[Gitelman syndrome. An overlooked disease with chronic hypomagnesemia and hypokalemia in adults].

Gitelmans syndrome represents the clinical manifestations of inactivating mutations in the gene encoding for the thiazide sensitive sodium chloride cotransporter in the distal convoluted tubule. Thus, the biochemical characteristics resemble those seen with thiazide diuretics: hypokalemia, hypomagnesemia, hypocalcuria, metabolic alkalosis and blood pressure in the low normal range. Until the genetic background was clarified in 1996, Gitelman's syndrome was often mistaken for Bartter's syndrome, which is now attributed to defects in the ion transportation system in the thick ascending limb of Henle's loop. In Bartter's syndrome, hypomagnesemia is not a constant finding and urinary calcium excretion is normal or high. Bartter,s syndrome is often diagnosed neonatally and followed by growth retardation and nefrocalcinosis. Gitelman's syndrome is typically diagnosed accidentally (hypokalemia) in adolescents or adults and the course is benign. If present, the most prominent symptoms are muscular fatigue or occasional tetany. Treatment includes magnesium and potassium supplements and potassium saving diuretics.