Solute carrier (SLC) genes that code chloride (Cl-)/bicarbonate (HCO3-) exchanger proteins are the SLC4 and SLC26 families. The chloride anion exchanger SLC26A3 (aka down-regulated in adenoma, DRA) mediates electrolyte and fluid absorption in the colon. It is also localised to the midpiece tail membrane of sperm where it plays a role in Cl-/HCO3- homeostasis during sperm epididymal maturation. Defects in SLC26A3 cause congenital chloride diarrhea 1 (DIAR1), a disease characterised by watery stools containing an excess of chloride resulting in dehydration, hypokalemia, and metabolic alkalosis (Alper & Sharma 2013, Wedenoja et al. 2011).