Gitelman syndrome is best described by which profile?

• A. High potassium and magnesium with high renin and aldosterone
• B. Low potassium and magnesium with low renin and aldosterone
• C. Normal potassium and magnesium with normal renin
• D. Low potassium and magnesium with low renin and aldosterone

Answer: (D)

Gitelman syndrome is a distal convoluted tubule defect in the Na-Cl cotransporter, producing a thiazide-like tubulopathy. This causes salt wasting with mild volume depletion, leading to low potassium and low magnesium in the blood. It also usually causes metabolic alkalosis and hypocalciuria. A distinguishing feature is that renin and aldosterone levels are not elevated; they are typically low to normal, unlike Bartter syndrome where renin and aldosterone are high due to more pronounced volume depletion. Therefore the profile of low potassium and magnesium with low renin and aldosterone best fits Gitelman syndrome.