KCC4 is expressed in tissues including the heart, nervous system, kidney, and inner ear and mice lacking KCC4 display progressive deafness and renal tubular acidosis (Marcoux et al., 2017; Mount et al., 1999; Karadsheh et al., 2004; Boettger et al., 2002). This evidence concerns the gene SLC12A7 and renal tubular acidosis.