Cystathioninuria not Associated with Vitamin B<sub>6</sub> Dependency: A Probably New Type of Cystathioninuria

Abstract

An infantile case of cystathioninuria was described. The patient had retarded development and marked cystathioninuria. Large doses of vitamin B6, were of no effect in diminishing cystathionine excretion, this finding being different from that in other patients with cystathioninuria so far reported. Using liver specimens biopsied from the patient, a difinitely low activity of cystathionase was demonstrated in the presence of an excess of pyridoxal phosphate. Both in vivo and in vitro studies indicate a defect in cystathionase itself. The present patient is thought to have a new type of cystathioninuria without vitamin B66 dependency.