[Homocysteinemia and vascular disease--a new risk factor is born].

In recent years there has been growing evidence that high levels of plasmatic homocysteine constitute an independent risk factor for early cardiovascular disease. In this article we review the main theories of atherosclerosis which take into account the proteins, namely homocysteine, homocysteine metabolism, the cause that may be responsible for high levels of homocysteinemia, the pathophysiologic mechanisms of vascular lesion induced by hyperhomocysteinemia, the clinical evidence that homocysteinemia constitutes a vascular risk factor and finally, the evidence that it is possible to control homocysteinemia with supplementation of co-factors of homocysteine metabolism, namely vitamin B6, B12 or folic acid.