The importance of NCC is apparent in patients with Gitelman’s syndrome, caused by inactivating mutations in the NCC-encoding SLC12A3 gene, whom usually present with hypotension, hypokalemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria (Mastroianni et al., 1996; Simon et al., 1996; Lemmink et al., 1998; Monkawa et al., 2000). This evidence concerns the gene SLC12A3 and familial primary hypomagnesemia.