Von Willebrand Disorder

Von Willebrand Disorder

What is von Willebrand Disorder (VWD)?
Von Willebrand Disorder (VWD) is due to a deficiency of von Willebrand Factor (VWF). VWF a plasma factor that circulates in the blood attached to Factor VIII. The major function of VWF to bind platelets, small cell fragments in the blood, to minor ruptures in blood vessels.

VWD is inherited but in a different manner to haemophilia. It affects women as often as men. The abnormal gene is not on the X chromosome (sex-related chromosome), but on the autosome (a regular chromosome, not a sex-related chromosome). A few people with severe VWD have two abnormal genes, one from each parent.

Most people with VWD have a mild-to-moderate form. In some families, VWD appears to be inherited as a dominant condition due to one abnormal gene from one parent (who may or may not have bleeding problems). However, in other families, VWD may be inherited as a recessive, with abnormal genes from both parents but no bleeding problems.

Both men and women with VWD often are frustrated because mild cases of the disorder may be difficult to diagnose. This is the most common bleeding disorder and affects an estimated 200,000 people in Australia, most of whom are undiagnosed.

How is von Willebrand Disorder inherited?
Von Willebrand disorder is mostly a genetic disorder. This means it is passed down through the genes from parent to child. The abnormal gene in von Willebrand disorder is on one of the regular chromosomes, not on one of the sex chromosomes (like haemophilia). This means that, unlike haemophilia which usually affects only males, von Willebrand disorder affects males and females in equal numbers.

In what is called the classical inheritance pattern, the von Willebrand disorder gene is usually dominant. This means a parent who has von Willebrand disorder has a 50% chance of passing a von Willebrand disorder gene along to each of his/her children. Types 1 and 2 von Willebrand disorder are usually inherited in this way.

In the less common inheritance pattern, two parents, each with von Willebrand disorder but without symptoms (called asymptomatic), may together have children who are severely affected by von Willebrand disorder. This form of inheritance is called "recessive". Type 3 von Willebrand disorder is usually inherited in a recessive pattern. Many people carrying the von Willebrand disorder gene are asymptomatic which means they will not have bleeding symptoms, but they can still pass the disorder on to their children.

How is von Willebrand Disorder treated?
Most people with mild von Willebrand disorder will only experience a mild form of the condition and no medication will be required except when having surgery, and/or dental extractions. Far more serious bleeding may need to be treated with infusions (injections) of medications (synthetic hormones) or blood clotting products into a vein or sprays and tablets. People with von Willebrand disorder should not take aspirin in any form because it aggravates bleeding.

MORE INFORMATION

For more information and frequently asked questions – click here - vWD FAQ

Download the Guide for people living with von Willebrand disorder (June 2010) - von Willebrand disorder booklet[PDF, 4.01MB]

REFERENCES
Australian Bleeding Disorders Registry. Annual Report 2009-2010. [PDF, 3MB] Canberra: National Blood Authority.
National Blood Authority; Australian Haemophilia Centre Directors’ Organisation. Evidence-based clinical practice guidelines for the use of recombinant and plasma-derived FVIII and FIX products. [PDF, 1.26MB] Canberra: Australian Health Ministers’ Advisory Council, June 2006.

Important Note: This information was developed by Haemophilia Foundation Australia for education and information purposes only and does not replace advice from a treating health professional. Always see your health care provider for assessment and advice about your individual health before taking action or relying on published information.

This information may be printed or photocopied for educational purposes.

Last Updated: 5th Nov 12