In patients with severe hemophilia A (factor VIII [FVIII] levels < 1 IU/dL), prophylaxis with FVIII replacement therapy remains the standard of care [1] and is associated with a reduction in bleeding, including joint bleeds, thereby protecting patients from further complications associated with recurrent bleeds such as joint disease and disability [1, 2]. The gene discussed is F8; the disease is hemophilia A.