Hemophilia is a communicable disease

Types of disease: what types of hemophilia are there?

Author: PD Dr. med. G. Tallen, created on: 01/10/2014, last changed: 04/01/2020

Hereditary diseases such as haemophilia are caused by altered genetic makeup (gene e) (see "causes"). In hemophilia, genes are affected that are responsible for the formation of certain proteins (coagulation factors). These coagulation factors are indispensable for normal, i.e. timely and successful, endogenous hemostasis.

Hemophilia A and B

In the majority of hemophiliacs, there is a change (mutation) in the genetic make-up for factor VIII (hemophilia A). Fewer patients suffer from haemophilia B, in which the gene for factor IX is mutated.

The distinction between the two forms of haemophilia A and B is vital for those affected: although the forms of the disease usually differ only slightly in their courses, the respective treatments cannot be transferred from one form of haemophilia to the other (see "Treatment").

Severity of hemophilia

The severity of hemophilia is genetically determined. The less the coagulation factor can be formed (residual activity), the more severe the disease and the greater the risk of bleeding for those affected.

The residual activity of coagulation factors VIII or IX in a patient's blood provides an indirect indication of the extent of the bleeding tendency for both patients with hemophilia A and B.

The bleeding tendency tends to be more pronounced in patients with haemophilia A than in haemophiles with factor IX deficiency. However, strong individual fluctuations are possible, so that this tendency cannot be generalized.

According to the definition of the International Society for Thrombosis and Haemostasis (isth), the following degrees of severity of haemophilia are differentiated based on the residual activity of the factor in the patient's blood:

  • severe haemophilia: residual activity below 2%
  • moderate haemophilia: residual activity 2 - 5%
  • mild haemophilia: residual activity over 5%

Details on the various degrees of severity can be found in the next chapter (see "Signs of illness").

International Society on Thrombosis and Haemostasis (isth)

The International Society for Thrombosis and Hemostasis was founded in 1969. Its headquarters are in Carborro, North Carolina (USA). Isth's committee, the Scientific and Standardization Committee (SSC), sets blood plasma standards.More