Abstract:

Objective   To evaluate associations of maternal methionine synthase (MTR) A2756G and methionine synthase reductase(MTRR) A66G polymorphisms with the offspring′s risk for neural tube defects (NTDs). Methods   The retrieval strategy and criteria for inclusion and exclusion were made. Literature was identified by searches for case-control studies on maternal MTR A2756G or MTRR G66A polymorphism and risk of NTDs in the offspring published in English or Chinese from following databases: China Biology Medical Literature Database(CBM), Database of Chinese Scientific and Technical Periodicals(VIP), China National Knowledge Infrastructure(CNKI), Digital Journal Full-text Database(CHINAINFO), PubMed and Web of Science from January 1990 to October 2010.Combined OR values and 95% CI were calculated with Review Manager 5.0. Results   18 eligible studies were included in the metaanalysis, among which 11 studies(907 cases and 1,978 controls) on maternal MTR A2756G polymorphism, and 11 (1123 casesand 1700 controls) on maternal MTRR A66G polymorphism. Statistical analysis of the combined data showed that there was no significant association between maternal MTR A2756G polymorphism and the risk of NTDs, while there were significant associations between maternal MTRR A66G polymorphism and the risk of NTDs in GG/AG vs. AA, GG vs. AA, AG vs. AA, GG vs. AG/AA and G vs. A genetic models, and their pooled OR values and 95% CI were 1.89（1.282.78）, 1.68（1.312.16）, 1.77（1.18-2.66）, 1.28（1.06-1.55） and 1.35（1.12-1.63）, respectively. Conclusion   Maternal MTRR A66G polymorphism is a risk factor for NTDs.

Key words: Neural tube defects; Genetic polymorphism; Methionine synthase; Methionine synthase reductase; Meta-analysis