GJB4 and hearing loss disorder: Accordingly, K+ recycling genes were shown to be indispensable for the process of hearing, as evidenced by the fact that multiple mutations in these genes (GJB1 (Cx32), GJB2 (Cx26), GJB3 (Cx31), GJB4 (Cx30.3), GJB6 (Cx30), KCNE1, KCNQ1, and KCNQ4) lead to both syndromic and nonsyndromic forms of hearing loss [6,14,15].