Fasting, postprandial, and post-methionine-load homocysteinaemia and methylenetetrahydrofolate reductase polymorphism in vascular disease

Hyperhomocysteinaemia is an independent risk factor for cardiovascular dise ase. The C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) is a common genetic cause of increased homocysteine (HCY) levels. Post-meth ionine-load HCY concentrations allow identification of certain cases of hyp erhomocysteinaemia not demonstrated by fasting levels. This study investiga ted the relationship between MTHFR polymorphism and (1) fasting HCY levels (77 patients); (2) post-methionine HCY levels (54 patients); and (3) postpr andial HCY concentrations (36 patients) in cardiovascular disease. As expec ted, mean fasting HCY value was higher in the +/+ patients. Moreover, patie nts who were homozygous for the mutation exhibited significantly increased mean post-methionine-load HCY; in contrast, literature results are conflict ing. Mean postprandial HCY, which is not known to be increased in controls, was also increased in the (+/+) patients, although the difference did not reach statistical significance, probably owing to the small size of the sam ple. MTFHR polymorphism is known to be aggravated by a drop in circulating folate. Additional risk factors may be more prevalent in patients with card iovascular disease.