For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.
At risk dogs are highly likely to show signs of this disease in their lifetime.
Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.
Clinical signs are first noticed around 2 months of age. Affected puppies are able to move but have generalized muscle atrophy and tremors leading to exercise intolerance. The clinical signs are relatively non-progressive. The disease should be a differential diagnosis based on breed history and clinical presentation when other possible causes have been ruled out. Serum creatine kinase levels are elevated in affected dogs and EMG and MNCV testing show typical changes. The diagnosis is confirmed by muscle biopsy.
There is no curative treatment for the disorder. Treatment is supportive care.
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 Nemaline Myopathy mutation can be safely bred with a clear dog with no copies of the Nemaline Myopathy mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the Nemaline Myopathy mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the Nemaline Myopathy mutation could develop due to a different genetic or clinical cause.
All coordinates reference CanFam3.1
Evans, J. M., Cox, M. L., Huska, J., Li, F., Gaitero, L., Guo, L. T., … Clark, L. A. (2016). Exome sequencing reveals a nebulin nonsense mutation in a dog model of nemaline myopathy. Mammalian Genome, 27(9–10), 495–502. View the article