HOMOCYSTINURIA is an inborn error of metabolism due to deficiency of the enzyme cystathionine synthetase. This results in an increased excretion of homocystine in the urine and raised homocystine and methionine levels in the blood and cerebrospinal fluid. Clinically there is a picture of ectopia lentis, due to zonular degeneration, skeletal changes, fine fair hair, shuffling gait, mental retard...
