Basolateral Mg2+ extrusion isNa+ dependent and achieved by CNNM2 and/or SLC41A3.Hypomagnesemia (serum Mg2+ <0.7 mmol/L) developswhen intestinal and/or renal Mg2+ (re)absorption is disturbed.Common causes include alcoholism, type 2 diabetes mellitus and the use ofpharmacological drugs, such as proton-pump inhibitors, calcineurin inhibitorsand thiazide diuretics. This evidence concerns the gene CNNM2 and familial primary hypomagnesemia.