Names of bleeding disorders
Haemophilia
This is the commonest type of severe bleeding disorder. There are two types -:
- Haemophilia A – this is commonest type of haemophilia in which, clotting factor VIII is abnormally low or absent.
- Haemophilia B – this is the less common type of haemophilia in which, clotting factor IX is abnormally low or absent. This is also known as Christmas disease.
Both haemophilia A and B are sex linked, recessive genetic conditions. This means that the abnormal gene is carried on the X chromosome. The X chromosome is a long chromosome that pairs with another X chromosome in women (XX) and with a very short Y chromosome in men (XY). The Y chromosome does not carry the genes for clotting factors. Women have two copies of the X chromosome carrying genes for clotting factors VIII and IX. In women with the haemophilia gene on one X chromosome the unaffected X chromosome ensures enough clotting factor is produced. In men with the affected X chromosome there is no second X chromosome to ensure clotting factor production and they have haemophilia. Boys with the affected chromosome will be affected by haemophilia, girls with the affected X chromosome will not have haemophilia but they will be carriers and their male children have a 50% chance of being affected by haemophilia. Some carriers may have impaired blood clotting to a level similar to that seen in mild haemophilia.
Around 6000 people have this condition in the UK.
Von Willebrand’s disease
Von Willebrand’s disease is often very mild and is often not diagnosed as there are no episodes of very severe bleeding. This condition is included here because it is occasionally severe. The complications and disability in this condition when severe are the same as in haemophilia. Assessment of impairment and disability should follow that described for haemophilia.
This is a much more common condition than haemophilia. Around 1% of the UK population is affected. Men and women are equally affected. Around 5000 people have been diagnosed with the condition.
Other clotting factor deficiencies are -:
- Factor II deficiency
- Factor VII deficiency
- Factor X deficiency
- Factor XI
- Factor XIII deficiency – often presents with bleeding into the brain and neurological impairment is often the first sign of this condition.
These conditions are very rare with treatment being very similar to haemophilia A and B i.e. with replacement of clotting factors. As with haemophilia, disability is related to complications of bleeding and assessment of impairment and disability should follow that described for haemophilia.
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Amended November 2009
