Three familial cases presenting with an immobile spine. Rigid spine or Emery-Dreifuss syndrome?

A father and his two sons presented with slowly progressive muscular weakness, contractures of the spine, elbows and ankles, and cardiac conduction disturbances in the father. Clinical and histological findings are discussed in relation to the hitherto reported cases of autosomal dominant variant of the Emery-Dreifuss syndrome and the distinction from the rigid spine syndrome.