Homocystinuria; after normal perinatal period, onset of seizures occurs at 6 months of age, with development of mental deficiency, dislocation of lenses, speech deficiency, clumsiness, and deficiency of cystathionine ?-synthetase. Also with buildup of homocystine and methionine in preschool years. Screening test is positive cyanide nitroprusside reaction in urine. Treatment is low-methionine diet with anticoagulant and antiplatelet drugs.