The mechanism leading to this hypomagnesemia is not fully understood but likely involves reduced intestinal absorption of magnesium through inhibition of TRPM6 and TRPM7 channels, as well as inhibition of the H+/K+ ATPase pump in the colon, resulting in altered intestinal luminal pH and decreased active transport of magnesium via TRPM6 [3,17]. The gene discussed is TRPM7; the disease is familial primary hypomagnesemia.