related terms: spinal dysraphism
Myelodysplasia refers to a number of malformations of the spinal cord that occur as a result of abnormal pre-natal development of the neural tube (which becomes the spinal column). Lesions are most severe in the lumbar (lower back) region. See also spina bifida.
How is myelodysplasia inherited?
In the Weimaraner, the mode of inheritance appears to be co-dominant with variable penetrance. The trait is lethal in the homozygous state (ie. a pup inherits the defective gene from both parents).
What breeds are affected by myelodysplasia?
Weimaraner, and a few other breeds sporadically.
For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.
What does myelodysplasia mean to your dog & you?
Clinical signs usually become evident around 4 to 6 weeks when puppies begin to walk around. The signs seen with this condition vary with the severity of the spinal cord malformation. Most commonly you will see a "bunny-hopping" hind limb gait with or without other hind end abnormalities.
The condition is non-progressive (does not get worse) and mildly affected animals - those with a tendency to bunny-hop and a slightly awkward gait - can lead a fairly normal life.
How is myelodysplasia diagnosed?
Diagnosis is made based on the clinical signs and by ruling out other possibilities with the aid of tests such as x-rays and cerebrospinal fluid analysis. Diagnosis can also be made on post-mortem, where a veterinary pathologist will find microscopic abnormalities typical of this condition.
For the veterinarian: Definitive diagnosis can only be made by histopathologic examination of the spinal cord. Lesions are most severe in the lumbar region.
Besides the typical bunny-hopping gait, there may be a crouching stance, abduction or overextension of one or both pelvic limbs, decreased pelvic limb conscious proprioception, or scoliosis. Spinal reflexes and pain perception are normal.
How is myelodysplasia treated?
There is no treatment. The condition will not get worse.
Affected animals should not be bred.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.
LeCouteur, R.A., Child, G. 1995. Diseases of the spinal cord. In S.J. Ettinger and E.C. Feldman (eds.) Textbook of Veterinary Internal Medicine, pp. 629-696. W.B. Saunders Co., Toronto.
Copyright © 1998 Canine Inherited Disorders Database. All rights reserved.
Revised: October 30, 2001.This database is a joint initiative of the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary College, University of Prince Edward Island, and the Canadian Veterinary Medical Association.