PASSOVOY DEFECT - FURTHER CHARACTERIZATION OF A HEREDITARY HEMORRHAGIC DIATHESIS

We studied a coagulation abnormality present in 12 members of five kindreds who bruised easily and bled excessively after minor trauma. Their activated partial thromboplastin times were between 32 and 39 seconds (normal, 22.8 to 28.8 seconds). Prothrombin times, thrombin times, platelet-function tests and the levels of factors XII, XI, IX, VIII, prekallikrein and high-molecular-weight kininogen were normal. Within these kindreds inheritance of prolonged partial thromboplastin times followed an autosomal and probably dominant pattern. The prolonged thromboplastin times were corrected by normal plasma and by normal plasma adsorbed with celite, but there was no mutual correction between plasmas of the patients. These subjects shared a common defect in the intrinsic pathway of coagulation that we designate by the proband's surname, Passovoy. (N Engl J Med 298:1045–1048, 1978) RECENTLY, we reported a hereditary bleeding diathesis characterized by a small but appreciable prolongation of the activated partial thromboplastin time.1 The patients had normal levels of all the reported clotting factors, including high-molecular-weight kininogen2 3 4 5 6 and Fletcher factor (prekallikrein) with no demonstrable inhibitor. Accordingly, the prolonged partial thromboplastin time was attributed to a deficiency of a hitherto unrecognized clotting factor and referred to as the Passovoy defect after the proband's surname, with the family's consent. In this communication we report studies on 12 patients with this defect from five kindreds and further investigations into the nature of the defect. Case Reports. © 1978, Massachusetts Medical Society. All rights reserved.