Partial deletion of the LAMA3 gene is responsible for hereditary junctional epidermolysis bullosa in the American Saddlebred Horse.
Laminin 5 is a heterotrimeric basement membrane protein integral to the structure and function of the dermal-epidermal junction. It consists of three glycoprotein subunits: the alpha3, beta3 and gamma2 chains, which are encoded by the LAMA3, LAMB3 and LAMC2 genes respectively. A mutation in any of these genes results in the condition known as hereditary junctional epidermolysis bullosa (JEB). A 6589-bp deletion spanning exons 24-27 was found in the LAMA3 gene in American Saddlebred foals born with the skin-blistering condition epitheliogenesis imperfecta. The deletion confirms that this autosomal recessive condition in the American Saddlebred Horse can indeed be classified as JEB and corresponds to Herlitz JEB in humans. A diagnostic test was developed and nine of 175 randomly selected American Saddlebred foals from the 2007 foal crop were found to be carriers of the mutation (frequency of 0.026).
Graves
K T
KT
Department of Veterinary Science, University of Kentucky, Lexington, KY 40546, USA. ktgraves@uky.edu
Henney
P J
PJ
Ennis
R B
RB
D000818:Animals; D016109:Epidermolysis Bullosa, Junctional / Q000235:genetics / Q000662:veterinary*; D005091:Exons; D017353:Gene Deletion; D006734:Horse Diseases / Q000235:genetics*; D006736:Horses; D007797:Laminin / Q000235:genetics*
D007797:Laminin; C095567:laminin alpha 3