Mutation analysis in the family of a Taiwanese boy with with epidermolysisbullosa simplex Dowling-Meara

Epidermolysis bullosa simplex (EBS) is a group of hereditary bullous diseas es characterized by intraepidermal blistering due to mechanical stress-indu ced degen eration of basal keratinocytes. The major subtypes of EBS, includ ing EBS Dowling Meara (EBS-DM), are caused by mutations of the basal kerati n genes, keratin 5 (KRT5) or keratin 14 (KRT14). Here, we describe the firs t reported pedigree of EBS-DM in Taiwan. The proband was a 5-day-old newbor n, who presented with numerous blisters of various sizes, some of which wer e hemorrhagic, as well as erosions on the extremities and hard palate since birth. Biopsy of a new vesicle showed subepidermal and basal cleavage with infiltration of eosinophils and neutrophils. Electron microscopy revealed cytolysis of basal eels and clumping of tonofilaments forming thick bundles and peculiar electron-dense round or oval basket-weave bodies. These featu res are characteristic of EBS-DM. The proband's mother had also suffered fr om a similar blistering disorder since birth, with gradual appearance of mo ttled pigmentation on the trunk, diffuse irregular or linear palmoplantar h yperkeratosis, and nail dystrophy. Mutation analysis revealed a heterozygou s point mutation (R125C) in helix 1A of keratin 14 in the proband and his m other. The detection of this pathogenic point mutation enables future prena tal diagnosis in this family.