[Schwartz-Jampel syndrome. Clinical and histopathological study of 4 cases].

Four cases of Schwartz-Jampel syndrome are reported. Clinical manifestations began in infancy with slowly progressive bone deformities, dwarfism and prominent myotonia. All patients were issued from 2 families with consanguineous healthy parents. Three among them belonged to the same sibship. Present evidence favors a recessive mode of inheritance. Nerve biopsy was normal. Muscle biopsy showed dystrophic changes with streaming of Z-lines in all four cases. Mitochondria were greatly swollen. Glycogen particles were present in the spaces between the affected myofibrils and in the swollen mitochondria. These data showed that the nerve was preserved and that the disease affected mainly voluntary muscle.