This rare inherited disease presents with abdominal pain, psychiatric symptoms and neuropathies. Because it may mimic an acute surgical (or lcss frequently, psychiatric) emergency, it is important in clinical practice. The complication of respiratory paralysis, with a mortality of over 90%, i s 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 f o r sedation or anesthesia.