Polycystic ovary syndrome susceptibility single nucleotide polymorphisms in women with a single PCOS clinical feature

Abstract

Study question: What is the direct genetic contribution of the polycystic ovary syndrome (PCOS) susceptibility single nucleotide polymorphisms (SNPs), identified by previous genome-wide association studies (GWAS) to the definitive clinical features of the syndrome?

Summary answer: Each single PCOS clinical feature had a specific genetic association, and rs4385527 in the chromosome 9 open reading frame 3 (C9orf3) conferred a particular risk to the three defined PCOS clinical features in this study, which suggested its fundamental role in the etiology of PCOS.

What is known already: PCOS is a heterogeneous disorder characterized by anovulation (OA), hyperandrogenism (HA) and polycystic ovary morphology (PCOM). Two previous GWAS in China have identified 15 independent susceptibility SNPs related to PCOS (PCOS-SNPs). However, little is known about the candidate gene of each clinical feature.

Study design, size, duration: Case-control study. Three independent groups of women were recruited from 2010 to 2012: 746 subjects with OA only, 278 subjects with HA only and 536 subjects with PCOM only. A total of 1790 healthy women with none of the above pathological characteristics were also enrolled as control subjects during the same time period.

Participants/materials, setting, methods: All participants were women of reproductive age. Genotype and allelic frequencies of 15 PCOS-SNPs were determined in all subjects using direct sequencing and Sequenom Arrays. The allelic frequencies of each case group were compared with the controls.

Main results and the role of chance: After adjustment for age and BMI, variants in luteinizing hormone/choriogonadotropin receptor (LHCGR) (rs13405728), C9orf3 (rs4385527) and insulin receptor gene (INSR) (rs2059807) were strongly associated with OA (Padjust < 0.01, <0.001 and <0.05, respectively); rs4385527 in C9orf3 was strongly associated with HA (Padjust< 0.001); variants in the thyroid adenoma associated gene (THADA) (rs13429458 and rs12478601), DENN/MADD domain containing 1A (DENND1A)(rs10818854), and C9orf3 (rs4385527) were significantly associated with PCOM (Padjust < 0.01, <0.001, <0.05 and <0.001, respectively).

Limitations, reasons for caution: The sample size of some case groups was relatively small, which therefore limited the statistical power of the analysis to a certain extent.

Wider implications of the findings: The present study indicates a potential common genetic basis of three PCOS clinical features. Other specific associated genes may play a synergistic role, leading to heterogeneous pathophysiological changes. Additionally, the increased frequency of PCOS-risk alleles in women with single PCOS clinical features suggests that these subjects have an elevated risk of developing the syndrome, although they cannot be currently diagnosed.

Study funding/competing interests: This research was supported by the National Basic Research Program of China (973 Program) (2012CB944700, 2011CB944502), the National Key Technology Research and Development Program(2011BAI17B00), the National Natural Science Foundation of China (81430029, 81201441, 81490743, 31371453), the Scientific Research Foundation of Shandong Province of Outstanding Young Scientist (2012BSE27089) and the Fundamental Research Funds of Shandong University(2014GN025). There were no competing interests.

Keywords: PCOS; SNP; anovulation; hyperandrogenism; polycystic ovary.