They present as Gitelman-like syndrome (hypomagnesaemia and hypocalciuria) related to the HNF1B transcription function over the FXYD Domain Containing Ion Transport Regulator 2 (fxyd2) gene that encodes sodium-potassium ATPase in the distal convoluted tubule, which plays an important role in magnesium reabsorption [14]. The gene discussed is FXYD2; the disease is Hypocalciuria.