The condition is caused by a quantitative or qualitative deficiency of von Willebrand factor (vWF), a protein that plays a central role in blood clotting. Von Willebrand's disease vWD usually comes in two major types, type I and type III. Type III is a severe bleeding disorder with a high risk of spontaneous bleeding as well as a risk of serious bleeding from trauma and surgery. Type 1 is a less severe form.
Dogs with vWD are prone to nose bleeds, bleeding from the gums, and prolonged bleeding during heat or after whelping. There may be prolonged bleeding from the umbilical cord at birth or when your pup sheds its baby teeth. Excessive bleeding after surgery or trauma is common, and may be the first sign of this condition in your dog. You may see blood in your dog's urine or stool. The clinical effects reported can range dramatically, with some dogs bleeding profusely, while others hardly showing any signs of bleeding at all.
The disease is described as an autosomal recessive condition. This means that a dog must inherit two copies of an abnormal gene (one from its mother and one from its father) before its health is affected. A dog that inherits only one copy of the abnormal gene (from its mother or its father) will have no signs of the disease, but will be a carrier and may pass the gene on to any offspring.
