Table 3 Transmission electron microscopy findings among selected EB subtypes
EB type | Major EB subtype | Level of cleavage | Associated ultrastructural findings |
|---|---|---|---|
EB simplex (suprabasal) | EB simplex superficialis | subcorneal | --- |
| Â | lethal acantholytic EB | suprabasal | acantholysis; perinuclear retraction of keratin filaments |
| Â | EBS, plakophilin deficiency | mid-epidermis | perinuclear retraction of keratin filaments; small suprabasal desmosomes |
EBS (basal) | EBS, localized | basal keratinocyte | --- |
| Â | EBS, Dowling-Meara | basal keratinocyte | clumped keratin filaments |
| Â | EBS, generalized other | basal keratinocyte | --- |
| Â | EBS, autosomal recessive | basal keratinocyte | absent or reduced keratin filaments within basal keratinocytes |
Junctional EB | JEB, Herlitz | intra-lamina lucida | markedly reduced or absent hemidesmosomes; absent subbasal dense plates; absent anchoring filaments |
| Â | JEB, non-Herlitz | intra-lamina lucida | hemidesmosomes may be normal or reduced in size and number |
| Â | JEB with pyloric atresia | intra-lamina lucida | small hemidesmosome plaques with attenuated subbasal dense plates |
Dominant dystrophic EB | DDEB, generalized | sub-lamina densa | normal or reduced numbers of anchoring fibrils |
| Â | DDEB, bullous dermolysis of the newborn | sub-lamina densa | electron-dense stellate shaped bodies within basal keratinocytes; reduced numbers of anchoring fibrils |
Recessive dystrophic EB | RDEB, severe generalized | sub-lamina densa | absent or rudimentary appearing anchoring fibrils |
| Â | RDEB, generalized other (generalized mitis) | sub-lamina densa | reduced or rudimentary appearing anchoring fibrils |