Which pairing matches a factor with its related bleeding disorder?

Which pairing matches a factor with its related bleeding disorder?

• A. Factor VIII — Hemophilia B
• B. Factor IX — Hemophilia B
• C. Factor X — Von Willebrand disease
• D. Factor XI — Hemophilia A

Answer: (B)

This question tests which coagulation factor deficiency underlies a specific inherited bleeding disorder. Hemophilia A is caused by a deficiency of factor VIII, while Hemophilia B is caused by a deficiency of factor IX. Von Willebrand disease results from a deficiency or dysfunction of von Willebrand factor, which helps platelets stick and also protects factor VIII, so it is not a deficiency of factor X. Therefore the correct pairing is factor IX with Hemophilia B, since Hemophilia B arises from a lack of factor IX. The other options mix wrong factor-deficiency pairings: a missing factor VIII is Hemophilia A, von Willebrand disease is not due to factor X deficiency, and factor XI deficiency is associated with Hemophilia C, not Hemophilia A.

This question tests which coagulation factor deficiency underlies a specific inherited bleeding disorder. Hemophilia A is caused by a deficiency of factor VIII, while Hemophilia B is caused by a deficiency of factor IX. Von Willebrand disease results from a deficiency or dysfunction of von Willebrand factor, which helps platelets stick and also protects factor VIII, so it is not a deficiency of factor X. Therefore the correct pairing is factor IX with Hemophilia B, since Hemophilia B arises from a lack of factor IX. The other options mix wrong factor-deficiency pairings: a missing factor VIII is Hemophilia A, von Willebrand disease is not due to factor X deficiency, and factor XI deficiency is associated with Hemophilia C, not Hemophilia A.