Dystrophic Epidermolysis Bullosa in Goats

Clinical, histopathological and ultrastructural findings of caprine dystrophic epidermolysis bullosa (DEB) with autosomal recessive inheritance are reported. The goats presented with exungulation, erosions, crusts and scars on the skin and ulcers in the oral cavity. Microscopically, the skin showed subepidermal separation with clefts filled occasionally with clear eosinophilic fluid, cellular debris or neutrophils. Ultrastructurally, the site of blister formation was the sublamina densa in the epidermal basement membrane zone. In skin with blister formation and in clinically uninvolved skin, the basal lamina was preserved, but the anchoring fibrils were sparse and rudimentary. A twin brother of an affected kid was mated over 5 years with his mother; three out of the 10 kids born presented with epidermolysis bullosa, indicating that the disease has an autosomal recessive mode of inheritance. It is suggested that the disease is similar to human severe generalized recessive DEB. © 2012 Elsevier Ltd.

Epidermolysis bullosa:evidence for linkage to genetic markers on chromosome 1 in a family with the autosomal dominant simplex form

DNA from members of a three-generation pedigree of Irish origin, displaying an autosomal dominant simplex form of epidermolysis bullosa of the epidermolytic, simplex, or Koebner variety (EBS2), was analyzed for linkage with a set of markers derived from the long arm of chromosome 1. Two-point analysis revealed positive lod scores for five of these markers, AT3 (Z = 2.107, theta = 0), APOA2 (Z = 1.939, theta = 0.15), D1S66 (Z = 1.204, theta = 0), D1S13 (Z = 1.026, theta = 0.15), and D1S65 (Z = 0.329, theta = 0.15). Multilocus analysis, incorporating the markers D1S19, D1S16, D1S13, APOA2, D1S66, AT3, and D1S65, resulted in a lod score of 3 maximizing at AT3. These data strongly support previous tentative indications of linkage between EBS2 and genetic markers on the long arm of chromosome 1.

Low-level laser therapy for the treatment of epidermolysis bullosa: A case report

Epidermolysis bullosa (EB) is a rare group of diseases characterized by skin fragility. There is no specific treatment, short of protection from trauma, currently available for these patients. Low-level laser therapy (LLLT) was effective as an analgesic and in accelerating cutaneous wound healing after six sessions of therapy in a child with dystrophic EB with cutaneous scarring and blisters on the limbs and trunk.

Epidermolysis bullosa in Danish Hereford calves is caused by a deletion in LAMC2 gene.

BACKGROUND Heritable forms of epidermolysis bullosa (EB) constitute a heterogeneous group of skin disorders of genetic aetiology that are characterised by skin and mucous membrane blistering and ulceration in response to even minor trauma. Here we report the occurrence of EB in three Danish Hereford cattle from one herd. RESULTS Two of the animals were necropsied and showed oral mucosal blistering, skin ulcerations and partly loss of horn on the claws. Lesions were histologically characterized by subepidermal blisters and ulcers. Analysis of the family tree indicated that inbreeding and the transmission of a single recessive mutation from a common ancestor could be causative. We performed whole genome sequencing of one affected calf and searched all coding DNA variants. Thereby, we detected a homozygous 2.4 kb deletion encompassing the first exon of the LAMC2 gene, encoding for laminin gamma 2 protein. This loss of function mutation completely removes the start codon of this gene and is therefore predicted to be completely disruptive. The deletion co-segregates with the EB phenotype in the family and absent in normal cattle of various breeds. Verifying the homozygous private variants present in candidate genes allowed us to quickly identify the causative mutation and contribute to the final diagnosis of junctional EB in Hereford cattle. CONCLUSIONS Our investigation confirms the known role of laminin gamma 2 in EB aetiology and shows the importance of whole genome sequencing in the analysis of rare diseases in livestock.

DNA-based diagnosis of rare diseases in veterinary medicine: a 4.4 kb deletion of ITGB4 is associated with epidermolysis bullosa in Charolais cattle.

BACKGROUND Rare diseases in livestock animals are traditionally poorly diagnosed. Other than clinical description and pathological examination, the underlying causes have, for the most part, remained unknown. A single case of congenital skin fragility in cattle was observed, necropsy, histological and ultrastructural examinations were carried out and whole genome sequencing was utilized to identify the causative mutation. RESULTS A single purebred female Charolais calf with severe skin lesions was delivered full-term and died spontaneously after birth. The clinical and pathological findings exactly matched the gross description given by previous reports on epitheliogenesis imperfecta and epidermolysis bullosa (EB) in cattle. Histological and ultrastructural changes were consistent with EB junctionalis (EBJ). Genetic analysis revealed a previously unpublished ITGB4 loss-of-function mutation; the affected calf was homozygous for a 4.4 kb deletion involving exons 17 to 22, and the dam carried a single copy of the deletion indicating recessive inheritance. The homozygous mutant genotype did not occur in healthy controls of various breeds but some heterozygous carriers were found among Charolais cattle belonging to the affected herd. The mutant allele was absent in a representative sample of unrelated sires of the German Charolais population. CONCLUSION This is the first time in which a recessively inherited ITGB4 associated EBJ has been reported in cattle. The identification of heterozygous carriers is of importance in avoiding the transmission of this defect in future. Current DNA sequencing methods offer a powerful tool for understanding the genetic background of rare diseases in domestic animals having a reference genome sequence available.

In vivo restoration of laminin 5 β3 expression and function in junctional epidermolysis bullosa

The blistering disorder, lethal junctional epidermolysis bullosa (JEB), can result from mutations in the LAMB3 gene, which encodes laminin 5 β3 (β3). Appropriate expression of LAMβ3 in JEB skin tissue could potentially ameliorate the symptoms of the underlying disease. To explore the utility of this therapeutic approach, primary keratinocytes from six unrelated JEB patients were transduced with a retroviral vector encoding β3 and used to regenerate human skin on severe combined immunodeficient (SCID) mice. Tissue regenerated from β3-transduced JEB keratinocytes produced phenotypically normal skin characterized by sustained β3 expression and the formation of hemidesmosomes. Additionally, β3 gene transfer corrected the distribution of a number of important basement membrane zone proteins including BPAG2, integrins β4/β1, and laminins α3/γ2. Skin produced from β3-negative (β3[−]) JEB cells mimicked the hallmarks of the disease state and did not exhibit any of the aforementioned traits. Therefore, by effecting therapeutic gene transfer to β3-deficient primary keratinocytes, it is possible to produce healthy, normal skin tissue in vivo. These data support the utility of gene therapy for JEB and highlight the potential for gene delivery in the treatment of human genetic skin disease.

Complete Cytolysis and Neonatal Lethality in Keratin 5 Knockout Mice Reveal Its Fundamental Role in Skin Integrity and in Epidermolysis Bullosa Simplex

In human patients, a wide range of mutations in keratin (K) 5 or K14 lead to the blistering skin disorder epidermolysis bullosa simplex. Given that K14 deficiency does not lead to the ablation of a basal cell cytoskeleton because of a compensatory role of K15, we have investigated the requirement for the keratin cytoskeleton in basal cells by inactivating the K5 gene in mice. We report that the K5−/− mice die shortly after birth, lack keratin filaments in the basal epidermis, and are more severely affected than K14−/− mice. In contrast to the K14−/− mice, we detected a strong induction of the wound-healing keratin K6 in the suprabasal epidermis of cytolyzed areas of postnatal K5−/− mice. In addition, K5 and K14 mice differed with respect to tongue lesions. Moreover, we show that in the absence of K5 and other type II keratins, residual K14 and K15 aggregated along hemidesmosomes, demonstrating that individual keratins without a partner are stable in vivo. Our data indicate that K5 may be the natural partner of K15 and K17. We suggest that K5 null mutations may be lethal in human epidermolysis bullosa simplex patients.

The genetic basis of epidermolysis bullosa simplex with mottled pigmentation.

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominant skin diseases characterized by blistering, due to mechanical stress-induced degeneration of basal epidermal cells. It is now well-established that the three major subtypes of EBS are genetic disorders of the basal epidermal keratins, keratin 5 (K5) and keratin 14 (K14). Here we show that a rare subtype, referred to as EBS with mottled pigmentation (MP), is also a disorder of these keratins. Affected members of two seemingly unrelated families with EBS-MP had a C to T point mutation in the second base position of codon 24 of one of two K5 alleles, leading to a Pro: Leu mutation. This mutation was not present in unaffected members nor in 100 alleles from normal individuals. Linkage analyses mapped the defect to this type II keratin gene (peak logarithm of odds score at phi = 0 of 3.9), which is located on chromosome 12q11-q13. This provides strong evidence that this mutation is responsible for the EBS-MP phenotype. Only conserved between K5 and K6, and not among any of the other type II keratins, Pro-24 is in the nonhelical head domain of K5, and only mildly perturbs the length of 10-nm keratin filaments assembled in vitro. However, this part of the K5 head domain is likely to protrude on the filament surface, perhaps leading to additional aberrations in intermediate filament architecture and/or in melanosome distribution that are seen ultrastructurally in patients with the mutation.