Hemophilia B is due to deficiency of-

Hemophilia B is due to deficiency of factor 9 and is also called as Christmas disease. Factor 8 deficiency causes Hemophilia A. There are two main types of haemophilia: haemophilia A, which occurs due to low amounts of clotting factor VIII, and haemophilia B, which occurs due to low levels of clotting factor IX. They are typically inherited from one's parents through an X chromosome with a nonfunctional gene. Rarely a new mutation may occur during early development or haemophilia may develop later in life due to antibodies forming against a clotting factor. Other types include haemophilia C, which occurs due to low levels of factor XI, and parahaemophilia, which occurs due to low levels of factor V. Acquired haemophilia is associated with cancers, autoimmune disorders, and pregnancy. Diagnosis is by testing the blood for its ability to clot and its levels of clotting factors Reference; Robbins and Cotran Pathologic basis of disease.South Asia Edition -9volume 1.page no. 662,663