F11

F11 Full Name

coagulation factor XI

F11 Introduction

Coagulation factor XI (FXI), encoded by the F11 gene, is a plasma serine protease that plays an important regulatory role in the intrinsic pathway of the blood coagulation cascade. FXI is primarily synthesized in the liver and circulates in the bloodstream as an inactive homodimeric zymogen. Upon activation, it is converted into factor XIa, which subsequently activates factor IX and amplifies thrombin generation, thereby promoting stable clot formation. For clinicians and researchers working on thrombosis, hemostasis disorders, and anticoagulant drug development, FXI has become a particularly compelling molecular target because it contributes significantly to pathological thrombosis while appearing less essential for normal hemostasis. This unique biological feature has sparked intense interest in FXI as a next-generation anticoagulant target, especially for patients who require effective thrombosis prevention but face high bleeding risks with conventional therapies.

Functionally, FXI acts as an amplification component within the coagulation network rather than as a primary initiator of clot formation. It can be activated by factor XIIa during contact activation or by thrombin through feedback activation, which strengthens and stabilizes clot propagation. Because this pathway contributes strongly to thrombosis in certain pathological conditions—such as surgical trauma, cardiovascular disease, or extracorporeal circulation—selective inhibition of FXI has emerged as a promising therapeutic strategy. Clinical research has demonstrated this concept in practice. For example, monoclonal antibody therapies targeting FXI, such as Abelacimab, have shown remarkable results in clinical trials for the prevention of venous thromboembolism after total knee arthroplasty. In these studies, a single intravenous administration significantly reduced the incidence of postoperative thrombotic events compared with standard anticoagulant therapy, while maintaining an extremely low bleeding risk. Such findings highlight FXI as a rare coagulation target capable of separating antithrombotic efficacy from bleeding complications—an ongoing challenge in anticoagulant drug development.

Beyond therapeutic targeting, the F11 gene is also closely associated with inherited bleeding disorders. Mutations in F11 can lead to factor XI deficiency, sometimes referred to as hemophilia C, a rare genetic condition characterized by reduced FXI activity and impaired clot stability. Unlike classical hemophilia, bleeding symptoms are often variable and may appear primarily after surgery or trauma, making diagnosis challenging. Recent genetic studies have identified multiple novel F11 variants that disrupt FXI secretion, stability, or enzymatic activity, expanding the known mutation spectrum of this disorder. Advances in genomic technologies such as whole-exome sequencing have further enabled the identification of rare pathogenic variants in affected families, improving molecular diagnosis and genetic counseling. Together, these discoveries underscore the dual importance of FXI in both thrombosis research and hereditary bleeding disorders, making it an increasingly valuable biomarker and therapeutic target in modern hematology and translational medicine.

Alternate Names for F11

F11; coagulation factor XI; FXI; PTA; plasma thromboplastin antecedent;

• 1.Jiang S, et al.; Gene Variants in Two Families with Inherited Coagulation Factor XI Deficiency and Identification of Mutations. Acta Haematol. 2023, 146(2):106-116.
  2.Liang C, et al.; Case Report: Allelic and biallelic variants in coagulation factor XI cause factor XI deficiency. Front Cardiovasc Med. 2024, 11:1461899.