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, 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: Two hundred thirteen unrelated patients with POI were screened for NOBOX mutations and luciferase reporter assays were performed for the identified mutations. Results: We reported 3 novel and 2 recurrent heterozygous missenses 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 has been tested on the classical growth differentiation factor-9 (GDF-9) 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 POI patients 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.