Degenerative myelopathy (DM) can be a devastating disease. Some breeds with this disease will lose the ability to walk in their later years – certainly after the age most dogs are bred. The mutation has been found in more than 70 breeds, which indicates that the original mutation might have occurred hundreds or thousands of years before many of the modern dog breeds emerged.
However, the frequency of the mutation varies between breeds and certainly the risk of developing the clinical disease seems quite distinct and breed-specific. For example, the frequency of carriers and homozygous mutation (affected) dogs in the Kerry blue terrier is about 52%(1), while carriers and affected dogs make up 91% of Pembroke Welsh corgis in Japan (2). Although wire fox terriers have a similar combined carrier and at-risk frequency of 90%, none have ever developed the clinical signs of DM (3).
In a 2001 study by Moore et al., German shepherd dogs had nearly twice the risk for death associated with spinal cord diseases, compared with Belgian shepherd dogs among military dogs (4). Although we don’t know for sure if the spinal cord disease was DM, certainly DM is one of the more common causes of this type of disorder ...