Common methylenetetrahidrofolate reductase and cystathionine-beta-synthase mutations and homocysteine levels in patients with coronary artery disease

Hyperhomocysteinemia is a risk factor for cardiovascular disease. Total plasma homocysteine (tHcy) is influenced by nutritional and genetic factors. The prevalence of common mutations, C677T in methylenetetrahydrofolate reductase (MTHFR) and 844 ins 68 in cystathionine beta-synthase gene (CBS) have been studied in 528 patients with angiographically confirmed coronary artery disease (CAD) and in 219 healthy age and sex matched control subjects. Severity of disease was expressed as number of affected vessels. tHcy was measured by FPIA. There was no significant difference in genotype distributions of the MTHFR and CBS genes between groups (p=0.08 and 0.31, respectively). However, patients with CT or TT genotype in MTHFR had significantly higher tHcy levels (p=0.009). Also, groups with 0, 1, 2 and 3 or more affected vessels differed in tHcy levels (ANOVA, p<0.001). In conclusion, MTHFR and CBS mutations are not independent risk factors for CAD, but C677T mutation influences tHcy levels.