Homocystinuria due to cystathionine synthase deficiency: the metabolism of L-methionine.

Abstract

During surveys of mentally retarded patients for evidence of metabolic errors, investigators in Ireland (1) and in America (2) independently dis- covered that abnormal excretion of homocystine in the urine may accompany retardation. A syn- drome has since been defined (3-9) with the rela- tively constant clinical features of mental defi- ciency, fine, fair hair, dislocated ocular lenses, malar flush, peculiar gait, and genu valgum; and with the variable features of pes cavus, long ex- tremities and digits, convulsions, thrombotic in- cidents that have been attributed to abnormal stickiness of the platelets (10), cardiovascular dis- orders, and fatty liver. Almost without exception the patients have had elevated concentrations of methionine and homocystine in the blood plasma in addition to increased amounts of homocystine in the urine.