Recently, a missense mutation (E269D) in the human ortholog of Cx29 supposed to contribute to non-syndromic hearing impairment (NSHI) at least disturbed the formation of gap junctions in HeLa cell transfectants (Hong et al., 2010) although targeted deletion of the Cx29 coding region in mice does not result in any obvious phenotypical alterations or abnormalities (Altevogt and Paul, 2004; Eiberger et al., 2006). The gene discussed is GJC3; the disease is Hearing impairment.