Histochemistry and morphometry of Werdnig-Hoffmann disease.

We report a case of the Werdnig-Hoffmann disease in a 4-month-old male infant. The morphological study revealed perimysial fibrosis, variability in the size of muscle fibers, absence of target fibers, few central nuclei and normality in vessels, nerves and neuromuscular junctions. The morphometrical examination showed the existence of normal-sized and atrophic fibers in both fibrillar types, as well as in hypertrophic type I fibers. The percentage of fibrillar types and the data obtained from the form factor are normal. Random distribution of type I and II muscle fibers were observed.