Von Willebrand disease type 1 / vWD I (VWF-related) - Dog

What does this test examine?

This genetic test examines the VWF variant c.7437G>A in dogs. The variant is linked to Von Willebrand disease type 1, also known as vWD type I, von Willebrand disease, von Willebrand factor deficiency or an inherited bleeding tendency.

What does type 1 vWD mean?

Von Willebrand factor helps platelets attach at the site of vessel injury and supports the first phase of normal clot formation. In type 1, the amount of available functional von Willebrand factor is reduced. Severity can differ markedly between dogs: some animals remain unnoticed for years, while others bleed more clearly during teething, heat, minor wounds, birth, dental procedures or surgery.

Possible signs include prolonged bleeding, nosebleeds, bleeding gums, bruising, blood in urine or stool and excessive bleeding after procedures. Because the risk is not always visible from the outside, a DNA result gives useful information before breeding, purchase decisions or medical procedures are planned.

Inheritance and result

Expression of this variant is breed- and individual-dependent. In several lines, type 1 is described as autosomal incompletely dominant: one copy can already be relevant, but not every dog with the variant develops the same bleeding tendency. In other breed contexts, a more recessive pattern has been described. The result should therefore be read as genetic risk information for this specific VWF variant.

The result labels are GG, GA en AA. The A allele is the tested variant.

Practical value of this test

This test is useful for breeders, owners and veterinarians because it reveals an inherited bleeding sensitivity that can otherwise remain hidden. The result supports safer breeding decisions, targeted family screening and better recognition of dogs with increased genetic bleeding risk before situations where blood loss matters.

• Distinguishes clear dogs from dogs with one or two copies of the variant.
• Supports breeding selection and line management in breeds where type 1 vWD occurs.
• Makes it easier to test relatives when a variant carrier is found.
• Provides practical information before dental procedures, surgery, trauma or reproduction.
• Improves transparency for purchase, sale and breeding decisions in risk lines.