Junctional Epidermolysis Bullosa
Affected Genes: LAMB3
Inheritance: Autosomal Recessive Inheritance
Variant(canFam6): chr7:8286613 A>G
Breed: Australian Shepherd
General Information: Junctional Epidermolysis Bullosa (JEB) is a rare inherited skin disorder in dogs caused by a mutation in the LAMB3 gene. This condition compromises the structural integrity of the skin at the dermal-epidermal junction, leading to extreme skin fragility and blistering. JEB is inherited in an Autosomal Recessive manner, meaning that a dog must inherit two copies of the mutated gene (one from each parent) to be affected. Dogs with only one copy of the mutation are considered carriers and will not exhibit clinical symptoms but can pass the mutation to their offspring.
Symptoms of JEB typically include blistering and ulceration of the skin, often occurring at sites of friction or trauma. Affected dogs may also exhibit sloughing of the paw pads, oral ulcers, and secondary infections due to the compromised skin barrier. In severe cases, the condition can be life-limiting due to the risk of widespread skin damage and complications such as infection. Treatment is supportive, focusing on wound management, preventing infections, and minimizing skin trauma.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog is a Carrier
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing for the LAMB3 gene variant can determine whether a dog is affected by or a carrier of Junctional Epidermolysis Bullosa. This disorder is inherited in an Autosomal Recessive manner, meaning that a dog must inherit two copies of the mutation to develop the condition. Dogs with one copy of the mutation are carriers and do not show symptoms but can pass the mutation to their offspring if bred.
Genetic testing is a crucial tool for breeding decisions. Breeding two carrier dogs has a 25% chance of producing affected puppies, a 50% chance of producing carriers, and a 25% chance of producing puppies free of the mutation. Responsible breeding practices can help reduce the occurrence of JEB in affected breeds.
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 11(9):1055