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Generalized junctional epidermolysis bullosa, non-Herlitz type
Generalized non-Herlitz-type junctional epidermolysis bullosa is a form of non-Herlitz-type junctional epidermolysis bullosa (JEB-nH, see this term) characterized by generalized skin blistering, atrophic scarring, nail dystrophy or nail absence, and enamel hypoplasia, with extracutaneous involvement.
- Generalized atrophic benign epidermolysis bullosa
- JEB-nH gen
- Junctional epidermolysis bullosa generalisata mitis
- Junctional epidermolysis bullosa, Disentis type
- Prevalence: Unknown
- Inheritance: Autosomal recessive
- Age of onset: Infancy, Neonatal
- ICD-10: Q81.8
- OMIM: 226650
- UMLS: -
- MeSH: -
- GARD: 12922
- MedDRA: -
Prevalence is unknown. The generalized form accounts for the vast majority of JEB-nH cases.
The condition is clinically apparent at birth. Skin blistering is generalized and healing can occur either with atrophic scars, sometimes accompanied by hypopigmentation or hyperpigmentation or, less commonly, with the formation of exuberant granulation tissue. Nail dystrophy or loss is a constant feature, focal keratoderma can develop over time. Progressive and permanent hair loss is frequently present, affecting the scalp, eyelashes and eyebrows; pubic and axillary hair are scant or do not fully develop. Mucosal lesions mainly affect the oral and nasal cavity, although there is considerable individual variability. Ocular involvement has been reported in some patients and comprises corneal erosions and scars, and, rarely, ectropion. The teeth regularly show enamel hypoplasia, leading to severe caries. Chronic anemia of multifactorial etiology, although of varying severity, is frequent and may be associated with a growth delay.
Generalized non-Herlitz junctional epidermolysis bullosa is caused by mutations in the COL17A1 (10q24.3) and LAMA3 (18q11.2), LAMB3 (1q32) and LAMC2 (1q25-q31) genes.
The condition follows an autosomal recessive pattern of inheritance.
Although generalized JEB-nH is less severe than JEB-H, death can occur in infancy and childhood due to sepsis, failure to thrive and respiratory failure. Adult patients with non-Herlitz JEB have an increased risk of developing squamous cell carcinomas in particular on the lower extremities, in areas of chronic blistering, long-standing erosions, or atrophic scarring.