Weber-Cockayne Type Epidermolysis Bullosa Simplex Resulting from a Novel Mutation (c. 608T>C) in the Keratin 5 Gene

Epidermolysis bullosa simplex (EBS), an inherited genetic disorder, is most often caused by a dominant-negative mutation in either the keratin 5 (KRT5) or the keratin 14 (KRT14) gene. These keratin mutants result in a weakened cytoskeleton and cause extensive cytolysis. It is important to analyze the KRT5 or KRT14 genes of the patient and their family members by mutational analysis in order to identify genetic defects as well as the need for genetic counseling. In this study, we present a 5-year-old Korean boy who had been developing blisters and erosions on the palms of his hands and soles of his feet since infancy. In addition, while his younger sister and father showed similar clinical manifestation, his mother did not. The patient was diagnosed with EBS based on clinical manifestation, which is characterized by the presence of blisters restricted to the palms and soles, histological findings, and mutational analysis. Mutational analysis of the patient's DNA revealed a thymine-to-cytosine transition at codon 608 in the KRT-5 gene, resulting in a leucine-to-proline substitution in the keratin 5 protein. The same mutation was identified in the paternal, but not maternal, DNA. Here, we report a case of Weber-Cockayne type EBS with vesicles and bullae restricted to the palms and soles with a novel, paternally inherited mutation in KRT5 gene (exon2, c.608T>C).

A Case of Weber-Cockayne Epidermolysis Bullosa Simplex - Ultrastructural Findings / 대한피부과학회지

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominantly inherited genetic disorders characterized by blistering due to mechanical- stress-induced degeneration of basal epiderrnal cells. Recently, it was discovered that EBS is induced by keratin 5 and 14 gene mutations. Weber Cockayne (W-C) EBS is the mildest type, with blistering concentrates primarily on palar and plantar regions, and basal cell cytolysis by keratin filament perturbations is present. Herein we report a case of W-C EBS with its ultrastructural findings. Electron microscopy showed cytolysis and separation of the basal epidermal cells, mainly at the subnuclear cytoplasm. The cyto- plasm of basal cells showed edema, loosening and intact rnitochondria. Besides the cytoplasmic changes, the nucleus also showed lytic degeneration. Characteristically, dense condensation of tonofilarnent was observed, which suggests that W-C EBS is. also a disorder of keratin.