This article outlines a genetic disorder that mainly German Shepherd dogs are prone to. There are other breeds affected by this condition too like Chesapeake Bay Retrievers, Corgis, Boxers, Wirehaired Fox Terriers and Rhodesian Ridgebacks, however, the disease is mostly seen in German Shepherds.
If one breaks down the name of the disease it describes what happens with the disease. Degeneration refers to a breaking down or deterioration of something. That “something” in this case is myelin which is the insulating sheath around neurons in the spinal cord. Neurons are the “electrical wires” of the nervous system and one can compare myelin to the insulating plastic around the wires, almost like one would find with an electrical cord. Whenever a term is followed by “pathy” it refers to a disease or disorder in a certain part of the body. In this case the spinal cord.