Test Detail

Junctional epidermolysis bullosa (JEB) in the German Shorthaired Pointer is a hereditary autosomal recessive genodermatosis characterised by skin fragility and blister formation at the dermo-epidermal junction (lamina lucida). It is caused by a 6.5-kb satellite DNA insertion in intron 35 of the LAMA3 gene, which encodes the alpha-3 chain of laminin 5, with reduced expression. It affects skin and mucous membranes and has no curative treatment.

JEB documented in the German Shorthaired Pointer; Italian studies describe its prevalence and genetic trend in the breed.

- Blistering and detachment of the skin from birth or the first weeks\n- Lesions in the mouth, muzzle and limbs\n- Onychomadesis (loss of nails)\n- Ulcers on the pads and mucous membranes\n- Difficulty feeding and growth retardation\n- Severe laryngeal/pharyngeal lesions in severe cases and secondary infections

JEB was recognised in the German Shorthaired Pointer as a natural animal model of human JEB. In 2005, Capt and collaborators identified the causal mutation in LAMA3 (6.5-kb insertion in intron 35) and established the dog as a gene therapy model. Later Italian studies have monitored the prevalence and genetic trend in the breed.

- Test German Shorthaired Pointer breeding animals before breeding\n- Do not mate two carriers (25% affected offspring)\n- A carrier may be mated to a clear animal; test the offspring intended for breeding\n- Avoid using carrier lines and record the results\n- Given the severity and absence of curative treatment, prioritise prevention

The differential diagnosis includes other forms of epidermolysis bullosa (simplex, dystrophic) and autoimmune blistering dermatoses. Biopsy with immunofluorescence and electron microscopy locates the separation at the lamina lucida; confirmation is genetic. Additional LAMA3 variants have been described in other breeds, different from the German Shorthaired Pointer one, so the test must be variant-specific.

1. Capt A et al. 2005. Inherited junctional epidermolysis bullosa in the German Pointer: establishment of a large animal model. J Invest Dermatol. PMID: 15737193
2. Pertica G et al. 2010. Prevalence of inherited junctional epidermolysis bullosa in German shorthaired pointers bred in Italy. Vet Rec. PMID: 21257512
3. Frattini S et al. 2021. Genetic trend of the junctional epidermolysis bullosa in the German shorthaired pointer in Italy. Vet Rec Open. PMID: 34457315
4. OMIA:001677-9615.