[Hereditary deficiency of a new coagulation factor acting at the "contact" level: the "Flaujeac" factor].

The observation of a coagulation defect which has been observed in an adult French woman is reported. This deficiency which induces no bleeding tendency is characterized by a considerable lengthening of the activated Partial Thromboplastin Time and an abnormality of the fibrinolysis activation. Circulating anticoagulant is absent. The levels of HF, PTA, AHF, PTC are normal and mutual correction with Fletcher factor deficient plasma is obtained. This result leads to the conclusion that patient's plasma is dificient in a hitherto undescribed coagulation factor. This factor seems to interfere, in vitro process, at the level of glass activation, and after the activation of Hageman factor.