KCNJ1 and Bartter syndrome: Bartter syndrome (OMIM #601678, #241200, #607364, #602522, #300971) is a rare inherited salt-losing tubulopathy caused by impaired transcellular NaCl reabsorption along the TAL, linked to different genetic variants (SLC12A1, KCNJ1, CLCNKA, CLCNKB, BSND, MAGED2) that encode, respectively, the Na+-K+-2Cl− cotransporter type 2 NKCC2, the potassium channel ROMK, the chloride channels ClC-Ka and ClC-Kb, the chloride channel subunit Barttin and MAGE-D2 [3].