von Willebrands Disease (Source: Haemophilia society website)
Von Willebrand’s Disease
Von Willebrand's disease (vWD) is characterised by either a shortage or defect (or both) in a
protein in the blood called von Willebrand Factor (vWF) that helps to make blood clot. It thus
takes longer in someone with vWD for the blood to clot and for bleeding episodes to stop. vWD is
the most common of bleeding disorders, affecting 1% to 2% of the population nationwideand is
named after the Finnish haematologist who first reported it. It varies in severity, and in its milder
form often goes undetected, unless unusual bleeding occurs during tooth extraction, surgery or an
accident. Most people with vWD live completely normal lives.
Von Willebrand's Disease is mostly a genetic disorder which is carried on the regular
chromosomes (autosomes), and unlike haemophilia, is not sex-linked. This means that it can
equally occur in males and females, with similar frequency and severity. A new mutation can
cause the appearance of the abnormal gene in vW during pregnancy, when neither parent has the
condition. It can also be an acquired disorder, appearing later on in life when antibodies are
developed by the body, usually associated with an autoimmune disease such as rheumatoid
arthritis.
Among women and girls, vWD can manifest in difficulties related to menstruation, fertility and
childbirth. Women are often misdiagnosed with gynecologic problems rather than blood
conditions by doctors due to the widespread belief that bleeding disorders are a men-only issue.
Although there is no cure for vWD, this condition can be treated effectively.
Because vWD affects many more people -of both sexes- than are thought, receiving full
information and advice is important to manage your condition effectively and live a full life.
Signs and symptoms of VWD
Many people with VWD have few or no symptoms. People with more serious VWD may have
more bleeding problems. Symptoms can also change over time and include:
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prolonged bleeding from minor skin cuts
easy bruising
frequent epistaxisnosebleeds
unusual bleeding from mouth or gums
bleeding in the gastrointestinal tract
bleeding into muscles and joints
excessive haemorrhage after injury, dental work or surgery
Classification. Types of vWD
There are three types of vWD according to whether a lack or a defect (or both) of von Willebrand
factor (vWF) occurs. vWF is an important protein for blood clotting. The vWF also carries factor
VIII, another protein involved in both blood coagulation and in the repair of damaged blood
vessels. When deficiencies in vWF exist (and sometimes of factor VIII as well) blood will take
longer to clot. Appropriate treatment is mostly determined by the type of vWD a person has. The
three types of vWD are:
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Type 1. This is the most common type. About 75% of people with vWD have this
type, characterized by reduced levels of vWF, It is inherited from one of the
parents through an autosomal dominant pattern. Symptoms are usually very mild.
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However, it is possible that frequent or serious bleeding may occur in someone
with Type 1 vWD.
Type 2 vWD is the next most common type (20-25% of VWD cases). It also is
passed on by one of the parents as carrier in an autosomal dominant patternIn
this type, a normal quantity of vWF is produced, but it does not work efficiently. As
a result, the binding of platelets to the wall of the punctured blood vessel may
occur too slowly, or these may be bound at a different location in the bloodstream.
Symptoms are usually moderate. This type is easily misdiagnosed and finding the
appropriate treatment can be difficult so assessment at a Haemophilia Centre is
necessary. Type 2 vWD is divided infour subtypes: 2a, 2b, 2m and 2n
• Type 2A is the most common type and is classed as moderate.The vWF, in this
case, does not work properly.
• Type 2B can be moderate to severe and is characterised by low platelet count
(thrombocytopaenia).
• Type 2M usually resembles type 1 vWD and as a result can be difficult to
diagnose. It can cause mild to moderate bleeding episodes.
• Type 2N causes reduced levels of vWF and factor VIII. It thus resembles
haemophilia A. Research is ongoing to distinguish the two conditions. Bleeding
ranges from mild to moderate.
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Type 3, also called severe vWD, is the rarest and most serious type.The defective
gene is inherited from both parents following a recessive pattern. As a result,
people with type 3 vWD have almost no vWF and can experience bleeding into
muscles and joints - even without injury. These patients are also likely to have low
levels of Factor VIII (haemophilia A), which also contributes to the clotting
process. As a result, people with Type 3 vWD often experience more severe
symptoms that resemble those in haemophilia A, and are prescribed a similar
treatment.
Each type can be mild, moderate, or severe. Bleeding symptoms can also vary considerably
within each type
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