Myelodysplasia (Spinal Dysraphism) in Dogs

Spinal dysraphism is present at birth and is an inherited condition that is co-dominant. Both parents pass the defective gene onto the puppies. The disease will become apparent between four and six weeks of age when puppies begin walking. The puppies will have an awkward gait or will bunny hop on the hind end. This is a non-progressive disease and most dogs diagnosed are able to live fairly normal lives. 

Even though this is a non-progressive disease and most affected dogs are able to live normal lives with some limitations, dogs that are known carriers or have been diagnosed with myelodysplasia should never be bred.

Myelodysplasia occurs as a result of pre-natal development that is abnormal and malformations of the spinal cord occur. Lesions in the spinal column form and are most severe in the lumbar or lower back region. Myelodysplasia is most prevalent in Weimaraners but can also occur sporadically in Dalmatians, Rottweilers, West Highland White Terriers, German Shepherds, Golden Retrievers and Alaskan Malamutes.

Symptoms of myelodysplasia will usually become noticeable when puppies become mobile; generally between four and six weeks of age. People who are familiar with the breed may be able to see abnormal spinal reflexes in newborn puppies. If you notice your puppy exhibiting any of these symptoms, contact your veterinarian for an appointment.

• Abnormal spinal reflexes
• Symmetrical bunny hopping gait
• Wide legged stance
• Overextended pelvic limbs
• Depressed proprioception
• Scoliosis
• Abnormal hair streams in the dorsal neck area
• Koilosternia or a gutter-like depression in the chest

Myelodysplasia is usually an inherited disease where each parent must pass on a copy of the defective gene in order for the puppies to be affected. It is a co-dominant disease and usually puppies that are affected are able to live fairly normal lives. It is a non-progressive disease.

Myelodysplasia is when there is faulty embryonic development and the spinal canal has defects. These defects will lead to neurological abnormalities. There is a genetic test for spinal dysraphism in Weimaraners, which is the breed where this disease is most prevalent.  

Dogs that are DNA tested will be classified as N/N, N/SD or SD/SD. N/N means that your dog has no copies of the spinal dysraphism mutation and your dog is normal. N/SD means that your dog carries one copy of the spinal dysraphism mutation and your dog is normal but is a carrier. SD/SD means that your dog has two copies of the spinal dysraphism mutation and your dog is affected.

Dogs that have been diagnosed with myelodysplasia should never be bred. Dogs that have been DNA tested as N/SD or carriers should also never be bred. Ideally, only dogs that are DNA tested N/N should be bred.

Your veterinarian will begin by performing a full examination of your dog or puppy. They will also need your dog’s medical history and what symptoms you have seen. Your veterinarian will begin by ruling out other possible causes for your dog’s symptoms. 

Your veterinarian may decide to draw a sample of cerebrospinal fluid for analysis. X-rays will also be needed to find any vertebral malformations. A CT scan and/or MRI may also be ordered for your veterinarian to see the spine and any lesions in more detail.

Once myelodysplasia has been diagnosed, your veterinarian will discuss treatment options. There is no universal treatment for myelodysplasia. Most dogs that are diagnosed with this disease are able to live a fairly normal life, with some limitations. Your veterinarian will be able to help you decide what life changes will need to take place for your dog to be comfortable and able to adapt to their disability.

Since this disease is non-progressive as your dog ages, the symptoms should not worsen. In some rare cases where the disease is so severe that your dog is unable to live without pain or is paralyzed, euthanasia is recommended.

Responsible breeders will do the DNA testing for spinal dysraphism and not breed dogs that are carriers or are affected. Dogs that are carriers or affected should be sterilized and never used as a breeding animal. This is especially true for Weimaraners who have a higher risk of developing myelodysplasia. 

When your dog is diagnosed with myelodysplasia, talk with your veterinarian about what limitations your dog will experience. Also, ask about any medications that can be given as your dog ages and begins to experience arthritic changes that can cause more problems for them.