Definition of Junctional epidermolysis bullosa

Junctional epidermolysis bullosa: A blistering skin condition inherited in an autosomal recessive manner, due to mutation of a gene that normally promotes the formation of anchoring filaments (thread-like fibers) or hemidesmosomes (complex structures composed of many proteins). These structures anchor the epidermis to the underlying basement membrane. The defect leads to tissue separation and blistering in the upper part of the basement membrane.

Junctional epidermolysis bullosa (JEB) is usually severe. In the most serious forms, large, ulcerated blisters on the face, trunk, and legs can be life-threatening due to complicated infections and loss of body fluid that leads to severe dehydration. Survival is also threatened by blisters that affect the esophagus, upper airway, stomach, intestines, and the urogenital system. Other signs found in both severe and mild forms of JEB include rough and thickened or absent fingernails and toenails; a thin appearance to the skin (called atrophic scarring); blisters on the scalp or loss of hair with scarring (scarring alopecia); malnutrition and anemia; growth retardation; involvement of soft tissue inside the mouth and nose; and poorly formed tooth enamel.

See also: Epidermolysis bullosa.