What is haemophilia?

Haemophilia is a severe inherited bleeding disorder in which the blood does not clot properly.

There are, among others, two forms of haemophilia, haemophilia A (the activity of clotting factor VIII is greatly reduced or completely absent) and haemophilia B (clotting factor IX is only produced to a very limited extent or not at all).

Many more people are affected by haemophilia A than by haemophilia B.

In both forms of the blood coagulation disorder, the disease occurs mainly in men.

Depending on the residual activity of the partially or completely missing clotting factor, this leads to spontaneous bleeding, mostly into the joints. People with haemophilia do not bleed more than people without haemophilia, but they bleed longer.1 Furthermore, the recurrent bleeding can lead to considerable damage, especially in the joints.

Haemophilia is always passed on from the mother to the male offspring, as it is an X-linked recessive trait. In the very rare case that a girl has haemophilia, the father with haemophilia is also involved in the transmission in addition to the mother.

As the most common form of haemophilia, haemophilia A affects 1,000,000 people worldwide1 and about 600 people in Switzerland.2

The following video clearly explains the clotting cascade:

Severity of haemophilia A

Haemophilia can be divided into different degrees of severity depending on how much the activity of the factor is reduced compared to unaffected people. The factor VIII activity of unaffected people serves as a baseline. The lower the residual activity of the clotting factors, the slower the blood clots and the more pronounced the symptoms.

The severity of haemophilia determines the treatment.1

Symptoms and diagnosis

Haemophilia is often diagnosed in the first years of life. The following symptoms may occur:

  • Frequent haematomas (bruises)

  • Muscle and joint bleeding

  • Spontaneous bleeding

  • Persistent bleeding after minor injuries or surgical procedures1

Overview of haemophilia therapies

The fundamental element of treatment is the replacement of the missing clotting function.


  1. Srivastava, A, Santagostino, E, Dougall, A, et al. WFH Guidelines for the Management of Hemophilia, 3rd edition. Haemophilia. 2020: 26(Suppl 6): 1‐ 158.

  2. Schweizerische Hämophilie-Gesellschaft. Hämophilie - Die Blutkrankheit. Last accessed 17. Februar 2022:


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