- A novel missense mutation in GJB2 disturbs gap junction protein transport and causes focal palmoplantar keratoderma with deafness. de Zwart-Storm, E.A., Hamm, H., Stoevesandt, J., Steijlen, P.M., Martin, P.E., van Geel, M., van Steensel, M.A. J. Med. Genet. (2008)