Does MTHFR C677T polymorphism predispose asthma? A North Indian study

Background: Involvement of impaired folate metabolism has been hypothesized to be a potential risk factor for the predisposition of asthma. The reports are conflicting on the potential association between atopic disease and polymorphism of the methylene-tetrahydrofolate reductase (MTHFR)-gene. Objective: We designed the study to investigate the association of C677T polymorphism of the MTHFR gene with asthma in the Indian population. Methodology: This was a hospital based case control study in which 200 asthmatic cases and 329 controls from North India population were enrolled and the MTHFR gene C677T polymorphism was genotyped by PCR-RFLP method. Result: We observed 92.85% of control group as wildtype homozygous, 11.24% and 1.51% as heterozygous and mutant homozygous respectively, while 98.25% and 3.75% of case group as wildtype homozygous and heterozygous respectively. Conclusion: Our finding suggests a lack of association of MTHFR C677T polymorphism with asthma. Further association studies in worldwide populations, involving different ethnic group samples with narrowly defined phenotypes of asthma, could contribute to the understanding of genetic susceptibility to asthma.