Risk test (DNA based) - DM (Degenerative myelopathy)

Details about the disease

This disease is a result of the deterioration of structures in the spinal cord that are responsible for transmission of nerve impulses. Although the changes may be found anywhere in the spinal cord, they are most severe in the lower back.

Clinical signs

The disease has an onset typically between 7 and 14 years of age. It begins with a loss of coordination (ataxia) in the hind limbs. The disease is chronic and progressive, resulting in paralysis.

How it is inherited?

The disease is believed to be an autosomal-recessive condition. This means that dogs that inherit two copies of an DM gene mutation (one from its mother and one from its father) will have an increased risk of developing the condition.

This disease is not fully understood and it is believed that environmental factors or other genetic influences can also contribute to whether a dog becomes affected. Having other factors that influence whether or not a dog is affected by this condition means that having two copies of the recessive mutant gene does not necessarily always result in clinical disease and similarly an absence of the gene is not a guarantee that the condition will not occur.

About this test

Since other factors can influence whether a dog becomes affected by this condition, unlike most other DNA tests, this test evaluates a dog’s risk of developing the disease, rather than giving a definitive result.

Which laboratories test for this condition?

Two lists of laboratories that test for DM can be found below.

Laboratories that send a copy of your dog's results straight to The Kennel Club, so you don't have to.

Laboratories	Contact details
Kennel Club CombiBreed (UK) Available as part of an all-on one health test package for the: French Bulldog German Shepherd Dog	Read more about CombiBreed
Animal Genetics (UK)	Email: Animal Genetics Web: www.animalgenetics.eu
Laboklin (UK)	Phone: 0161 282 3066 Email: Laboklin Web: www.laboklin.co.uk
Pet Genetics Lab (UK)	Phone: 01624 679 720 Email: Pet Genetics Lab Web: www.petgeneticslab.co.uk

Where will your dog's results be published?

DNA test results from these laboratories are sent directly to The Kennel Club and are recorded on to the dog's record in the registration database, and are published:

in the next available Breed Records Supplement
on the Health Test Results Finder

Laboratories that do not send a copy of your dog's results to The Kennel Club. You'll need to do this yourself.

Laboratories	Contact details
Antagene (France)	Email: Antagene Web: www.antagene.com/en
DDC Veterinary (USA)	Email: DDC Veterinary Web: www.vetdnacenter.com
Genetic Technologies Ltd (Animal Network) - Australia	Web: www.animalnetwork.com.au
Orthopedic Foundation for Animals (USA)	Email: Orthopedic Foundation for Animals Web: www.ofa.org
Paw Print Genetics (USA)	Email: Paw Print Genetics Web: www.pawprintgenetics.com
Van Haeringen (Holland)	Email: Van Haeringen Web: www.vhlgenetics.com
VetGen (USA) Only available for the following breeds: French Bulldog German Shepherd Dog Chesapeake Bay Retriever Collie (Rough) Collie (Smooth)	Email: VetGen Web: www.pawprintgenetics.com

How to submit DNA test results to The Kennel Club

The laboratories listed above do not send your dog's DNA test results to The Kennel Club. To have these results placed on your dog's record please submit them yourself by scanning and emailing them to our health results team.

What we require on the results certificate

Please note that we require at least two forms of identification on the result certificate. These must include the dog's microchip or tattoo number along with either the dog's registered name or registered number. Results without these details cannot be accepted by us.

Where will your dog's results be published once you have submitted them?

DNA test results received by The Kennel Club are recorded on to the dog's record in the registration database, and are published:

in the next available Breed Records Supplement
on the Health Test Results Finder

How do we record your results?

Tested dogs will be recorded on The Kennel Club's systems as at “minimal risk (0)”, “minimal risk (1)” or “increased risk (2)”. The numbers assigned to each status indicate the number of copies of the DM gene variant a dog has.

Minimal risk (0) - these dogs do not have any copies of the DM gene variant and are at significantly reduced risk of developing the condition
Minimal risk (1) - these dogs have one copy of the DM gene variant, but are at reduced risk of developing the condition and may pass either one copy of the normal gene, or one copy of the abnormal gene on to future puppies
Increased risk (2) - these dogs have two copies of the DM gene variant and have an increased risk of developing DM. However, of these dogs, it is estimated that 3 in 4 will ever become affected by the condition itself

How to find out if a potential mate has been DNA tested

The Kennel Club’s Health Test Results Finder allows you to find the results of DNA tests carried out as part of The Kennel Club's official DNA testing schemes for any dog on The Kennel Club’s Breed Register.

Breeding information

Breeding information is available below to provide you with details on all possible breeding outcomes.

If your dog is minimal risk (0)

These dogs can be mated to any dogs without increasing the risk of the puppies developing DM. Your chosen mate should always be tested and your decision should be informed by their results.

Minimal risk (0) x Minimal risk (0)

Each puppy born has a:

100% chance of having a minimal risk (0) status
0% chance of having a minimal risk (1) status
0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing DM and will not carry a copy of the DM risk gene variant tested for.

Minimal risk (0) x Minimal risk (1)

Each puppy born has a:

50% chance of having a minimal risk (0) status
50% chance of having a minimal risk (1) status
0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing DM, but will have a 50% chance of carrying a copy of the DM risk gene variant. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies.

Minimal risk (0) x increased risk (2)

Each puppy born has a:

0% chance of having a minimal risk (0) status
100% chance of having a minimal risk (1) status
0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing DM, but will carry a copy of the DM risk gene variant and could pass this gene variant on to any possible future puppies they have.

If your dog is minimal risk (1)

These dogs can be used for mating, but your chosen mate should always be tested and your decision should be informed by their results.

Minimal risk (1) x minimal risk (0)

Each puppy born has a:

50% chance of having a minimal risk (0) status
50% chance of having a minimal risk (1) status
0% chance of having an increased risk (2) status

This means that each puppy born will have the lowest chance of developing DM and a 50% chance of carrying a copy of the DM risk gene variant. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies,

Minimal risk (1) x minimal risk (1)

Each puppy born has a:

25% chance of having a minimal risk (0) status
50% chance of having a minimal risk (1)
25% chance of having an increased risk (2) status

This means that each puppy born has a 25% chance of possibly being affected by DM.

Each puppy will also have a 75% chance of carrying at least one copy of the DM risk gene variant. Dogs that are minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are increased risk (2) will pass this gene variant on to any future puppies

Minimal risk (1) x increased risk (2)

Each puppy born has a:

0% chance of having a minimal risk (0) status
50% chance of having a minimal risk (1)
50% chance of having an increased risk (2) status

This mans that each puppy born has a 50% chance of possibly being affected by DM.

Each puppy will also carry at least one copy of the DM risk gene variant. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are born increased risk (2) will pass this gene variant on to any future puppies.

If your dog is increased risk (2)

These dogs can be used for mating, but your chosen mate should always be tested and your decision should be informed by their results.

Increased risk (2) x minimal risk (0)

Each puppy born has a:

0% chance of having a minimal risk (0) status
100% chance of having a minimal risk (1) status
0% chance of having an increased risk (2) status

Increased risk (2) x minimal risk (1)

Each puppy born has a:

0% chance of having a minimal risk (0) status
50% chance of having a minimal risk (1)
50% chance of having an increased risk (2) status

This means that each puppy born has a 50% chance of possibly being affected by DM.

Each puppy will carry at least one copy of the DM risk gene variant. Dogs that are born minimal risk (1) could pass this gene variant on to any possible future puppies, while dogs that are born increased risk (2) will pass this gene variant on to any future puppies.

Increased risk (2) x increased risk (2)

Each puppy born has a:

0% chance of having a minimal risk (0) status
0% chance of having a minimal risk (1)
100% chance of having an increased risk (2) status

This means that each puppy born has a 100% chance of possibly being affected by DM.

Each puppy will carry two copies of the DM risk gene variant and will pass one of these on to any future puppies.

Potentially producing affected puppies

A mating which may produce affected puppies could have a serious impact on their welfare. If this mating occurs, it is important to test all of the puppies before they are bred from or are passed on to new homes. Veterinary advice should be sought as to the clinical management of any affected puppies.

Further breeding information

Why breed from carriers and affected dogs?

Breeding only from clear dogs can have a significant impact on genetic diversity within a breed, increasing inbreeding and therefore the likelihood of new inherited diseases emerging.

With simple autosomal recessive disorders, a carrier will not be affected by the condition you have tested for, but they could pass on a copy of the faulty gene if they themselves are bred from
Only when a dog inherits two copies of a faulty gene (one from its mother and one from its father) will they be at increased risk
When used responsibly, carriers are an important part of any breeding plan and should not be overlooked
By breeding from carriers, you can keep good, healthy dogs in the breeding population, helping to maintain genetic diversity
Ultimately, however, over the course of a few generations it would be beneficial to aim to produce only clear puppies, thereby reducing the frequency of the disease causing variant of the gene in the breed

Similarly an affected dog could still be used in a breeding programme, but this will very much be dependent on the condition and whether the dog's welfare would be affected by the mating/whelping process. They should only be mated to clear dogs, to ensure no affected puppies are produced.

Are clear dogs 100% clear?

Clear dogs are only known to be clear for the condition that they have been tested for, and may carry other unknown mutations which can be passed on to their offspring - it is almost certain that all individuals carry some versions of genes that if inherited in duplicate, would result in disease. If a particular dog has many offspring that go on to breed themselves, these unknown mutations may then increase in frequency in the breed and a new inherited disease could emerge. In other words, no dog is completely risk free, but there are ways a breeder can reduce the risk of known and unknown inherited disease.

Additional cautions about using carriers or affected dogs

Sticking to these rules will mean that you can still use these dogs for breeding, while maintaining genetic diversity within the breed.

Never overuse a carrier or affected dog for mating. If a dog has one or two copies of a known faulty gene it should never be overused for breeding. Overusing these dogs risks increasing the frequency of the faulty gene within the population, making it more difficult for future generations to breed without increasing the risk of producing affected dogs
Do your research. If all breeders decided to use carriers or affected dogs for mating, then there is a possibility that as the frequency of mutant genes increases, then the proportion of 'clear' dogs would decline. You can use carriers and affected, but you always want to make sure you have a big enough supply of clear dogs. You may wish to talk to health representatives at your local breed club who will have access to summary information on the results of dogs that have been DNA tested and can advise you appropriately on the current situation in your breed
Any possible carrier puppies that go on to be bred from should be DNA tested prior to mating. If you do decide to produce puppies that are potential carriers, but are concerned that they may be used by their new owners for breeding, then you may wish to consider placing an endorsement on the puppy, or include a statement in your puppy contract that any puppies used for breeding must be tested prior to mating and if the puppy is a carrier, it must only be mated to a clear dog

Making balanced breeding decisions

As well as considering the implications of a dog’s DNA test results, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.