Adult type mucolipidosis with beta-galactosidase and sialidase deficiency. Histological and biochemical studies.

A case of adult type mucolipidosis with beta-galactosidase and sialidase deficiency is described. This patient, a woman aged 20, had mental retardation, macular cherry-red spots, corneal clouding, gargoyle-like face, cerebellar ataxia, myoclonus and convulsions beginning at the age of 14. Bony deformities, vacuoles in the peripheral lymphocyte and foamy cells in the bone marrow were also noted. Biopsy study of the sural nerve and vermiform appendix disclosed many vacuoles in almost every kind of cells, although the accumulated substance in these vacuoles could not be characterized histochemically or ultrastructurally. Deficient leukocyte beta-galactosidase and sialidase were confirmed. There was increased urinary sialoglycopeptide and increased siliac acid and hexosamine in the glycoprotein of lymphocytes. Leukocytes sialidase activites of the parents were 30 to 50% of the control values. These results suggest a genetic defect of sialidase.