Von Willebrand's disease is the most common hereditary bleeding disorder. It affects both sexes approximately equally. Most cases are mild, and bleeding may occur after a surgical procedure or tooth extraction. The condition is worsened by the use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). Bleeding may decrease during pregnancy.It arises from a qualitative or quantitative deficiency of von Willebrand factor (vWF), a multimeric protein that is required for platelet adhesion.

The disease is very common, affecting at least 1% of the population. A family history of a bleeding disorder is the primary risk factor. In women with heavy or prolonged menstrual bleeding, Von Willebrand's is more common in Caucasian women than African American women.

vWF is mainly active in conditions of high blood flow and shear stress. Deficiency of vWF therefore shows primarily in organs with extensive small vessels, such as the skin, the gastrointestinal tract and the uterus. In angiodysplasia, a form of telangiectasia of the colon, shear stress is much higher than in average capillaries, and the risk of bleeding is increased concomitantly.

Most people with von Willebrand's disease have only mild bleeding problems. But in some, bleeding is severe. Bleeding problems may include:

• Easy bruising
• Nosebleeds
• Bleeding from the gums
• Excessive bleeding after a cut or removal of a tooth
• Bleeding after circumcision or other surgery
• A child with von Willebrand's disease typically has a parent who has a history of bleeding problems. A doctor may confirm the diagnosis by special blood tests.

The U.S. Food and Drug Administration has approved a biologic product called Alphanate for people with a bleeding disorder called von Willebrand disease (vWD) who require surgery.

People with vWD, the most common inherited bleeding disorder affecting about 1 percent of the U.S. population, have a missing or ineffective hormone called desmopressin. In most cases, people with the clotting disorder do not require treatment to stop bleeding after an injury or surgery, the FDA said.

But for some 2,000 people in the United States with moderate-to-severe forms of the disease, bleeding can be excessive if not treated.

Antihemophilic factor (AHF) is a protein found in normal plasma which is necessary for clot formation. If you do not have enough AHF and you become injured, your blood will not form clots as it should, and you may bleed into and damage your muscles and joints. Von Willebrand disease, in which there is a risk of bleeding. AHF also may be used for other conditions as determined by your doctor.

Alphanate is made from purified human plasma that has been screened for blood-borne viruses, the agency said in a statement. But it conceded that transmission of certain viruses "while very low, cannot be totally eliminated."

Alphanate, made by Los Angeles-based Grifols Biologicals Inc., is already approved for other bleeding disorders including hemophilia A, the agency said.

Women who have this condition generally do not experience excessive bleeding during childbirth.

Life span is usually normal. Since this disease is genetically transmitted, genetic counseling may be recommended for parents.