SCREENING OF SIX CANDIDATE GENES FOR PRIMARY OVARIAN INSUFFICIENCY (POI) IN A LARGE CAUCASIAN FEMALE POPULATION

Primary Ovarian Insufficiency (POI) is a heterogeneous disorder that occurs with Primary or Secondary Amenorrhea (PA or SA, respectively) in 1% of women before 40 years, with elevated serum gonadotropins and accounts for about 10% of all female infertility. POI etiology is still largely unknown but the common finding of familial cases together with the relatively high frequency of associated chromosomal abnormalities suggests a major genetic component. In few cases genes responsible for POI have been identified. A relevant role in the pathogenesis of POI has been demonstrated for the FMR1 premutations and BMP15 mutations, identified in the larger sub-group of patients (10% and 2-4%, respectively). Numerous other candidate genes that exert known hormonal effects (FSHR) or affecting follicle development (belonging to the GDFs/BMPs pathway) have been described but the frequency of their involvement is still uncharacterized in large POI series. We report the mutational analysis of six POI candidate genes: GDF9 (PA=36, SA=206), INHA (PA=24, SA=172), BMPR1B (PA=22, SA=38), FSHR (PA=14, SA=20), NOBOX (PA=10) and GPR3 (SA=83). Our cohort consists of a total of 251 POI Caucasian women (12-40 years, FSH>30U/L) affected with PA (44) or SA (207), in familiar (PA=13, SA=66) or sporadic (PA=31, SA=141) form. Genetic screening was performed by dHPLC and direct automatic sequencing of genomic DNA and revealed several novel variations in TGFbeta family correlated genes: a) two variants involving the proregion sequence of GDF9 gene (c.117G>T  p.E39D and c.362C>T  p.T121I) in 3 SA out of 242 cases; b) two missense variants in the BMPR1B signal peptide sequence (c.11G>A  p.R4Q and c.16G>A  p.A6T) in 3 SA and a 3’UTR alteration (c.*9G>C) in 2 PA and 1 SA out of 60 cases; c) a novel missense substitution (c.832C>T  p.R278W) in INHA gene in 1/196 cases. All identified variants are in the heterozygous state and none was found in 100 control women with physiological menopause. No variants of FSHR, NOBOX and GPR3 genes were found in our cohort. In conclusion, we performed a candidate gene approach leading to the identification of several new variants associated with POI in genes belonging to the BMP/GDF pathway. Alterations in several TGFbeta family correlated genes with a fundamental role in control of ovarian function may be of relevance for the prediction of disease risk.