A de novo mutation in KRT5 in a crossbred calf with epidermolysis bullosa simplex

A 6-day-old Belgian Blue-Holstein calf was referred because of a syndrome resembling epidermolysis bullosa simplex (EBS). The clinical phenotype included irregular and differently sized erosions and ulcerations spread over the body, in particular on the limbs and over bone prominences, as well as in the nasal planum and oral mucosa. Blisters were easily induced by rubbing the skin. The skin lesions displayed a clear dermal-epidermal separation at the level of the basal cell layer. Post mortem examination revealed erosions in the pharynx, proximal esophagus, and rumen. Whole-genome sequencing revealed a heterozygous disruptive in-frame deletion variant in KRT5 (c.534_536delCAA). Genotyping of both parents confirmed the variant as de novo mutation. Clinicopathological and genetic findings were consistent with the diagnosis of KRT5-related EBS providing the second example of a spontaneous mutation causing epidermolysis bullosa in cattle.     

Rudimentary hemidesmosome formation in congenital generalized junctional epidermolysis bullosa in the Sprague-Dawley rat

Seven of 14 newborn pups in a litter of Sprague-Dawley rats were found to have generalized detachment of the epidermis, which was thin, wrinkled, and hung in loose folds over distal extremities. Histologic and ultrastructural examination of the skin showed noninflammatory separation of the epidermis from the dermis at the lamina lucida of the basement membrane zone. Ultrastructurally, hemidesmosomes were small and had a rudimentary appearance; keratin tonofilaments in basal keratinocytes were detached from the hemidesmosomes. The skin lesions were consistent with generalized junctional epidermolysis bullosa, which has not previously been reported in the rat. In humans, generalized junctional epidermolysis bullosa is most commonly caused by autosomal recessive inheritance of defective proteins of the hemidesmosomes or anchoring filaments. The specific protein defect involved in the rat lesion was not determined because fresh frozen tissue was not available.     

An epidermolysis bullosa in a Galloway calf

Abstract A congenital skin disease characterised by mild erosion and ulceration of areas exposed to trauma was seen in a 3-day-old Galloway Calf. Bilateral, almost symmetrical erosions were Seen On the cheeks, 'PPer and lower lips, nasal plane, hard palate and dorsal surface of the tongue. There was also loss of skin and ulceration from anterior areas of the carpi, upper fetlocks and coronary band of both fore and hindlimbs.     

An epidermolysis bullosa in a Galloway calf

A congenital skin disease characterised by mild erosion and ulceration of areas exposed to trauma was seen in a 3-day-old Galloway Calf. Bilateral, almost symmetrical erosions were Seen On the cheeks, 'PPer and lower lips, nasal plane, hard palate and dorsal surface of the tongue. There was also loss of skin and ulceration from anterior areas of the carpi, upper fetlocks and coronary band of both fore and hindlimbs.     

Junctional epidermolysis bullosa in two domestic shorthair kittens

This article describes two cases of junctional epidermolysis bullosa in nonrelated kittens. Both cats exhibited pinnal erosions, oral ulcerations and severe onychomadesis. Histopathology, electron microscopy and/or indirect immunoperoxidase revealed subepidermal clefting, with the lamina densa remaining attached to the floor of the vesicles. Indirect immunofluorescence revealed reduced staining for laminin-5 gamma2 subunit in case 1 and beta3 subunit in case 2.     

P-35 Nonlethal junctional epidermolysis bullosa in a dog

A 3-year-old Burmese cat was presented with a history of nonresolving crusted and papular lesions of the face and prior treatment with prednisolone. Skin biopsies revealed typical pox lesions with hyperplasia and ulceration of the epidermis and eosinophilic cytoplasmic inclusion bodies in the epidermal cells. In the upper dermis there was prominent diffuse mast cell infiltration and mild neutrophilic and eosinophilic inflammation. Rare cytoplasmic inclusion bodies were also present in swollen endothelial cells of dermal venules, which showed no other degenerative changes. Histological diagnosis was confirmed by electron microscopic evidence of pox virus particles in inclusion bodies of epidermal cells. The lesions resolved within 6 weeks with systemic antibiotic therapy and supportive care. A 2-year-old domestic short-haired cat was presented with multiple disseminated papular and ulcerative pox lesions with central eschar over the entire body. Histologically, large epidermal inclusion bodies (up to 6 μm in diameter) were present. Widespread haemorrhage and vascular wall necrosis was visible in the dermis and subcutis. Some subcutaneous vessels showed neutrophilic vasculitis. In addition to diffuse dermal neutrophilic and eosinophilic inflammation, a lymphohistiocytic panniculitis was also present. The cat died as a result of massive haemorrhage and lymphedema, despite supportive care.
Funding: Self-funded.     

Reduced anchoring fibril formation and collagen VII immunoreactivity in feline dystrophic epidermolysis bullosa

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 inflammation 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.