Von Willebrand's Disease 2 (VWF gene)

Type 2 von Willebrand's disease is a type of bleeding disorder that affects dogs less frequently than type 1. It is characterized by excessive bleeding with injuries and surgical interventions and can become severe in some cases.

Symptoms

Dogs with von Willebrand's disease may have symptoms that range from moderate to severe and include easy or prolonged bleeding, such as nosebleeds, bleeding from the gums, or bleeding after surgery or injury. In the most severe cases, the dog may suffer internal bleeding that can be life-threatening.

Disease Management

There is no cure for the disease, but symptoms can be managed with supportive care such as blood transfusions during severe bleeding episodes.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

Von Willebrand's disease is the most common genetic bleeding disorder seen in dogs and is quite characteristic in Doberman Pinscher dogs. This disease is caused by abnormalities in von Willebrand factor (vWF), a protein crucial for blood clotting. VWF is a large protein that is synthesized in endothelial cells lining blood vessels and in megakaryocytes, the precursor cells of platelets, in the bone marrow. VWF has a dual role in coagulation, it transports another clotting factor in the blood, factor VIII, and participates in the adhesion of platelets to damaged epithelium when there is an injury. Depending on the severity of symptoms and alteration of vWF it is classified into 3 types. Type 1, characterized by low plasma concentrations of vWF and mild to moderate hemorrhagic symptoms. Type 2 is characterized by qualitative abnormalities of vWF protein and moderate to severe bleeding. Type 3 is the most severe form of the disease and the least frequent, in which vWF is virtually undetectable. Here we analyzed the c.1657T>G variant of the VWF gene that encodes for FvW protein and has been associated with type 2 von Willebrand disease in German Pointer dogs (Kramer et al., 2004). In dogs affected by the disease, two copies of c.1657T>G have been found to be present.

Most affected breeds

Chinese Crested Dog
German Shorthaired Pointer
German Wirehaired Pointer

Bibliography

Vos-Loohuis M, van Oost BA, Dangel C,et al. A novel VWF variant associated with type 2 von Willebrand disease in German Wirehaired Pointers and German Shorthaired Pointers. Anim Genet. 2017 Aug;48(4):493-496.