Degenerative myelopathy

Degenerative myelopathy is a slow, painless deterioration of the spinal cord in older dogs, usually starting after five years and on average at about nine in large breeds¹. It is most common in the German Shepherd Dog, Pembroke Welsh Corgi, Boxer, Rhodesian Ridgeback and Chesapeake Bay Retriever¹². A mutation in the SOD1 gene is associated with the disease; dogs carrying two copies are at much higher risk, though not all of them develop it³⁴. The same gene is involved in one form of motor neurone disease in people³.

The first signs are easy to mistake for arthritis: scuffing or knuckling of a back paw, worn nails on the back feet, swaying hindquarters, and crossing the back legs when turning¹. The difference is that the dog is not in pain and the weakness advances over months. Diagnosis rests on ruling out other causes; a DNA test shows whether a dog carries the mutation²⁴.

There is no cure. Physiotherapy, non-slip footing, a rear harness and, later, a cart keep affected dogs mobile and comfortable for as long as possible².

This is general information, not a diagnosis. Your vet knows your dog.

Sources

1. Degenerative Diseases of the Spinal Column and Cord in Animals. Merck Veterinary Manual. Accessed 2026-09-22.
2. Canine Degenerative Myelopathy (Coates JR, Wininger FA). Veterinary Clinics of North America: Small Animal Practice 40(5):929-950, 2010 (peer reviewed). Accessed 2026-09-22.
3. Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis (Awano T et al.). Proceedings of the National Academy of Sciences 106(8):2794-2799, 2009 (peer reviewed). Accessed 2026-09-22.
4. Breed Distribution of SOD1 Alleles Previously Associated with Canine Degenerative Myelopathy (Zeng R et al.). Journal of Veterinary Internal Medicine 28(2):515-521, 2014 (peer reviewed). Accessed 2026-09-22.