The exponential increase in the number of known genes associated with CMT images, possibly mainly due to exome sequencing (WES) techniques, has made traditional classification systems increasingly complex, leading since 2018 to the revision of these systems and classification based on causative gene alterations [1]) Within each category (CMT1, CMT2, etc.), the association with a specific gene is indicated by a letter of the alphabet (e.g., CMT1A, CMT1B, etc.). The gene discussed is PMP22; the disease is Charcot-Marie-Tooth disease.