blood disorders
Von Willebrand Disease
Introduction
Von Willebrand disease is a hereditary deficiency or abnormality of the blood proteinvon Willebrand factor, which affects platelet function, causing excessive bleeding. (See also Overview of Platelet Disorders and is present in plasma, platelets, and the walls of blood vessels. Platelets are cells that are made in the bone marrow and circulate in the bloodstream and help How Blood Clots . When the Platelets are cells that circulate in the bloodstream and help How Blood Clots . The blood usually contains about 140,000 to 440,000 platelets per microliter (140 to 440 × 10 There are three main types of von Willebrand disease, all of which are inherited. The types differ on the degree of deficiency of the factor. People with the greatest deficiency have a higher risk of bleeding. Less commonly, people can develop von Willebrand disease without inheriting an abnormal gene, and this condition is called acquired von Willebrand disease. For example, people with certain cancers or autoimmune disorders sometimes form antibodies tovon Willebrand factor. In other people with certain heart and blood vessel diseases,von Willebrand factoris broken down and becomes deficient. In both cases, as in inherited von Willebrand disease, the result is increased bleeding. 