ABSENT EXPRESSION OF COLLAGEN-XVII (BPAG2, BP180) IN CANINE FAMILIAL LOCALIZED JUNCTIONAL EPIDERMOLYSIS-BULLOSA

Hereditary junctional epidermolysis bullosa (JEB) represents a subset of mechanobullous diseases associated with defective hemidesmosome/anc horing filament proteins leading to cleavage in the lamina lucida of t he epidermal basement membrane. In humans, most cases of JEB have been related to a deficiency of either laminin-5, collagen XVII (BPAG2, BP 180) or integrin beta 4. We describe the existence of a previously unr eported form of familial localized non-lethal JEB in German Shorthaire d Pointer littermates. Acral, auricular and oral erosions and ulcers w ere observed. Severe ulceration of the footpads was present. Skin biop sy specimens of non-lesional and lesional skin of affected dogs were s creened for a defect in basement membrane proteins using indirect immu nofluorescence and immunoperoxidase testing. Epidermal staining for la minin-5 and integrin alpha 6 beta 4 was similar in affected and normal control dogs. Lack of expression of collagen XVII was uniquely identi fied in all sections of JEB probands compared with normal control dogs . The defective expression of collagen XVII is likely to be caused by mutation(s) of the COL17A1 gene, as previously reported in humans. Thi s is, to date, the first report of a deficient basement membrane prote in in canine JEB.