AbstractSince the immunochemical identification of the bullous pemphigoid antigen 230 (BP230) as one of the major target autoantigens of bullous pemphigoid (BP) in 1981, our understanding of this protein has significantly increased. Cloning of its gene, development and characterization of animal models with engineered gene mutations or spontaneous mouse mutations have revealed an unexpected complexity of the gene encodingBP230. The latter, now calleddystonin(DST), is composed of at least 100 exons and gives rise to three major isoforms, an epithelial, a neuronal and a muscular isoform, namedBPAG1e (corresponding to the originalBP230),BPAG1a andBPAG1b, respectively. The variousBPAG1 isoforms play a key role in fundamental processes, such as cell adhesion, cytoskeleton organization, and cell migration. Genetic defects ofBPAG1 isoforms are the culprits of epidermolysis bullosa and complex, devastating neurological diseases. In this review, we summarize recent advances of our knowledge about severalBPAG1 isoforms, their role in various biological processes and in human diseases.