Hereditary junctional epidermolysis bullosa, HJEB – Belgian | Laboratoire de génétique vétérinaire

Hereditary junctional epidermolysis bullosa, HJEB – Belgian

Gene: LAMC2

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease. Both parents of an affected animal must be carriers of at least one copy of the mutation. Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Insertion, LAMC2 gene; c.1368, ins.C, p.(R458P fs), exon10

Medical system: Dermal

Breed: Belgian

Age of onset of symptoms: At birth

HJEB (Hereditary Junctional Epidermolysis Bullosa) in Belgian horses is a genetic disease characterized by fragile skin and the presence of blisters in the skin and in the mouth. The mutation that causes the disease occurs in the gene that codes for the laminin C2 protein, which has several roles in maintaining the integrity of the skin. Clinical signs in affected animals appear soon after birth: there are blisters in the mouth that go on to rupture, and the teeth and enamel are abnormally formed. Skin lesions are mainly found on the friction points and there can even be loss of hoofs. The affected animal may die after a few days due to secondary bacterial infections. Animals that survive are often euthanized for humanitarian reasons.

References:

OMIA: [1678-9796]

Cappelli K, Brachelente C, Passamonti F, et al. (2015) First report of junctional epidermolysis bullosa (JEB) in the Italian draft horse. BMC Vet Res. 11:55. [pubmed/25889423]

Graves KT, Henney PJ, Ennis RB. (2008) Partial deletion of the LAMA3 gene is responsible for hereditary junctional epidermolysis bullosa in the American Saddlebred horse. Animal Genetics 40(1):35-41. [pubmed/19016681]

Spirito F, Charlesworth A, Linder K, et al. (2002) Animal models for skin blistering conditions: absence of laminin 5 causes hereditary junctional mechanobullous disease in the Belgian horse. J Invest Dermatol. 119(3):684-691. [pubmed/12230513]