Gosset Molecular Classification
Serine protease zymogen, Coagulation factor
Other Names
Factor XI, Plasma thromboplastin antecedent, PTA, F11
Disease Roles
Coagulation Factor XI Overview
Coagulation factor XI (FXI), also known as plasma thromboplastin antecedent (PTA), is a serine protease zymogen that plays a critical role in the intrinsic pathway of blood coagulation. It circulates in plasma primarily as an inactive homodimer and is activated by factor XIIa, thrombin, or FXIa itself. Once activated to FXIa, it cleaves and activates factor IX (FIX), leading to thrombin generation and fibrin clot formation. Deficiency in FXI can cause a mild to moderate bleeding disorder. Emerging therapies target FXIa to prevent thrombosis, highlighting a complex role for FXI in both bleeding and clotting.
Mechanism of Action
Inhibition of FXIa activity (e.g., antisense oligonucleotides)
Biological Functions
Blood coagulation
Hemostasis
Activation of coagulation cascade
Activation of FIX
Thrombin generation
Disease Associations
Factor XI deficiency
Thrombosis (potential paradoxical role)
Safety Considerations
- Bleeding risk (in deficiency states)
- Thrombotic risk (with FXIa inhibitors - potential paradox)
Associated Biomarkers
| Biomarker |
|---|
| FXI activity levels |
| FXI antigen levels |
| F11 gene mutations |