In 1962, 30 years after the discovery by du Vigneaud have pathologic consequences. One potentially sig- of a new sulfur amino acid, homocysteine; Carson and nificant health outcome of such mild to moderate Neil reported two siblings with mental retardation in hyperhomocysteinemia is an increased risk of occlu- northern Ireland with elevated urinary homocystine. sive vascular disease. Homocysteine concentrations in Nearly simultaneously, Gerritsen...