A case of epidermolytic hyperkeratosis with no facial involvement associated with mutation in keratin 10

Abstract

Conflict of interest: none declared A 22‐year‐old Japanese woman, born to nonconsanguineous healthy parents, presented to our hospital with diffuse erythema and marked hyperkeratosis on the trunk and limbs. However, her face, palms and soles were unaffected (Fig. 1). There was no family history of similar keratinizing skin disorders. The patient had developed severe generalized erythroderma with blistering and erosions at birth. Later in life, the erythema, blistering and erosions decreased. but scaling and hyperkeratosis on the trunk and limbs became more prominent. A biopsy was taken from lesional skin on the forearm, and histological examination revealed marked orthohyperkeratosis and vacuolar changes in the keratinocytes of the upper spinous and granular layers. Electron microscopy showed clumping of keratin intermediate filament bundles in the keratinocytes of the upper spinous and granular layer. The basal epidermal layer appeared normal. Direct nucleotide sequencing of the PCR product spanning exon 1 of the keratin 10 gene (KRT10) revealed a heterozygous C→G transition at nucleotide position 457 (c.457C→G), which converts a leucine (CTG) to valine (GTG) in codon 153; this point mutation is designated p.L153V in the conserved 1 A region of keratin 10 (Fig. 2). This mutation was previously described by Ishiko et al. in 2001.1