Von Willebrand's disease

Von Willebrand's disease (vWD) is a hereditary clotting disorder that arises from a deficiency of von Willebrand factor (vWF), known to affect humans and dogs. It is a disease caused by problems with platelet adhesion.

In humans, the incidence of vWD is roughly about 1 in 1000 individuals.

There are three described types of vWD, type I, type II and type III, of which type I and II are inherited as autosomal dominant traits and type III is inherited as autosomal recessive.

Type I vWD patients have clearly impaired clotting but usually end up leading a nearly normal life (trouble usually arises in the form of dental surgery or troublesome menorrhagia/periods). Type III is the most severe form of vWD and may have severe mucosal bleeding, no detectable vWF antigen, and/or may have sufficiently low factor VIII that they have occasional hemarthroses like mild hemophiliacs.

Patients with vWD can be treated with cyroprecipitate or with Factor VIII. Mild cases of vWD can be trialled on 1-desamino-8-D-arginine vasopressin (DDAVP), which works by raising the patient's own plasma levels of vWf.

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Information obtained partly from Harrison's textbook of Internal Medicine, online version, Chapter 177.

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Eponymous diseases metanode

Since von Willebrand's is a genetic disorder--probably the most common one in the world--it's technically not a disease, although the name remains. In layperson's terms, the major symptoms include:

- easy or unexplained bruising
- tendency to bleed from the gums/mouth
- frequent and/or long-lasting nosebleeds
- heavy menstrual flow in women

No treatment is usually required, although doctors and surgeons should be aware of the condition before treatment. However, it's unlikely to cause serious problems during surgery unless it's oral surgery. Additionally, since von Willebrand factor naturally increases during pregnancy, abnormal bleeding during birth is relatively uncommon. Those with extreme cases should avoid contact sports.

Von Willebrand's is inherited but autosomal. Both men and women can have the disorder or be non-active carriers. However, many people, including health care professionals, still believe that bleeding disorders only affect males, so the disorder is frequently undiagnosed in women.

It was described by a Finnish doctor, Von Willebrand, in the 1920s. The current preferred name is von Willebrand disease, and reports of its incidence, following further research, have risen to 1 in 100. You can read more about it in any medical database or textbook.

See also:

• pseudohemophilia

This congenital disease, which is caused a deficiency of a blood factor that promotes platelet adhesion, is characterized by prolonged bleeding and poor blood coagulation.

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From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.