Still a Breeder’s Nightmare?

Many things have changed since I wrote my first article almost twenty years ago, but many other things have not. Over the years, I have continued to learn things about DMS in Collies and in people. I hope this helps you as a Collie breeder, owner and fancier to be more informed if this disease ever touches you.


DMS is still widespread and affects Collies and Shelties in numbers that are alarming. The symptoms are the same and can differ from dog to dog. Remember, DMS is an auto-immune related disease. This is a two-part disease affecting skin, muscle or both. It can be a lethal disease. DMS can be a hard thing for both the dog, breeder and the owner to deal with. It puts any breeder in a horrible position as to what should be done with their breeding program and what should be done with a pet puppy they sold. What we suspected in the 1990s, seems to be a little more obvious than we could have known at the time. I want to remind everyone, I’m not a veterinarian. Just like in my first article, this piece’s focus is on my opinions and my thoughts. This comes from my years in Collies, dealing with this disease personally and being passionate about Collie health and the Collie Health Foundation.

Helpful Information

We are lucky to have more information today to help us as breeders make hard decisions about our breeding program. With the DMS Risk Assessment Test developed by Dr. Clark at Clemson University, breeders have added an important tool to their toolbox. The DMS test allows us to test our dogs to see what the “A”, “B” and “C” alleles are in our dogs. Dr. Clark has developed a chart to show where the highest risks lie for breaking with DMS. It’s important to remember that the American Collies all have the same “C” allele which puts all our Collies at risk. Fortunately for Shetland Sheepdogs, they do vary in the “C” allele and can carry the little “c” allele.

How do we use this new tool? It’s important that you understand that the test is a “RISK ASSESMENT” test and not a genetic marker test. In DMS, there is no such thing as “normal”, “clear” or “carrier”. The best any dog can be is low risk. This means they can still get it or pass it along. My opinion has not changed about breeding a Collie with DMS. I would never do it. Once you have had dogs with DMS it’s different than knowing someone who had it. Whether you place a dog in a pet home or keep it, you still need to be in contact with the owner until the dog dies or must be euthanized.

These are the charts that are published on the American Shetland Sheepdog Association’s website. The Collie Health Foundation has a link on our Dermatomyositis page to the ASSA website. The charts make it easy to figure what a breeding may produce if both parents have been tested for the DMS risk assessment. Remember, “By Parentage” can only be used for the first generation of any breeding for any genetic test. For DMS, it is only useful if the whole litter will be the same because of the parent’s alleles. For instance, a stud dog that is AA/bb is bred to a bitch that is aa/bb, the whole litter must be Aa/bb and you are able to use the “by parentage” for this generation. The small cap letters are in blue because they are “low risk” and the large cap letters are in red to denote “higher risk”.

Another important point all breeders need to know about is if you suspect a dog has DMS and they do a punch biopsy the result could be inconclusive. A large number of the biopsies come back “inconclusive”. The pathologist report may say it appears or could be DMS, but the test is not conclusive. Any breeder can then say their Collie was tested but did not have it or that it was inconclusive. I have talked with veterinary dermatologists that say it’s very difficult to find an active lesion to biopsy. I think I’m able to make an assessment looking at dogs whether they may have it but testing needs to be done. The lesions that are caused by DMS are very distinctive and their location is too. Lesions usually appear on the face first then ears and legs. The first sign may look like a bug bite or a bee sting. It may look a lot like demodectic mange. Skin scrapings can rule out mange. When lesions heal, they usually leave black skin in their place. In some severe cases muscle wasting can start younger. In other cases, you may not see it until the dog reaches an older age. At this time, it usually shows in the wasting of the back skull. Beautiful skulls that were cornered and filled become boney. It may affect any of the muscles in the body including the tongue. This is very serious and if not controlled will lead to euthanasia.

When I judged in Germany a couple of years ago, I judged a dog that I was pretty sure had DMS. The club I judged for keeps its own stud book recording all health tests that breeding dogs have done. I told my hostess about my fear and the dog was tested and was positive for DMS. We must be honest with each other especially if the biopsy comes back inconclusive. We have this tool now, so every breeder needs to be asking the stud dog owner or the brood bitch owner for their health test results before a breeding is decided. You just might save yourself and maybe a puppy buyer an expensive heartache.

I’m including the charts from 2017 that show the risks and percentages for a dog with results for specific alleles. These charts were set by Dr. Clark when they found no movement in the numbers as additional Collie and Shelties were tested. Currently prednisone has been the best treatment for DMS. Using these new tools should help us stay away from it if we can.

The Future

We are in some very exciting times with more and more genetic tests becoming available. The Collie Health Foundation is working again with Dr. Leigh Anne Clark while she looks for a modifier gene for DMS. We know that there must be some factor that allows one puppy in a litter to break with DMS and no one else in the litter breaks with it. In the beginning we talked about environmental triggers or even that a shot could bring DMS to the surface. If Dr. Clark can find that modifier, we are one step closer to finding an answer to this horrible disease.

As many of you know MARS purchased OptiGen this year through their Wisdom Health division. Wisdom Health has been diligent in getting licenses and starting a partnership with the researchers that created many of the genetic tests on their panel. Wisdom Health is in the process of running blind tests on DMS and rcd2-PRA. As soon as they are confident in the test results, OptiGen will be closed for all genetic testing. DMS and rcd2-PRA will become part of the panel test, now called Optimal Selection™. OptiGen will close in September if not sooner. Therefore, OptiGen is asking everyone to be patient for their results because they only have a skeleton staff. I have a promise from Wisdom Health that they will not close OptiGen until they are able to provide the two Collie specific tests.

CHF is working closely with Wisdom Health to provide testing at our CCA Nationals. CHF And Wisdom Health are close to having an agreement where CHF members receive a one-time use code and they only pay the difference between the cost of testing minus the rebate. We know this helps with the cost of testing for all the CHF members. This cuts back on the amount of work for granting rebates and we hope it will continue to help contribute to more breeders doing health testing. Once we know exactly how we will work with Wisdom Health, we will announce it to our members, on our website, and on our Facebook page.

CHF is working with the ASSA and AKC/Canine Health Foundation on a grant for a clinical trial to see how treatments may help dogs affected with DMS. The early process of this trial has already shown a slowdown of the progression of the disease, and in some cases some reversal of muscle wasting. When the grant is funded, we will need Collies and Shelties with DMS for this important clinical trial. Working together we just might find answers to many of the diseases that affect our beloved dogs.

I want to thank Dr. Clark and Sarah Murphy for their dedication to research in DMS. A special thanks for Dr. Clark. She has answered so many of my questions, so my knowledge of this disease continues to grow. For those of you who have reached out to me, thank you too. I hope I was able to help. Please see for more information and a link to the video of Dr. Clark’s presentation at our dinner at the 2018 National.

We need your Help!

Dermatomyositis Modifier Study: Clemson University – Dr. Leigh Anne Clark
Collies that are 8 years old and older – DMS Genotype AA/bb & Collies with signs of DMS
Clemson will test any dog with signs of DMS for free. Please contact Sarah Murphy at