Deletion of Cx30 is normally associated with substantial downregulation of Cx26 expression in Cx30(−/−) mice (Ortolano et al., 2008) as well as in DFNB1 patients (Lerer et al., 2001; Pallares-Ruiz et al., 2002; del Castillo et al., 2002; Rodriguez-Paris and Schrijver, 2009). The gene discussed is GJB2; the disease is autosomal recessive nonsyndromic hearing loss 1A.