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Based on the ultrastructural localisation of blisters(ultrastructural localisation of cleavage) , EB is divided into 4 main categories. At electron microscopic resolution, the blistering in EB simplex (EBS) occurs within the basal keratinocyte layer, in junctional EB (JEB) it is within the basement membrane along the lamina lucida, and in dystrophic EB (DEB) it is under the lamina densa
(see Dermo-epidermal junction zone).
The classification of the subtypes has been adjusted to the molecular genetic background and is now less related to the clinical features of the variable clinical findings. Numerous mutation analyses over the past 10 years have confirmed that the 4 main forms are genetically distinguishable, and also, that many of the uniquely named subtypes cannot really be considered as individual disorders (see Genetics). Nevertheless, some different acronyms are still present in the new classification (Fine et al 2008), since they are already so well-established in medical practice.
- EBS: a defect in the tonofilaments of the keratinocytes in the basal keratinocyte layer.
- JEB: defects in the hemidesmosomes or anchoring filaments in the area of the lamina lucida.
- DEB: defects of the anchoring filaments underneath the basement membrane.
- Kindler Syndrome
