SLC12A2 and Hearing impairment: In addition, we investigated whether blocking another solute carrier, NKCC1 (encoded by the Slc12a2 gene), Cl–, Na+, and/or K+ ion transporter involved in hearing impairments, might also affect AJ and TJ gene expression in a wildtype-derived endothelial cell monolayer (Gamba, 2005).