Comparative Neurology Program

PNA? Canine Multiple System Degeneration?

It doesn't matter what you want to call the hereditary movement disorder of Kerry Blue Terriers & Chinese Crested Dogs because now there is a DNA test to eliminate the disease.

Thank You!

We could not have done this research without the help of all the veterinarians, breeders and pet owners who assisted us in collecting samples and patiently awaited the day when we would finally identify the mutation responsible for this disease.

If you would like to continue to help us search for the answers to hereditary disease, consider making a donation to the University of Missouri, College of Veterinary Medicine to support our research. Click Here to make a donation and be sure to direct your donation to support canine genetic research at the College of Veterinary Medicine.

Kerry with PNA

What took so long?

Almost two decades ago two Chinese Crested dogs came to the University of Missouri College of Veterinary Medicine because they could not walk normally. When we found degeneration of multiple parts of the motor system in the brain of these dogs, we called the disease Canine Multiple System Degeneration (CMSD). We soon realized that they suffered from the same hereditary movement disorder that had been recognized in Kerry Blue Terriers since the 1940s. This condition had gone under a variety of names but was most commonly called PNA by the Kerry breeders. Thus began our quest to find the mutation responsible so that we could understand the disease and help breeders eliminate it.

Canine genomics was still in its infancy 20 years ago. We applied the tools available and in 2004 we thought we had found the culprit. In research, however, you cannot just think you are right. You have to prove you are right. As we worked further to get that final proof, we discovered we were barking up the wrong tree. We continued to work on the problem and we are happy to report that we have proved what the mutation causing the disease is and a DNA TEST is now available through the Orthopedic Foundation for Animals.

What is CMSD/PNA?

Canine multiple system degeneration (CMSD) is a hereditary movement disorder that affects Kerry Blue Terriers and Chinese Crested Dogs. Affected pup develop normally until about 4 months of age. Then their head starts to shake when the focus on something, and rather than becoming stronger and more coordinated, they develop exaggerated, goose-stepping movements (cerebellar ataxia). Dogs can function with cerebellar ataxia, but CMSD progresses to a more severe movement disorder by 12-18 months of age. Affected dog have difficulty even starting a movement and fall frequently. They become incapacitated by 2 years of age.

What else can look like CMSD/PNA?

To complicate the picture, we have identified another hereditary movement disorder in Kerry Blue Terriers, a pure cerebellar ataxia. Fortunately, dogs with this condition do not progress past the ataxia stage and can live happy lives. It could, however, be confused with CMSD. If you have a Kerry Blue Terrier that you suspect has this pure cerebellar ataxia, please contact us. We hope to be able to find the mutation responsible for this one as well.

How do I get a DNA test?

A DNA test is now available and can be ordered through the Orthopedic Foundation for Animals.

To order a DNA test from the OFA website, Click Here

Owners of dogs previously sampled for this or other research projects, or with DNA banked at Missouri for any reason can request a discounted test. CLICK HERE to request a discounted test or contact Liz Hansen if you have questions.

With the DNA test, carriers of the mutant gene can still be used for breeding as long as they are bred to a dog that is clear of the mutation. That way no affected dogs will be born, but the desirable genetic diversity that these dogs provide the breed will be maintained. When selecting future breeding stock, the gene status can be considered in deciding which pups to keep but does not have to be the sole factor. As discussed above there are other both hereditary and acquired causes of cerebellar ataxia. Thus not every dog with ataxia will have the mutation.


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The Canine Genetic Diseases Network is a group of researchers dedicated to eliminating genetic disease in dogs