| Description: |
Factor X is a vitamin K-dependent clotting factor synthesized in the liver. Activated factor X (factor Xa) converts prothrombin to thrombin in the final common pathway of clotting. Deficiencies in factor X therefore result in prolongation of both the PT and PTT. Congenital deficiency is inherited as an autosomal recessive trait. Acquired deficiency most commonly occurs with liver disease, vitamin K deficiency, or warfarin therapy. Acquired factor X deficiency has also been described in patients with amyloidosis (due to absorption of factor X by amyloid) and in acute leukemia. Acquired inhibitors to factor X are rare. Severe deficiencies of factor X (activity <1%) result in a bleeding diathesis similar to that of severe hemophilia A. |
