What is it?
When you're injured and a blood vessel is damaged, there are several steps in the normal formation of a clot. When bleeding starts, blood vessels first constrict to slow the flow of blood at the area of injury. Then, small blood cells called platelets, which circulate in the blood, stick to the damaged blood vessel and spread out along the vessel wall, forming a platelet plug. The binding activity of a protein called von Willebrand factor (VWF) helps start the process of holding these platelets in place at the site of damage to the blood vessel. The platelets then create a surface on which the blood clot can form. Clotting proteins circulating in the blood move to the surface of the platelets to create a mesh-like fibrin clot that resembles a scab. This solid clot helps stop the bleeding.1,4-6
When you have von Willebrand disease (VWD), your body doesn't make enough VWF or the VWF that it does make doesn’t function properly, so a solid clot can’t form the way it should or takes longer to form. Prolonged bleeding may result.5,7
During the clotting process, VWF has 2 important functions that are related to the amount, size, and shape of the protein. First, VWF is one of the proteins that helps platelets stick together and, without it, the platelet plug cannot be formed. Another role of VWF in the body is to carry clotting factor VIII in the blood. Factor VIII is one of the proteins needed for a solid clot to develop. Even though people with VWD are usually able to make their own factor VIII, levels of factor VIII can be low because VWF is not present to protect and transport it, and factor VIII eventually breaks down. 4,5,8
In a healthy blood vessel, hemostasis helps control bleeding.
When an injury occurs, the blood vessel constricts to slow blood flow to the area.5
Blood cells called platelets join together with the help of VWF at the site of the injury to form a plug.1,5
VWF adheres the plug to the site of injury. More blood proteins move in to cover the platelets and stick them together to create a solid clot that helps stop the bleeding.1,5
There are three main types of VWD: types 1, 2 and 3. The type does not necessarily indicate the severity of the disease, but how the VWF malfunctions in the body. In all types, bleeds can be serious if left untreated and a physician should be consulted.6
Type 1 is the most common and accounts for about 75% of all cases of VWD. In type 1, VWF works as it should but lower levels of VWF are present overall. Someone with type 1 has all the right components to form clots, but since there is less VWF, it may or may not happen.6,7
In type 2, which affects 15%-30% of people with VWD, the body makes enough VWF, but it doesn’t function the way it’s supposed to. Type 2 has 4 subtypes, which may be treated in different ways, making an accurate diagnosis extremely important.5,7,9
Type 3 is very rare and is estimated to affect 1 in a million people. With type 3, individuals have very low levels of VWF and because of that bleeding may happen frequently and spontaneously.5,6,9
Injuries and surgery can lead to severe bleeding with all types of VWD, which is why it’s important for people who suspect they may have symptoms to check with their healthcare provider (HCP).5Read more about types
VWD occurs in men and women equally, but it’s often viewed as disproportionately affecting females for a number of reasons. The most likely cause is that women are more apt to experience symptoms due to increased or prolonged bleeding during menstrual periods (menorrhagia or heavy menstrual bleeding), as well as during pregnancy and childbirth. Men often go undiagnosed until they have a bleeding episode after surgery, a dental procedure or an injury that may cause a bleed.1,5
VWD is a genetic disorder, which means it is inherited from one or both parents and tends to run in families. Less commonly, VWD may occur spontaneously as a genetic change.5
Sometimes, VWD occurs as a spontaneous genetic change with no family history.7