not previously related to a Mendelian phenotype or POI: ELAVL2, NLRP11, CENPE, SPATA33, CCDC150, CCDC185, including DNA repair genes: C17orf53(HROB), HELQ, SWI5 yielding high chromosomal fragility. We confirmed the causal role of BRCA2, FANCM, BNC1, ERCC6, MSH4, BMPR1A, BMPR1B, BMPR2, ESR2, CAV1, SPIDR, RCBTB1 and ATG7 previously reported in isolated patients/families. In 8.5% of cases, POI is the only symptom of a multi-organ genetic disease. New pathways were identified: NF-kB, post-translational regulation, and mitophagy (mitochondrial autophagy), providing future therapeutic targets. Three new genes have been shown to affect the age of natural menopause supporting a genetic link. INTERPRETATION: We have developed high-performance genetic diagnostic of POI, dissecting the molecular pathogenesis of POI and enabling personalized medicine to i) prevent/cure comorbidities for tumour/cancer susceptibility genes that could affect life-expectancy (37.4% of cases), or for genetically-revealed syndromic POI (8.5% of cases), ii) predict residual ovarian reserve (60.5% of cases). Genetic diagnosis could help to identify patients who may benefit from the promising in vitro activation-IVA technique in the near future, greatly improving its success in treating infertility. FUNDING: Université Paris Saclay, Agence Nationale de Biomédecine.

BRCA1/2 gene mutations do not affect the capacity of oocytes from breast cancer candidates for fertility preservation to mature in vitro.

STUDY QUESTION: Are the maturation rates of oocytes recovered from small antral follicles different between breast cancer patients presenting with or without a BRCA 1/2 gene mutation? SUMMARY ANSWER: BRCA 1/2 gene mutations do not affect the capacity of oocytes from breast cancer candidates for fertility preservation to mature in vitro. WHAT IS KNOWN ALREADY: Mutations in the BRCA1 and BRCA2 genes are associated with an increased risk for developing breast and ovarian cancer. Controversy exists about fertility and ovarian reserve in BRCA mutation carriers. Studies suggest that these patients may have low ovarian reserve and poor response to ovarian stimulation. The impaired ability of the mutated BRCA gene to repair double-strand breaks in DNA may prompt oocyte aging, apoptosis and meiotic errors. IVM of oocytes retrieved at germinal vesicle stage, followed by vitrification of metaphase II (MII) oocytes has recently emerged as an option for young women seeking fertility preservation, when ovarian stimulation is unfeasible. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study involving 329 breast cancer candidates for fertility preservation using IVM between January 2014 and December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Inclusion criteria were: age 18-40 years; two ovaries present; no history of chemotherapy; test for BRCA 1/2 mutations performed. Before immature oocyte retrieval, all follicles measuring 2-9 mm in diameter were precisely counted on both ovaries and serum anti-Müllerian hormone (AMH) was measured irrespective of the phase of the cycle. Number of cumulus oocyte complexes (COC) retrieved, maturation rate and number of MII oocytes cryopreserved were compared according to BRCA mutation status. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, BRCA-mutated women (n = 52) and BRCA-negative women (n = 277) were comparable in terms of age (31.7 ± 3.9 versus 32.3 ± 3.8 years, respectively, P = 0.3), BMI (23.4 ± 4.7 versus 22.6 ± 3.7 kg/m2, respectively, P = 0.3) and ovarian reserve tests (antral follicle count: 20.5 ± 11.4 versus 21.7 ± 12.1 follicles, P = 0.5; serum AMH levels: 3.6 ± 2.9 versus 4.1 ± 3.6 ng/ml, P = 0.3, respectively). The number of COCs retrieved did not differ significantly between both groups (8.9 ± 6.9 versus 9.9 ± 8.1 oocytes, P = 0.5). After similar IVM rates (67 ± 24 versus 62 ± 23%, P = 0.2), the number of MII oocytes cryopreserved was similar in patients presenting BRCA mutation or not (5.1 ± 3.8 versus 6.1 ± 5.1, P = 0.1, respectively). LIMITATIONS, REASONS FOR CAUTION: Given the low incidence of the mutation, these preliminary findings should be confirmed by further multi-center studies. WIDER IMPLICATIONS OF THE FINDINGS: Although BRCA mutations are known to alter DNA repair mechanism, it does not seem to impair oocyte capacity to mature in vitro. STUDY FUNDING/COMPETING INTEREST(s): None.