Degenerative myelopathy (DM) is a neurologic condition that usually leads to paralysis. It is similar to ALS (Lou Gehrig’s disease) in humans. The myelin sheaths that insulate the nerves degenerate disrupting the transmission of electrical impulses to muscles. The disease usually affects the nerves of the lower spinal cord. It starts with weakness in the rear legs that makes it difficult for the affected dog to get up and walk on slippery floors. As the nerves degenerate further, the dog starts to drag their paws causing worn nails and abrasions on the top of their paws. Although the disease can wax and wane, most dogs are paralyzed within a year. They also lose control of their bowel and bladder.
DM (also called degenerative radiculomyelopathy) is caused by a genetic mutation called superoxide dismutase 1. I have diagnosed DM in Boxers, Bernese mountain dogs, Great Pyrenees, Pugs, Chesapeake Bay retrievers and my own German Shepherd dog. Gretchen was just 3 years old when she started slipping on a concrete porch. Her back legs were completely paralyzed three months later. DM is also sometimes called German shepherd degenerative myelopathy because it is so common in this breed. It is also reported in American Water Spaniels, Bloodhounds, Borzoi, Canaan Dogs, English Cocker Spaniels, Kerry blue terriers, Pembroke Welsh Corgis, Sealyham terriers and Whippets.
Unfortunately, there is no treatment for DMe at this time to stop the degeneration of the myelin sheaths. Perhaps this may be an area for stem cell therapy in the future. Intensive physical therapy that slows muscle loss is the only option available. Most dogs are euthanized due to quality of life concerns.
Prevention is based on identifying dogs with the mutation before breeding. The Orthopedic Foundation for Animals performs DNA testing for superoxide dismutase 1 gene. I strongly encourage all breeders to check their dogs for this mutation before breeding.
Source:
Lundgren, Beck. Degenerative Myelopathy. Veterinary Partner, VIN, originally published 7/2/2007, revised 4/27/2015.