Von Willebrand disease (VWD) is a genetic disorder caused by missing or defective von Willebrand factor (VWF), a clotting protein. VWF binds factor VIII, a key clotting protein, and platelets in blood vessel walls, which help form a platelet plug during the clotting process. The condition is named after Finnish physician Erik von Willebrand, a man who first described it in the 1920's.
VWD is the most common bleeding disorder, affecting up to 1% of the US population. It is carried on chromosome 12 and occurs equally in men and women.
People with VWD experience frequent nosebleeds, easy bruising and excessive bleeding during and after invasive procedures, such as tooth extractions and surgery. Women often experience menorrhagia, heavy menstrual periods that last longer than average, and hemorrhaging after childbirth.
There are three (3) main types of VWD based on qualitative or quantitative defects in VWF. A fourth type, acquired VWD, is not hereditary.
Type 1 VWD is found in 60% - 80% of patients. People with type 1 VWD have a quantitative deficiency of VWF. Levels of VWF in the blood range from 20% - 50% of normal. The symptoms are usually mild.
Type 2 VWD is found in 15% - 30% of patients. People with type 2 VWD have a qualitative deficiency in their VWF. Type 2 is broken down in four (4) subtypes: type 2A, type 2B, type 2M, and type 2N, depending on the presence and behavior of multimers, molecular chains of VWF. Symptoms are mild to moderate.
Type 3 VWD is found in 5% - 10% of patients. People with type 3 VWD have a quantitative deficiency of VWF. Systems are typically severe, and include spontaneous bleeding episodes, often into their joints and muscles.
Acquired VWD. This type of VWD in adults results after a diagnosis of an autoimmune disease, such as lupus, or from heart disease or some types of cancer. It can also occur after taking certain medications.