This disorder results from a deficiency or defect in the protein known as von Willebrand Factor (VWF).
It is named after the Swedish clinician who first discovered the condition. VWF is involved in more than one stage of blood clotting. It is the protein that binds platelets to damaged tissue promoting their aggregation at the earliest stage of clot formation. It also acts as a transporter of Factor VIII in the circulation. In plasma, Factor VIII is bound to VWF which protects it and stops its breakdown.
VWD is quite a common condition, and as many as 1 in 100 of the population may be mildly affected, although most are not aware of it because they have no symptoms. Fortunately, a large majority of those affected do not have the most severe form of VWD. The disorder is not sex-linked and both males and females may be affected. The bleeding problems experienced by VWD patients are often mucosal (nose bleeds, gastrointestinal bleeds, heavy menstrual bleeding for women, etc.). Some people with VWD receive treatment with the hormone analogue DDAVP (which is not a blood product). Where DDAVP is not effective, then replacement using plasma-derived VWF concentrates takes place.