👉 Hemophilia is a genetic disorder that affects the production of clotting factors in the body. Hemophilia A, which is the most common form, affects the production of factor VIII and IX from the clotting cell line (platelets). Hemophilia B is caused by a mutation in the gene for factor VII but does not affect clotting factors. Hemophilia C is an autosomal recessive disorder that causes hemophilia A and B.