title: Quantitative analysis of follistatin (FST) promoter methylation in peripheral blood of patients with polycystic ovary syndrome.
abstract: Epigenetic mechanisms may contribute to polycystic ovary syndrome (PCOS). To date, however, no studies have associated CpG methylation levels of any candidate gene with PCOS susceptibility. Follistatin (FST), an activin-binding protein, is expressed in numerous tissues and is shown to have linkage with PCOS. However, results from case-control association analyses between this gene and PCOS are inconsistent. Thus, this study investigated possible association of methylation levels in the promoter and 5'-untranscribed region (UTR) of the FST gene with PCOS incidence in peripheral blood leukocytes and endometrial tissue. Using mass array quantitative methylation analysis, first the 5'-UTR methylation in FST was analysed in 130 PCOS patients and 120 controls. The methylation level of the FST gene was further studied in endometrium from 24 controls and 24 PCOS patients. This study demonstrates that methylation levels of CpG sites in the FST promoter and 5'-UTR are not associated with PCOS. Nonetheless, this was the first study to quantitatively evaluate the methylation levels of a candidate gene in association with PCOS. Further studies should be performed to examine methylation in other candidate genes. Understanding the epigenetic mechanisms involved in PCOS may yield new insights into the pathophysiology of the disorder. Animal models demonstrate that epigenetic reprogramming may contribute to polycystic ovary syndrome (PCOS). To date, however, no studies have associated CpG methylation levels of any candidate gene with PCOS susceptibility. Follistatin (FST), an activin-binding protein, is expressed in numerous tissues and is a PCOS candidate gene. However, results from association analyses between this gene and PCOS are inconsistent. Thus, we investigated possible association of methylation levels in the promoter and 5'-UTR of the FST gene with PCOS incidence in peripheral blood leukocytes and endometrial tissue. Using mass array quantitative methylation analysis, we firstly analysed 5'-UTR methylation in 40 PCOS patients and 40 controls. We then validated results in a second sample consisting of 90 PCOS patients and 80 controls. The methylation level of the FST gene was further studied in endometrium from 24 controls and 24 PCOS patients. Finally, we quantitatively analysed FST expression in the endometrium using real-time PCR. Our study demonstrated that methylation levels of CpG sites in the FST promoter and 5'-UTR are not associated with PCOS. Nonetheless, as far as is known, this is the first study to quantitatively evaluate the methylation levels of a candidate gene in association with PCOS. Further studies should be performed to examine methylation in other candidate genes. Understanding the epigenetic mechanisms involved in PCOS may yield new insights into the pathophysiology of the disorder.
authors.affiliation: State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Sang
authors.forename: Shaozhen
authors.initials: S
authors.lastname: Zhang
authors.forename: Shien
authors.initials: S
authors.lastname: Zou
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Ruizhi
authors.initials: R
authors.lastname: Feng
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Jin
authors.forename: Lin
authors.initials: L
authors.lastname: He
authors.forename: Qinghe
authors.initials: Q
authors.lastname: Xing
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D020121:5' Untranslated Regions; D000328:Adult; D016022:Case-Control Studies; D018899:CpG Islands; D004247:DNA / Q000097:blood / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004717:Endometrium / Q000378:metabolism; D005260:Female; D038681:Follistatin / Q000235:genetics*; D006801:Humans; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D020121:5' Untranslated Regions; C503233:FST protein, human; D038681:Follistatin; D012333:RNA, Messenger; D004247:DNA