Inherited Leonberger Polyneuropathy & Laryngeal Paralysis
A small number of Leonbergers suffer from an inherited neurological disease called Leonberger Polyneuropathy (LPN).
Very often, Laryngeal Paralysis is associated with this disorder. There is an ongoing coordinated international research effort, supported by the international community of Leonberger Clubs, which is focused on identifying the underlying genetic basis of this disease, with the ultimate goal of developing one or more genetic marker tests that can be done from a simple blood sample. Through the use of such a test, carriers of the defective gene or genes may be identified so that they can be eliminated from future breeding programmes.
In June of 2010 the first marker test for a particularly harsh early onset form of LPN was released. This test will identify the mutation responsible for One Form of the illness, designated as LPN1. This is not the only form, and we await further progress to unlock the mutation for all forms of polyneuropathy in our breed. At present, a Leonberger tested clear of the LPN1 mutation may still suffer from a second form of the illness. The only way to determine this is through the submission of a nerve / muscle tissue sample for microscopic analysis. We recommend using the Comparative Neuromuscular Laboratory at the University of California , San Diego . We also recommend that such a sample be taken post mortem, and that any Leonberger exhibiting the symptoms of LPN during its life not be bred from.
At the 2010 AGM of the Leonberger Club of Great Britain it was decided to add mandatory LPN1 testing to our Breeders' Code of Ethics. Under this Code of Ethics, the Club will only permit clear to clear or clear to carrier matings.
Details for submitting samples may be found here:
For the most comprehensive collection of details on this genetic illness, please go to the ILP page of the International Leonberger Union here:
Symptoms of Inherited Leonberger Polyneuropathy in the Leonberger Dog
Two symptoms of Inherited Leonberger Polyneuropathy (ILP) are laryngeal paralysis (LP) and rear weakness or lack of coordination caused by Polyneuropathy (PN). They do not usually appear at the same time and LP is observed by way of coughing after eating or drinking, or a slight bark change sounding like the dog is hoarse, sometimes called “stridor” and louder or heavier breathing then you would expect after minor exercise.
Some young dogs will not be able to play or walk as long as you think they should. They have to stop and rest. Veterinarians who are not experienced with LP will make the mistake of telling you because the dog does not have the “stridor” he does not have LP. The “stridor” is the end stage of LP, not the beginning.
We've been told by the specialists who do the emergency surgeries on these dogs that many veterinarians are not used to recognizing the problem before the dog is in crisis.Polyneuropathy may initially be so mild that many owners will miss it, sometimes just becoming used to the very gradual changes taking place. You may notice your Leo taking just a split second extra to put a foot down when he walks – like his movement is off a beat. You may see her stumble when backing up or occasionally dragging a rear foot.
Minor things can start years before the major ones.The disease affects both males and females. It has both an early onset (1-3 years) as well as a later onset (past 7 years). Most affected dogs seem to fall into the 3-5 year range to begin showing symptoms. We know that older onset Leos can still produce early onset offspring. We know that some Leos are affected very mildly while others in the same litter are affected very severely. We know that ILP has affected dogs from the US, Germany, France, Sweden, Switzerland, Belgium, the UK, and Canada and probably other countries as well.
If you are seeing symptoms in your Leonberger, these questions may help you speak with your veterinarian.LP/PN· does my dog quickly tire after exercise? A young dog should be able to run and play for a fairly long time in normal weather.· has his “bark” changed over the past year. Does he sound “hoarse” now when he barks?· is he panting more than he used to, especially after excitement?· is his breathing getting louder, so that you find yourself raising your voice when he is in a room with you so you can be heard above his breathing?·
is he “awkward”, sometimes tripping over his own feet?· do you sometimes notice “something just not quite right“ for a second or two, when you watch him move around your yard? You'll notice it more while he is walking not trotting.· is he “high stepping” with his rear legs? Does he look like he is trying to walk through high grass, lifting his knee up high and then plopping his foot down on the ground?· does your vet tell you “it's probably just arthritis” when you ask about his gait? Or that he is an older dog and they all sound loud when they pant?· have you been told he has allergies or tonsillitis or has he had cruciate ligament problems?
Many of the ILP dogs have been misdiagnosed with allergies or tonsillitis when the actual problem is that LP can cause the symptoms of allergies and tonsillitis. A number have also had cruciate ligament surgeries possibly due to injury from the lack of muscle mass.If you are noticing any of the above symptoms in either a young or old Leo, please don't be misled into thinking they are only due to his being a “large breed” or an “old dog”. “Old age” isn't a disease and the above symptoms are not “normal.”
If you are the owner or breeder of a Leonberger diagnosed with, or showing symptoms of ILP, there is a Support Group email list available to you whose membership now totals over 60 Leo lovers. Please contact and we will send you an invitation.
Leonberger polyneuropathy (LPN)
Since July 2010 a genetic test is available for 1 type of Leonberger Polyneuropathycalled the Lpn1 mutation.
The test results are shown as follows:
N/N=Clear= 2 copies of the normal gene.
D/N=Carrier= 1 copy of the normal gene & 1 copy of the LPN1 mutation.
D/D=Affected= 2 copies of the of the LPN1 mutation.
Indications for breeding Parents genotype
Probability for N/N ofspring Probability for D/N ofspring Probability for D/D ofspring
N/N x N/N 100 % 0 % 0 %
N/N x D/N 50 % 50 % 0 %
N/N x D/D 0 % 100 % 0 %
D/N x D/N 25 % 50 % 25 %
D/N x D/D 0 % 50 % 50 %
D/D x D/D 0 % 0 % 100 %
We strongly discourage the matings depicted in red!
In other words: From N/N x N/N or N/N x D/N you will never have a pup with the severe early- onset LPN1 polyneuropathy.At this time researchers do not recommend to use exclusively N/N dogs for breeding.Exceptional carriers may be still used in breeding, if they are mated with homozygous free (N/N) dogs. A strict exclusion of all carriers would narrow the restricted gene pool of Leonbergers too much. This might lead to an increase of other hereditary diseases.
However, breeders are strongly encouraged to contemplate such combinations only once, and then to select a clear (N/N) offspring of such a combination to move on with. By adopting this sort of a “breed and replace” practice, the mutation can eventually be eliminated from valuable lines, while retaining other desirable qualities these lines may have to offer the breed.
Valuable D/N breeding dogs can therefore be used at the moment and will have 50% free offspring, if they are mated to N/N animals. The free offspring can then be used to select the best dogs with the desired traits for the next generation. Second and third (or more) generations of D/N carriers are strongly discouraged.
The introduction of LPN1 genetic testing cannot completely eliminate polyneuropathy from the Leonberger population. LPN1 genetics testing recognizes only one of potentially several forms of polyneuropathy in the leonberger.Therefore, it is possible that even from the mating of two LPN1-free dogs offspring with a different form of polyneuropathy may be born.
However, LPN1 genetic testing can reliably avoid a severe early-onset form of polyneuropathy and this test can significantly reduce the overall frequency of polyneuropathy in Leonbergers.
FAQ’s about LPN1 tests:
Instructions for ordering the Lpn1 test:
In North America:
Veterinary Diagnostic LaboratoryCollege of Veterinary MedicineUniversity of Minnesota
1333 Gortner AvenueSt Paul MN 55108-1098
Phone: (612) 625-8787 or (800) 605-8787
Institut für GenetikStichwort "Leonberger"Bremgartenstrasse
109ACH-3001 Bern. Switzerland
More information can be found at: