Susceptibility Gene Of Polycystic Ovary Syndrome And Its Pathogenic Mechanism Study

Chapter I Family-based Analysis of Eight Susceptibility Loci in Polycystic Ovary SyndromeBackground: Polycystic ovary syndrome(PCOS) is a complex endocrine disorder and is proposed to have genetic basis. Recently, a genome-wide association study(GWAS) identified eight new risk loci which independently associated with PCOS. To overcome spurious associations due to population stratification in GWAS, a family-based analysis was needed to validate the association.Methods: A total of 321 case-parent trios(963 participants) having a proband affected with PCOS were recruited for family-based study. The transmission disequilibrium test(TDT) was used to analyze the association between PCOS and ten single nucleotide polymorphisms(SNPs) mapped to eight new susceptibility loci.Results: Significant differences in transmission have been observed for the SNP rs2349415(P = 1.00E-04) and rs3802457(P = 1.00E-04), even after correction for multiply testing.Conclusions: Family-based analysis confirms that SNP rs2349415(located in FSHR gene) and rs3802457(located in C9orf3 gene), are significantly associated with PCOS.Chapter II Micro RNA-601 Contribute to the Pathogenesis of Polycystic Ovary Syndrome via Its Target SIRT1Background: Polycystic ovary syndrome(PCOS) is the most common cause of dysfunctional ovulation-affecting female fertility. In quest of causal variants, genomewide association studies(GWAS) have revealed new susceptibility loci for PCOS. However there has been no report about the role of micro RNAs(mi RNAs), located in the most validated candidate area, in the pathogenesis of PCOS.The purpose of this study is to analyze the differential expression of mi R-601 in PCOS patients and to investigate its possible mechanism to confer risk for PCOS.Methods: We quantified the expression of mi R-601 in peripheral blood and ovary granulosa cells of PCOS and controls and analyzed its correlation with different phenotype. We further explored the role of mi R-601 in vitro ovary cell culture system and its pathogenic mechanism.Results: The expression of mi R-601 was upregulated in PCOS patients’ in peripheral blood and ovary granulosa cells compared with normally-ovulating women, and was closely related to LH, T, E2 and AMH, respectively. In vitro, mi R-601 promoted testosterone synthesis in theca-intertitial cell, while had no significant effect on estradiol level in granulosa cells. Mi R-601 targeted the 3’ untranslated region(3’-UTR) of SIRT1 m RNA through a highly conserved binding site. SIRT1 activator and inhibitor also regulate testosterone synthesis.Conclusion: Our study provides evidence that the dysregulated expression of mi R-601 might contribute to the pathophysiology of PCOS, like abnormal steroidogenesis, possibly via its target gene SIRT1. This study also suggest the mi RNA located in the GWAS candidate area had an important role in the pathogenesis of PCOS.Chapter III An Association Study between USP34 and Polycystic Ovary SyndromeBackground: Polycystic ovary syndrome(PCOS) is a complex multifactor disorder and genetic factors have been implicated in its pathogenesis. Our previous genomewide association study(GWAS) had identified allele frequencies in several single nucleotide polymorphisms(SNPs) in gene USP34(Ubiquitin-Specific Protease) were significantly different between PCOS cases and controls. This study was aimed to replicate the previous results in another independent cohort.Methods: 1218 PCOS cases and 1057 controls were recruited. Genotyping of two SNPs(rs17008097 and rs17008940) in USP34 gene were performed by Taq Man-MGB probe assay and genotype-phenotype analysis was conducted subsequently.Results: The differences of allele or genotype frequencies were not significant statistically between PCOS and controls, even after age and BMI adjustment. For clinical and metabolic features(LH, T and HOMA-IR) analysis in PCOS cases, no statistical differences among three genotypes of rs17008097 and rs17008940 were found. However, rs17008940 was shown to be slightly associated with BMI in PCOS cases rather than in controls, even after age adjustment(TC vs CC P = 0.006, OR = 1.042, 95%CI 1.012-1.073; TT vs CC P = 0.037, OR = 1.050, 95%CI 1.003-1.100).Conclusions: USP34 gene polymorphisms(rs17008097 and rs17008940) may not be associated with PCOS in the Han Chinese women.