Von Willebrand disease ..., (Von Willebrand Disease) - VWF Gene.

The von Willebrand disease is a bleeding disorder that slows the blood clotting process, causing prolonged bleeding after an injury.

The von Willebrand disease is divided into three types, based on the amount of von Willebrand factor produced. Type 1 is the mildest and most common of the three types, accounting for 75 percent of affected individuals. Type 2 is subdivided into four subtypes. The four subtypes of type 2 are intermediates in severity. Type 3 is the most severe and rarest form of the disease.

People with this condition often experience easy bruising, prolonged nosebleeds, and excessive bleeding after injury, surgery or dental procedures. Mild forms of von Willebrand disease may become evident only when an abnormal bleeding after surgery or serious injury occurs. Women with this condition usually have heavy or prolonged bleeding during menstruation (menorrhagia), and some may also experience genital bleeding during pregnancy and childbirth. In severe cases of the disease, profuse bleeding occurring after minor or even without injury (spontaneous bleeding) trauma. Symptoms of von Willebrand's disease can change over time.

This process is due to mutations in the VWF gene, located on the short arm of chromosome 12 (12p13.3), encoding the clotting factor called von Willebrand factor, which is essential for coagulation. We found over 300 mutations in the VWF gene causing the von Willebrand disease. The von Willebrand factor acts as an adhesion member between blood clots by preventing degradation of other coagulation proteins. If the Von Willebrand factor does not work normally or does poorly, blood clots can not form properly. The von Willebrand factor is localized within endothelial cells lining the inner surface of blood vessels and cells of the bone marrow. The factor is composed of several identical subunits. To facilitate attachment to various cells and proteins, these subunits are cleaved into smaller fragments by an enzyme called ADAMTS13.

Von Willebrand's disease can have different patterns of inheritance. Most cases of von Willebrand disease type 1 and type 2 are inherited in an autosomal dominant pattern, which means that a copy of the altered gene in each cell is sufficient to cause the disorder. In type 3, some cases of type 2, and a small number of cases of type 1 disease is inherited in an autosomal recessive pattern, which means that both copies of the gene in every cell have mutations. Often, parents of an individual with an autosomal recessive condition carry one copy of the mutated gene, but do not show signs and symptoms of the disease.  

Tests in IVAMI: in IVAMI perform detection of mutations associated with von Willebrand disease, by complete PCR amplification of the exons of the VWF gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).