Lundehund Syndrome is an inherited gastrointestinal (GI) disease affecting dogs. Affected dogs display wide variability in age of onset, but typically present between 2 to 10 years of age with diarrhea, vomiting, weight loss, hair loss, and lethargy. Some dogs may also develop swelling of the limbs and fluid in the abdominal cavity. The blood work of affected dogs typically reveals decreased protein and calcium levels as well as other abnormalities consistent with severe GI disease. Treatment with anti-inflammatory drugs, specialized diets, and vitamin supplementation can help but the prognosis of affected dogs varies widely from a minor, often recurrent, chronic diarrhea to severe treatment-resistant disease resulting in death or euthanasia.
Genetic testing of the LEPREL1 gene in dogs will reliably determine whether a dog is a genetic Carrier of Lundehund Syndrome. Lundehund Syndrome 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 LEPREL1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, 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. 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.
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Metzger J, Pfahler S, Distl O. Variant detection and runs of homozygosity in next generation sequencing data elucidate the genetic background of Lundehund syndrome. BMC Genomics. 2016 Aug 2;17:535. doi: 10.1186/s12864-016-2844-6.