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Generalized atrophic benign epidermolysis bullosa
T N Darling1, J W Bauer, H Hintner
1Dermatology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
Advances in Dermatology
|January 1, 1997
Summary
Generalized atrophic benign epidermolysis bullosa (GABEB) is linked to reduced type XVII collagen due to COL17A1 gene mutations. This discovery aids in distinguishing GABEB from other JEB forms and understanding collagen
Area of Science:
- Dermatology
- Genetics
- Molecular Biology
Background:
- Junctional epidermolysis bullosa (JEB) encompasses various genetic skin disorders.
- Generalized atrophic benign epidermolysis bullosa (GABEB) is a JEB subtype with chronic blistering from birth, nail dystrophy, hair loss, and abnormal teeth.
- Previous studies suggested a defect in type XVII collagen in GABEB patients.
Purpose of the Study:
- To determine the molecular basis of GABEB.
- To differentiate GABEB from the lethal Herlitz JEB variant.
- To elucidate the function of type XVII collagen in skin adhesion.
Main Methods:
- Immunofluorescence microscopy to assess protein expression in patient skin.
- Mutation analysis of the COL17A1 gene.
- Comparison of GABEB with Herlitz JEB based on protein expression patterns.
Main Results:
- Absent or decreased expression of type XVII collagen in the epidermal basement membrane of GABEB patients.
- Identification of mutations in the COL17A1 gene in GABEB patients, often leading to premature termination codons (PTCs).
- Distinction between GABEB (decreased type XVII collagen) and Herlitz JEB (decreased laminin 5).
Conclusions:
- GABEB is caused by homozygous mutations in the COL17A1 gene, resulting in deficient type XVII collagen and subsequent skin fragility.
- Type XVII collagen is crucial for basal keratinocyte adhesion to the epidermal basement membrane.
- Further research into GABEB may lead to therapeutic strategies and reveal additional functions of type XVII collagen.