Epidermolysis Bullosa
Epidermolysis Bullosa (EB) is a rare genetic disease characterized by the presence of extremely fragile skin and recurrent blister formation, resulting from minor mechanical friction or trauma.
Forms
There are three main forms of inherited EB. These different subtypes are defined by the depth of blister location within the skin layers, and the location of the dissolution of the skin.
EB Simplex (EBS) -- ABOVE the basement membrane
See main article at Epidermolysis Bullosa simplex.
Blister formation of EB Simplex is within the basal keratinocyte of the epidermis. Sometimes EB simplex is called epidermolytic. There are four subtypes of EBS:
EBS - Weber-Cockayne (EBS-WC)
EBS - Koebner (EBS-K)
EBS - Dowling-Meara (EBS-DM) -- caused by missense mutation in KRT5 (E477K) or one of two missense mutations in KRT14 (R125C and R125H)
EBS - Mottled Pigmentation (EBS-MP) - caused by one missense mutation in KRT5 (I161S) or by missense mutations in the plectin gene (Koss-Harnes et al., 1997;Koss-Harnes et al., 2002).
Junctional EB (JEB) -- THROUGH the basement membrane
Condition characterized by spontaneous blistering of the skin and mucous membranes at the level of the lamina lucida within the basement membrane zone. Condition is caused by defects in the structures of laminin 5, laminin 6, collagen XVII, proteins that contribute to the cohesion of the dermis and epidermis. A severe form of the disease, JEB gravis is often fatal early in life. Death occurs as a result of epithelial blistering of the respiratory, digestive and genitourinary systems.
Dystrophic EB (DEB) -- UNDER the basement membrane
See main article at Epidermolysis Bullosa dystrophica.
Dystrophic EB (DEB) forms which can lead to scarring occur in a deeper tissue level; the sub-lamina densa region (the beneath the lamina densa) within the upper dermis.
Layman's Terms