Coagulation factor VIII (FVIII) and factor IX (FIX) play a major role in the endogenous and exogenous thrombin pathways, are used to diagnose hemophilia, are often associated with chronic liver disease, act as risk factors for thrombosis, and are used as quality markers of fresh-frozen plasma (FFP) and cryoprecipitate1, 4, 5, 6. The gene discussed is F9; the disease is hemophilia.