SLC12A1 and gallstones: Barter syndrome type I is caused by loss-of-function mutations in sodium–potassium–chloride cotransporter gene SLC12A1, while type II is in potassium channel gene KCNJ1. In a study conducted by Puricelli et al. involving 34 patients diagnosed with Bartter’s syndrome type 1 and type 2 and 50 healthy controls, an increased risk of gallstones and persistent cholestasis was found.