Version June 2024
| EB type | Pathogenesis | Key clinical features |
| EB simplex (most common) | Autosomal dominant; most due to mutations in genes for keratins 5 and 14 expressed on epithelial cell cytoskeleton | Typically presents at birth or early infancy. Bullae with mild trauma, heal without scarring. Most forms with mild or no mucosal involvement. Chronic course but blistering tends to decrease with age, usually normal lifespan. |
| Intraepidermal separation | ||
| Junctional EB | Autosomal recessive; mutation in genes encoding hemidesmosomal proteins such as laminin 5 resulting in defective cell adhesion | More severe variant characterized by widespread bullae and erosions with nonhealing granulation tissue; associated with absent nails, dysplastic teeth, oral lesions, and pyloric stenosis. Death usually occurs in early childhood due to malnutrition or infection. Normal life expectancy in patients with milder variant who develop bullae, primarily on the extremities, that may heal with atrophic scarring. |
| Intra-lamina lucida separation | ||
| Dystrophic EB | Autosomal recessive and autosomal dominant; type VII collagen mutation leading to defective anchoring fibrils | Onset at birth; generalized bullae, heal with extensive scarring, milia. Repeated episodes of severe blistering and scarring lead to contraction flexures at knees and elbows and fusion of digits ("mitten deformities") of hands and feet. Oral, GI, and ocular mucous membrane involvement is also frequently seen and can be severe. Risk of developing squamous cell cancer within scars. Patients often die in early adulthood from complications such as infection or severe malnutrition. Milder phenotype seen with autosomal dominant forms. |
| Sub-basal lamina separation | ||
| Kindler EB | Autosomal recessive | Blisters induced by mild trauma, progressive poikiloderma, and skin atrophy (particularly of the dorsal hands and feet). Photosensitivity may or may not be present. Additional features may include desquamative gingivitis and strictures of the esophagus, anus, vagina, and urethra. Blistering and photosensitivity may decrease with age. |
| Separation at the level of the basal keratinocytes, within the lamina lucida, or sub-basal lamina separation |
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