Which of the following coagulation factors is affected in hemophilia B?

A Factor VIII
B Factor IX ✓
C Factor XI
D Factor XIII

Explanation

Hemophilia B, also known as Christmas disease, is caused by a deficiency or dysfunction of factor IX.

Mnemonic

B = Broken X (factor IX)

Source

Robbins and Cotran Pathologic Basis of Disease
Hematology Hematology: Coagulation Disorders Hematology: Coagulation Disorders Easy MEDICAL PYQ 2018 2018 Confidence: high