The cause of the disease is associated with a mutation in the SOD1 gene. It is not known exactly how the mutation of this gene leads to degeneration of the spinal cord in dogs, but the disease does interfere with the brain’s communication to the limbs, resulting in difficulty walking.
Dr. Beth Boudreau, clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, further explained the disease. “In degenerative myelopathy, the pathways that carry neural information in the spinal cord lose their insulatory coating and begin to fragment, and eventually the neurons that produce those signals also begin to die,” she said. “This results in a loss of motor control that begins in the hind limbs, but can spread to involve the front limbs as well as the pathways that control breathing, urination, and defecation. Currently, these changes are irreversible. Advanced cases may cause difficulty breathing as well. The disease is considered to be eventually fatal.”
The signs of degenerative myelopathy often begin around eight to nine years of age in larger breeds, and small breeds may have a later onset of signs around eleven years of age. Initially, mild stumbling, weakness, or incoordination of the hind limbs may be apparent. Although both hind limbs are usually affected, one is often weaker than the other. The signs slowly progress over a period of weeks to months and the disease does not cause the dog any apparent pain.
Dr. Beth Boudreau, clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, further explained the disease. “In degenerative myelopathy, the pathways that carry neural information in the spinal cord lose their insulatory coating and begin to fragment, and eventually the neurons that produce those signals also begin to die,” she said. “This results in a loss of motor control that begins in the hind limbs, but can spread to involve the front limbs as well as the pathways that control breathing, urination, and defecation. Currently, these changes are irreversible. Advanced cases may cause difficulty breathing as well. The disease is considered to be eventually fatal.”
The signs of degenerative myelopathy often begin around eight to nine years of age in larger breeds, and small breeds may have a later onset of signs around eleven years of age. Initially, mild stumbling, weakness, or incoordination of the hind limbs may be apparent. Although both hind limbs are usually affected, one is often weaker than the other. The signs slowly progress over a period of weeks to months and the disease does not cause the dog any apparent pain.