Von Willebrand's factor is a protein that helps platelets stick together and to the inside walls of broken blood vessels when there is an injury, forming the initial “plug” to stop bleeding. There are three known forms of von Willebrand’s disease. Type I is the least severe, and the most common cause of heritable coagulopathy in dogs. Von Willebrand’s Disease (vWD) Type 1 typically causes mild bleeding tendencies although some affected dogs may have more severe signs. Unlike more severe forms of vWD, vWDI causes low levels of normal von Willebrand's factor (vWF), rather than abnormal protein or complete absence of it.
As the most common coagulopathy in dogs, many breeds carry this variant. Although the Doberman Pinscher is the most well known, there are many breeds with high allelic frequency, including many of the small spitzes, such as the Pomeranian, and German Spitz, Kerry Blue Terrier, Prague Ratter, the Pembroke and Cardigan Welsh Corgi, and Stabyhoun. More about breed frequencies can be found here and here.
Wisdom Panel breeder mode of inheritance is updating from autosomal recessive to autosomal dominant with incomplete penetrance based on reports of dogs with one copy of the variant showing signs of the disease. In previous Optimal Selection™ Canine and MyDogDNA™ reports, dogs with one copy of the variant were labeled with the “Notable/Carrier” status, as this was the current scientific understanding of the disorder. With this update, dogs with one copy will be labeled “At Risk.” However, it is important to note that not all dogs with one copy of the variant will show clinical signs of the disease, and it is normal for individual dogs to have fluctuating levels of vWF depending on health and other factors. Dogs with one copy of the vWDI variant are considered to be at lower risk of clinical disease than dogs with two copies. Your veterinarian can perform a von Willebrand factor antigen assay on your dog’s blood to determine their concentration of von Willebrand’s factor.
Wisdom is committed to the health of purebred dogs, and this update reflects our commitment to reporting the latest in scientific research to inform breeders. Most registries understand that this disorder is prevalent in many breeds, and that breeders must slowly reduce frequency of this disorder in their breed in order to avoid damage due to genetic bottlenecks. If there is concern about the impact of this reporting update within your registry, we welcome you to contact our breeder team and we would be happy to discuss the subject with you and your registry.
Donner J, Freyer J, Davison S, Anderson H, Blades M, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2): e1010651. https://doi.org/10.1371/journal.pgen.1010651
Crespi JA, Barrientos LS, Giovambattista G. (2018) von Willebrand disease type 1 in Doberman Pinscher dogs: genotyping and prevalence of the mutation in the Buenos Aires region, Argentina. Journal of Veterinary Diagnostic Investigation. 30(2):310-314. doi:10.1177/1040638717750429
