CLCNKB and familial primary hypomagnesemia: Over a dozen genes directly or indirectly implicated in transport of magnesium ions have been identified so far and classified into four groups: (i) hypercalciuric hypomagnesemias CLDN16, CLDN19, CASR, and CLCNKB; (ii) Gitelman-like hypomagnesemias, CLCNKB, SLC12A3, BSND, KCNJ10, FYXD2, HNF1B, and PCBD1; (iii) mitochondrial hypomagnesemias, SARS2 and MT-TI; and (iv) other hypomagnesemias, TRPM6, CNMM2, EGF, EGFR, KCNA1, and FAM111A [32].