Von Willebrand disease
Von Willebrand disease (VWD) is an inheritable bleeding
disorder. Many different proteins are needed to make a person’s blood clot
successfully. People with VWD are either missing or low in the clotting protein
von Willebrand factor (VWF) – or it doesn’t work as it’s supposed to. For a
person to make a successful clot, VWF binds to factor VIII (8), another
clotting protein, and platelets in blood vessel walls. This process will help
form a platelet plug during the clotting process. People with VWD are not able
to form this platelet plug, or it will take longer to form. The condition is
named after Finnish physician Erik von Willebrand, who first described it in
VWD is the most common bleeding disorder, affecting up to 1% of the US population – or approximately 1 in every 100 people. It occurs equally in men and women. However, women may be more symptomatic due to heavy menstrual bleeding (periods). VWD occurs equally across all races and ethnicities.
Von Willebrand disease is classified into 3 types:
· Type 1: A quantitative deficiency of VWF, which is the most common form and is an autosomal dominant disorder
· Type 2: A qualitative impairment in synthesis of VWF that can result from various genetic abnormalities and is an autosomal dominant disorder
· Type 3: A rare autosomal recessive disorder in which homozygotes have no detectable VWF
These 3 types are all inherited.
There's also a rare type that is not inherited called "acquired von Willebrand disease". This can start at any age and is usually associated with other conditions that affect the blood, immune system or heart.
Although VWD, like hemophilia A, is a hereditary disorder that may cause factor VIII deficiency, the factor VIII deficiency in VWD is usually only moderate.
The main symptoms of VWD are:
The usual cause of von Willebrand disease is an inherited abnormal gene that controls von Willebrand factor — a protein that plays a key role in blood clotting.
When you have low levels of this protein or it doesn't work as it should, small blood cells called platelets cannot stick together properly nor attach themselves normally to the blood vessel walls when an injury has occurred. This interferes with the clotting process and can sometimes cause uncontrolled bleeding.
Many people with von Willebrand disease also have low levels of factor VIII, another protein that helps in clotting.
Factor VIII is involved in another inherited clotting disorder called hemophilia. But unlike hemophilia, which mainly affects males, von Willebrand disease affects males and females and is usually milder.
Rarely, von Willebrand disease can develop later in life in people who didn't inherit an affected gene from a parent. This is known as acquired von Willebrand syndrome, and it's likely caused by an underlying medical condition.
The name for several hereditary genetic illnesses that impair the body’s ability to control bleeding. People with hemophilia have low or absent levels of clotting proteins such as Factor VIII (Hemophilia A), Factor IX (Hemophilia B), or Factor XI (Hemophilia C). Hemophilia A and B are sex-linked disorders and affect one in 7,000 boys born in the U.S. Other rarer bleeding disorders include deficiencies of Fibrinogen, Prothrombin, Factor V, Factor VII, Factor X, and Factor XIII and may occur in both boys and girls.
The most common hereditary bleeding disorder, although it can also be acquired as a result of other medical conditions. It is caused by deficiency or abnormalities of von Willebrand factor (vWD), a clotting protein that is required for platelet clumping and stabilization of Factor VIII. There are 3 main types of vWD, ranging from type 1, which is usually mild, and type 3, which is more severe.