| Popis: |
A 28 year old black man who had never had a bleeding syndrome was found to have a long plasma activated partial thromboplastin time which could not be attributed to deficiencies of Hageman factor, Fletcher factor (a prekallikrein), PTA, Factor VIII, or factor IX. The prothrombin time was normal. In addition to delayed clotting, the release of kinin and generation of fibrinolytic activity upon exposure of the plasma to an activating surface was markedly impaired. Defective blood coagulation and kinin release were corrected by plasma from persons with Hageman trait, Fletcher factor deficiency, and PTA deficiency, but not by plasma from each of 2 patients with Fitzgerald trait. The addition of preparations of activated Hageman factor and of kallikrein to this defective plasma did not correct the coagulation defect. The concentration of kininogen in the plasma of the propositus was less than 1% of that in normal plasma, as measured by the release of kinin from the heated plasma during treatment with trypsin. The incidence of the defect in this kindred indicates that it is inherited as an autosomal recessive trait, for 5 of 13 relatives in 3 generations were partially deficient in Fitzgerald factor, determined with a coagulation assay, and in kininogen, quantified as kinin released by trypsin. Thus, Fitzgerald trait appears to be associated with a functional deficiency of a kininogen which may be important for the effective function of activated Hageman factor in generating clot promoting and fibrinolytic activity in plasma. |
