e-ISSN 2329-0072




Hiperhomocysteinemia as ischemic heart disease risk factor

Krzysztof Chiżyński

Med Sci Tech 2007; 48(2): RP89-94

ID: 881548

Available online:

Published: 2007-03-18

Hiperhomocysteinemia is increasingly recognised as an independent risk factor for coronary artery disease and myocardial infarction. In general population there are 5-10 percent patients with hiperhomocysteinemia. In blood, homocysteine is oxidised to form homocysteine, mixed disulphides, and homocysteine thiolactone. Homocysteine induced atherosclerosis is characterised by endothelial dysfunction and injury followed by platelet activation and thrombus formation. Homocysteine level increase is caused by nutritional deficiencies in vitamin cofactors, or by genetic defects in the enzymes which are involved in the metabolism of this amino acid. Genetic defect, a thermolabile variant of MTHFR has been described which is caused by a mutation (C677T) in the coding region for the MTHFR binding site, leading to the substitution of valine for alanine. This gene variation was associated with increased levels of homocysteine. In many studies, the potential link between this gene polymorphism and ischemic heart disease has been investigated and some investigators identified the presence of T gene as a risk factor of cardiovascular disease. Vitamin B12 is an essential cofactor for methionine synthase, N5-methyl-tetrahydrofolate is the methyl donor in this reaction, and N5,N10-methylenetetrahydrofolate reductase (MTHFR) functions as a catalyst in the remethylation process. Not only gene variation is associated with increased levels of homocysteine. Increased homocysteine plasma levels are caused by nutritional deficiencies in vitamin cofactors: folic acid and/or vitamin B6 and B12, medicine therapy (the use folic acid antagonists e.g. methotrexate, vitamin B6 or B12 antagonists, phenytoin treatment, and hormonal therapy), endocrine disturbances, renal insufficiency, smoking, alcohol intake. (Clin Exp Med Lett 2007; 48(2): 89-94)

Keywords: hiperhomocysteinemia, Coronary Artery Disease, C677T MTHFR polymorphism