Hemophilia is a rare disorder in which blood doesn’t clot in the typical way because it doesn’t have enough blood-clotting proteins (clotting factors).

The two most common types of hemophilia are A and B.

Hemophilia A is the most common type of hemophilia and is caused by a lack of blood clotting factor VIII, whereas hemophilia B is caused by a lack of factor IX (FIX).

The more severe the condition, the less able a person is to form blood clots, making them more vulnerable to bleeding.

gene therapy aims to enable patients to create their own factor, potentially delivering lasting bleed protection for years. Gene therapy can potentially provide long-term benefits of sustained factor activity levels from a single administration of treatment, potentially reducing or even eliminating the need for regular, long-term prophylaxis.