Centronuclear Myopathy (Discovered in the Labrador Retriever)

In Labrador Retrievers, weakened or non-existent peripheral reflexes of the legs can occasionally be observed as early as 1 month of age, although more typically not until the puppies are 2 to 5 months old. At the age of 5 months, the affected puppies manifest decreased movement and exercise intolerance. The condition does not usually progress after the first year of life. In adult dogs, the most common signs are severe skeletal muscle atrophy especially in the areas of head, neck, and legs that limit the dog's ability to keep his head raised (ventroflexion) as well as abnormalities in posture and movements. Although the disorder limits the dog's athletic potential, it can still have a normal life span as a pet.

Treatment is supportive care and limiting exercise.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to develop. A carrier dog with one copy of the CNM mutation can be safely bred with a clear dog with no copies of the CNM mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the CNM mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Please note: It is possible that disease signs similar to the ones caused by the CNM mutation could develop due to a different genetic or clinical cause.