What Is the Definition of Hemophilia B?

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Hemophilia B is also called factor IX (FIX) deficiency. Stephen Christmas was the first patient diagnosed with hemophilia B in 1952. Therefore, the disease is also known as Christmas disease. The other name factor IX (FIX) deficiency is named after its cause. The disease is a genetic disorder due to missing or defective factor IX. The factor IX, which is located on the X chromosome, is a protein to form blood clots. It is an X-linked recessive trait. Most patients develop the disease by inheritance. However, about 1/3 of patients develop the disease due to spontaneous genetic mutation. It is estimated that the incidence of hemophilia B is four times less than hemophilia A.   Keywords: hemophilia vs b; hemophilia b; chromosome hemophilia