title: Geographical and Ethnic Distributions of the MTHFR C677T, A1298C and MTRR A66G Gene Polymorphisms in Chinese Populations: A Meta-Analysis.
abstract: BACKGROUND
  The geographical and ethnic distributions of the polymorphic methylenetetrahydrofolate reductase (MTHFR) mutations (C677T and A1298C) and methionine synthase reductase (MTRR) mutation (A66G) remain heterogeneous in China. The goal of this study was to estimate the pooled frequencies of the alleles and associated genotypes of these gene polymorphisms among healthy populations in Mainland China.
  
  
  OBJECTIVE
  We systematically reviewed published epidemiological studies on the distributions of 3 genetic variants in Chinese healthy populations living in Mainland China through a meta-analysis. The relevant electronic databases were searched. All of the raw data of the eligible citations were extracted. The frequency estimates were stratified by geography, ethnicity and sex.
  
  
  RESULTS
  Sixty-six studies were identified with a total of 92277 study participants. The meta-analysis revealed that the frequencies of the MTHFR C677T, A1298C, and MTRR A66G gene polymorphisms varied significantly between different ethnic groups and along geographical gradients. The frequencies of the 677T allele and 677TT genotype increased along the southern-central-northern direction across Mainland China (all Pvalues≤0.001). The frequencies of the 1298C, 1298CC, 66G and 66GG genotypes decreased along the south-central-north direction across the country (all Pvalues≤0.001).
  
  
  CONCLUSIONS
  Our meta-analysis strongly indicates significant geographical and ethnic variations in the frequencies of the C677T, A1298C, and A66G gene polymorphisms in the folate metabolism pathway among Chinese populations.
authors.affiliation: Department of Gynecology, Liuzhou Municipal Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, China.
authors.forename: Xingmin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Gynecology, Liuzhou Municipal Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, China.
authors.forename: Jinjian
authors.initials: J
authors.lastname: Fu
authors.affiliation: Department of Gynecology, Liuzhou Municipal Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, China.
authors.forename: Qianxi
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Gynecology, Liuzhou Municipal Maternity and Child Healthcare Hospital, Liuzhou, Guangxi, China.
authors.forename: Dingyuan
authors.initials: D
authors.lastname: Zeng
mesh_terms: D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005287:Ferredoxin-NADP Reductase / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005843:Geography; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011379:Prognosis; D012307:Risk Factors
chemical_list: C111241:methionine synthase reductase; D005287:Ferredoxin-NADP Reductase; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)