A polymorphism of the methylenetetrahydrofolate reductase and methionine synthase gene in CAD patients: association with plasma folate, vitamin B12 and homocysteine

Elevated plasma total homocysteine (hcy), a risk factor for Coronary Artery Disease (CAD), is due to defects in genes encoding for enzymes involved in hcy metabolism or from inadequate status of vitamins involved in hcy disposal. The present study was designed to examine the relationship between the genetic factors, folate and vitamin B12 status. Relationship between plasma total homocysteine, folate, vitamin B12 and genetic variation at the methylenetetrahydrofolate reductase (MTHFR) (677C→T) and methionine synthase (MS) (2756A→G) loci were measured in 149 CAD men and 230 healthy men aged 34–74 yr in Korea. There was an association of elevated plasma hcy and CAD. However, MTHFR or MS mutation were not strong determinants on the development of CAD. Our results also indicate an interaction between the MTHFR, but not MS, homozygous mutant genotype and folate and vitamin B12 status in the elevation of plasma hcy, especially in CAD men.