PMP22 and Charcot-Marie-Tooth disease: Eventually, Hereditary Neuropathy with liability to Pressure Palsies is an autosomal dominant disorder characterised by recurrent focal neuropathies, which are typically painless and transient, and it is associated with the deletion of the PMP22 gene, whereas the duplication of the same gene with PMP22 overexpression is associated with the most frequent CMT subtype, CMT1A.