Dermatomyositis (DMS) is an autoimmune disease of the skin and muscle that occurs in both humans and dogs and is caused by a combination of environmental and genetic factors. In dogs, DMS is most often diagnosed in Shetland Sheepdogs and Collies. Skin lesions consist of hair loss and crusts on areas with minimal muscle overlying the bone such as the face, ear tips, legs and feet, and the tip of the tail.
The Clark Laboratory at Clemson University (http://www.clemsoncaninegenetics.com/ ) developed a 3-gene DNA test for DMS in Shetland Sheepdogs and Collies that became available in 2017. The test will help determine the likelihood of an individual dog developing DMS and help breeders avoid producing puppies with high risk genotypes .
This test is different from many DNA tests as 3 genes are considered together to give a probability of low, moderate, or high risk for each dog tested to develop DMS. It does not yield a clear, carrier, or affected report. The genotype reported can be used to guide breeding decisions and assess risk of various genotypes occurring in offspring of a mating pair. To find a list of laboratories that are approved by OFA to run the DMS test see: https://www.ofa.org/diseases/dna-tested-diseases/all-dna-tests. When at that link, click on “Disease” and choose Dermatomyositis, the click on “Breed” and select Shetland Sheepdog. DMS test results from the laboratories on that list will be accepted by OFA into their database.
Only a dog’s genotype (and not the associated risk) will appear in the OFA database since, for breeding purposes, knowing the genotype is needed to make breeding decisions. The goal is to use the genetic information wisely, not to reflexively shun a dog with a high-risk genotype or to continue to breed dogs with unknown genotypes.
To learn more about DMS, the test and how to use it, go to the following link: https://americanshetlandsheepdogassociation.org/dermatomyositis/
 Evans JM, Noorai RE, Tsai KL, Starr-Moss AN, Hill CM, Anderson KJ, et al. (2017) Beyond the MHC: A canine model of dermatomyositis shows a complex pattern of genetic risk involving novel loci. PLoS Genet 13(2): e1006604. doi:10.1371/journal.pgen.1006604. http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1006604#abstract1