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Dystrophic Epidermolysis Bullosa.

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GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2014.
2006 Aug 21 [updated 2010 Nov 04].

Excerpt

DISEASE CHARACTERISTICS:

Based on the most recent classification system, dystrophic epidermolysis bullosa (DEB) includes three subtypes: Recessive DEB, severe generalized (RDEB-sev gen) (formerly called Hallopeau-Siemens type (RDEB-HS). Recessive DEB, generalized other (RDEB-O) (formerly called non-Hallopeau-Siemens type (RDEB-non-HS). Dominant DEB (DDEB) . In RDEB-sev gen, blisters affecting the whole body may be present in the neonatal period. Oral involvement may lead to mouth blistering, fusion of the tongue to the floor of the mouth, and progressive diminution of the size of the oral cavity. Esophageal erosions can lead to webs and strictures that can cause severe dysphagia. Consequently, severe nutritional deficiency and secondary problems are common. Corneal erosions can lead to scarring and loss of vision. Blistering of the hands and feet followed by scarring fuses the digits into "mitten" hands and feet, a hallmark of this disorder. The lifetime risk of aggressive squamous cell carcinoma is over 90%. In contrast, the blistering in the less severe forms of RDEB-O may be localized to hands, feet, knees, and elbows with or without involvement of flexural areas and the trunk, and without the severe, mutilating scarring seen in RDEB-sev gen. In DDEB, blistering is often mild and limited to hands, feet, knees, and elbows, but nonetheless heals with scarring. Dystrophic nails, especially toenails, are common and may be the only manifestation of DDEB.

DIAGNOSIS/TESTING:

Examination of a skin biopsy by transmission electron microscopy (EM) and/or immunofluorescent (IF) antibody/antigen mapping is the best way to reliably establish the diagnosis. The only gene known to be associated with DEB is COL7A1. Sequencing of exons 73, 74, and 75 of COL7A1 detects mutations in 75% of families with DDEB; sequencing of all coding exons detects mutations in about 95% of individuals with either DDEB or RDEB.

MANAGEMENT:

Treatment of manifestations: New blisters should be lanced, drained, and in most cases dressed with a non-adherent material, covered with padding for stability and protection, and secured with an elastic wrap for integrity. Infants and children with RDEB-sev gen and failure to thrive require attention to fluid and electrolyte balance and may require nutritional support, including feeding gastrostomy. Anemia is treated with iron supplements and transfusions as needed. Other nutritional supplements may include calcium, vitamin D, selenium, carnitine, and zinc. Occupational therapy may help prevent hand contractures. Surgical release of fingers often needs to be repeated. Surveillance: Biopsies of abnormal-appearing wounds that do not heal or have exuberant scar tissue are indicated for evidence of squamous cell carcinoma beginning in the second decade. Screening for deficiencies of iron, zinc, vitamin D, selenium, and carnitine should start after the first year of life. Routine echocardiograms are recommended to identify dilated cardiomyopathy and bone mineral density studies to identify osteoporosis. Agents/circumstances to avoid: Activities/bandages that traumatize the skin; all adhesives.

GENETIC COUNSELING:

Dystrophic epidermolysis bullosa is inherited in either an autosomal dominant (DDEB) or autosomal recessive (RDEB) manner. Molecular characterization of pathogenic mutations is the only accurate method to determine mode of inheritance and recurrence risk; phenotype severity and EM/IF findings alone are not sufficient. DDEB. About 70% of individuals diagnosed with DDEB are reported to have an affected parent. If a parent of a proband with DDEB is affected, the risk to the sibs is 50%. Each child of an individual with DDEB has a 50% chance of inheriting the mutation. RDEB. Each sib of an affected individual whose parents are both carriers has at conception a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Prenatal testing for pregnancies at increased risk for all subtypes of DEB is possible if the disease-causing allele(s) of an affected family member are known.

Copyright © 1993-2014, University of Washington, Seattle. All rights reserved.

PMID:
20301481
[PubMed]
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