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 is to bind platelets, small cell fragments in the blood, to minor ruptures in blood vessels.
VWD is inherited but in a different manner to hemophilia. 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 who are undiagnosed.