Human Homocysteine Catabolism: Three Major Pathways and Their Relevance to Development of Arterial Occlusive Disease

The metabolic effects of long-term betaine therapy of ten patients who have homocystinuria due to biallelic deficiency of cystathionine beta-synthase were examined. Stimulation of betaine-dependent homocysteine remethylation causes a commensurate decrease in plasma homocysteine that can be maintained as long as betaine is taken.