Von Willebrand disease (vWD) type 1 is an inherited coagulopathy caused by a quantitative deficiency of von Willebrand factor (vWF), a protein required for platelet adhesion to damaged endothelium. The result is a tendency to excessive bleeding, especially from mucous membranes (gums, nose, bladder, digestive tract), after surgery, dental extractions or trauma. The classic and best characterised form in the Doberman is associated with a specific variant of the VWF gene and is inherited in an autosomal dominant manner with incomplete penetrance.

Published frequencies vary by population and breed; in the Doberman, relevant allele frequencies have been described in specific population studies (Rungsipipat et al. 2018). In other breeds (Miniature Schnauzer, Shetland Sheepdog, Golden Retriever, Labrador, Cocker Spaniel, German Shepherd) vWD has been described with its own frequencies and variants; general population data are limited.

- Excessive bleeding after surgery, dental extractions or trauma\n- Epistaxis (nasal bleeding)\n- Haematuria (blood in urine)\n- Haematemesis (vomiting blood) and melaena (black faeces from digestive bleeding)\n- Gingival bleeding (bleeding gums)\n- Spontaneous or disproportionate subcutaneous haematomas\n- Prolonged bleeding after vaccination or blood collection

Canine vWD was described in the Doberman Pinscher in 1979 and classified into types according to the quantitative or qualitative defect of vWF. In the Doberman, type 1 is associated with the VWF c.7437G>A variant; genotyping studies in Doberman populations confirm autosomal dominant inheritance with incomplete penetrance (Crespi et al. 2018). The laboratory's internal dossier records that same variant for the vWD type 1 test.

- Test breeding animals with the test for the variant corresponding to their breed before mating\n- As it is dominant with incomplete penetrance, a carrier can transmit the variant to ~50 % of the offspring; consider mating with a clear animal\n- Avoid matings between carriers when a clear alternative exists, prioritising the maintenance of genetic diversity\n- Communicate the status to buyers and the veterinarian, to plan the management of bleeding during surgery or trauma\n- Discarding breeding animals based on an isolated result without assessing the vWF level and the clinical history of the line is not recommended

Diagnosis is suspected from a history of mucocutaneous bleeding and compatible coagulation times; determination of the vWF level and the genetic test complement each other. vWD type 1 is quantitative and is usually milder than types 2 and 3. There is no cure: management is supportive (desmopressin before invasive procedures when indicated, plasma or blood in emergencies, avoiding drugs that alter platelet function). Differentiate from haemophilias and hereditary thrombopathies.

1. Crespi JA et al. 2018, genotipificación y prevalencia de la mutación de vWD tipo 1 en Doberman Pinscher (PMID 29271313)
2. Brooks M et al. 2001, fenotipo de vWD y genotipo de marcadores del factor von Willebrand en Doberman Pinscher (PMID 11277201)
3. OMIA:001057 Enfermedad de von Willebrand tipo 1