Which statement correctly lists the factors involved with Hemophilia A, B, and C?

Which statement correctly lists the factors involved with Hemophilia A, B, and C?

• A. Hemophilia A = Factor VIII; Hemophilia B = Factor IX; Hemophilia C = Factor XI
• B. Hemophilia A = Factor IX; Hemophilia B = Factor VIII; Hemophilia C = Factor XI
• C. Hemophilia A = Factor XI; Hemophilia B = Factor XII; Hemophilia C = Factor VIII
• D. Hemophilia A = Factor II; Hemophilia B = Factor X; Hemophilia C = Factor VII

Answer: (D)

Clotting disorders named hemophilia are defined by which clotting factor is deficient in the intrinsic pathway. Hemophilia A is due to lack of factor VIII, Hemophilia B to lack of factor IX, and Hemophilia C to lack of factor XI. Those factors (VIII and IX) form part of the intrinsic tenase complex that amplifies thrombin generation, while XI activates IX to feed the same pathway. In contrast, factors II (prothrombin), VII, and X belong to other parts of the cascade—VII with the extrinsic pathway and X with the common pathway—so pairing Hemophilia A with II, Hemophilia B with X, and Hemophilia C with VII misidentifies the diseases. The correct understanding is that A maps to VIII, B maps to IX, and C maps to XI, with Hemophilia C being autosomal recessive and often milder.

Clotting disorders named hemophilia are defined by which clotting factor is deficient in the intrinsic pathway. Hemophilia A is due to lack of factor VIII, Hemophilia B to lack of factor IX, and Hemophilia C to lack of factor XI. Those factors (VIII and IX) form part of the intrinsic tenase complex that amplifies thrombin generation, while XI activates IX to feed the same pathway. In contrast, factors II (prothrombin), VII, and X belong to other parts of the cascade—VII with the extrinsic pathway and X with the common pathway—so pairing Hemophilia A with II, Hemophilia B with X, and Hemophilia C with VII misidentifies the diseases. The correct understanding is that A maps to VIII, B maps to IX, and C maps to XI, with Hemophilia C being autosomal recessive and often milder.