ABSTRACT
<p><b>OBJECTIVE</b>To investigate the changes of plasma homocysteine (Hcy) level in patients with ischemic cerebrovascular or cardiovascular disease and analyze the relationship between plasma Hcy levels and the mutations in Hcy metabolism related enzymes, including methylene tetrahydrofolate reductase (MTHFR) C677T, cystathionine beta-synthetase (CBS) 844ins68 and methionine synthetase (MS) A2756G.</p><p><b>METHODS</b>By using the HPLC-FLD method, the plasma total homocysteine (tHcy) concentration was determined in 86 patients with cerebral infarction, 66 with myocardial infarction and 80 healthy controls. The association of plasma tHcy levels with cardiovascular or cerebrovascular disease and mutations of MTHFR C677T, CBS 844 ins 68 and MS A2756G were evaluated by statistic methods.</p><p><b>RESULTS</b>In the patient groups, the plasma tHcy concentrations increased significantly as compared with healthy controls. The individuals homozygous for MTHFR C677T mutation had significantly higher plasma Hcy levels.</p><p><b>CONCLUSION</b>Hyperhomocysteinemia is an important risk factor for ischemic cerebrovascular and cardiovascular disease. The homozygosity of MTHFR C677T may contribute to the increase of plasma Hcy and vascular damage.</p>