NEUROAXONAL DYSTROPHY IN INFANTILE ALPHA-N-ACETYLGALACTOSAMINIDASE DEFICIENCY

Morphologic alterations in biopsies of central and peripheral nervous tissue were investigated at the light-and electron-microscopic level i n the first cases of lysosomal alpha-N-acetylgalactosaminidase deficie ncy. Widespread spheroid formation was observed in terminal and preter minal axons. Neocortical and peripheral autonomic axons contained tubu lovesicular and lamelliform membranous arrays, prominent acicular clef ts, and electron-dense axoplasmic matrix, the typical ultrastructural abnormalities corresponding to axonal spheroids in many inherited and acquired axonopathies. Central and peripheral membranous distal axonal spheroids were the only neuropathologic abnormality identified; other alterations resembling those in various neuronopathic lysosomal stora ge diseases were not observed. The morphologic findings and the distri bution of the lesion in the present disorder are remarkably similar to those reported in the inherited infantile form of neuroaxonal dystrop hy with normal alpha-N-acetylgalactosaminidase activity (Seitelberger disease).