If both parents are carriers (N/A) each puppy has a 25% chance of being clear (N/N), 50% chance of being a carrier (N/A), and 25% chance of being affected and carrier (A/A)
If one parent is clear (N/N) and one parent is affected (A/A) then all puppies will be carriers (N/A)
If one parent is a carrier (N/A) and one is at risk (A/A) each puppy has a 50% chance of being a carrier(N/A) and 50% chance of being affected and carrier (A/A)
If both parents are at risk (A/A) then all puppies will be affected and carrier (A/A)

Symptoms
Degenerative myelopathy initially affects the back legs and causes muscle weakness and loss, and lack of coordination. These cause a staggering affect that may appear to be arthritis. The dog may drag one or both rear paws when it walks. This dragging can cause the nails of one foot to be worn down. The condition may lead to extensive paralysis of the back legs. As the disease progresses, the animal may display symptoms such as incontinence and has considerable difficulties with both balance and walking. If allowed to progress, the animal will show front limb involvement and extensive muscle atrophy and paralysis. Eventually cranial nerve or respiratory muscle involvement necessitates euthanasia or long term palliative care.Progression of the disease is generally slow but highly variable. The animal could be crippled within a few months, or may survive as long as three years or more. Causes
The etiology of this disease is unknown.
Recent research has shown that a mutation in the SOD1 gene is a risk factor for developing degenerative myelopathy in several breeds. Mutations in SOD1 are also associated with familial amyotrophic lateral sclerosis (Lou Gehrigs disease) in people. More than 100 SOD1 gene mutations are involved in human familial amyotrophic lateral sclerosis (ALS), and the pathologic spinal lesions of ALS are similar to those of canine DM, making canine DM a potentially useful animal model of ALS. Known causes of spinal cord dysfunction should be excluded before accepting the diagnosis of degenerative myelopathy;  disc disease (protrusions) or spinal cord tumors can cause compression of the spinal cord with similar signs to degenerative myelopathy. Treatment
Degenerative myelopathy is an irreversible, progressive disease that cannot currently be cured. There are no treatments that have been clearly shown to stop or slow progression of DM. Exercise
Exercise has been recommended to maintain the dogs ability to walk. Physiotherapy may prolong the length of time that the dog remains mobile and increase survival time. Canine hydrotherapy (swimming) may be more useful than walking. Use of a belly sling or hand-held harness allows the handler the ability to support the dogs hind legs for exercising or going up and down stairs. A 2-wheel dog cart, or "dog wheelchair" can allow the dog to remain active and maintain its quality of life once signs of weakness or paralysis of the hind limbs is detected. Prognosis
The prognosis for the disease is generally poor.