Degenerative Myelopathy in German Shepherds

This is Pancho! Pancho is a 9 year old German Shepherd cross. Pancho is a very sweet, smart and intuitive dog. He has always been very gentle and a pleasure to work with, and I always look forward to my visits with him.

Pancho came in for a checkup in December of 2014 because his owners noticed that he had been dragging his left hind leg. At that time, I noticed that Pancho had with placing his left hind foot on the ground correctly, and he had a very mild sway to his walk - he looked looser and less coordinated than I would have expected while he was walking. I saw Pancho again a few months later, and his mobility was dramatically decreased - he could barely use his left hind leg, and his coordination was severely impaired. He was not showing any signs of pain, and his personality appeared remarkably unaffected by his disease. Pancho's family and I discussed the list of diseases that could account for Pancho's clinical signs, including a disease called degenerative myelopathy.

Degenerative myelopathy is an irreversible, progressive neurological disease that affects a dog's ability to walk. This disease causes degeneration and loss of nerve fibres in the spinal cord. Affected dogs initially show loss of co-ordination and loss of muscle mass in their hindlimbs. Over the next 6-12 months, complete paralysis will develop. This is fortunately not a painful condition, but there is no treatment for degenerative myelopathy, and many dogs will be euthanized due to quality of life issues resulting from the paralysis.

The image to the left shows cross sections from the spinal cord of a normal dog (on the right) and a dog with degenerative myelopathy (on the left). The loss of the blue-staining tissue in the spinal cord with degenerative myelopathy shows loss of the normal nerve tissue that conducts signals from the brain to the limbs.

Degenerative myelopathy is caused by a DNA mutation in a gene called superoxide dismutase (SOD1). Dogs need to have two copies of this abnormal gene in order to develop degenerative myelopathy, and not every dog with two copies of the gene will develop disease. Dogs with one normal gene and one mutated gene are called carriers, and can potentially pass this disease on to their offspring if they are bred with another carrier. Commonly affected breeds include German Shepherds, Pembroke Welsh Corgis, Chesapeake Bay Retrievers, Boxers, and Rhodesian Ridgebacks. The only way to prevent degenerative myelopathy is through careful breeding of dogs who do not carry the gene. There is an inexpensive genetic test available through the Orthopedic Foundation for Animals.

As devastating as this disease is, Pancho is very lucky to have an amazing family committed to giving him the best quality of life possible. Pancho's family made him a prototype cart to ensure that he would feel comfortable in a cart, and once they were confident he would do well in a cart, they purchased one for him. Pancho is incredible in his cart - he was happily moving around the exam room while I talked to his family, and when he got stuck behind the table at one point, he backed himself up like he was backing up a truck. We took Pancho outside so that he could sniff the fenceline and go for a pee, and Pancho showed us how well he could do in his cart:

If your dog develops paralysis from degenerative myelopathy or another disease, your veterinarian can help you decide if trying a cart is right for your dog.