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The Leonberger is not one of the most common dog breeds in the UK and not all dog lovers will even have spotted a Leonberger in the flesh when out and about, but this large, gentle an very affectionate dog breed still has a strong following of fans and enthusiasts who appreciate all of the breed’s core traits.
There are a lot of good points about Leonbergers for the right types of owners, but the breed’s general health is not as robust as it could be, and there are a number of hereditary health conditions that can be found within a reasonable number of individual dogs of the breed as a whole.
One of these is called Leonberger polyneuropathy LPN2, and this is a type of neuromuscular disorder that is present in affected dogs from birth. Another is called leukoencephalomyelopathy or simply LEMP for short, and this is a neurodegenerative disorder that causes a number of similar symptoms to Leonberger polyneuropathy.
In order to help to improve the health of the breed as a whole and reduce the incidence rates of polyneuropathy and leukoencephalomyelopathy within the breed population, the Kennel Club announced in April 2019 that they’ve introduced two new DNA testing schemes for the breed, to identify the genetic markers of these conditions in parent stock.
In this article we will provide an introduction to polyneuropathy and leukoencephalomyelopathy in the Leonberger, how the conditions can be tested for in parent stock, and how the new Kennel Club approved DNA testing scheme works. Read on to learn more.
Polyneuropathy comes in a number of different variants, and one of the ones that specifically affect the Leonberger breed is called LPN2.
This is a hereditary condition that is passed on from parent dogs to their young, beginning with serious neuromuscular disease when the dog is still young, and which develops to cause a progressive intolerance for exercise, an abnormal moving gait, and wastage of the muscles in the back legs. It can also cause breathing difficulties in some cases.
Additionally, there is already another recognised form of Leonberger polyneuropathy called LPN1, for which an existing DNA test is available.
Leukoencephalomyelopathy or LEMP is another degenerative disorder that affects the dog in a similar way to polyneuropathy, resulting in many similar symptoms in affected dogs. This condition is not, however, painful, although it has a significant and acute impact on the dog’s quality of life.
However, the cause of LEMP is not the same as the cause of LPN2 (or LPN1), and it is caused or triggered by a different gene mutation.
The Kennel Club have now introduced two new DNA tests for the Leonberger breed, to identify the markers of LPN2 and LEMP respectively in prospective parent dogs prior to their being used for breeding.
However, whilst the heredity of many canine health conditions can be definitively confirmed or ruled out by DNA testing, for the new DNA testing protocols in the Leonberger breed, test results can help to guide a decision and reduce breeding risk factors, but they are not 100% fool proof.
The LPN2 test can identify if a dog is likely to have LPN2, but the absence of the genetic markers that indicate this do not necessarily mean that the dog is in the clear, as this condition and its heredity, as well as the specific combination of genes involved in it, are still the subject of research.
When it comes to the LEMP test, a genetic mutation that has been strongly correlated to the development of leukoencephalomyelopathy has been identified and used as the basis of the LEMP DNA test, but again, there are some grey areas.
Out of the results returned for tested dogs prior to the new Kennel Club testing scheme’s launch, all of the dogs who had been diagnosed with LEMP inherited two copies of the relevant gene mutation; however, not all dogs that did inherit two copies were affected, for reasons that are unclear.
This indicates that there is potentially another factor involved in heredity, but that dogs who inherit two copies of the gene mutation have a very night chance of being affected themselves.
However, dogs that do not inherit the marker for the condition from either parent, or who inherit it from just one side of their ancestry are unaffected.
Putting all of this together, the LPN2 and LEMP DNA tests for the Leonberger can be used to inform and guide breeders on the best choices to make to produce a healthy litter, and this will reduce the chances of breeding unhealthy puppies. However, given the mentioned variables for the condition’s testing and results, this information should be used as a guide only.
If you wish to get your own Leonberger tested for LPN and LEMP prior to breeding from them, you just need to let your vet know of your plans and ask them to take a DNA sample from your dog. The samples are then sent away to one of the Kennel Club’s approved laboratories, who return the results to the dog’s owner.
Owners of tested Leonbergers can also send copies of their dog’s test results to the Kennel Club for inclusion within the breed database and health test results finder, to add an additional layer of reassurance to prospective puppy buyers.
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