Von Willebrand disease
Von Willebrand disease (vWD) is a lifelong bleeding disorder caused by a defect or deficiency of a blood-clotting protein called von Willebrand factor. Von Willebrand factor is a protein that works in the initial stages of blood clotting. This glue-like protein interacts with blood cells called platelets to form a plug, which prevents the blood from flowing at the site of injury. People with vWD are unable to make this plug because they do not have enough von Willebrand factor or their factor is abnormal.