New congenital deficiency of high molecular weight kininogen and prekallikrein (Fitzgerald trait). Study of response to DDAVP and venous occlusion.

: The prolonged partial thromboplastin time observed in the plasma of a 36 year old asymptomatic man was related to the reduced prekallikrein activities (coagulant; antigenic; and amidolytic) and the absence of coagulant and immunologic activities of high molecular weight kininogen (HMWKg). The patient's plasma also exhibited impaired surface-mediated fibrinolysis and impaired generation of kallikrein. The coagulation defect was identified as the "Fitzgerald trait". The levels of CH50, C2, C4 and C-1 inactivator were normal. Venous occlusion in the patient gave rise to a normal release of extrinsic plasminogen activator from the vascular endothelium. The administration of DDAVP led to a FVIII/VWF response which was similar to that obtained in healthy subjects. No alteration could be observed in the contact phase proteins after DDAVP administration.