Degenerative Myelopathy (DM) is a devastating neurological disease that affects the spinal cord in dogs, leading to progressive weakness and eventual paralysis in the hind limbs. Often misunderstood or mistaken for Hip Dysplasia or Arthritis in the early stages, DM can leave pet owners feeling helpless as they watch their once-active companions lose mobility over time.

In this post, we'll dive into what DM is, what causes it, how it affects dogs, and what you can do to help your dog live as comfortably as possible.

What Exactly Is Degenerative Myelopathy?

• Degenerative Myelopathy is a progressive neurodegenerative disease of the spinal cord, similar in some ways to ALS (Lou Gehrig's disease) in humans.
• It typically begins in adult or senior dogs, most commonly after age 7.
• It affects the white matter of the spinal cord, which is responsible for transmitting signals from the brain to the limbs.
• As the white matter deteriorates, dogs begin to lose coordination and control over their hind legs.
• DM is not painful in itself, but the resulting weakness and immobility significantly reduce the quality of life.

What Causes It?

The primary known cause is a genetic mutation in a gene called SOD1 (superoxide dismutase 1), which plays a role in protecting nerve cells from damage.

Key Contributing Factors:

• Genetics: Dogs with two copies of the mutated SOD1 gene (homozygous) are at highest risk.
• Immune-mediated degeneration: In some cases, an immune system component may be involved in attacking the spinal cord.
• Age: It usually manifests in dogs older than 7 years, though signs can start earlier.

Dogs can be:

• Clear (no mutation)
• Carriers (1 copy, low risk)
• At-risk (2 copies, high risk)

Genetic testing (such as via OFA or Wisdom Panel) is available and recommended for breeding dogs.

How Does It Affect the Dog?

Degenerative Myelopathy progresses in stages, usually over 6 months to 3 years. Here’s how it typically unfolds:

• Early Stage

  • Subtle hind limb weakness
  • Occasional dragging of back feet or "knuckling" (flipping foot upside down)
  • Mild loss of coordination (ataxia)
  • Slight muscle loss in the rear legs

• Mid Stage

  • Noticeable wobbling when walking
  • Difficulty standing up, especially on slippery surfaces
  • Incontinence may begin (loss of bladder/bowel control)
  • Muscles in the hindquarters atrophy significantly

• Late Stage

  • Complete paralysis of the hind limbs
  • Loss of deep pain perception
  • May affect front limbs or breathing in very advanced cases
  • Most dogs are euthanised before the disease reaches this stage due to quality-of-life concerns

Important Note: DM is not painful, but the dog’s frustration or anxiety may increase due to its inability to move properly.

How to Prevent or Manage It?

Unfortunately, there is no known cure for degenerative myelopathy. However, some steps can be taken to manage the condition and improve the dog’s comfort and quality of life.

Prevention

• Genetic Testing: Breeding programs should test for the SOD1 gene to avoid producing at-risk puppies.
• Avoid breeding two carriers or affected dogs.
• Routine vet visits to catch early signs.

Management & Supportive Care

• Physical therapy and hydrotherapy can help slow muscle atrophy and maintain function.
• Mobility aids like harnesses, wheelchairs, and booties can help dogs get around comfortably.
• Anti-inflammatory and mobility supplements may support nerve and joint health.
• Good hygiene is essential, especially if incontinence sets in.
• Laser therapy or acupuncture may help in some cases, though results vary.
• Regular exercise and maintaining a healthy weight are critical to prolonging mobility.

Which Breeds are Commonly Affected by Degenerative Myelopathy (DM)?

While DM can affect any breed, it's most common in medium to large breeds with a genetic predisposition. These include the Chesapeake Bay Retriever, German Shepherd, Rhodesian Ridgeback, Bernese Mountain Dog, Boxer, Labrador, Golden Retriever, etc.

Some smaller breeds like the Pug, Corgi and Cavalier King Charles Spaniel have also been reported with DM, though it's rarer.

Final Thoughts

Canine Degenerative Myelopathy is a heartbreaking condition, especially because it strikes dogs in the prime or twilight of their lives when they should be enjoying their golden years. While there's no cure, early diagnosis and proactive support can extend their mobility and well-being significantly.

If your dog is showing signs of hind limb weakness or coordination issues, consult your vet immediately. A proper diagnosis, including genetic testing, can help distinguish DM from other orthopaedic or neurological problems like hip dysplasia or disc disease.