von willebrand disease
Von Willebrand disease (VWD) is a genetic disorder caused by missing or defective von Willebrand factor (VWF), a clotting protein. VWF binds factor VIII (FVIII), a key clotting protein, and platelets in blood vessel walls. Without VWF a platelet plug cannot be formed during the clotting process. VWF also transports and protects clotting FVIII in the blood. Eventually the FVIII breaks down, leaving persons with VWD with low levels of FVIII. This medical condition is named after Finnish physician Erik von Willebrand, a who first described it in the 1920s. VWD is the most common bleeding disorder, occurring in approximately 1% of the world’s 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 main types of VW, and a fourth acquired type that is not genetically inherited:
- 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 tend to be mild.
- Type 2 VWD is found in 15%-30% of patients. People with type 2 VWD have a qualitative deficiency in their 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. Symptoms 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.
Treatment for VWD depends on the diagnosis and severity. The primary treatment is DDAVP (desmopressin acetate), the synthetic version of a natural hormone vasopressin that stimulates the release of VWF from cells, which also increases factor VIII. Infusion replacement therapies are also used to treat VWD. When it is not properly treated, hemophilia can lead to severe crippling, brain damage and death.