Gitelman syndrome (GS) is an autosomal recessive tubulopathy due to loss of function mutation in SLC12A3 gene encoding thiazide-sensitive NaCl co-transporter in the distal convoluted tubule. GS is characterized by hypokalemia, metabolic alkalosis, hypomagnesemia, hypocalciuria and low-to-normal blood pressure.
We present an 18 month old boy with psychomotor retardation, where hypokalemia, metabolic alkalosis and hypocalciuria, together with normonatremia, normocalcemia pointed to the very rare diagnosis of GS, which was confirmed by two mutations in SLC12A3 gene (c.2576T>C and c.2929C>T).