vWDIII – Von Willebrand’s disease (vWD)

Description:  Von Willebrand’s disease (vWD) is the most common hereditary bleeding disorder in both dogs and humans. vWD is due to the partial or total absence of von Willebrand factor (vWF) or its dysfunction due to structural abnormality. von Willebrand factor is a multimeric plasma glycoprotein that plays a major role in hemostasis, in the body’s response to blood vessel damage and bleeding. The vWF protein is required for normal platelet adhesion at vascular injury sites and promotes platelet aggregation. In addition, it also stabilizes the blood clotting factor VIII (FVIII). Characteristic clinical signs of vWD are the incidence of prolonged and persistent bleeding even in areas of minor skin injuries, spontaneous bleeding from the nasal cavity, gut and gum, postoperative and post-traumatic injuries. Despite the importance of vWF in blood coagulation, the partial or total absence of vWF in the blood is not always lethal, just as vWD can remain unnoticed for years. Affected individuals may have mild, moderate, or severe bleeding since vWD is a genetically and clinically heterogeneous disease. There are three types of von Willebrand’s disease in dogs and various mutations in the VWF gene are responsible for the quantitative and qualitative properties of vWF, which are the basis for dividing vWD into:

vWD type I – partial absence of vWF,

vWD type II – non-functional vWF,

vWD type III – complete absence of vWF.

Type III vWD is the most severe form of vWD caused by the complete absence of plasma vWF and is often fatal. Therefore, affected dogs that have severe bleeding episodes require a blood transfusion.

Inheritance: autosomal recessive

Mutation: c.738delT v géne VWF, chr27:38868884 (canFam3): 1 bp deletion (del T)

Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of the dog’s identity by Veterinarian is recommended.

The analysis is suitable for the following breeds: Shetland sheepdog

Notes: vWDIII-Kooikerhondje has the mutation chr27:38892182 (canFam3): G>A, and vWDIII- Scottish Terrier has the mutation chr27:38848107 (canFam3): 1 bp deletion (del C) in vWF gene.