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                                               Health testing for LPN1, LPN2 and in 2017 LEMP or Leukoencephalomyelopathy

                                                                            Links on other health at bottom of page

LPN or Leonberger Polyneuropathy, can be found in Leonbergers. It is a condition which can paralyse the back legs and also can cause paralysis of the larynx. It is a neurological disease of which there are many strains, only two strains are so far identifiable.

In 2010   a genetic marker was found for one strain called LPN1, followed by LPN2 in 2014. In 2017, a genetic marker was also found for LEMP. As far as is known, there has only been one litter born affected with LEMP in the UK.


Our experience of Polyneuropathy to date has been having a litter with 3 pups affected & one of our own boy's lose his life to this at just five years old. The strain to which he was affected has not yet been identified. He was not bred by us and we do know that he was not the only dog affected in that litter. In those days, testing wasn't available so we were breeding blind, no one is to blame, unlike today where we have more information and statistics. It was a very unpleasant experience for us as doubt was cast that Ozzy had any problems. We went on to post a video of him to prove our case. 

Video of Ozzy here

Pedigree of Ozzy 


In 2010 and for our very first litter, we unknowingly mated two D/N parents and from a litter of 11 puppies, 3 went on to develop the disease, D/D affected. They all reached eight year's of age in March 2018, however, two of them passed away later that year. Two others in the litter have passed away at young ages but unrelated to any LPN issues. One of them was our very own Neva who  died 10.02.2017,  just one month short of her seventh Birthday. Four of them have reached 10 years old in 2020, one of them is a D/D affected dog, Nando has done very well to reach such a good age considering his condition. Apart from looking thin with a lot of muscle waste to his back end, he seems to have held up very well. Nando passed away at 10 years, 8 months. The oldest dog in the litter, Jessie lived until she was 11 years, 6 months.

This brings in many unanswered questions for us with regards to the the whole LPN1/2 scenario, if dogs are dying before the D/D affected dogs,  perhaps the severity of LPN isn't as bad as was first thought? It would seem that much of the information given to us by the geneticists in USA, has been disproven one way or another, their figures  certainly don't add up.

While we have taken their advice on breeding with D/N girls, we have never agreed with their notion to only keep a clear puppy for future breeding. Our belief is to take the best puppy overall, more below:

Pedigree of our affected litter

Twelve years on, we are in a much better position to realise the unnecessary knee jerk reactions taken by some breeders in the early days, who panicked and insisted that all D/N dogs should be withdrawn from breeding, even though we were advised by the professional geneticists, that breeding  an affected dog was not possible from a D/N to N/N clear mating. We now know, as we have always believed, that the D/N dogs are as  healthy as a clear dog and should not be removed from breeding, to do so is damaging to the genetic diversity of the breed. Quite a change in a short time, it has even been suggested that a D/N tested dog may  have a stronger ability to thwart other bad genes? We know that to fix 1 faulty gene, others will appear.

An excellent article about genetics and carrier dogs, Bad Genes, babies and bathwater

We have always chosen to breed from D/N dogs due to our belief that they are of better quality than the clear dogs that we have bred. Personal opinion! 


Testing a whole litter of puppies proved nonsensical to us, firstly, we had a litter of 8 puppies in 2012 and due to the time scale in which it takes to get results back, we had the results from USA just two days before the puppies were to leave us. By this time all puppies had been chosen including the three puppies that we were keeping from that litter. Aslan was a Clear dog but the two girls we kept were both D/N carrier's and were both in breeding, they passed away through old age at ages 9 and 10.  A clear female from the litter was in our opinion, not the best specimen of the breed and she has not been in any of our breeding plans. She passed away at eight years old. Aslan is still alive at just past 10, there was no difference in health for either clear or D/N.


Since then, we have had three female's tested Clear which we have felt have not been of a good enough standard to breed from. We feel that we will always take the best dog from a  litter  regardless of the LPN1 status of that dog. The standard being the most important aspect for us as breeders. We will not take an inferior dog from a litter just because it is LPN1 Clear. The available tests are our tools to make better informed decisions, not to remove dogs from breeding. We still breed within the breeding code of ethics and health is at the top of our list with every litter.

Anyone who contradicts this statement does not do so with honesty,  this can be confirmed on the University of Minnesota website where there is more information.

Katie Minor, geneticist at Minnesota USA recently wrote "The goal of genetic testing should be to keep as many dogs as possible in the breeding population without producing animals with disease. By testing you can safely breed carriers, knowing no affected will be produced."


In 2014, a genetic marker was found for the LPN2 strain of Polyneuropathy. This was totally different from LPN1 as it was advised not to breed from carrier D/N dogs. There is evidence that known carrier dogs had lived long lives and had not produced any affected dogs, many litters have been born from D/N dogs over the years but there seems no substantial evidence or statistics to rule out the use of these dogs. In following the advocated advice, have breeders created damage to an already small gene pool by removing these carrier dogs?

We have tested our dogs in  breeding and they are all LPN2 clear.

An excellent article on LPN2 here written by Mr Grant Saggers of Leonmoor Leonbergers 


In 2017, a genetic marker was found for LEMP which has been met with a great deal of skepticism from breeders all over the world. In many countries it is unheard of and we know of only one affected litter in the UK to date. This was in Ireland, no cases anywhere else.

As with LPN2, the statistics are not clear. Even with an affected D/D status dog, not all will show clinical symptoms in their lifetime.

This strain has affected many breeders in the UK who were previously opposed to using D/N dogs. However, they are now met with the dilemma that they have quality breeding lines and longevity, losing those dogs from breeding could result in the loss of those  valuable breeding lines altogether and again, reduce the gene pool further. 

These tests are for our guide only to allow us to make better decisions. There are many breeds  out there who need to carry out different health testing, those breeders don't eliminate D/N carrier dogs from breeding. These dogs are healthy and they should be treated in exactly the same way as an N/N clear dog but must be mated to a clear. It is only carrier to carrier matings that will produce affected offspring. As above link suggests, don't throw the baby out with the water.

Are we health testing the Leonberger to extinction?  Another superb article written by Mr Grant Saggers

The Leonberger is a relatively healthy breed in comparison to some other giant breeds, but over the last few years, we have seen more cases of Osteosarcoma. Cancer in all breeds is known to be the biggest killer.

We are now in our tenth  year of breeding, and have not had  a single case of Osteosarcoma diagnosed in our lines so far. We know that one day it may come knocking on our door. We will also be breeding for the first time from LPN1 clear females as opposed to carrier girls.  It will be interesting to see if cancer appears more in the near future because of this? We have proven that our D/N girls didn't seem to carry the devastating cancer gene. We can only say that unlike cancer, this is not a definite killer and even affected dogs can live to a good age, albeit have a slower pace of life. With regards to losing Neva, we would much prefer to have her alive with LPN than not here at all!

With this information in mind, we would also use a D/N tested male in the future, if they are perfectly healthy and are a quality specimen of the breed.


It would be fair to say that until more research is done and genetic markers are found for other strains of LPN, we cannot extrapolate with accuracy, the impact that Polyneuropathy has on the breed overall.

In a recent discussion on social media about D/N dogs, there was some contradictory comments from USA & Europe. Firstly it was said that D/N dogs are perfectly healthy and should not be withdrawn from breeding. The next sentence said to test progeny and breed from clear offspring. So if they are perfectly healthy and not likely to develop symptoms,   why do we need to test puppies and breed only from clear? It is not in the best interests of the breed  to  totally eradicate this gene if we are likely to develop other faulty genes in the process.

What we can establish is the continuous money river from Great Britain to Minnesota USA! food for thought?

The following links make interesting reading

Laboklin for genetic testing also LPN1 & 2 Manchester UK

Are annual vaccinations necessary?

Exercise for young dogs & growing bones

Impact of exercise on growth plates

Genetic diversity and selection

Should you shave your dogs coat?

The backyard Geneticist


Bad genes, babies & Bathwater 







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