Degenerative myelopathy is a slow, incurable disease of the spinal cord. It usually appears after the age of seven, and it affects the dog's ability to walk and control its back legs.
What it is
DM is a progressive condition of the spinal cord. There is no cure, and the changes it causes cannot be reversed. The disease moves slowly in most dogs, but the speed varies a great deal from one dog to another.
Symptoms
The first signs are usually weakness and poor coordination in the back legs. A dog may stand with its legs close together, or may not correct an unusual foot position, because the sense of where the foot is has faded. Walking can look unsteady, a bit like arthritis. The dog may drag one or both back paws, and the nails on one foot can wear down from the dragging.
As the disease moves on, the back legs may become partly or fully paralysed. Some dogs lose control of their bladder. Balance and walking become harder. In the later stages, the front legs can be affected too, and muscle loss becomes obvious. If the disease reaches the nerves that control breathing, euthanasia or long term palliative care becomes necessary.
Some dogs go downhill within a few months. Others live comfortably for three years or more.
Care and treatment
There is no treatment that has been shown to stop or slow DM. What helps is keeping the dog mobile and comfortable for as long as possible.
Regular gentle exercise is useful. Physiotherapy can extend the time a dog stays mobile and may add to its survival time. Swimming, or canine hydrotherapy, is often easier on the dog than walking. A belly sling or a hand-held harness lets you support the back legs when the dog exercises or goes up and down stairs. Once weakness or paralysis sets in, a two-wheel dog cart, or dog wheelchair, can keep the dog active and protect its quality of life.
DNA testing
The Orthopedic Foundation for Animals offers a DNA test for the mutated gene linked to DM. The sample is collected by swabbing the inside of the cheek with a sterile cotton swab, or through a blood draw. The test shows whether the mutated copy of SOD1 is present.
Results should be read with care. A veterinarian will interpret them together with the dog's clinical signs and other lab results. The test is most useful in breeds where DM is known to occur, and it has made it possible to breed the condition out over time.
Breeding advice
Breeding risk can be worked out with a simple Punnett square. The letters are N for the normal copy and A for the mutated copy.
- Clear (N/N) to clear (N/N): all puppies clear.
- Carrier (N/A) to clear (N/N): about half the puppies clear, half carriers.
- Carrier (N/A) to carrier (N/A): about a quarter clear, half carriers, a quarter at risk.
- Clear (N/N) to at risk (A/A): all puppies carriers.
- Carrier (N/A) to at risk (A/A): about half carriers, half at risk.
- At risk (A/A) to at risk (A/A): all puppies at risk.
What the numbers say for our breed
From 1974 to 2012, the OFA recorded 48 DM evaluations for Coton de Tulear dogs. Of those, 79.2 percent were normal and none were abnormal. For the remaining 20.8 percent there is no OFA information on file.
These figures are old. As of 2026 the club encourages breeders to test their stock and to share results, so the picture keeps improving. If you are buying a puppy, ask the breeder about DM testing for the parents.
If you have questions about DM, or you are not sure how the test results apply to your dog, please write to us, call us, or come and visit us at a club event.
Source: Wikipedia, Canine degenerative myelopathy.
