Identification of Multiple Gene Mutations Accounts for a new Genetic Architecture of Primary Ovarian Insufficiency.

CONTEXT: Idiopathic primary ovarian insufficiency (POI) is a major cause of amenorrhea and infertility. POI affects 1% of women before age 40 years, and several genetic causes have been reported. To date, POI has been considered a monogenic disorder. OBJECTIVE: The aim of this study was to identify novel gene variations and to investigate if individuals with POI harbor mutation in multiple loci. PATIENTS AND METHODS: One hundred well-phenotyped POI patients were systematically screened for variants in 19 known POI loci (and potential candidate genes) using next-generation sequencing. RESULTS: At least one rare protein-altering gene variant was identified in 19 patients, including missense mutations in new candidate genes, namely SMC1ß and REC8 (involved in the cohesin complex) and LHX8, a gene encoding a transcription factor. Novel or recurrent deleterious mutations were also detected in the known POI candidate genes NOBOX, FOXL2, SOHLH1, FIGLA, GDF9, BMP15, and GALT. Seven patients harbor mutations in two loci, and this digenicity seems to influence the age of symptom onset. CONCLUSIONS: Genetic anomalies in women with POI are more frequent than previously believed. Digenic findings in several cases suggest that POI is not a purely monogenic disorder and points to a role of digenicity. The genotype-phenotype correlations in some kindreds suggest that a synergistic effect of several mutations may underlie the POI phenotype.

New NOBOX mutations identified in a large cohort of women with primary ovarian insufficiency decrease KIT-L expression.

CONTEXT: Primary ovarian insufficiency (POI) is a major cause of anovulation and infertility in women. This disease affects 1% of women before 40 years, and several genetic causes have been reported. OBJECTIVE: The aim of the study was to evaluate the prevalence of NOBOX mutations in a new large cohort of women with POI and to characterize these variants and identify a NOBOX novel target gene. PATIENTS AND METHODS: A total of 213 unrelated patients with POI were screened for NOBOX mutations, and luciferase reporter assays were performed for the mutations identified. RESULTS: We reported 3 novel and 2 recurrent heterozygous missense NOBOX rare variants found in 12 patients but not in 724 alleles from ethnic-matched individual women with occurrence of menopause at a normal age. Their functional impact had been tested on the classic growth differentiation factor-9 (GDF9) promoter and on KIT-L, a new NOBOX target gene. The p.Gly91Thr, p.Gly111Arg, p.Arg117Trp, p.Lys371Thr, and p.Pro619Leu mutations were deleterious for protein function. CONCLUSIONS: In our series, 5.6% of the patients with POI displayed heterozygous NOBOX mutations. We demonstrate that KIT-L could be now a direct NOBOX target. These findings replicate the high prevalence of the association between the NOBOX rare variants and POI.