Abstract
Electron microscopic observation was perfor med on biopsied muscles from two cases of Werdnig-Hoffmann disease.
The electron micrographs of degenerated muscles revealed various morphologic alterations consisted of: disarray and disappearance of myofilament; vacuolation of mitochondria and sarcoplasmic reticulum; irregularity and frag mentation of Zdisc; an increase in the width of the interfibrillary space; and focal dissociation of the basement membrane from the plasma mem brane. The degenerated nuclei with vacuolation and deep infoldings of nuclear membrane were found in atrophic muscle fibers.
The primary lesion of muscle degeneration could not be identified, due to an irregular ap pearance of above-mentioned histologic changes in our material obtained from severely affected children. Peripheral nerve fibers and muscle spindles among atrophic fibers showed no ultra structural change.
The satellite cells did not increase in number and contained only a few cell organelles showing a regressive alterations along with muscle fiber degeneration.
