von Willebrand Disease (vWD)
von Willebrand's Disease (vWD) is an autosomal dominant inherited bleeding disorder that occurs from birth and affects both sexes. It occurs due to a defect in the genes. Autosomal dominant means that even if one parent has the abnormal gene, you could inherit the disease. vWD has a prevalence of 1 to 3% of the population and has no ethnic predominance. The disease was first described by Erik Adolf von Willebrand in 1926.
In a normal individual, Von Willebrand factor acts like glue to help the platelets (essential for blood clotting) stick together and form a blood clot. Clotting factor VIII is an important protein that helps the blood clot and vWF also serves as a carrier for this factor. Lack of vWF leads to von Willebrand Disease.
The gene for von Willebrand factor is on the short arm of chromosome 12.
Types of von Willebrand's Disease
There are three types of Hereditary vWD:
Type1: Type1 vWF is the mildest and most common form of VWD. Type 1 vWD accounts for 75 to 80% of patients and is inherited predominantly via an autosomal dominant mode.
Type2: Type 2 von Willebrand disease can be either autosomal dominant or autosomal recessive. Type 2 is divided into subtypes: 2A, 2B, 2M, and 2N. Type 2A von Willebrand disease is by far the most common.
Type3: This is the most severe form of von Willebrand disease. There is almost complete absence of circulating vWF. It is an exceedingly rare variant that occurs in 1 of every 1 million individuals
Some forms of vVD may not be inherited. They may be seen in conditions like:
Congenital heart disease
Systemic lupus erythematosus (SLE)
Seizure disorders treated with valproic acid