Von Willebrand factor (vWF) is a large hemostatic glycoprotein which serves several roles in platelet aggregation and the clotting cascade.
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Physiology
vWF is synthesized by vascular endothelial cells and megakaryocytes. A series of complex post-translational modifications result in the creation of physiologically active large-molecular-weight vWF multimers (LMWMs) and ultra large-molecular-weight multimers (ULMWMs) 1. It is encoded by the large VWF gene on the short arm of chromosome 12 3.
The active forms of vWF are released by injured endothelium, which promotes hemostasis by three mechanisms 2,3:
platelet adhesion: vWF binds to exposed collagen, which allows binding of GpIb resulting in platelet adhesion
platelet aggregation: vWF on adhered activated platelets irreversibly binds to GpIIb/IIIa to form the initial platelet plug
coagulation: vWF binds and stabilizes factor VIII in the clotting cascade, prolonging its half-life
Ongoing research is identifying further interactions of vWF in inflammation, hemorrhagic shock and traumatic brain injury 3.
Related pathology
Von Willebrand disease is a bleeding diathesis due to a deficiency in vWF. It is the most common inherited disorder of hemostasis.
History and etymology
It is named after Erik Adolf von Willebrand (1870-1949), Finnish physician and medical professor, who first described von Williebrand disease in 1926 2.