Presents the rare inherited disease with abdominal pain, psychiatric symptoms and neuropathies, because it may mimic an acute surgical (or less frequently psychiatric) emergency. The complication of respiratory paralysis, with a mortality of over 90%, is almost solely due to aggravation of an attack by drugs, usually barbiturates. It is, therefore, important to diagnose the disease in surgical practice before barbiturates-are used for sedation or anesthesia. Incidence, course of illness, signs and symptoms, treatment and clinical records are described.