Juvenile GM1 Gangliosidosis

Abstract

A 12-year-old girl with G_M1gangliosidosis had been well until 5 years of age when she first developed spasticity and slow progressive intellectual deterioration. When assayed with artificial substrates (<i>p</i>-nitrophenyl-β-galactoside and 4-methylumbelliferyl-β-galactoside), βgalactosidase activity was virtually absent in leukocytes, urinary protein, and cultured fibroblasts. Enzyme activity was also decreased when the natural substrates G_M1ganglioside (5% of control cells) and ceramide lactoside (24% of control cells) were used. Cerebroside βgalactosidase activity was in the high normal range. We propose a new nomenclature for the G_M1gangliosidoses in which this patient would be classified as having the juvenile O variant.