Haemophilia B is a bleeding disorder where a protein made by the body to help make blood clot is either partly or completely missing. This protein is called a clotting factor: with haemophilia B there is a deficiency of clotting factor IX (nine).

It is a genetic condition with everyone who has it was born with it. Around two thirds have a family history of the disorder whilst in the rest it is a new case. Haemophilia B mainly affects boys and men; women can be 'carriers' of the affected gene and may experience symptoms. Only about 20% of people with haemophilia have haemophilia B, so it is a rare condition, affecting about one in every 50,000 males.

Haemophilia B is classed as mild, moderate or severe, depending on the level of clotting factor IX in the blood. It is diagnosed through blood tests.

The main symptoms are:

• A tendency to bruise easily especially in early childhood
• Excessive bleeding from cuts that takes a long time to stop
• A tendency to bleed into joints and muscles causing pain, swelling and limitation of movement

Haemophilia B is treated by replacing the missing clotting factor IX in the blood through an intravenous infusion of clotting factor concentrate.

Bleeding episodes must be treated promptly to avoid lasting effects. Once the bleeding stops, pain rapidly diminishes and, in the case of limbs, full use returns.

With the right treatment and care, people with haemophilia B can lead fulfilled and healthy lives into old age. However, there is currently no cure for haemophilia B.