Hemophilia A

What is Hemophilia A?

Hemophilia A is the most common type of hemophilia. It is caused by a mutation in the gene that makes clotting factor 8 (VIII). This makes it hard for the blood to clot, so people often spontaneously bleed or bleed for a long time after an injury. Hemophilia A is also known as classic hemophilia.(1)

Other condition names

  • FVIII deficiency
  • Factor VIII deficiency

Inheritance type

X-linked recessive


  • United States: 1-9 in 100,000
  • Europe: 1-9 in 100,000

Age of Onset

  • Childhood
  • Infancy
  • Neonatal

  1. What is Hemophilia? Centers for Disease Control and Prevention. Available at https://www.cdc.gov/ncbddd/hemophilia/facts.html. Accessed 12/8/2022.

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