Degenerative myelopathy is an autosomal recessive genetic disease, meaning inheriting one or two copies of the gene (SOD1), increases the risk of developing the disease; however, not all dogs who carry even both genes will develop DM.
DM is an inherited neurologic disease typically affecting dogs around eight years of age or older. It causes gradual muscle wasting and incoordination in the hind limbs, and then progresses to an inability to walk after six to twelve months.
Canine Degenerative Myelopathy (DM)
Dogs with a single mutation of the gene are carriers and could pass the condition on to puppies if bred with another carrier.
Late Stages of Degenerative Myelopathy
Degenerative Myelopathy in dogs can progress quickly, especially when it reaches its final stages. Signs of late-stage DM appear to happen overnight or within a few days.
Most dogs with degenerative myelopathy initially present with clinical signs of spasticity and general proprioceptive ataxia in the pelvic limbs. This varies from patient to patient based on the stage at which the dog is brought in for clinical evaluation.
A genetic mutation, SOD-1, has been identified as a major risk factor for DM. DM is considered a disease of middle-aged to older dogs including German Shepherds, German Shepherd crosses, Siberian Huskies, and Collies.
DM may be painless, but most dogs with severe chronic pain will display no signs. Therefore, I have also seen cases of severe hip dysplasia, cruciate ligament rupture or arthritis get mistaken for DM. Degenerative myelopathy is described as a diagnosis by exclusion.
14 Disorders that often mimic and coexist with DM include degenerative lumbosacral syndrome, intervertebral disc disease, spinal cord neoplasia and degenerative joint diseases such as hip dysplasia or cranial cruciate ligament rupture.
This disease is not uncommon in some pure bred dogs with an overall prevalence rate of 0.19%. Although the German Shepherd Dog is the most commonly affected breed, DM has been reported in other breeds and most recently in the Pembroke Welsh Corgi (PWC).
How long do dogs live with Degenerative Myelopathy? Dogs generally live with DM for anywhere between six months and three years. Rehab therapy and regular exercise can help improve the quality of life for dogs with DM. Unfortunately, Degenerative Myelopathy has no cure at the moment.
Although any dog can be tested for Degenerative Myelopathy, it is possible that the genetic background that predominates in some breeds prevents the development of symptoms even in dogs testing affected (at risk).
However, in breeds where the SOD1A variant is associated with DM risk, carriers should not be bred to other carriers (or at-risk dogs) as this will lead to the production of at-risk puppies.
For just $75, AffinityDNA will test whether your dog carries the genes associated with Degenerative Myelopathy. Using a simple swab from the inner cheek of your dog, we will ascertain whether or not your dog carries the genetic mutation that is likely to develop into the condition.
Stem Cell Therapy for Degenerative Myelopathy in Dogs is showing encoring evidence in slowing the progression of this tragic neurological condition and possibly even reversing it.
Yes, dogs with Degenerative Myelopathy should stay as active as possible. Keeping a DM dog active can actually help slow down the progression of the disease. Physical therapy and regular structured exercises, including walking, can help dogs with DM maintain muscle strength and minimize their risk of muscle atrophy.
As cervical myelopathy presents with such a variety of symptoms associated with other conditions, it can often lead to a delay in diagnosis and, sometimes, misdiagnosis in primary care. For example, sciatica can mimic certain symptoms of cervical myelopathy in the lower limb.
Fecal and urinary incontinence inevitably follow. The rear legs become so weak that your dog will need help getting up. She'll have trouble holding a position to pee or poop. (Dogs with degenerative myelopathy often walk and poop.)
The disease is inherited in an autosomal recessive fashion with incomplete penetrance, and is caused by a mutation (c. 118G>A) in the gene SOD1. Thus, two copies of the SOD1 mutation (DM/DM) confer increased risk for DM but not all DM/DM dogs across breeds will develop the disease.
Diagnosis of Myelopathy
Diagnostic tests your doctor may include are: A spine X-ray to rule out other causes of back or neck pain. Spine MRI or spine CT, to show areas of pressure on the spinal canal. Myelography, to determine location and presence of abnormalities of the spinal cord.
There's still much to be discovered and learn about DM and its causes. The genetic test isn't 100% foolproof, but it provides a common-sense prediction of which dogs are at risk—and the degree of risk—and which dogs aren't. The classic clinical signs of DM are: Sudden onset of clinical neurological signs without trauma.
As horrible as all of this sounds, degenerative myelopathy is not painful That being said, dogs that suffer from degenerative myelopathy may become sore from overuse of other areas of their body while trying to compensate for their hind end weakness.
Symptoms of Degenerative Myelopathy in Dogs
Affected dogs will be wobbly and may knuckle over the paws, cross the hind limbs, or stumble while walking. With progression of the condition, a severely affected dog will lose the ability to stand on or move the hind limbs.
STAGE 4 – LMN tetraplegia and brain stem signs (~ over 36 months) – At the end of the disease, the degeneration can progress to involve neck, brain stem, and brain. Patients will not be able to move all four limbs, have trouble breathing, and have difficulty with swallowing and tongue movement.