Definition of Hemophilia B

Hemophilia B: Hemophilia due to deficiency of coagulation factor IX in the blood which results in prolonged oozing after minor and major injuries, tooth extractions, or surgery. There is renewed bleeding after the initial bleeding has stopped.

The gene for hemophilia B gene is on the X chromosome, so males are affected and females carry the gene. About 10% of carrier females are at risk for bleeding. Each son of a female carrier stands a 50 percent chance of receiving the gene and having hemophilia B.

Treatment is by blood products that introduce clotting factor IX and replace lost blood. Hemophilia B is also called Christmas disease (so-named for the first patient studied in detail with the disease).