Pathological involvement of primary sensory neurons in Werdnig-Hoffmann disease.

Seven patients with the typical clinical picture and muscle biopsy findings of classical Werdnig-Hoffmann disease showed Wallerian degeneration in their biopsied sural nerves. In dorsal root ganglia of one patient there were residual nodules and several chromatolytic neurons. By electron microscopy the changes of chromatolysis were confirmed and found to be consistent with an axonal reaction. Involvement of the primary sensory neuron is probably a regular pathologic feature of Werdnig-Hoffmann disease. The type of abnormality suggests in initial failure of the axon distal to the nerve roots.