Which coagulation factor is known as the "Christmas factor"?

Factor IX is commonly referred to as the "Christmas factor." This name originates from a historical case involving a patient named Stephen Christmas, who was diagnosed with hemophilia B, a condition linked to deficiencies in Factor IX. Hemophilia B is characterized by an inability to properly form blood clots due to the lack of this specific factor, which is critical for the coagulation cascade.

In the coagulation process, Factor IX plays a vital role in activating Factor X, which leads to the conversion of prothrombin to thrombin, ultimately aiding in the formation of a clot. The significance of Factor IX is underscored by its role in maintaining hemostasis, and its deficiency results in bleeding disorders primarily affecting males.

The other factors mentioned, such as Factor VIII, Factor VII, and Factor X, while important in the coagulation pathway, are not associated with the term "Christmas factor." Factor VIII is linked to hemophilia A, Factor VII is involved in the extrinsic pathway of coagulation, and Factor X is part of both intrinsic and extrinsic pathways but is not synonymous with the Christmas factor designation.