Mutations in the superoxide dismutase 1 (SOD1) gene and subsequent conformational alterations to the SOD1 protein and associated toxicity are responsible for 20% of genetic ALS and most cases of canine DM.3 Although the German Shepherd Dog is the most commonly affected breed, DM is now known to occur in multiple breeds, with an overall prevalence of 0.19%.4 Here, SOD1 is linked to amyotrophic lateral sclerosis.