Synaptic alterations of anterior horn cells in Werdnig-Hoffmann disease.

The most characteristic neuropathologic feature of Werdnig-Hoffmann disease is degenerative change in the anterior horn cells of the spinal cord, the mechanisms of which have not yet been clearly determined. To assess the synaptic changes in the motor neurons, we examined immunoreactivities for synaptophysin in the spinal cord of 11 patients with Werdnig-Hoffmann disease. Decreased synaptophysin immunoreactivity was observed in the anterior horn cell column in all patients with Werdnig-Hoffmann disease and correlated with the degree of degenerative change in the motor neurons. Synaptophysin immunoreactivity was relatively preserved on the surface of the residual anterior horn cells. Both atrophic neurons and chromatolytic neurons had dense accumulations of synaptophysin-immunoreactive products on the surface of the cell body and their proximal processes. These observations suggest that synaptic changes in the anterior horn cell column are secondary to the degenerative processes of the anterior horn cells.