View our Factor IX products
Factor IX Quick Facts
- Molecular weight: 55 400 D
- Synthesis: Liver
- Half-life: 18 – 30 hours
- Plasma concentration: 3 – 5μg/ml
- Normal range: 70 – 130%
Factor IX (Christmas factor) is one of the serine proteases of the coagulation system.
Factor IX protein deficiency causes hemophilia B.
Factor IX is produced as a zymogen, an inactive precursor. It is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (contact pathway) or factor VIIa (tissue factor pathway) to produce a two-chain form where the chains are linked by a disulfide bridge. When activated into factor IXa, in the presence of Ca2+, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa.
Factor IX is inhibited by antithrombin.
Biochemistry of Factor IX (FIX)
The vitamin K-dependent factor IX (also called Antihaemophilic Globulin B or Christmas-Factor) is activated by factor XIa from the intrinsic system and by the tissue factor/factor VIIa-complex of the extrinsic system (Josso-loop). Factor IXa with factor VIII as cofactor, phospholipids and calcium ions forms the tenase-complex on which the activation of factor X takes place.
Clinical significance of Factor IX
Hereditary factor IX deficiency is passed on X-chromosomally recessive and is defined as hemophilia B. Its course and symptoms are comparable to those of hemophilia A. However, the course of the disease, in which spontaneous bleeding may occur, is somewhat milder. An acquired factor IX-deficiency occurs as a result of vitamin K-deficiency, liver disease, asparaginase therapy and DIC. In substitution therapy formation of inhibitors against factor IX can be observed in 2-4% of the subjects.
Clinical or Research use of Factor IX
- Suspected hemophilia B
- Monitoring of substitution therapy in hemophilia B
- Suspected inhibitor formation against factor IX
- Factor IX determination in factor IX-concentrates View our Factor IX products