SLC12A1 and Bartter syndrome: On the other hand, hypotension is induced by loss-of-function mutations of the NCC in Gitelman syndrome, as well as loss-of-function mutations of Na+-K+-2Cl− cotransporter 2 (NKCC2), the renal outer medullary potassium channel (ROMK), or the ClC-Kb chloride channel in Bartter syndrome.