A 20-year-old man showed myoclonus epilepsy, cerebellar ataxia, and macular cherry-red spot. Assay of lysosomal enzymes demonstrated that the liver, leukocytes, and blood plasma were severely deficient in acid β-galactosidase. Partial deficiency of β-galactosidase activity was shown in kidney tissue. The plasma and leukocytes were also moderately deficient in β-galactosidase. There was an increase in the less acidic mucopolysaccharides in the patient's urine. A coarse face and the deformity of lumbar vertebrae also suggested a disturbance of mucopolysaccharide metabolism.
The case resembles the ones reported recently from two laboratories, but the localization of the enzyme deficiency was different in each. These cases seem to be in a series of GM1-gangliosidosis variants caused by a localized deficiency of β-galactosidase.
Yamamoto A, Adachi S, Kawamura S, et al. Localized ß-Galactosidase Deficiency: Occurrence in Cerebellar Ataxia With Myoclonus Epilepsy and Macular Cherry-Red Spot— A New Variant of GM1-Gangliosidosis? Arch Intern Med. 1974;134(4):627–634. doi:10.1001/archinte.1974.00320220029002
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