After Cx26 mutations were found to be associated with hearing loss (Kelsell et al., 1997), this hypothesis was further linked to the mechanism of Cx26 mutations induced hearing loss (Figure 1C), since Cx26 is a predominant isoform in the cochlea (Kikuchi et al., 1995; Lautermann et al., 1998; Forge et al., 2003; Zhao and Yu, 2006; Liu and Zhao, 2008). Here, GJB2 is linked to hearing loss disorder.