Common Symptoms
Pompe Disease is an inherited metabolic disorder affecting Swedish Lapphunds. Glycogen is the primary carbohydrate used by the body for energy. Affected dogs do not have sufficient enzymes to break down glycogen causing accumulation of glycogen in the multiple organs, including muscle, liver, heart and brain. Affected puppies typically present at about 6 months of age with generalized muscle weakness. Dogs with this disease develop an enlarged heart and dilated esophagus (megaesophagus). Megaesophagus causes regurgitation and vomiting and predisposes dogs to aspiration pneumonia. Over time the muscle weakness and regurgitation/vomiting worsen. Dogs may also have an unusual sounding bark, pant excessively, and have difficulty breathing. Dogs usually are euthanized or die of heart failure by 1.5 years of age.
Breed-Specific Information for the Swedish Lapphund
The Mutation of the GAA gene associated with Pompe Disease has been identified in Swedish Lapphunds, although its overall frequency in this breed is unknown.
Testing Tips
Genetic testing of the GAA gene in Swedish Lapphunds will reliably determine whether a dog is a genetic Carrier of Pompe Disease. Pompe Disease 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 GAA gene mutation. 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 to each other is not recommended. Swedish Lapphunds 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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Seppälä EH, Reuser AJ, Lohi H. A nonsense mutation in the acid α-glucosidase gene causes Pompe disease in Finnish and Swedish Lapphunds. PLoS One. 2013;8(2):e56825.
[PubMed: 23457621]
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Walvoort HC. Glycogen storage disease type II in the Lapland dog. Vet Q. 1985. Jul;7(3):187-90. Review.
[PubMed: 3901497]
