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Types of Hemophilia / Haemophilia

Hemophilia A and Hemophilia B

There are two main types of hemophilia - Hemophilia A (due to factor VIII deficiency) and Hemophilia B (due to factor IX deficiency). They are clinically almost identical and are associated with spontaneous bleeding into joints and muscles and internal or external bleeding after injury or surgery.

After repeated bleeding episodes permanent damage may be caused to the joints and muscles that have been affected, particularly the ankles, knees and elbows.

Approximately 1 in 5,000 males is born with Hemophilia A, and 1 in 30,000 males is born with Hemophilia B. Hemophilia affects people of all races and ethnic origins globally. The conditions are both X-linked and virtually all sufferers of hemophilia are males. Female carriers may also bleed abnormally, because some have low levels of the relevant clotting factor.

People with hemophilia have a genetic mutation in the affected gene on the X chromosome, which results in reduced production of Factor VIII or IX and creates a bleeding tendency, because coagulation takes much longer than normal, thus making the clot weak and unstable

Approximately one third of patients with hemophilia have no family history of the disease, either because of new genetic mutations, or because previous affected generations either had daughters (who were carriers) or sons who died in early childhood from hemophilia or any other cause or who were not affected.

Acquired hemophilia

This is very rare. The patient develops the condition during his/her lifetime and it does not have a genetic or heritable cause. It occurs when the body forms antibodies that attack one or more blood clotting factors, (usually factor VIII), thus preventing the blood clotting mechanism from working properly. Patients may be male or female and the pattern of bleeding is rather different from that of classical hemophilia, the joints being rarely affected. The disorder is particularly associated with old age and occasionally complicates pregnancy.





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This Hemophilia information section was written by Christian Nordqvist for Medical News Today, and may not be re-produced in any way without the permission of Medical News Today. Additional materials provided by Wyeth.


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Disclaimer: The Hemophilia section on Medical News Today is funded by an educational grant from Wyeth. This guide is provided for general information purposes only. The materials contained within this guide do not constitute medical or pharmaceutical advice, which should be sought from qualified medical and pharmaceutical advisers. Full disclaimer.


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Blood / Hematology

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Hemophilia is a group of inherited blood disorders in which the blood does not clot properly. Bleeding disorders are due to defects in the blood vessels, the coagulation mechanism, or the blood platelets. Read more...

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