Sulfite oxidase deficiency in man: demonstration of the enzymatic defect.

An infant who died with neurological abnormalities, mental retardation, and dislocated ocular lenses excreted in his urine abnormally large amounts of S-sulfo-L-cysteine, sulfite, and thiosulfate and virtulally no inorganic sutlfate. The present report establishes the occurrence of an ezymatic defect in this infant. His liver, brain, and kidney specifically lacked sulfite oxidase activity. Deficiency of sulfite oxidase, which has not apparently been described in man, provides a reasonable explanation for the abnormalities in this infant.