Fetal MTHFR C677T polymorphism confers no susceptibility to Down syndrome: Evidence from meta-analysis

Abstract

Maternal methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is reported as risk factor for Down syndrome (DS) pregnancy but fetal MTHFR C677T polymorphism was not well studied as risk factor for DS. Some studies were published, but results were controversial. Hence a meta-analysis of all published studies investigated DS case MTHFR polymorphism were performed to explore the association between C677T polymorphism of individual and DS risk. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association. The analyses were conducted with meta-Analyst and MIX software. Total five case-control studies with 401 DS cases and 529 controls were included in present meta-analysis.

Meta-analysis results suggested that MTHFR C677T polymorphism did not contribute any DS risk in overall population using four genetic models (for T vs. C: OR = 1.56, 95% CI = 0.83–2.89). However, codominant model analysis showed significant association between MTHFR C677T polymorphism and DS risk (OR = 1.66; 95% CI = 1.22–2.25; p = 0.001). Less heterogeneity (I² = 48.31), so fixed effect model was used. In conclusion, present meta-analysis suggests that MTHFR C677T polymorphism of fetus is not risk factor for DS.

Keywords: Down syndrome, MTHFR, C677T, Polymorphism, Meta-analysis, Homocysteine