A FUNCTIONAL FACTOR-X DEFICIENCY

A functional factor X deficiency is described which caused pronounced reduction in the in vitro activation of the extrinsic system while mar ginally affecting the in vitro activation of the intrinsic pathway. Al l studies were normal with the exception of a prolonged PT, an elevate d factor X antigen, and low factor X activity. Western blot analysis r evealed the presence of two factor X species. The abnormal molecule wa s of higher molecular weight. Interestingly, there was no bleeding ass ociated with this deficiency. The biochemical basis of this defect is currently under investigation. (C) 1995 Wiley-Liss, Inc.