A Familial Hemorrhagic Trait Associated With a Deficiency of a Clot-Promoting Fraction of Plasma 1

Recently, three patients have been studied in whom the clotting time of venous blood was greatly prolonged. None of the patients had significant hemorrhagic symptoms. The trait was apparently familial and appeared in both sexes. The pa- tients' disorder could not be identified with any known bleeding disease. However, in each case, the plasma was deficient in a substance found in normal globulin which accelerated the clotting of normal, platelet-deficient plasma.