Degenerative myelopathy SOD1B (Bernese mountain dog type) is caused by a Mutation of the SOD1 gene currently only identified in the Bernese mountain dog. Bernese mountain dogs are known to develop a more slowly progressive form of degenerative myelopathy (DM) associated with this mutation. In general, there is variable presentation between dogs with this disease suggesting that there are environmental or other genetic factors responsible for modifying disease expression. The average age of onset for dogs with DM is approximately nine years of age. The disease affects the White Matter tissue of the spinal cord and is considered the canine equivalent to amyotrophic lateral sclerosis (Lou Gehrig’s disease) found in humans. Affected dogs usually present in adulthood with gradual muscle Atrophy and loss of coordination typically beginning in the hind limbs due to degeneration of the nerves. The condition is not typically painful for the dog, but will progress until the dog is no longer able to walk. The gait of dogs affected with DM can be difficult to distinguish from those with hip dysplasia, arthritis of other joints of the hind limbs, or intervertebral disc disease. Late in the progression of DM, dogs may lose fecal and urinary continence and the forelimbs may be affected. Affected dogs may fully lose the ability to walk within 2 years after the onset of symptoms. Medium to large breed dogs that are affected with DM, such as the Bernese mountain dog, can be difficult to manage and owners often elect euthanasia when their dog can no longer support weight in the hind limbs.