Prx (Periaxin) is required for the maintenance of peripheral nerve myelin and patients with Prx mutations have early-onset autosomal recessive demyelinating Charcot-Marie-Tooth disease (CMT4F) or Déjèrine-Sottas neuropathy (DSN) [63]. The gene discussed is PRX; the disease is Charcot-Marie-Tooth disease type 4A.