Distribution of central nervous system lesions in beta-mannosidosis.

Central nervous system (CNS) morphological changes were delineated in goats affected with beta-mannosidosis to determine the extent and distribution of lesions associated with this inherited glycoprotein metabolic perturbation. Coronal sections of one cerebral hemisphere, sagittal sections of one cerebellar hemisphere, and transverse sections of the brain stem of 4- and 16-week-old affected and control goats were analyzed. Lysosomal storage vacuoles, probably representing storage of uncleaved oligosaccharides, were present to various extents in different cell types, with variation in the size of vacuoles. Axonal spheroids were present throughout the white matter, but were most numerous in the rostal thalamic peduncle and brachium of the inferior colliculus. Mineralization occurred only in the globus pallidus and cerebellum. Unlike related storage disorders, severe deficiency of myelin occurred throughout the brain, with regional variation in the extent of myelin deficits. White matter of the corpus callosum, anterior commissure, alveus, fornix, fimbria, and medullary pyramids showed the most severe myelin paucity. Reduction in the number of oligodendroglia and vacuolation of remaining oligodendroglia occurred throughout the white matter. In general, later myelinating tracts showed the most severe myelin deficiency, suggesting that the time of myelination may be a major factor in determining the severity of myelin paucity in beta-mannosidosis.