Goats affected with
beta-mannosidosis, an autosomal recessive disease of
glycoprotein metabolism, have deficient activity of the lysosomal
enzyme beta-mannosidase along with tissue storage of
oligosaccharides, including
a trisaccharide [Man(beta 1-4)GlcNAc(beta 1-4)GlcNAc] and a
disaccharide [Man(beta 1-4)GlcNAc]. CNS myelin deficiency, with regional variation in severity, is a major pathological characteristic of affected goats. This study was designed to investigate regional CNS differences in
oligosaccharide accumulation to assess the extent of correlation between
oligosaccharide accumulation and severity of myelin deficits. The concentrations of accumulated
disaccharide and
trisaccharide and the activity of
beta-mannosidase were determined in cerebral hemisphere gray and white matter and in spinal cord from three affected and two control neonatal goats. In affected goats, the content of
trisaccharide and
disaccharide in spinal cord (moderate myelin deficiency) was similar to or greater than that in cerebral hemispheres (severe myelin deficiency). Thus, greater
oligosaccharide accumulation was not associated with more severe myelin deficiency. Regional
beta-mannosidase activity levels in control goats were consistent with the affected goat
oligosaccharide accumulation pattern. The similarity of
trisaccharide and
disaccharide content in cerebral hemisphere gray and white matter suggested that lysosomal storage vacuoles, more numerous in gray matter, may not be the only location of stored CNS
oligosaccharides.