Epidermolysis bullosa simplex (EBS) is a disorder resulting from mutations in the genes encoding keratin 5 or keratin 14.Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. . It is one of the major forms of epidermolysis bullosa, a group of genetic conditions that cause the skin to be very fragile and to blister easily.
Signs and symptoms EBS causes blister formation at the dermal-epidermal junction. The skin blisters easily, even from very minor friction and rubbing.
Cause Epidermolysis bullosa simplex is caused by genetic mutations that prevent the proper formation of protein structures in the skin’s epidermis. The proteins of the outer epidermis do not bond properly with those of the inner dermis layer (dermal-epidermal junction). The affected genes, KRT5 and the KRT14, which are responsible for the creation of keratin 5 and keratin 14 proteins respectively, are tied to the four major types of epidermolysis bullosa simplex. However, a small number of epidermolysis bullosa simplex patients do not have mutations in their KRT5 and KRT14 genes. Mutations in the PLEC gene are also being researched, specifically in the gene’s role in the Ogna form of epidermolysis bullosa simplex. The PLEC gene is responsible for the formation of plectin, another skin protein that attaches the epidermis to the skin’s deeper layers.
Diagnosis Classification Epidermolysis bullosa simplex may be divided into multiple types:
Type Locus & Gene OMIM Epidermolysis bullosa simplex with migratory circinate erythema 12q13 (KRT5) Epidermolysis bullosa simplex with mottled pigmentation. Associated with a recurrent mutation in KRT14.James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. .Harel, A, et al. "Epidermolysis Bullosa Simplex with Mottled Pigmentation Resulting from a Recurrent Mutation in KRT14." Journal of Investigative Dermatology. (2006) 126, 1654–1657. ; published online 6 April 2006. 12q13 (KRT5) Epidermolysis bullosa simplex, autosomal recessive 17q12-q21 (KRT14) Generalized epidermolysis bullosa simplex Also known as "Koebner variant of generalized epidermolysis bullosa simplex", presents at birth to early infancy with a predilection for the hands, feet, and extremities, and palmar-plantar hyperkeratosis and erosions may be present. 17q12-q21 (KRT5), 12q13 (KRT14) Localized epidermolysis bullosa simplex Also known as "Weber–Cockayne syndrome" and "Weber–Cockayne variant of generalized epidermolysis bullosa simplex", is characterized by onset in childhood or later in life, and is the most common variant of epidermolysis bullosa simplex. 17q12-q21 (KRT5), 17q11-qter, 12q13 (KRT14) Epidermolysis bullosa herpetiformis Also known as "Dowling-Meara epidermolysis bullosa simplex", presents at birth with a generalized distribution, often with oral mucosa involvement and variable lesions in infancy. 17q12-q21 (KRT5), 12q13 (KRT14) Epidermolysis bullosa simplex with muscular dystrophy A rare clinical entity, and is the only epidermolytic epidermolysis bullosa described that is not caused by a keratin mutation, presenting as a generalized intraepidermal blistering similar to the Koebner variant of generalized epidermolysis bullosa simplex, but also associated with adult onset muscular dystrophy. 8q24 (PLEC1) Epidermolysis bullosa simplex with pyloric atresia 8q24 (PLEC1) Epidermolysis bullosa simplex of Ogna Has onset in infancy, presenting with seasonal blistering on acral areas during summer months. 8q24 (PLEC1)
Management No cure for EB Treat symptoms Protect skin, stop blister formation, promote healing Prevent complications Necessary treatment: use oral and topical steroid for healing and prevent complication Maintain cool environment, avoid overheating and decreases friction
See also Epidermolysis bullosa List of cutaneous conditions caused by mutations in keratins
References
Further reading
GeneReviews/NCBI/UW/NIH entry on Epidermolysis Bullosa Simplex
External links