GJB2 and deafness: Cx26 is vital for potassium ion recycling within the cochlea, and GJB2 mutations have been implicated in both syndromic and non-syndromic forms of deafness.[6] Of over 100 identified GJB2 mutations, only a small subset-including D50N-are associated with syndromic phenotypes marked by hyperkeratosis, hearing loss, and ocular involvement.[7]