Low Levels of Clotting Factor XI (Hemophilia C)
Much like hemophilia A and B, hemophilia C (known as Rosenthal syndrome) is also a resulting autosomal recessive genetic disorder caused by a deficiency in a clotting factor, this time clotting factor XI (plasma thromboplastin antecedent).
Factor XI (FXI) is the zymogen of a serine protease enzyme. It is produced in the liver and can be found in the intrinsic pathway of the blood coagulation cascade. It circulates with prekallikrein and HMWK and is considered essential in creating a stable fibrin clot. A deficiency in the FXI may result in another type of hemophilia, hemophilia C. It is brought by either creating a more dysfunctional protein or a decreased concentration of normal FXI.
Hemophilia C, brought by a deficiency in Factor XI or plasma thromboplastin antecedent deficiency, was first recognized in 1953 when scientists and doctors found that some patients experienced severe bleeding after dental extractions. Despite the discovery, the disorder remains quite rare as the incidence of hemophilia C is only estimated at 1 in every 100,000 of the general population.
