epidermolysis bullosa simplex

epidermolysis bullosa sim·plex -'sim-.pleks n any of several forms of epidermolysis bullosa that are marked by blister formation within the epidermis sometimes accompanied by thickening of the skin but usu. no scarring and that are chiefly inherited as an autosomal dominant trait

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any of a heterogeneous group of nonscarring forms of epidermolysis bullosa caused mainly by mutations in either of two genes that encode basal layer keratins: KRT5 (locus: 12q13), which encodes keratin 5, or KRT14 (locus: 17q12-q21), which encodes keratin 14; rarely, it may result from other mutations. It is characterized by blistering within the basal layer of the epidermis, or more uncommonly within the epidermis above the basal layer; age of onset is variable; and progressive improvement is common. Inheritance is mainly autosomal dominant, The localized or Weber-Cockayne type is the mildest form and appears in infancy or sometimes later and is characterized by blistering primarily on the hands and feet. In the Koebner type, the lesions are generalized and onset is at birth or in early infancy. The Dowling-Meara type is the most severe, with generalized lesions that often occur in clusters and onset at birth or in early infancy.