GJB1 and Charcot-Marie-Tooth disease: Most patients withEGR2-related CMT have mutations in the ZNF DNA-binding domain.13, 14, 15, 16, 17, 18, 19TheEGR2gene encodes a C2H2-type zinc-finger transcription factor that regulates the expression of genes involved in myelin formation and maintenance, including myelin-associated glycoprotein (MAG), myelin basic protein (MBP), myelin protein zero (MPZ), gap junction beta 1 (GJB1), peripheral myelin protein (PMP22), and periaxin (PRX).12, 13The variation in clinical severity seen with disease-causing variants in the ZNF domain appears to correlate with the level of residual DNA binding.12