The thiazide-sensitive NaCl cotransporter (NCC, encoded by SLC12A3) plays a key role in the regulation of Na+, Cl- and K+ balance and BP, as underscored by Gitelman syndrome (loss-of-function mutation in SLC12A3) resulting in normal to low blood pressure, hypokalaemia and metabolic alkalosis, combined with significant hypomagnesaemia and hypocalciuria. This evidence concerns the gene SLC12A3 and Hypocalciuria.