Friday, October 26, 2012

Type/Dystrophic Epidermolysis Bullosa (DEB)


Dystrophic Epidermolysis Bullosa (DEB)

Dystrophic Epidermolysis Bullosa (DEB)~ whose subtypes range from mild to severe, generally becomes apparent at birth or during early childhood. In Dystrophic Epidermolysis Bullosa (DEB), the mutation is involved in the production of a type of collagen, a strong protein in the fibers that hold the deepest, toughest layer of your skin together. As a result, the fibers are either missing or non-functional. DEB can be either dominant or recessive.
This is a group of diseases caused by defects of anchoring fibrils. Blisters heal followed by dystrophic scarring. Formation of milia (1- to 4-mm white papules) results as a consequence of damage to hair follicles.

Dominantly inherited dystrophic epidermolysis bullosa

The onset of disease usually is at birth or during infancy, with generalized blistering as a common presentation. With increasing age, an evolution to localized blistering is present. A common variant described by Cockayne-Touraine has an acral distribution and minimal oral or tooth involvement. Another variant described by Pasini features more extensive blistering, scarlike papules on the trunk (termed albopapuloid lesions), and involvement of the oral mucosa and teeth. Dystrophic or absent nails are common in both of these dominantly inherited dystrophic epidermolysis bullosa variants.

Recessively inherited epidermolysis bullosa

This group of diseases ranges from mild to severe in presentation.
A localized form, termed recessively inherited epidermolysis bullosa mitis, often involves acral areas and nails but shows little mucosal involvement. This subtype also demonstrates clinical manifestations similar to the dominantly inherited forms of dystrophic epidermolysis bullosa.
Severe recessively inherited epidermolysis bullosa, as described by Hallopeau-Siemens, usually shows generalized blistering at birth and subsequent extensive dystrophic scarring that is most prominent on the acral surfaces. This can produce pseudosyndactyly (mitten-hand deformity) of the hands and feet. Flexion contractures of the extremities are increasingly common with age. Nails and teeth also are affected. Involvement of internal mucosa can result in esophageal strictures and webs, urethral and anal stenosis, phimosis, and corneal scarring. Malabsorption commonly results in a mixed anemia resulting from a lack of iron absorption, and overall malnutrition may cause failure to thrive. Patients with severe recessively inherited epidermolysis bullosa who survive to childhood are at significant risk of developing aggressive SCC in areas of chronic erosions.

Recessively inherited dystrophic epidermolysis bullosa pseudosyndactyly (mitten-hand deformity) of the hands and feet
Ectodermal dysplasia-skin fragility syndrome is a rare disorder characterized by skin erosions, skin fragility and peeling beginning at birth or infancy that may be accompanied by alopecia, palmoplantar keratoderma, painful fissures, and nail dystrophy. Failure to thrive, cheilitis, hypohidrosis, and pruritus are other potential complications. The underlying molecular defect has been shown to be loss of function of the desmosomal protein plakophillin1. Plakophillin is expressed mainly in suprabasilar keratinocytes and outer root sheath cells. Microscopic findings in this disease usually show intraepidermal acantholysis, located in the areas where plakophillin 1 is normally expressed. The molecular defect involves loss of function mutations in the PKP1 gene coding for plakophillin 1.


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