The human SLC26 gene family consists of eleven members which encode multifunctional anion exchangers.These exchangers are capable of transporting a variety of anions such as sulphate, bicarbonate, oxalate, hydroxyl, formate, iodide and chloride. SLC26 members can be grouped according to functional similiarities and three groups can be classified this way. Group 1 are selective sulphate transporters and include SLC26A1 and 2. Group 2 are Cl-/HCO3- exchangers and include SLC26A3, 4 and 6. Group 3 function as ion channels and include SLC26A7 and 9.