[Hyperhomocysteinemia: risk factor for premature atheromatosis].

Hyperhomocysteinemia is an independent risk factor for atherosclerosis and cardiovascular disease. The cause of hyperhomocysteinemia is either an inborn metabolic defect or acquired. Main causes are either a defective homocysteine remethylation (thermolability of the enzyme 5,10-methylenetetrahydrofolate reductase) or nutritional deficiencies of B vitamins especially folic acid. The relative risk for myocardial infarction has been found of 3,1 in case of hyperhomocysteinemia. It is considered that a 5 microM/l homocysteine increment elevates vascular risk by as much as cholesterol increases of 20 mg/dl. B vitamins supplements are potentially useful.