Canine GM₁ gangliosidosis: An Ultrastructural and Biochemical Study

The ultrastructural and biochemical features of canine GM₁ gangliosidosis were studied. B-Galactosidase activity assayed using both skin fibroblast tissue culture strains and fresh skin revealed enzyme activities in three groups (normals, heterozygotes, and homozygotes) corresponding to an autosomal recessive inheritance. The concentration of ganglioside GM₁ was greatly increased in cerebral gray matter and kidney. A striking elevation of tissue oligosaccharides was found in liver, kidney, and spleen. Most neurons in the cerebral cortex and deep gray matter were filled by spherical lamellated inclusions. Hepatocytes contained vacuoles with an amorphous granular material which may correspond to the accumulation of galactose-oligosac-charides determined chemically. The disease in dogs has features similar to both the infantile and juvenile form of human GM₁ gangliosidosis.