Dermatomyositis (DMS) is an autoimmune disease of the skin and muscle that occurs in both humans and dogs. In dogs, DMS is most often diagnosed in Shetland Sheepdogs and Collies and is caused by a combination of environmental and genetic factors. In most case skin lesions involving hair loss and crusty scabs in areas such as the face, ear tips, legs and feet, and the tip of the tail. The disease can develop in puppies as early as 3 months of age or develop later in mature dogs. There are 3 genes which when combined measure the risk factor for DMA. These are PAN2, MAP3K7CL and DLA-DRB1 each on separate chromosomes and separate tests.