The mutation lies within the PRX domain of the protein and has previously been described in the literature (chr19.hg19:g.40901051; rs104894708) to cause Charcot–Marie–Tooth disease type 4 F (CMT4F) and Dejerine–Sottas disease.6, 7, 8, 9, 10, 11 Sanger sequencing confirmed the PRX mutation and showed it segregated with disease in the family in a recessive manner (Figure 1). Here, PRX is linked to Charcot-Marie-Tooth disease type 4F.