Exercise-Induced Collapse (EIC) is an inherited neuromuscular disorder affecting Australian Labradoodles. EIC presents as exercise intolerance in apparently healthy dogs. Affected dogs are usually diagnosed before two years of age and appear normal during low to moderately strenuous activity. However, shortly after 5-20 minutes of strenuous exercise affected dogs will begin to walk with a wobbly, uncoordinated gait that often only affects the hind limbs. Dogs remain mentally alert and are not in pain during episodes of EIC. In some circumstances, the symptoms of EIC can progress to full body weakness with low muscle tone (flaccid paralysis), confusion, loss of consciousness, seizures and very rarely, death. The episodes typically last 5-10 minutes and most dogs will completely recover within 15-30 minutes.
Breed-Specific Information for the Australian Labradoodle
The Mutation of the DNM1 gene associated with exercise-induced collapse has been identified in the Australian Labradoodle. Although the exact frequency in the overall Australian Labradoodle population is unknown 39% out of 30,592 Labrador Retrievers tested were carriers of the mutation and 7% were at-risk/affected. The reported frequency of disease in Labrador Retrievers carrying two copies of the mutation is approximately 84%, so not all dogs with two copies of the mutation will have clinical signs, but they can still pass the mutation on to their offspring.
Genetic testing of the DNM1 gene in Australian Labradoodles will reliably determine whether a dog is a genetic Carrier of exercise-induced collapse. Exercise-Induced Collapse is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the DNM1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because this mutation shows Variable Expressivity, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Australian Labradoodles that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
Exercise induced collapse. [Internet]. 1 Dec 2013 update [cited 18 Dec 2013]. Available at http://www.vdl.umn.edu/prod/groups/cvm/@pub/@cvm/@vdl/documents/asset/cvm_asset_403528.pdf
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