[Gitelman's syndrome--a differential diagnosis in hypokalemia].

BACKGROUND: Gitelman's syndrome is a rare disease characterised by low levels of potassium and magnesium in the blood. It is caused by mutations in the gene encoding the thiazide-sensitive sodium chloride cotransporter in the distal collecting duct. MATERIAL AND METHODS: We present four patients (two brothers and two sisters) with Gitelman's syndrome and review the literature regarding the disease. RESULTS AND INTERPRETATION: Gitelman's syndrome should be considered in patients with persistently low levels of potassium and magnesium. The diagnosis is confirmed by genetic testing.