A neuropathological investigation of a case of tyrosinosis.

An autopsy case of tyrosinosis was reported. The patient was a 5-month-old boy who had jaundice and hepatosplenomegaly since 10 weeks after his birth. Tyrosine blood level was 6.937 mg/dl and the level of p-HPPA oxidase low. Neuropathologically, the cerebral lesions were characterized by a spongy state, vacuoles in neuronal cells and focal deposition of PAS-positive substance in and around the axon. The electron microscopic examination revealed axonal degeneration and unusual deep cortical structure, possibly axons, containing numerous lysosomes, elongated mitochondria and MCB-like bodies in unmyelinated axon. These facts were suggested to represent morphologic evidence of altered cellular metabolism, related to impaired tyrosine degradation.