- The peripheral myelin protein gene PMP-22 is contained within the Charcot-Marie-Tooth disease type 1A duplication. Timmerman, V., Nelis, E., Van Hul, W., Nieuwenhuijsen, B.W., Chen, K.L., Wang, S., Ben Othman, K., Cullen, B., Leach, R.J., Hanemann, C.O. Nat. Genet. (1992)