Junctional Epidermolysis Bullosa (Australian Shepherd Type)

Affected Genes: LAMB3
Inheritance: Autosomal Recessive
Mutation: chr7:8075232 (canFam4): A/G
Breed(s): Aussiedoodle, Australian Shepherd, Miniature American Shepherd, Miniature Australian Shepherd, Toy Australian Shepherd

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Common Symptoms

Junctional Epidermolysis Bullosa (Australian Shepherd type) is a hereditary skin disease affecting dogs. Affected dogs typically present within a few weeks of age with fragile skin that is easily damaged from rubbing or trauma resulting in blisters and ulcers. Areas that are most prone to blisters are the face, foot pads, and ears. The skin around the toenails may be affected causing them to slough. In addition, affected dogs can develop blisters and ulcers inside the mouth, throat, and esophagus. Ulcerations of the skin and mucous membranes are painful and can become infected. Affected dogs are smaller than littermates, likely due to difficulties eating. Affected dogs are often euthanized within a few months of age due to poor quality of life.

Testing Tips

Genetic testing of the LAMB3 gene will reliably determine whether a dog is a genetic Carrier of Junctional Epidermolysis Bullosa (Australian Shepherd type). This 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 LAMB3 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. 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

  • Kiener S, Laprais A, Mauldin EA, Jagannathan V, Olivry T, Leeb T. LAMB3 Missense Variant in Australian Shepherd Dogs with Junctional Epidermolysis Bullosa. Genes (Basel). 2020 Sep 7;11(9):1055. [PubMed: 32906717]