The correlation between methylenetetrahydrofolate reductase gene 677C > T polymorphism and fetal congenital defects: A meta-analysis

Objective To investigate the correlation between the methylenetetrahydrofolate reductase (MTHFR) gene 677C> T polymorphism and fetal congenital defects. Method Original studies relevant to the MTHFR gene 677C>T single nucleotide polymorphism and fetal congenital defects were systematically searched in the electronic databases of Medline, EMBSE and China National Knowledge Infrastructure (CNKI). All relevant publications were screened for inclusion in the present work. The correlation between the MTHFR gene 677C > T single nucleotide polymorphism and the occurrence of fetal congenital defects was expressed as an odds ratio (OR) and its 95% confidence interval (95% CI). Publication bias was assessed by Begg's funnel plot and Egger's line regression test. Results Nineteen case-control studies were ultimately included in the present meta-analysis. The pooled results indicated that the general risk of fetal congenital defects was significantly elevated in subjects with the 677T allele of the MTHFR gene in dominant (OR=1.07,95%CI:1.03-1.12, P<0.05), homozygous (OR=1.17,95%CI:1.06-1.30, P<0.05) and recessive genetic models (OR=1.16,95%CI:1.03-1.31, P<0.05) through the random effect method. However, significant publication bias was identified upon pooling the individual data and evaluating the correlation. Conclusion According to the present evidence, the MTHFR gene 677C>T single nucleotide polymorphism is correlated with poor pregnancy outcomes, and subjects with the T allele have an increased risk of developing general fetal congenital defects.