Footnotes

• Contributors CB-M: collected clinical data and wrote the original manuscript. AB: co-author of the manuscript. BF: co-author of the manuscript, follow the patient. GC: performed initial electrophysiological examination. ME: supervised the project. SA: contributed to the final manuscrit and supervised the project. ED: performed nerve biopsy and contributed to the final manuscrit. EF: co-author the manuscript, created the figure and supervised the project.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.