Haemophilia A and B (ICD9: 286.0 and 286.1; ICD-10-CM code D66) encompass congenital deficiencies of the intrinsic pathway coagulation factors VIII (FVIII) and IX (FIX), respectively, with a variable risk for bleeding based on the type of haemophilia and the extent of factor deficiency [1]. The gene discussed is F8; the disease is hemophilia A.