Which factor is deficient in Hemophilia A?

Hemophilia A is specifically associated with a deficiency in Factor VIII, which is crucial for the blood coagulation process. This factor plays a significant role in the intrinsic pathway of the coagulation cascade, aiding in the activation of Factor X, which ultimately leads to the conversion of prothrombin to thrombin and the formation of fibrin. When there is a deficiency of Factor VIII, the body's ability to form stable blood clots is severely impaired, leading to excessive bleeding from minor injuries or spontaneously.

The other factors listed—Factors IX, X, and V—are associated with different bleeding disorders or aspects of the coagulation pathway but are not linked to Hemophilia A. Factor IX is deficient in Hemophilia B, while Factors X and V are involved in different stages of coagulation and do not pertain to the condition of Hemophilia A. Understanding the specific deficiencies associated with different types of hemophilia is crucial for diagnosis and management.