Common Symptoms
Duchenne muscular dystrophy is an inherited disease affecting dogs. Affected dogs are unable to produce adequate amounts of a protein important for muscle contraction and relaxation. Clinical signs of affected dogs include generalized muscle Atrophy, a stiff or shuffling gait, difficulty standing, exercise intolerance and over flexion of the ankle joint. Affected dogs have difficulties feeding and often drool. Affected dogs are often significantly smaller than littermates by 6 weeks of age. Cardiac muscle is also compromised in affected dogs, potentially resulting in clinical heart disease.
Testing Tips
Genetic testing of the DMD gene will reliably determine whether a dog is a genetic Carrier of this form of Duchenne muscular dystrophy. Duchenne muscular dystrophy is inherited in an X-Linked Recessive manner in dogs meaning that female dogs must receive two copies of the mutated gene (one from each parent) to develop the disease while male dogs only require one copy of the mutated gene from the mother in order to develop disease. Therefore, male dogs more commonly present with symptoms of the disease. Each male pup that is born to a female dog known to be a carrier of Duchenne muscular dystrophy has a 50% chance of inheriting the disease. Female dogs that are not carriers of this Mutation have no increased risk of having affected pups. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs 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.
References
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Smith BF, Yue Y, Woods PR, Kornegay JN, Shin JH, Williams RR, Duan D. An intronic LINE-1 element insertion in the dystrophin gene aborts dystrophin expression and results in Duchenne-like muscular dystrophy in the corgi breed. Lab Invest. 2011 Feb;91(2):216-31.
[PubMed: 20714321]
