Prevalence of the C677T single-nucleotide polymorphism in the methylenetetrahydrofolate reductase gene among Pakistani ethnic groups.

Methylenetetrahydrofolate reductase is an important enzyme in metabolism of homocysteine, and a mutation in the gene predisposes individuals to several disorders related to homocysteine levels. Polymorphism at C677T shows marked heterogeneity based upon ethnicity and geographical location. Pakistani population consists of various ethnic groups confined to different regions of the country where congenital and genetic defects are a major health concern. We have analyzed the distribution of C677T alleles in different Pakistani ethnic groups. A cross-sectional study was conducted from all the four provinces of the country with samples representing the 14 different ethnic clans. A questionnaire with details of their ethnic origin was used, and informed consent was obtained. Blood samples from 701 individuals were collected for DNA isolation and subsequent C677T single-nucleotide polymorphism determination. The data were statistically analyzed. The study revealed that genotypic frequency for CC varied from 0.89 (Mohanna) to 0.38 (Hazara), CT from 0.56 (Hazara) to 0.11 (Mohanna), and TT from 0.06 to 0. Our data revealed a varied distribution of C677T mutation. This information could be helpful for designing future public health strategies, as it can be used to predict the prevalence of several disorders associated with genetic predisposition due to methylenetetrahydrofolate reductase C677T alleles.