SLC12A1 and Bartter syndrome: In Bartter syndrome, the transcellular NaCl reabsorption in the TAL is disrupted, due to mutations in the Na-K-Cl cotransporter 2 (NKCC2), the renal outer medullary potassium channel (ROMK1) or the Cl– channel Kb (ClC-Kb) [33,34,35,36].