Homocysteine--an innocent bystander in vascular disease?

Homocysteine is derived from the metabolism of methionine, an essential amino acid primarily found in dietary animal protein. Homocysteine concentrations are determined by genetic and nutritional factors; mutations in the genes for enzymes involved in homocysteine metabolism, such as the common 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C T mutation, and deficiencies of vitamins B6, B12, and folic acid, are associated with hyperhomocysteinaemia.