Von Willebrand's Disease (vWD type II) Testing for Dogs

Von Willebrand’s disease (vWD) is a hereditary canine health condition that affects the coagulation and clotting of the dog’s blood, due to a lack of the necessary clotting factor. This can lead to uncontrolled bleeding, meaning that a dog that gets a small cut or graze may potentially bleed heavily and have problems clotting even small injuries, which can be potentially life threatening in some cases.

The factor responsible for blood clotting that is missing in Von Willebrand’s disease is called Von Willebrand Factor, and this is a type of plasma protein that helps the blood to clot.

The effect that the condition has on affected dogs is similar to that of haemophilia, although a different missing factor is the cause of haemophilia, and unlike haemophilia, both male and female dogs can be affected by Von Willebrand’s disease.

Additionally, Von Willebrand’s disease comes in three different sub-types, each of which have varying degrees of severity, and each of which tend to affect different breeds of dog.

In this article, we will look at Von Willebrand’s disease Type Two in more detail, including what sort of dogs can be affected by the condition, and how to get your dog tested for it. Read on to learn more.

More about Von Willebrand’s disease type two

In order to understand Von Willebrand’s disease type two, it is necessary to compare it to types one and three respectively. It is also worth noting that dogs diagnosed with hypothyroidism are at exponentially higher risk of developing a blood clotting disorder like Von Willebrand’s disease, and the two conditions are often diagnosed concomitantly.

• Type 1 is the most common type of Von Willebrand’s disease, and this is also generally the mildest form of the condition, presenting with only mild to moderate symptoms.
• Type 2 is a severe form of the condition, and is rather less common than type one.
• Type 3 is the most acute and severe form of the condition, and the variant that poses the greatest risk to the general health and life of affected dogs.

What sort of dogs can be affected by Von Willebrand’s disease type two?

Von Willebrand’s disease type two is like the other forms of the condition a hereditary health issue, which means that it is mainly restricted to certain breeds of dog across which the condition has spread comparatively widely.

The two breeds considered to be at the highest risk of inheriting Von Willebrand’s disease type two are the German wirehaired pointer and the German shorthaired pointer.

Additionally, cross-breed and hybrid breed dogs with ancestry from either of these two breeds may potentially inherit the gene mutation that causes the condition from one side of their heritage, but this alone may not be enough to lead to the affected form of the condition unless they have two ancestors from the at-risk breeds.

How does the heredity of the condition work?

Von Willebrand’s disease type two is inherited by means of autosomal recessive heredity, which means that the status of any given litter can be determined by knowing the status of the two parent dogs. Dogs are designated a status of either clear, carrier or affected, with carriers not presenting with any symptoms of the condition themselves, but still capable of passing the gene mutation that causes it onto their own offspring. This is why knowing the status of both parent dogs is so important; in order to determine the health of the litter and so, make a decision about whether or not to go ahead with any given mating match.

The means of heredity of Von Willebrand’s disease type two can be outlined as followed:

• Two clear dogs will have a clear litter.
• Two affected dogs will have an affected litter.
• Two carriers will have a mixed litter of 50% carriers, 25% clear and 25% affected.
• A clear dog and a carrier will have 50% clear and 50% affected.
• A clear dog and an affected dog will have a litter of carriers.
• A carrier and an affected dog will have 50% carriers and 50% affected.

This means that carriers can be used for breeding and still produce a healthy litter, depending on the status of the other dog in the mating match; but it is important to bear in mind that some of that litter will in turn, go on to be carriers and so, need careful matching if bred from.

How to get your dog tested

If you own a German shorthaired pointer or a German wirehaired pointer and wish to breed from them, it is important to have both sides of the mating match tested before going ahead.

Testing is performed by analysis of a DNA sample, and this means that you will need to ask your vet to take either a vial of blood or a buccal swab from your dog, and then send it off to one of The Kennel Club’s approved laboratories for assessment.