For hearing loss, the vast majority of mutations occur in Cx26, and its importance in auditory function is evidenced by the fact that Cx26 mutations account for ∼50% of severe-to-profound inherited deafness cases across diverse ethnic populations (Angeli et al., 2012; Apps et al., 2007; Chan and Chang, 2014; Duman and Tekin, 2012). The gene discussed is GJB2; the disease is deafness.