Vet Pathol 36:616–618 (1999) Reduced Anchoring Fibril Formation and Collagen VII Immunoreactivity in Feline

Abstract. Dystrophic epidermolysis bullosa was diagnosed in a cat with juvenile-onset epithelial sloughing of the oral mucosa, footpads, and haired skin. Dermoepidermal separation occurred in the absence of inflam-mation or cytolysis of basal epidermal cells. Collagen IV-specific immunostaining corroborated the fact that clefting took place below the epidermal basement membrane. Ultrastructural examination revealed that the proband’s anchoring fibrils exhibited a filamentous morphology and were decreased in number compared with those in a normal cat. Finally, the attenuated immunoreactivity for collagen VII in our patient led us to suspect that its encoding gene, COL7A1, could be mutated in this case of feline dystrophic epidermolysis bullosa. Key words: Anchoring fibrils; cats; collagen VII; dystrophic epidermolysis bullosa; epidermal basement membrane; skin. Dystrophic epidermolysis bullosa (DEB) is a rare heredi-tary dermatosis of humans characterized by tense blisters that evolve into ulcers and heal with scarring. Microscopi-cally, dermoepidermal separation occurs in the sub-lamina densa and is associated with abnormal anchoring fibrils (AFs).2 In humans, DEB is subdivided based on the mod