Sodium-hydrogen exchangers (NHEs), such as SLC9A8, are integral transmembrane proteins that exchange extracellular Na+ for intracellular H+. NHEs have multiple functions, including intracellular pH homeostasis, cell volume regulation, and electroneutral NaCl absorption in epithelia (Xu et al., 2008 [PubMed 18209477]).[supplied by OMIM, Apr 2009].