Degenerative Myelopathy (DM) is becoming more prevalent in German Shepherds because of dogs being bred that are Carriers or Affected. It is a horrible disease that is preventable if breeders, owners and prospective owners act responsibly and are willing to avoid breeding and purchasing German Shepherds that are DM Carriers-N/DM and DM Affected-DM/DM. A responsible breeder should be able and willing to provide DM test results of their dogs especially for all of those they breed. You can order a DM test kit that requires that you just simply swab the gums and inside cheeks of the dog and mail the swab to the lab in the pre-addressed envelope provided with the test kit. These test kits can be ordered from AKC, Amazon, Chewy and other suppliers.
Canine Degenerative Myelopathy (DM) is a severe disease that typically develops late at around 8 years of age but has also been diagnosed earlier. Degenerative Myelopathy was first described as a spinal cord disease, particularly in German Shepherds. Degenerative Myelopathy is a deterioration of the nervous system and is characterized by muscle weakness and the progressive loss of balance and coordination. More specifically it affects the myelin which functions like a sheath to protect the spinal cord. In cases of Degenerative Myelopathy this myelin sheath begins to degenerate or break down eventually leading to paralysis. The first clinical signs are seen in the dysfunction of the hindquarters as unstable and wobbly. As the disease progresses, it spreads to the forelimbs causing a loss of reflexes and leads to paralysis. I would imagine that there would also be a progressive decline in the dogs mental well-being as the paralysis progresses, causing the dog to become more and more confused.