Symptoms of Inherited Leonberger
Polyneuropathy in the Leonberger Dog

Two symptoms of Inherited Leonberger Polyneuropathy are laryngeal paralysis and rear weakness or lack of coordination. They do not usually appear at the same time.  The early symptoms noted here do not automatically mean your Leo is affected; they are just signs that you may want to monitor to determine if they are isolated events, or if there is change or worsening over time. Some of them may also be symptoms of other health problems in addition to possibly being early signs of Inherited Leonberger Polyneuropathy.

Laryngeal paralysis (LP) is often first observed as coughing after eating or drinking, a slight bark change sounding like the dog is hoarse, 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 might make the mistake of telling you that because the dog does not have the “stridor” (a harsh, high pitched roaring sound when breathing in), 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; and monitoring changes over time may be helpful information for your veterinarian later.

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) presentation. 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 victims from the US, Germany, France, Sweden, Switzerland, Belgium, the UK, Canada, and probably other countries as well.  

If you are seeing symptoms in your Leonberger, these questions may help you speak with your veterinarian:


·        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? Has he perhaps, stopped barking altogether.

·        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 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?

·        Has he lost muscle mass in his rear legs or his head?

·        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 similar symptoms as allergies and
    tonsillitis. A number have also had cruciate ligament surgeries, possibly due to injury
    from the lack of muscle mass.

LP and PN are symptoms rather than separate diseases, and can also be caused by diseases such as hypothyroidism, which is very easily treated. 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.”  Contact the LCA Health Committee for help and more information, or ask your vet to contact Dr. Diane Shelton, the researcher working with the LCA on ILP syndrome, for referrals to a specialist in your area who is familiar with the disease in Leonbergers.

            Dr. Shelton’s contact information is:

            Phone: 858-534-1537
            Fax: 858-534-7319

If you are the owner or breeder of a Leonberger diagnosed with, or showing symptoms of ILP, there is a Support Group E-mail List available to you; the membership now totals over 60 Leo lovers. Please contact and we will send you an invitation.


Last updated 08/01/2017 .
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