[Schwart-Jampel osteo-chondro-muscular dystrophy. 2 familial cases].

A complex syndrome was observed in two sisters. It associated important and dysharmonious dwarfism, craniofacial dysmorphy (blepharophimosis and microstomy), osteo-chondro dystrophy (vertebral column, pelvis, coxofemoral joints), oligophrenia and a muscular syndrome of myotonic type. The myotonic muscular syndrome is characterized by the prevalence at the face. Clinical and electric myotonia is clear. Voluntary muscular contractions induce prolonged myotonic responses. However there is no basal activity as observed in other cases. Curarization does not induce any disappearance of myotonic discharges. No specific histological change was shown: Schwartz-Jampel's muscular syndrome is not univocal; however it seems to depend on an abnormality of neuro-muscular activity, at the level of the end plate.