Recent advances in molecular and cell biology of the cutaneous basement membrane zone have drastically increased our knowledge of the pathomechanisms underlying skin blistering disorders. Defects in genes coding for the structural proteins of the basement membrane zone have been defined in epidermolysis bullosa (EB), and abnormal expression of the structural proteins in some of its subtypes. The underlying cause for several subtypes of dystrophic EB are mutations in the gene for collagen VII, COL7A1. In vitro studies utilizing cells derived from the skin of such patients have helped understanding the pathogenetic pathways that lead from the mutation to the symptom, skin blistering. The data accumulated from analyses of the genetic disorders will also yield indirect information on the normal physiology of the skin and be highly relevant for the clarification of the etiopathogenesis of acquired blistering diseases.