Molecular Classification
Serine protease zymogen, Peptidase family S1, Vitamin K-dependent protein
Other Names
Christmas factor, F9, HEMB, P19, PTC, THPH8, Blood coagulation factor IX, Plasma thromboplastin component
Disease Roles
Hemophilia BBleeding disorder

Coagulation Factor IX Overview

Coagulation Factor IX (FIX), also known as Christmas factor, is a vitamin K-dependent serine protease zymogen essential for normal hemostasis and blood clot formation. It is activated to Factor IXa by Factor XIa or VIIa/tissue factor, which then forms a complex with Factor VIIIa to activate Factor X. Deficiency or dysfunction leads to hemophilia B, treated with replacement therapy using plasma-derived or recombinant FIX.

Mechanism of Action

Replaces deficient or non-functional Factor IX to restore normal blood clotting ability.

Biological Functions

Blood coagulation
Hemostasis
Activation of Factor X

Disease Associations

Hemophilia B
Bleeding disorder

Safety Considerations

  • Thromboembolic events
  • Hypersensitivity reactions
  • Development of inhibitors (antibodies against Factor IX)
  • Anaphylaxis

Interacting Drugs

Benefix®
Idelvion®
Ixinity®
Rixubis®
Recombinant human Coagulation Factor IX

Associated Biomarkers

Biomarker
Factor IX activity levels
Factor IX antigen levels