Mouse models have shown that while genetic deletion of Cx26 invariably results in deafness, deletion of Cx30 does not as long as sufficient expression levels of Cx26 are maintained; expression of Cx26 and Cx30 are coregulated through the sharing of cis-acting elements between their encoding regions that lie within the DFNB1 locus (Ahmad et al., 2007; Boulay et al., 2013; Moisan et al., 2019). The gene discussed is GJB2; the disease is deafness.