🐾 Discovering DNA- Degenerative Myelopathy (DM)

What Is Degenerative Myelopathy

Degenerative Myelopathy (DM) is a progressive neurological disease affecting the spinal cord, typically in older dogs.

It is caused by the degeneration of the white matter in the spinal cord, leading to weakness and eventual paralysis of the hind limbs.

DM is most often associated with breeds like German Shepherds, Corgis, and Boxers, but it can occur in many breeds.

DM in Cavaliers

DNA testing for DM looks for a mutation in the SOD1 gene.

Cavaliers can carry this mutation — labs like Orivet, Embark, and Animal Genetics report results as:

• Clear (N/N) – no mutation

• Carrier (A/N) – one copy of the mutation

• At Risk (A/A) – two copies of the mutation

The Controversy

Proven?

While Cavaliers have been found with the SOD1 mutation, there is very little evidence linking it to actual clinical cases of DM in the breed. Currently Orivet state- "No Published Risk Segregation In The Breed"

Why test then?

It can help prevent confusion if the dog later develops mobility issues from other causes such as arthritis or spinal disease.

📌 How is DM Diagnosed?

Because there’s no single test to confirm DM in a living dog, diagnosis is based on a combination of factors:

1. DNA Test

   • Checks for the SOD1 mutation (Clear, Carrier, or At Risk).

   • At Risk does not equal a diagnosis — especially rare in Cavaliers.

2. Neurological Exam

   • Performed by a vet or neurologist to assess gait, reflexes, and coordination.

   • DM causes gradual, painless hind limb weakness.

3. Ruling Out Other Causes

   • Imaging (X-ray, MRI, CT) and lab tests are used to exclude arthritis, IVDD, hip problems, or injuries.

4. Final Confirmation

   • 100% confirmation is only possible through spinal cord examination after death.

   • In practice, diagnosis is usually presumptive once other causes are ruled out.

💡 In Cavaliers: DM is extremely rare, so vets prioritize ruling out more common causes first.

Should Owners Worry About DM?

In short — no.

DM is not a disease you need to lose sleep over. While the mutation can be found in the breed, confirmed clinical cases are extremely rare. Most Cavaliers will never show signs, even if genetically “at risk.” Your attention is better spent on the conditions that truly impact Cavaliers more often, like heart health, luxating patellar, EFS & CC/DE.

💖 At Sielle Place Cavaliers, our priority is keeping our families informed and confident about their dog’s health.

If you have questions about CMTP or any DNA test result, we’re always happy to help explain