Hyperhomocysteinemia: an independent risk factor for vascular disease.

TLDR: Hyperhomocysteinemia is an independent risk factor for vascular disease, including coronary disease, and in most instances is probably due to cystathionine beta-synthase deficiency.

Abstract: Background. Hyperhomocysteinemia arising from impaired methionine metabolism, probably usually due to a deficiency of cystathionine β-synthase, is associated with premature cerebral, peripheral, and possibly coronary vascular disease. Both the strength of this association and its independence of other risk factors for cardiovascular disease are uncertain. We studied the extent to which the association could be explained by heterozygous cystathionine β-synthase deficiency. Methods. We first established a diagnostic criterion for hyperhomocysteinemia by comparing peak serum levels of homocysteine after a standard methionine-loading test in 25 obligate heterozygotes with respect to cystathionine β-synthase deficiency (whose children were known to be homozygous for homocystinuria due to this enzyme defect) with the levels in 27 unrelated age- and sex-matched normal subjects. A level of 24.0 μmol per liter or more was 92 percent sensitive and 100 percent specific in distinguishing the two groups. The ...