Association of coronary artery disease with polymorphisms of angiotensin-converting enzyme and methylenetetrahydrofolate reductase gene.

Objective: Angiotensin-converting enzyme plays an important role in maintaining blood pressure, while methylenetetrahydrofolate reductase is involved in homocysteine metabolism. As hypertension and elevated homocysteine levels are among the various risk factors for coronary artery disease, the two polypeptides might need to be considered while determining the risk. Our study aimed to assess the association between common polymorphisms in these genes and susceptibility to coronary artery disease.

Methods: We studied 268 north Indian individuals with coronary artery disease and 90 age-matched controls. The distribution of the genotypes and allele frequencies of both genes were analyzed using polymerase chain reaction amplification and restriction fragment length polymorphism analysis.

Results: The frequency of the D allele was significantly higher among the patients (62%) than the controls (44%) (p=0.001, odds ratio=2.06). The same goes for the DD genotype (37% vs 21%) (p=0.004). The combined frequency of the D allele carriers was significantly higher among patients of coronary heart disease, with a difference of 20% (85% vs 65%) (p=0.003, odds ratio=3.1; CI: 1.3-7.29). However, the frequency of the T and C alleles, as well as that of the CC, CT and TT genotypes of the methylenetetrahydrofolate reductase gene, did not differ significantly between the two groups.

Conclusion: We conclude that coronary artery disease in north Indian patients is strongly associated with the carrier state of the angiotensin-converting enzyme D allele, but not with the C677T transition in the methylenetetrahydrofolate reductase gene.