Gitelman syndrome (GS) is an autosomal recessive kidney tubule disorder characterized by low blood levels of potassium and magnesium, decreased excretion of calcium in the urine, and elevated blood pH. The disorder is caused by genetic mutations resulting in improper function of the thiazide-sensitive sodium-chloride symporter (SLC12A3, also known as NCC, NCCT, or TSC) located in the distal convoluted tubule of the kidney. The distal convoluted tubule of the kidney plays an important homoestatic role in sodium and chloride absorption as well as of the reabsorption of magnesium and calcium.Genetic mutations of NCC, lead to loss of function and subsequent reduced transport of sodium and chloride via NCC. Secondary derangement of calcium, magnesium, and potassium concentrations are cuased by secondary effects in the distal tubule and collecting duct. [Source: Wikipedia ]