title: Associations of C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR) gene with male infertility risk: A meta-analysis.
abstract: OBJECTIVE
  Methylenetetrahydrofolate reductase is one of the key enzymes in folate metabolism. But the association between polymorphism and the risk of male infertility is still controversial. Therefore, this study used a meta-analysis on the collection of data to analyze MTHFR gene C677T polymorphism (known as c.665 C>T, rs1801133, p.Ala222Val).
  
  
  METHODS
  PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Wan fang. Data were searched to identify eligible studies. We sifted the data collection by Hardy-Weinberg equilibrium calculator and used odds ratios (ORs) and 95% confidence intervals (95% CIs) to conduct data through RevMan5.0 and StataSE12.0 software.
  
  
  RESULTS
  A total of 15 studies have 3853 patients with infertility and 3613 healthy controls in this meta-analysis. Our results showed that T variant of MTHFR C677T gene polymorphism was significantly associated with an increased risk of male infertility (forT vs. C: OR=1.38, 95% CI=1.18-1.63; for TT vs. CC: OR=1.86, 95% CI=1.36-2.54; for CT vs. CC: OR=1.34, 95% CI=1.03-1.74; for TT vs. CT: OR=1.52, 95% CI=1.26-1.84; for TT vs. CT+CC: OR=1.42, 95% CI=1.19-1.70; for TT+CT versus CC: OR=1.46, 95%CI=1.05-2.04). In addition, the results indicated that T allele had the positive association which was driven by East-asian populations (random: OR=1.44, 95% CI=1.2-1.74; fixed: OR=1.39, 95% CI=1.20-1.61), Middle-eastern populations (random: OR=1.30, 95% CI=1.05-1.63; fixed: OR=1.30, 95% CI=1.05-1.63) and Mixed-race (random: OR=1.96, 95% CI=1.35-2.85; fixed: OR=1.31, 95% CI=1.20-1.43).
  
  
  CONCLUSIONS
  This meta-analysis suggests that MTHFR C677T polymorphism is associated with male infertility.
authors.affiliation: Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China.
authors.forename: Hui-Hui
authors.initials: HH
authors.lastname: Hong
authors.affiliation: Department of Gynecology & Oncology , Shaanxi Provincial Tumor Hospital, Xi'an 710061, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Gynecology and Obstetrics, Kangfu Hospital of Shaanxi Province, Xi'an, China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Yu
authors.affiliation: Reproductive Medicine Center, North-West Maternal and child Hospital, Xi'an 710003, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China.
authors.forename: Mo-Qi
authors.initials: MQ
authors.lastname: Lv
authors.affiliation: Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Reproductive Medicine Center, North-West Maternal and child Hospital, Xi'an 710003, China.
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Ren
authors.affiliation: Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China. Electronic address: Dangxia75@163.com.
authors.forename: Dang-Xia
authors.initials: DX
authors.lastname: Zhou
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D005492:Folic Acid / Q000378:metabolism; D006801:Humans; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors
chemical_list: D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: MTHFR C677T; Male infertility; Meta-analysis; Polymorphism