Prekallikrein deficiency or Fletcher factor deficiency (KTK) DNA testing for the Shih Tzu dog breed

The Shih Tzu is one of the most popular dog breeds of all in the UK, being ranked in 8th place out of a total of 244 different dog breeds and types. These small, lovable little dogs are classed within the Kennel Club’s utility grouping, which comes as a surprise to many people who assume that Shih Tzus are toy dogs!

Whilst most of today’s pet Shih Tzus are pampered pets, the breed actually has working origins, as indicated by their inclusion within the utility group.

Shih Tzus are small dogs that are very loving and personable, and that form strong bonds with their owners. They thrive on lots of company and attention, and are quite sensitive dogs that don’t thrive if left alone or ignored for very long. However, they don’t have overly onerous exercise requirements and like to spend plenty of time cuddled up with their favourite people, which means that they’re a great fit for those looking for a small, quiet lapdog type that they will spend a lot of time with.

Because Shih Tzus are so popular within the UK there is a large population of them, and so the breed isn’t one that tends to suffer from a huge amount of hereditary health issues thanks to the diversity of their wider gene pool. However, as is the case for most pedigree dog breeds, there are a number of inherited health conditions that can be found in Shih Tzus, which can be passed on from parent dogs to their young.

One such Shih Tzu hereditary health condition is called prekallikrein deficiency or Fletcher factor deficiency, and this is a type of hereditary bleeding disorder that can have a significant impact on the care needs and longevity of affected dogs. There is a DNA test available for Shih Tzu prekallikrein deficiency that dog breeders can elect to perform on their parent stock prior to breeding, to identify the markers of the condition in breeding stock and so, make healthy mating matches.

In this article we will look at prekallikrein deficiency or Fletcher factor deficiency in the Shih Tzu in more detail, covering the effects that the condition has on dogs, its mode of heredity, and how to get your own dog DNA tested to find out their status. Read on to learn more.

What is Shih Tzu prekallikrein deficiency or Fletcher factor deficiency?

Prekallikrein deficiency is also sometimes known as Fletcher factor deficiency, and you may hear your vet use either term to refer to the same underlying condition.

Prekallikrein deficiency is an uncommon hereditary health condition that affects the way that dogs heal after injuries, which can be very serious as it means that even a small injury and particularly, large traumas such as surgery can result in uncontrolled bleeding that does not clot and heal in the normal way.

This means that Shih Tzus with prekallikrein deficiency may bleed excessively after even a minor knock or graze, and that they are also at greater risk of internal bleeding too, such as bleeding of the gastrointestinal tract that can result in bloody urine.

Even within the Shih Tzu dog breed, prekallikrein deficiency is relatively rare, and the condition is not found in any other dog breeds at the time of writing.

How is Shih Tzu prekallikrein deficiency inherited?

Prekallikrein deficiency or Fletcher factor deficiency in the Shih Tzu is inherited, and cannot be caught or passed on in any other way. It is an autosomal recessive health condition, which means that in order to determine whether or not any litter or puppy has the condition, you need to know the status of both of their parents, as it is the combined gene package that dogs inherit from both sides of their ancestry that dictates the status of their young.

When you know the status of any two parent dogs – clear, carrier or affected – you can work out what status their litter would have too, as follows:

• Two clear parent dogs will have all clear offspring.
• Two affected parent dogs will have all affected offspring.
• Two carrier parent dogs will have offspring that each have a 50% chance of being a carrier, a 25% chance of being affected, and a 25% chance of being clear.
• A clear parent mated with an affected parent will have a litter of carriers.
• A clear parent mated with a carrier parent will have a litter where each pup has 50:50 chances for whether they will be clear or a carriers.
• A carrier parent mated with a clear parent will have a litter where each pup has 50:50 chances for whether they will be clear or carriers.

Finding out your Shih Tzu’s prekallikrein deficiency status with DNA testing

If you intend to breed from your Shih Tzu and want to undertake pre-breeding DNA testing in order to produce healthy litters, both parent dogs within your prospective mating match need to be DNA tested.

Ask your vet to take a blood sample or buccal swab from the dog, which is then sent off to an approved laboratory within the UK that can test for prekallikrein deficiency in the Shih Tzu, and who will then return the results for each dog to their owner.