GJB2 and hearing loss disorder: Mutations in the gene for connexin 26, GJB2, are responsible for a nonsyndromic hearing loss that is usually accompanied by normal vision, vestibular responses, and no malformations at CT scan; varying skin phenotypes including palmoplantar keratoderma or keratitis-ichthyosis-deafness have been described associated with hearing deafness in case of autosomical dominant deafness.