beta-Galactosidase-neuraminidase deficiency (galactosialidosis): clinical, pathological, and enzymatic studies in a postmortem case.

Three male siblings in a Japanese family were affected with beta-galactosidase-neuraminidase deficiency (galactosialidosis). One patient died at 45 years of age, and postmortem liver and brain tissues were studied enzymatically. The residual activity of neuraminidase was relatively high in these tissues. Neuraminidase activity did not change in the tissues after repeated freezing and thawing of the homogenates, whereas this enzyme in control tissues lost 30 to 60% of its activity. There was a profound deficiency of beta-galactosidase in the tissues of the patient. Michaelis constant, pH profiles, and cryostability were identical for the patient and control patients. Cathepsin B was moderately increased in activity in the patient's tissues.