Canine Degenerative Myelopathy - Testing

Testing

The Orthopedic Foundation For Animals has a DNA test that can be purchased to screen for the SOD1 mutation that has been seen in dogs with DM. The test is only recommended for predisposed breeds, but can be performed on DNA from any dog on samples collected through swabbing the inside of the animal's cheek with a sterile cotton swab or through venipuncture.

The test determines whether the mutated copy of SOD1 is present in the DNA sample submitted. It must be interpreted with caution by a veterinary clinician in combination with the animal's clinical signs and other lab test results.

The results reported are:

• Normal / Normal (N/N, or 'clear'): The dog does not have the mutation and is extremely unlikely to develop DM. Through hundreds of dogs tested so far at the University of Missouri, only 2 dogs with results of N/N have been confirmed to have DM through postmortem necropsy.
• Normal / Abnormal (N/A or 'carrier'): The dog has one mutated copy of the gene (is heterozygous) and is unlikely to develop DM, but may pass the mutation to offspring. A thorough examination of the dog's pedigree and clinical disease status of ancestors should be undertaken prior to breeding a dog with this result.
• Abnormal / Abnormal (A/A or 'affected'): The dog has two copies (is homozygous) for the mutation and may develop DM. Not all dogs with A/A results will develop DM.

The OFA DNA Test only tests for the most common form of the disease. The German Shepherd dog is 1 of 17 breeds listed on the OFA site that are tested for DM. Other breeds may be tested as well. The OFA has modified its website to reflect the latest findings.