Prevalence of methylene tetrahydrofolate reductase polymorphism in South Indian population

Prevalence of methylene tetrahydrofolate reductase (MTHFR) gene mutations in South Indian population was investigated from a total of 608 samples, 420 adults and 188 newborns. Detection of mutation was carried out focussing on the two most common mutations of the MTHFR gene (C677T and A1298C) using PCRbased RFLP method. T-allele frequency was almost similar between the newborns and adults (0.0904, 0.1012). However, a higher T-allele frequency was observed in females (0.1538 and 0.12 in adults and newborns respectively) than males (0.0556 and 0.05 in adults and newborns respectively). In the case of the other mutation, C-allele frequency was almost similar with no sex-bias (0.414 and 0.402 in males and females respectively). Biochemical correlation of fasting plasma total homocysteine to MTHFR genotype revealed mild to moderate hyperhomocysteinemia in mutants. Plasma total homocysteine in males was found to be higher than in females in both normal and mutant individuals. TT homozygous women had higher plasma homocysteine. The high T-allele frequency, elevated plasma homocysteine and low folate intake in women could well be a risk factor for birth defects. The gender bias observed in this autosomal recessive trait was an interesting finding and is discussed.