Candidate gene analyses in Caucasian patients with Primary Ovarian Insufficiency (POI)

Primary ovarian insufficiency (POI) is a heterogeneous disorder characterized by primary (PA) or secondary (SA) amenorrhea associated with increased levels of gonadotropins. POI affects about 1% of women before the age of 40 years. A major genetic component has been suggested for idiopathic POI due to the frequent familiarity for this defect. Indeed, FMR1 premutations can be found in 10–15% and BMP15 mutations in 2–5% of POI patients. Numerous other candidate genes have been described but the frequency of their involvement is still uncharacterized in large POI series. Here, we report the mutational analysis of six candidate genes: GDF9 (PA=36, SA=206), INHA (PA=24, SA=172), BMPR1B (PA=18, SA=30), FSHR (PA=14, SA=7), NOBOX (PA=10) and GPR3 (SA=83). Our cohort included a total of 251 POI Caucasian women (12–40 years, FSH>30 U/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; 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; c.16G>A → p.A6T) in 3 SA and a 3′UTR alteration (c.*9G>C) in 2 PA and 1 SA out of 48 cases; c) a missense substitution (c.832C>T → p.R278W) in INHA gene in 1/196 cases. All identified variants were in the heterozygous state and none was found in 100 control alleles. No variations were found in FSHR, NOBOX and GPR3 genes. In conclusion, we used a candidate gene approach leading to the identification of several new variants associated with POI. Alterations in several TGFbeta family correlated genes with a prevailing ovarian expression may frequently contribute to POI pathogenesis.