Persistent hypokalemia due to a rare mutation in gitelman's syndrome.

Chronic hypokalemia is the main finding in patients with Gitelman's syndrome (GS). GS, a variant of Bartter's syndrome, is an autosomal recessive renal disorder characterized by hypokalemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria. GS is caused by inactivating mutations in the thiazide-sensitive sodium-chloride cotransporter gene.