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Von Willebrand's Disease 3 (VWF gene, Scottish Terrier)

Von Willebrand's Disease 3 (VWF gene, Scottish Terrier)

Type 3 von Willebrand's disease is a type of bleeding disorder that affects dogs, and is the least common type of the disease.

Symptoms

Symptoms in dogs with von Willebrand disease type 3 are usually severe and appear before the first year of life. The disease can cause easy or prolonged bleeding, such as nosebleeds, bleeding gums, bleeding after surgery or injury, blood in the urine and recurrent hemorrhagic diarrhea. In severe cases, the dog may suffer life-threatening internal bleeding.

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 commonly observed bleeding disorder of genetic origin 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 coagulation factor in the blood, factor VIII, and participates in the adhesion of platelets to the 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. The variant of the VWF gene that we analyze here is the c.255del deletion. In this variant a single nucleotide is deleted from the gene sequence and a truncated protein is produced that is not functional. For the disease to occur Scottish terrier dogs must carry two copies of the deletion.

Most affected breeds

Dutch Kooiker
Scottish Terrier
Shetland Sheepdog

Bibliography

Venta PJ, Li J, Yuzbasiyan-Gurkan V, Brewer GJ,et al. Mutation causing von Willebrand's disease in Scottish Terriers. J Vet Intern Med. 2000 Jan-Feb;14(1):10-9.