GJB2 and deafness: Because the Cx26 deafness mutant p.R75W can impair the spread of Ca++-waves among cells (Beltramello et al., 2005; Yum et al., 2010; Zhang et al., 2011; Kamiya et al., 2014), it has been hypothesized that Cx26 deficiency may impair Ca++-wave propagation in the cochlea leading to hearing loss (Beltramello et al., 2005).