A novel mutation in the L12 domain of keratin 5 in the Köbner variant of epidermolysis bullosa simplex

Epidermolysis bullosa simplex (EBS) is a group of hereditary bullous diseases, characterized by intraepidermal blistering due to mechanical stress-induced degeneration of basal keratinocytes. Three major subtypes have been identified with autosomal dominant inheritance: Weber-Cockayne type, Köbner type (EBS-K), and Dowling-Meara type. These three EBS subtypes are all caused by mutations in either keratin 5 gene or keratin 14 gene, the major keratins expressed in the basal layer of the epidermis. We describe a female newborn with generalized blistering over the whole body since birth. Based on the clinical features of widespread blistering at birth, histopathological finding of intra-basal vesicle and ultrastructural findings of basal cell cytolysis without prominent clumping of tonofilaments, EBS-K was diagnosed. Mutational analysis revealed a novel keratin 5 mutation (967G>A) that produces an amino acid change (valine to methionine) at position 323 (V323M) of the seventh residue within the L12 linker domain.