I-cell disease: report of an autopsy case.

The history and findings at autopsy of a 9-year-old female with I-cell disease are reported. She manifested gargoyle face, progressive psychomotor retardation, and increased serum levels of lysosomal enzymes with decreased activities in peripheral blood lymphocytes. She received a bone marrow transplantation from her HLA-mismatched father when she was 8 years old. Rejection followed, and 9 months later, she died of cardiac failure secondary to aortic regurgitation. The characteristic inclusion bodies, ultrastructurally corresponding to double-membranous lamellar vacuoles and empty single membrane-bound vacuoles, were identified in dermal fibro blasts, macrophages, glomerular epithelial cells, cardiomyocytes and smooth muscle cells. Pale bodies, faintly eosinophilic cytoplasmic globular inclusions immunoreactive for plasma proteins, were observed in hepatocytes and renal collecting tubular epithelial cells. Enzyme histochemical analyses were performed for N-acetyl-beta-glucosaminidase, beta-glucuronidase, nonspecific esterase and acid phosphatase. Decreased activities of the acid hydrolases and their diffusion in the cytoplasm were seen in Kupffer's cells. Ultrastructural localization of acid phosphatase activity suggested the labilization of the lysosomal membrane. The abnormality in the intracellular transport of the acid hydrolases into the lysosomes in I-cell disease is briefly reviewed and discussed.