Familial Bartter's syndrome.

Two sisters were found to have Bartter's syndrome. Both had hypokalemia, hyperreninemia, normal BPs, and decreased pressor responses to angiotensin II. During a water diuresis, patient 1 had an abnormally low distal tubular fractional reabsorption of chloride initially, but this normalized after hypokalemia was corrected for one year. Patient 2 had no demonstrable defect in chloride transport. Hypokalemia in Bartter's syndrome may be caused by some hereditary mechanisms other than defective reabsorption of chloride in the distal tubules.