UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

Degenerative Myelopathy

Degenerative myelopathy (DM) is an inherited neurologic disorder of dogs similar to Lou Gehrig’s disease in humans and results from a mutation (c.118G>A) in the SOD1 gene. Affected dogs usually present clinical signs of disease in adulthood (at least 8 years of age) with gradual muscle wasting and loss of coordination that typically begins in the hind limbs because of nerve degeneration. Disease progression continues until the dog is unable to walk. Small breed dogs tend to progress more slowly. In late stages of the disease, dogs may become incontinent and the forelimbs may be affected. Affected dogs may fully lose the ability to walk 6 months to 2 years after the onset of signs. The disease is inherited in an autosomal recessive fashion with incomplete penetrance. Thus, two copies of the SOD1 mutation (DM/DM) confer increased risk for DM but not all DM/DM dogs across breeds will develop the disease. The variable presentation between breeds suggests that other genetic and environmental factors play a role in disease expression. There is ongoing research to identify other genetic factors that modify risk for DM in different breeds. In addition, similar disease presentation is observed in some animals lacking the SOD1 mutation. Breeding two carriers of the SOD1 mutation together is predicted to produce 25% of pups that may develop DM.

The VGL offers a genetic test for the SOD1 c.118G>A mutation, reported here as DM. Genetic screening helps breeders establish the genetic status of breeding stock and select mating pairs appropriately to reduce the risk of producing DM-affected offspring.

Testing is appropriate for: many breeds

The Degenerative Myelopathy (DM) test is a patented test. The Veterinary Genetics Laboratory is authorized to offer the DM test to residents of the United States, Canada and Australia.

Allow 5-10 business days for results.

Results reported as:


No copies of the DM mutation


1 copy of the DM mutation


2 copies of the DM mutation; dog may develop DM disease


Awano T, Johnson GS, Wade CM, Katz ML, Johnson GC, Taylor JF, Perloski M, Biagi T, Baranowska I, Long S, March PA, Olby NJ, Shelton GD, Khan S, O'Brien DP, Lindblad-Toh K, Coates JR. 2009. Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis. Proc Natl Acad Sci U S A. 106(8):2794-2799. [PubMed: 19188595]

Coates JR, March PA, Oglesbee M, Ruaux CG, Olby NJ, Berghaus RD, O'Brien DP, Keating JH, Johnson GS, Williams DA. 2007. Clinical characterization of a familial degenerative myelopathy in Pembroke Welsh Corgi dogs. J Vet Intern Med. 21(6):1323-1331. [PubMed: 18196743]

Shelton GD, Johnson GC, O’Brien DP, Katz ML, Pesayco JP, Chang BJ, Mizisin AP, Coates JR. 2012. Degenerative myelopathy associated with a missense mutation in the superoxide dismutase 1 (SOD1) gene progresses to peripheral neuropathy in Pembroke Welsh Corgis and Boxers. J Neurol Sci 318(1-2):55-64. [PubMed: 22542607]

Zeng R, Coates JR, Johnson GC, Hansen L, Awano T, Kolicheski A, Ivansson E, Perloski M, Lindblad-Toh K, O'Brien DP, Guo J, Katz ML, Johnson GS. 2014. Breed Distribution of SOD1 Alleles Previously Associated with Canine Degenerative Myelopathy. J Vet Intern Med 28(2):515-521. [PubMed: 24524809]

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL