Gitelman's syndrome: report of one case.

Gitelman's syndrome (GS) is a rare autosomal recessive renal tubular disorder characterized by hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria. It is primarily caused by inactivating mutations of the SLC12A3 gene encoding the thiazide-sensitive Na-Cl cotransporter (NCC) on the apical membrane of distal convoluted tubule. We report an eight-year-old girl with incidental hypokalemia prior to appendectomy. All biochemical studies were consistent with GS. Genetic analysis of the NCC gene revealed two novel mutations (N442K and IVS6-1G > A). With regular potassium and magnesium supplementation, the patient has remained normal growth and development during two years of follow-up.