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Haemophilia B

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A form of haemophilia that is caused by a deficiency in blood clotting factor IX due to a gene defect in the long arm of the X chromosome


Haemophilia is a congenital tendency to uncontrolled bleeding from the mouth, gums, lips, and tongue. Other symptoms include haematuria, haemarthoses, and subcutaneous and intramuscular haemorrhages. Haemophilia is often affecting males and is transmitted from mother to son. There are different forms of haemophilia: haemophilia A, haemophilia B, haemophilia C, and parahaemophilia.

Haemophilia B is caused by a gene defect near the telomere of the long arm of the X chromosome. Most cases are transmitted as X-linked recessive trait. It is usually transmitted from mother to son. The gene defect leads to an impaired production of factor IX. Thus, the resulting deficiency in factor IX could hamper blood clot formation since factor IX is an essential component of blood coagulation system that ultimately converts fibrinogen into insoluble fibrin mesh network, which is essential in stabilizing the platelet plug formed during tissue injury repair (blood vessel injury).


  • hemophilia B


  • Christmas disease
  • factor IX deficiency
  • coagulation factor IX deficiency
  • clotting factor IX deficiency
  • FIX deficiency

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