Evidence for a New Plasma Thromboplastin Factor I. Case Report, Coagulation Studies and Physicochemical Properties

Abstract Studies of defective plasma thromboplastin formation in four siblings indicated a defect which was different from any of the known coagulation factor deficiency states. Although none of the children had any history of hemorrhagic tendencies, a prolonged whole blood clotting time in an 11-year-old girl led to the findings of a markedly prolonged partial thromboplastin time (PTT), abnormal thromboplastin generation test (TGT), and a normal prothrombin time in the patient and in three of her ten siblings. The abnormal PTT and TGT were corrected by aluminum hydroxide adsorbed fresh plasma and by serum. Using the kaolin-PTT system, equal mixtures of plasma from the patients and normal plasma produced a normal time. In addition, plasmas deficient in plasma thromboplastin antecedent (PTA), Hageman factor (HF), antihemophilic factor (AHF), or plasma thromboplastin component (PTC) corrected the abnormality. Physical and chemical properties of plasma correcting the defect in vitro indicated that the defect is closely related to that found in PTA and HF deficient plasma.