P-204: Evaluation of FMR1 Gene Regulatory Region for The Epigenetic Mark of H3K9 Acetylation in Blood Cells of Patients with Diminished Ovarian Reserve Reffered to Royan Institute

Background: Diminished ovarian reserve (DOR) is a heterogeneous disorder causing infertility, characterized by a decreased number of oocytes and high FSH level, the genetic cause of which is still unknown. The association between FMR1 premutations(50-200 CGG repeats) and the premature ovarian failure( POF) disease has suggested that FMR1 gene acts as a risk factor for POF and recently for DOR pathogenesis. Expansion of CGG repeat numbers results in silencing of FMR1 gene expression. This expansion triggers methylation of FMR1 CpG island, hypoacetylation of associated histones, and chromatin condensation, all characteristics of a transcriptionally inactive gene. This study aimed to evaluate the acetylation level of lysine 9 of histone 3(H3K9ac), on the regulatory region of FMR1 gene in blood cells of patients with DOR Materials and Methods: Local ethical approval was gained for this study and informed consent was given by patients. Blood samples were collected from 30 infertile women referred to Royan Institute. These samples distributed into two groups (DOR patients and non-DOR patients), based on the number of follicles, serum FSH level and number of CGG repeats. The patients group included samples that had higher levels of FSH (>11), number of CGG repeats between 50-200 and follicles number lower than three. Each group contained 15 samples. Using chromatin immunoprecipitation(ChIP) coupled with real-time PCR, H3K9 acetylation changes in the promoter and exon1 regions of FMR1 gene were quantitatively compared Results: The data clearly demonstrated that incorporation of H3K9ac were significantly higher in the regulatory region of FMR1 in DOR patient in comparison with non- DOR patients Conclusion: Our experiments indicate that H3K9 acetylation can be considered as a dynamic epigenetic switch in regulation of FMR1 gene in DOR, causing female infertility. This indicates that the promoter and exon 1 regions are the critical sites for epigenetic regulation of the FMR1 gene in DOR.