Inherited lysosomal storage disease associated with deficiencies of β‐galactosidase and α‐neuraminidase in sheep

Abstract

Histopathologic, ultrastructural and Golgi impregnation studies disclosed lesions characteristic of a neuronal lysosomal storage disease in related sheep with onset of neurologic signs at 4-6 months. Biochemical and enzymatic evaluation disclosed storage of GM1 ganglioside, asialo-GM1, and neutral long chain oligosaccharides in brain, urinary excretion of neutral long chain oligosaccharides, and deficiencies of lysosomal beta-galactosidase and alpha-neuraminidase. Retrospective and limited prospective genetic studies suggested autosomal recessive inheritance. A gene-dosage effect on beta-galactosidase levels was documented in fibroblasts from putative heterozygous sheep. Fibroblasts from affected sheep did not have increased beta-galactosidase activity after incubation with the protease inhibitor, leupeptin. In some aspects this disease is similar to GM1 gangliosidosis, but is unique in that a genetic defect in lysosomal beta-galactosidase may cause the deficiency of lysosomal alpha-neuraminidase.