MTHFR C677T gene polymorphism in Type 2 diabetes mellitus patients with and without vascular complications: A case-control study

Abstract

PurposeEvidences suggest that polymorphism in genes involved in folate metabolism plays a critical role in the etiology of diabetes and diabetic complications. Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism. MTHFRC677T gene polymorphism, which is located within the N terminal catalytic domain makes enzyme thermolabile with reduced activity. The present study was conducted to investigate whether the MTHFR C677T gene polymorphism is associated with the susceptibility to Type 2 diabetes mellitus (T2DM) in patients with and without vascular (micro and macro) complications and controls. MethodsThe study included 200 T2DM patients (n=100, with vascular complications and n=100, without complications) and 100 healthy individuals as controls. DNA was isolated from the blood samples and genotyping of MTHFR C677T gene polymorphism was performed using polymerase chain reaction followed by restriction fragment length polymorphism method. ResultsThe results indicated that the occurrence of homozygous mutant (TT) was completely absent in T2DM patients without complications and controls. The type 2 diabetes patients with vascular complications have shown only 2% of MTHFR 677TT genotype. The calculated genotype frequencies between the patients with and without vascular complications and controls did not differ significantly from frequencies predicted on the basis of the Hardy Weinberg law of population genetics. Odds ratio (OR) of the genotypes did not show significant difference between T2DM patients without complications and controls {OR/P; (Confidence Intervals)=0.516/0.21; (0.183-1.45)}. Similarly, there were no significant differences between T2DM patients with vascular complications and controls {OR/P; (Confidence Intervals)=0.335/0.02; (0.125-0.895)}. ConclusionsWe suggest that the MTHFR C677T gene polymorphism is not considered as a risk factor for the development of T2DM and its vascular complications in the south Indian population.