→ Skin blistering and ulcerations due to inproper connection between skin and underlying tissue.
- Large ulcerating skin lesions (especially at legs and buccal mucous membranes)
- Tooth abnormalities
- Skin blistering
- Hoof detachment
- Improper cell-cell adhesion causes skin layers to detach and blister, especially on legs and gums.
- Symptoms are present during or shortly after birth.
- Lesions may cause infection and early death.
- Affected foals are usually euthanized because of poor quality of life.
- A different mutation causing similar symptoms is known in the American Saddlebred breed.
Inheritance: autosomal recessive
→ Animals with two copies of the variant (jeb1/jeb1) are affected. Animals with only one copy of the variant are clinically normal carriers (N/jeb1).
|Genotype||The horse is:
|N/N||normal.||The horse has no copies of the genetic variant causative for JEB-1 and therefore cannot pass it on to its offspring.
|N/jeb1||a carrier.||The horse is clinically normal. The genetic variant will be passed on to its offspring with a probability of 50%.
|jeb1/jeb1||affected.||The horse will not live long enough to reproduce.
- Carriers may be bred to normal animals (N/jeb1 x N/N) without any risk of producing affected offspring. The offspring should also be tested before breeding to determine if they are carriers or normal.
- Breeding two carriers (N/jeb1 x N/jeb1) is not recommended due to the possibility of 25% of the offspring being affected.
- Affected animals (jeb1/jeb1) should not be used for breeding.
Test information: This test detects the single basepair insertion in the LAMC2 gene.
Cappelli, K., Brachelente, C., Passamonti, F., Flati, A., Silvestrelli, M., Capomaccio, S.: First report of junctional epidermolysis bullosa (JEB) in the Italian draft horse. BMC Vet Res 11:55, 2015. Pubmed reference: 25889423. DOI: 10.1186/s12917-015-0374-0.
Milenkovic, D., Chaffaux, S., Taourit, S., Guerin, G.: A mutation in the LAMC2 gene causes the Herlitz junctional epidermolysis bullosa (H-JEB) in two French draft horse breeds Genetics Selection Evolution 35:249-56, 2003. Pubmed reference: 12633536. DOI: 10.1051/gse:2003007
Spirito, F., Charlesworth, A., Linder, K., Ortonne, J. P., Baird, J., & Meneguzzi, G. (2002). Animal models for skin blistering conditions: absence of laminin 5 causes hereditary junctional mechanobullous disease in the Belgian horse. Journal of Investigative Dermatology, 119(3), 684-691. DOI:
Further information is available at Online Mendelian Inheritance in Animals.