Understanding Haemophilia


What is haemophilia or von Willebrand’s disease?


Haemophilia is a genetically inherited bleeding disorder where there is a deficiency of a clotting factor in the blood. This results in a form of bleeding tendency. Thus, individuals with haemophilia often suffer from easy bruising and bleeding into muscles and joints. Because of the genetic pattern of inheritance, the disorder generally affects males only. Females with the haemophilia genes are known as carriers.

There are 2 types of haemophilia:

1. haemophilia A: Deficiency of clotting factor 8 (VIII)
2. haemophilia B: Deficiency of clotting factor 9 (IX)

There is another hereditary bleeding disorder known as von Willebrand’s disease (vWD). A patient with vWD has a diminished production of the von Willebrand clotting factor. In contrast with haemophilia, vWD affects both males and females equally. They usually bleed from the nose, mouth or intestinal tract.


The incidence of haemophilia A is 1 in 10,000 males.

The incidence of haemophilia B is 1 in 50,000 males.

There is no known geographical variation in the incidence of haemophilia.

Globally, there are about 350,000 people with severe or moderate haemophilia A. In Singapore, about 200 people are patients of haemophilia A and B.


The severity of the bleeding tendency depends on the range of activity of factor 8 or 9:


Activity Range

Amount of Clotting Factor

Normal person

50 – 200%

0.5 – 2 IU


25 – 49%

0.25 – 0.49 IU



6 – 25%

0.06 – 0.25 IU


1 – 5%

0.01   0.05 IU


< 1%

< 0.01 IU


Additional Reading

Knowing more about haemophilia helps you to understand what your best options are. Ignorance often results in poor treatment and more pain for the individual. Below is a list of books and web references that contain useful information for haemophilia patients.

World Federation of Haemophilia

The website of the World Federation of Haemophilia boasts a large range of literature on haemophilia and related issues, most of which are available for download in pdf format. Recommended for those who have limited knowledge on haemophilia.

Novel treatment product newsletter

This newsletter provides a general overview and understanding of the rapidly evolving landscape of medicinal product development in rare bleeding disorders.

This booklet provides specific information on extended half-life (EHL) clotting factor concentrates.


An additional infographic about treatments-for-haemophilia can be viewed by clicking this link.

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