Investigation of Patients With Mild Thrombasthenia—a Haemorrhagic Disorder With Prolonged Bleeding Time Probably Due to a Primary Platelet Defect

Fifteen families with a haemorrhagic disorder are reported. The patients had a bleeding tendency characterized by easy bruisability, nose bleeding, menorrhagia and bleeding after tooth extractions, accidents or surgery. Laboratory investigation showed prolonged Ivy bleeding time and usually decreased platelet adhesiveness, as measured by Hellem's whole blood method, Salzman's method and occasionally Hellem's plasma‐ADP method. Factor VIII and other coagulation factors were normal. The prothrombin consumption test was mostly normal and there was no pathologic fibrinolysis. The inheritance was probably dominant, but the penetrance weak. The disease was probably caused by a primary platelet defect, especially since a similar syndrome was found among relatives of a family with severe thrombasthenia of Glanzmann's type. We call the condition mild thrombasthenia.