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 SMC1l3 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, BMP1 5, 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.