Von Willebrand disease is a bleeding disorder that slows the blood clotting process, causing prolonged bleeding after an injury. People with this condition often experience easy bruising, long-lasting nosebleeds, and excessive bleeding or oozing following an injury, surgery, or dental work. Mild forms of von Willebrand disease may become apparent only when abnormal bleeding occurs following surgery or a serious injury. People with this condition who have menstrual periods typically have heavy or prolonged bleeding during menstruation (menorrhagia), and some may also experience reproductive tract bleeding during pregnancy and childbirth. In severe cases of von Willebrand disease, heavy bleeding occurs after minor trauma or even in the absence of injury (spontaneous bleeding). Symptoms of von Willebrand disease may change over time. Increased age, pregnancy, exercise, and stress may cause bleeding symptoms to become less frequent.
Von Willebrand disease is divided into three types. Type 1 has one subtype (1C), and type 2 is divided into four subtypes (2A, 2B, 2M, and 2N). Type 1 is the most common of the three types, accounting for 75 percent of affected individuals. Type 1 is typically mild, but some people are severely affected. Type 2 accounts for about 15 percent of cases. This type is usually of intermediate severity. Type 3 is the rarest form of the condition, accounting for about 5 percent of affected individuals, and is usually the most severe.
Another form of the disorder, acquired von Willebrand syndrome, is not caused by inherited gene variants (also called mutations). Acquired von Willebrand syndrome is typically seen in people with other disorders, such as diseases that affect bone marrow or immune cell function. This rare form of the condition is characterized by abnormal bleeding into the skin and other soft tissues, usually beginning in adulthood. [from
MedlinePlus Genetics]