Bartter and Gitelman syndromes.

Since the initial description in the 1960s of patients with seemingly inherited disorders characterized by hypokalemia and metabolic alkalosis, the pathophysiologic processes underlying Bartter and Gitelman syndromes have generated tremendous study and speculation. Recently described mutations in genes encoding transport proteins important in sodium and chloride reabsorption in the thick ascending limb of Henle and distal convoluted tubule have confirmed these processes as the proximate defects in Bartter and Gitelman syndromes, respectively. Basic understanding of the role of these proteins in normal sodium and chloride homeostasis, and review of the secondary mediators stimulated by loss of their function provide insight into the clinical manifestations and response to treatment observed in these disorders.