Caprine oligosaccharide storage disease. Accumulation of β-mannosyl (1→4) β-N-acetylglucosaminyl (1→4) β-N-acetylglucosamine in brain
In 1975 a new caprine neurovisceral storage disease was identified in related Nubian goats in Michigan. The affected kids of both sexes showed profound neurological deficits at birth, lack of myelination in cerebral hemispheres and cerebellum, axonal lesions, and cytoplasmic vacuolation. A similar genetic syndrome arose independently in a population of Anglo-Nubian goats in New South Wales. Preliminary chemical characterization of an accumulated metabolite was performed. An extract of 1 g of brain from an affected goat was found to contain 2.2 μmol of the trisaccharide Man (β1→4)GlcNAc(β1→4)GlcNAc (β-mannosylchitobiose). The accumulation of this substance suggests the possibility of a genetic defect in β-mannosidase in the catabolic pathway for N-linked complex glycopeptides and would be the first indication of a β-mannosidosis.