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 of this disorder emerge around three months of age and begin with weakness of movement in the limbs, causing a spastic swimming-puppy-like position of the front legs. The dog can also develop other neurological signs, such as mild vestibular signs and myoclonic jerks. The chest of affected puppies can be flat and regurgitation can occur. The disorder is progressive and in a few weeks, the limb weakness during voluntary movement progresses to where the dog is unable to stand. The disease should be a differential diagnosis based on breed history and clinical presentation when other possible causes have been ruled out. MRI and electrodiagnostic tests can be used for further diagnostics.
The disorder is progressive and there is no cure. Treatment is supportive and the prognosis is poor.
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 Alexander Disease mutation can be safely bred with a clear dog with no copies of the Alexander Disease mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the Alexander Disease 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 Alexander Disease mutation could develop due to a different genetic or clinical cause.
All coordinates reference CanFam3.1
Van Poucke, M., Martlé, V., Van Brantegem, L., Ducatelle, R., Van Ham, L., Bhatti, S., & Peelman, L. J. (2016). A canine orthologue of the human GFAP c.716G>A (p.Arg239His) variant causes Alexander disease in a Labrador retriever. European Journal of Human Genetics, 24(6), 852–856. View the article