Small fiber neuropathy (SFN) is a disorder in which only the small unmyelinated sensory fibres are affected. In skin conditions such as recessive dystrophic Epidermolysis Bullosa (RDEB), there is degeneration of the distal part of these fibres secondary to chronic skin injury, followed by a failure of these fibres to regenerate, even when the skin injury has receded.  In the periphery, sensory nervous system regeneration is dependent on the production of neurotrophic factors by targets of innervation such as skin cells. Particularly small unmyelinated fibres depend on NGF (peptidergic ones) or GDNF (non peptidergic ones) to regenerate during adulthood. In the skin, keratinocytes, fibroblasts and infiltrating immune cells are known to express these neurotrophic factors to guide axonal re growth after injury. We hypothesize that in SFN secondary to RDEB (SFN-GDNF), the axons of small fibers are not able to get enough neurotrophic factors to stimulate regeneration of the distal terminals in the skin. This could be due to a lack or reduction of the production of the neurotrophic factors by skin cells.