Autoimmune and inherited subepidermal blistering diseases: advances in the clinic and the laboratory.

Anchoring complexes are specialized focal attachment sites within the cutaneous basement membrane zone (BMZ) and play a crucial role in dermo-epidermal adhesion. Structural weakness that may be caused by the binding of autoantibodies to components of the anchoring complex or by aberrant expression of these components as a result of genetic defects can lead to subepidermal blisters. Autoimmune subepidermal blistering disorders include bullous pemphigoid, pemphigoid gestationis, lichen planus pemphigoides, linear IgA disease, cicatricial pemphigoid, anti-p200, anti-p105, and anti-p450 pemphigoid, epidermolysis bullosa acquisita, and bullous systemic lupus erythematosus. The autoantigen in the skin of patients with dermatitis herpetiformis remains to be identified. More than 300 distinct mutations in 10 different genes corresponding to structural components of the BMZ have been described that result in skin fragility and dermo-epidermal separation associated with characteristic extracutaneous manifestations. This group of genodermatoses, collectively referred to as epidermolysis bullosa (EB), consists of distinct variants, such as EB simplex, EB with muscular dystrophy, EB with pyloric atresia, generalized atrophic benign EB, Herlitz junctional EB, and dystrophic EB. Recent advances in the molecular characterization of BMZ components have led to a better understanding of the interaction between these molecules as well as the autoimmune response against these proteins. In addition, by the elucidation of genetic defects in the different variants of EB, genotype-phenotype correlations now begin to arise and genetic counseling has been improved.