C677T Polymorphism of the Methylenetetrahydrofolate Reductase gene as a possible maternal risk factor for the presentation of Down syndrome in the population of Guayaquil

Aim: to assess the presence of the C677T polymorphism of the MTHFR gene as a possible maternal risk factor for Down syndrome in the population of Guayaquil. Methodology: a case study and control research involving 51 mothers of boys and girls with Down syndrome and 52 women who delivered a healthy offspring of either sex in their last pregnancy. Venous blood samples were collected in the months of December 2010 and May 2011 after that, a DNA extraction and genotyping of the C667T poly morphism of the MTHFR gene were performed. Pearson’s Chi-squared test (X2), and odds Ratio (OR) with confidence interval of 95% (95% CI) were used for the statistical analysis. Values of p<0.05 were considered statistically significant. Results: 51 women mothers of sons / daughters with Down syndrome and 52 control mothers were included. The T-allele frequency was higher in the cases (X²=0.944, p:0.331). In the simultaneous analysis of heterozygous and homozygous genotype variant of MTHFR 667 (CT and TT) in the case and control groups, no risk increase for the syndrome (OR=0.87 [IC 95% 0.34 – 2.20]; p=0.772) was observed. Conclusion: no relationship was found between the presence of MTHFR C677T polymorphism and increased maternal risk for Down syndrome. It is necessary to perform further research on the general Ecuadorian population to determine the association of various polymorphisms in different genes.