Gitelman Syndrome: Diagnosis from an incidental finding of hypokalemia

Gitelman Syndrome (GS) is an autosomal recessive tubulopathy caused by mutations in the SLC12A3 gene, which encodes sodium chloride (NaCl) and magnesium (Mg) transporters in the apical membrane of distal convoluted tubule cells. It is characterized by hypokalemia, metabolic alkalosis, hypocalciuria, hypomagnesemia, and hyperreninemic hyperaldosteronism. Diagnosis is based on clinical symptoms and the previously described biochemical abnormalities. Symptoms can vary from mild (cramps, weakness) or even asymptomatic cases to severe symptoms (tetany, seizures). Definitive diagnosis is confirmed by genetic testing. The differential diagnosis includes Bartter syndrome type III and renal hypomagnesemia with hypocalciuria. Treatment is symptomatic and involves supplementation with potassium and magnesium.