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What is VWD?

von Willebrand disease, or VWD, is the most common inherited bleeding disorder, affecting both men and women. Because most cases of VWD are mild and may not produce noticeable symptoms, it often goes undiagnosed.

What causes VWD?

VWD occurs when von Willebrand factor (VWF), a protein that helps form blood clots to stop bleeding, is missing or doesn’t work the way it should. Because of this, when people with VWD bleed from cuts or injuries, their bleeding takes longer to stop.

woman holding little girl

The clotting process—Step by step

Terms to Know

Factor VIII (FVIII): A protein in the blood, called a clotting factor, that is needed for clot formation

Coagulation cascade: A process involving the interaction of multiple clotting factors, resulting in the formation of fibrin, which strengthens the blood clot

Platelets: Blood cells that gather at the site of injury

Fibrin: A tough web-like protein that holds platelets together and keeps the clot in place

Normal clotting

normal blood vessel with normal clotting

Normal blood vessel

injured blood vessel with normal clotting

Blood vessel is injured

  • VWF binds to FVIII and triggers blood platelets to join together, forming a plug to support clotting
  • In this process, called platelet adhesion, platelets stick together at the site of injury
clot forms and stabilizes with normal clotting

Clot forms and stabilizes

  • The platelet plug is reinforced by a tough mesh of fibrin, which forms a fibrin clot
  • Other clotting factors in the coagulation cascade are important in clot formation

Abnormal clotting

normal blood vessel with abnormal clotting

Normal blood vessel

injured blood vessel with abnormal clotting

Blood vessel is injured

clot forms incorrectly with abnormal clotting

Clot forms incorrectly or not at all

Adapted from the National Heart, Lung and Blood Institute. The Diagnosis, Evaluation, and Management of von Willlebrand disease. Bethesda, MD: National Institutes of Health; 2007. NIH publication 08-5832

Learn how HUMATE-P can help treat VWD


  1. Centers for Disease Control and Prevention (CDC). Facts about von Willebrand Disease. Published March 20, 2015. Accessed April 27, 2015.
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