Cx30 inactivation causes profound deafness (Teubner, 2003; Cohen-Salmon et al., 2007; Sun et al., 2009; Chen et al., 2022), but in some cases, it strongly reduces the expression of Cx26 (Ortolano et al., 2008; Lynn et al., 2011). This evidence concerns the gene GJB6 and deafness.