Pathogenesis (development of disease)
Hemophilia A is caused by the decrease or complete absence of clotting factor VIII (FVIII, hemophilia A). Hemophilia B, on the other hand, is caused by the reduction or complete absence of clotting factor IX (FIX, hemophilia B).
The clotting factors are part of the clotting cascade. If any part of this cascade is disturbed, bleeding tendency occurs.
Hemophilia is inherited in an X-linked recessive manner. X-linked means that the gene for the disease is located on the X chromosome. Recessive means that the gene is recessive to its partner in inheritance. As a result, hemophilia occurs almost exclusively in males, since they do not have a second X chromosome (XY). Very rarely it happens that a woman has two X chromosomes with the gene for the disease (= homozygous carrier), then she also suffers from hemophilia.
Approximately 15% of the diseases develop sporadically or through spontaneous mutations.
Etiology (Causes)
Biographic causes
- Genetic burden from parents, grandparents.
