Hemophilia A is the most common form of hemophilia. People with hemophilia A, also called “classic hemophilia,” have a deficiency in clotting factor VIII. The clotting factor is either missing or is present at a low level.³

Hemophilia A occurs across all populations in the world.¹ Hemophilia A is found almost exclusively in males, occurring in about 1 in every 10,000 males.³ Approximately 18,000 individuals in the United States have hemophilia.³