MTR and coronary artery disorder: Early work in our laboratory and other literature reveal that genetic polymorphisms of genes related to the maternal folate-homocysteine metabolism pathway, such as methylene-tetrahydrofolate reductase (MTHFR) (7), cystathionine beta synthase (CBS) (8), and methionine synthase (MS) (9), are closely associated with the development of CHD.