Amyotrophic lateral sclerosis, ALS, is a rapidly progressing neurodegenerative disease that targets the nerve cells in the brains and spinal cords of humans. In dogs, a similar version of the disease, known as degenerative myelopathy, attacks the white matter in spinal cords and peripheral nerves. This degeneration interrupts movement commands from the brain to the limbs, often resulting in movement difficulty and paralysis. While the disease is not painful, it has no cure. Therapy and assistive devices can help manage the disease and extend survival time.
While degenerative myelopathy can occur in any breed, a genetic predisposition is common in American Eskimos, Bernese mountain dogs, borzois, boxers, Chesapeake Bay retrievers, corgis, German shepherds, golden retrievers, Great Pyrenees, Kerry blue terriers, pugs, Rhodesian Ridgebacks, Shetland sheepdogs, standard poodles, Wheaten terriers and wire fox terriers.
The average age of symptom onset is between 8 and 14 years of age. Initial symptoms include loss of coordination in the hind legs, wobbling and difficulty with rear-end mobility, such as when squatting to go to the bathroom. Often the weakness begins in one leg before spreading to the other. As the disease progresses, weakness increases to full paralysis, and urine and bowel control diminishes. Progression to this stage typically occurs in six months to 1 year.
Degenerative myelopathy has no cure. Treatment focuses on slowing the progression and maintaining a sustainable quality of life for your dog. Regular low-impact exercise, such as walking or swimming, helps maintain muscle mass and increases ambulatory time. As the disease progresses and your dog loses mobility, close monitoring is necessary to prevent pressure sores. Assistive devices, such as dog wheelchairs or carts, allows a dog some mobility once paralysis sets in.
Researchers have uncovered a mutation in the superoxide dismutase 1 gene as a risk factor for degenerative myelopathy. If your dog is one of the breeds at risk, or if his family line has a history of degenerative myelopathy, DNA testing can determine whether the mutated gene is present. The test lets you know if your dog has normal genes, one mutated gene or two mutated genes. With one gene mutation, your dog is a carrier of the disease. If both genes show mutation, he is at a greater risk of developing degenerative myelopathy, though it's not guaranteed he will. Talk to your veterinarian about testing options.
- ALS Association: What Is ALS?
- GA Veterinary Rehabilitation, Fitness and Pain Management: Degenerative Myelopathy
- The Veterinary Clinics of North America: Canine Degenerative Myelopathy
- VeterinaryPartner.com: Degenerative Myelopathy
- Orthopedic Foundation for Animals: DNA Testing for Degenerative Myelopathy
- CGD Network: Degenerative Myelopathy
- China Photos/Getty Images News/Getty Images