Mutations in the Genes Regulating Methylene Tetrahydrofolate Reductase (MTHFR C!T677) and Cystathione b b-Synthase (CBS G!A919, CBS T!c833) Are Not Associated with Myocardial Infarction in

Moderate hyperhomocysteinemia is a putative risk factor for cardiovascular disease. Molecular studies have demonstrated increased plasma homocysteine levels in the presence of DNA mutations in either the methylenetetrahydrofolate reductase (MTHFR) enzyme found in the remethylation pathway or the enzyme cystathione b-synthase (CBS) of the transsulfuration pathway. To determine whether the mutation C ! T677 in the MTHFR gene or the T ! C833/ 844ins68 and G ! A919 mutations in the CBS gene are associated with myocardial infarction (MI) in African Americans, DNA was analyzed from samples obtained from a case –c ontrol study conducted at a large, inner-city hospital. One-hundred ten African American subjects with a diagnosis of MI and 185 race- and age-matched controls were recruited. Our results demonstrated that 15% of the MI cases were heterozygous for the C ! T677 (MTHFR) mutation, while 1.8% were homozygous. When compared to the