Haemophilia B is a disorder that causes undue bleeding due to deficiencies with normal blood clotting. It is caused by a genetic mutation of the Factor IX (9) gene, leading to a deficiency of Factor IX. It is the less common form of haemophilia, rarer than haemophilia A, where Factor VIII (8) is involved. It is sometimes called Christmas disease after Stephen Christmas, the first patient described with this disease. In addition, the first report of its identification was published in a Christmas edition of the British Medical Journal.
Haemophilia is a rare genetic blood clotting disorder that primarily affects males. People with haemophilia do not have enough of, or are missing, one of the blood clotting proteins naturally found in blood. People with haemophilia do not bleed more profusely or bleed faster than normal; they bleed for a longer period of time and may suffer from spontaneous internal bleeding.
The two most common forms of haemophilia are haemophilia A and haemophilia B. In people with haemophilia A (also called "classic haemophilia", clotting factor VIII is either not present in sufficient amounts or is absent altogether. In people with haemophilia B (also called "Christmas disease"), clotting factor IX is not present in sufficient amounts or is absent altogether. The majority of people who have haemophilia are male and have inherited the disease. Women can be "carriers" but do not generally have haemophilila themselves. Although it is a genetic disorder, in as many as 30% of cases, there is no family history of haemophilia. In these cases, the mother may carry the gene for haemophilia without being aware of it, or a gene mutation may have occurred spontaneously.
Following correct identification of the type of haemophilia, the usual treatment is replacement of the missing clotting factor to control or prevent bleeding.
Not all treatments are the same
Recombinant DNA technology and the discovery of the genes that control production of factor VIII and factor IX have led to the development of recombinant factor concentrates that are not produced from plasma at all. (Patients should discuss with their physicians which factor replacement therapy is best for them.)
What´ s next? Gene therapy. Research is actively under way to develop a safe and effective gene replacement therapy. This therapy will aim to replace the missing or deficient gene that has the instructions for producing clotting factor, reducing or eliminating the need for factor replacement therapy.