title: Association between MTR A2756G and MTRR A66G polymorphisms and maternal risk for neural tube defects: a meta-analysis.
abstract: BACKGROUND
  Methionine synthase (MTR) and methionine synthase reductase (MTRR) genes have been considered to be implicated in the development of neural tube defects (NTDs). However, the results are inconsistent. Accordingly, we conducted a meta-analysis to further investigate such an association.
  
  
  METHODS
  Published literature from PubMed and Embase databases was retrieved. All studies evaluating the association between MTR A2756G or MTRR A66G polymorphism and maternal risk for NTDs were included. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using the fixed- or random-effects model.
  
  
  RESULTS
  A total of 11 studies (1005 cases and 2098 controls) on MTR A2756G polymorphism and 10 studies (1211 cases and 2003 controls) on MTRR A66G polymorphism were included. Overall, this meta-analysis revealed no significant association between maternal MTR A2756G polymorphism and NTD susceptibility in either genetic model. A significant association between MTRR A66G polymorphism and maternal risk for NTDs was observed for GG vs. AA (OR=1.31, 95% CI 1.03-1.67) among Caucasians.
  
  
  CONCLUSIONS
  The present meta-analysis indicated that MTRR A66G polymorphism, but not MTR A2756G, is significantly associated with maternal risk for NTDs in Caucasians.
authors.affiliation: Dept. of Biochemistry, Capital Institute of Pediatrics, Beijing 100020, China.
authors.forename: Shengrong
authors.initials: S
authors.lastname: Ouyang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Li
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Liu
authors.forename: Huibo
authors.initials: H
authors.lastname: Chang
authors.forename: Jianxin
authors.initials: J
authors.lastname: Wu
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000235:genetics*; D016022:Case-Control Studies; D005287:Ferredoxin-NADP Reductase / Q000235:genetics*; D005787:Gene Frequency; D056726:Genetic Association Studies; D006801:Humans; D009035:Mothers; D009436:Neural Tube Defects / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D017594:Publication Bias; D012306:Risk
chemical_list: C111241:methionine synthase reductase; D005287:Ferredoxin-NADP Reductase; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase