An inherited hemorrhagic diathesis due to plasmin inhibitor deficiency was described by Koie et al. (1978) in a 25-year-old Okinawa man. He had suffered prolonged bleeding and ecchymoses after minor trauma, spontaneous joint hemorrhage, and one episode of hemothorax. The bleeding episodes were reduced in frequency and severity by an antiplasminic drug. Laboratory abnormalities were limited to shortened euglobulin-lysis time and whole blood clot lysis time. No circulating alpha-2-plasmin inhibitor was found in the plasma. Even though only one case was observed, autosomal recessive inheritance was undoubted because the parents were consanguineous and both had plasma antiplasmin levels about half normal. The authors called the condition Miyasato disease after the proband's surname.