title: Polymorphism T→C of gene CYP17 promoter and polycystic ovary syndrome risk: a meta-analysis.
abstract: The T→C polymorphism of CYP17 gene has been inconsistently associated with polycystic ovary syndrome (PCOS) risk. We examined the association by performing a meta-analysis. Two investigators independently searched the Medline, Embase, CNKI, and Chinese Biomedicine Databases. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) for CYP17 polymorphism and PCOS were calculated in a fixed-effects model and a random-effects model when appropriate. The pooled ORs were performed for co-dominant model (CC vs. TT, TC vs. TT), dominant model (CC+TC vs. TT), and recessive model (CC vs. TC+TT). Subgroup analyses were performed by ethnicity, country, Hardy-Weinberg equilibrium (HWE) in controls and study sample size. This meta-analysis included 10 case-control studies, which included 1321 PCOS cases and 1017 controls. Overall, the variant genotypes (CC and TC) were not associated with PCOS risk, compared with the wild-type TT homozygote. Similarly, no associations were found in the dominant and recessive models. Stratified analyses by ethnicity/country also detected no significant association. However, limiting the analysis to the studies within HWE, a significantly increased risk was observed (TC vs. TT, OR=1.44, 95% CI=1.10-1.88; dominant model, OR=1.41, 95% CI=1.10-1.81). Moreover, when stratifying by study sample size, a significantly elevated risk was found among small sample studies (≤200 subjects), but not among large sample studies (> 200 subjects). This meta-analysis suggests that the CYP17 T/C polymorphism may be not associated with PCOS risk, while the observed increase in risk of PCOS may be due to small-study bias.
authors.affiliation: Division of Reproductive Medical Center, West China Second University Hospital of Sichuan University, 3 Duan 20 Hao Ren Min Nan Lu, City of Chengdu, Sichuan 610041, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Shan
authors.initials: S
authors.lastname: Luo
authors.forename: Han
authors.initials: H
authors.lastname: Hu
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Li
authors.forename: Shang-Wei
authors.initials: SW
authors.lastname: Li
mesh_terms: D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008954:Models, Biological; D011085:Polycystic Ovary Syndrome / Q000235:genetics*; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D012306:Risk; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics*
chemical_list: D013254:Steroid 17-alpha-Hydroxylase