,3,4 Its prevalence is approximately 1 per 5000–10,000 live male births for hemophilia A, and 1 per 30,000–40,000 live male births for hemophilia B.1,4,5 According to the consensus of the International Society of Thrombosis and Haemostasis, this dyscrasia is classified based on plasma levels of factor VIII (FVIII) or factor IX (FIX): severe (<1 % of normal), moderate (1–5 % of normal), and mild (5–40 % of normal).1 This evidence concerns the gene F8 and hemophilia B.