Expert consensus for the diagnosis and treatment of patients with Gitelman syndrome

Abstract

Gitelman syndrome (GS) is an autosomal recessive, salt-losing tubulopathy caused by inactivating mutations in the SLC12A3 gene that encodes the thiazide-sensitive sodium-chloride cotransporter (NCC). GS is characterized by hypokalemic metabolic alkalosis, hypomagnesemia and hypocalciuria. GS is one of the most common inherited renal tubulopathy with a prevalence estimated at about one to ten per 40 000 people. The prevalence of GS is even higher in Asia than other countries. The majority of GS patients present mild and nonspecific symptoms during adolescence or adulthood. Common clinical manifestations are associated with electrolyte abnormalities, such as muscle weakness, salt craving and tetany. However, the phenotype of GS is highly variable and links to the quality of life. Diagnosis of GS is based on the clinical symptoms, biochemical abnormalities (normal/low blood pressure, metabolic alkalosis, hypomagnesemia, hypocalciuria and increased activity of renin-angiotensin- aldosterone system) and genetic test. Genetic diagnosis of GS is recommended for all patients and the diagnosis is confirmed when biallelic inactivating SLC12A3 mutations are identified. The differential diagnosis includes renal tubular acidosis, primary hyperaldosteronism, Bartter syndrome, Liddle syndrome and other diseases that cause hypokalemia. Among them Bartter syndrome (especially type Ⅲ) is the most important genetic disorder to consider due to its similar manifestations with GS. All GS patients are encouraged to keep high-sodium diet. Magnesium and potassium supplements (oral or intravenous) are usually given to GS patients to improve clinical symptoms. Other medicines such as aldosterone receptor antagonists, angiotensin-converting-enzyme inhibitors (ACEIs), angiotensin Ⅱ receptor blockers (ARBs) and prostaglandin synthetase inhibitors (PGSIs) are alternative choices of treating hypokalemia, but the side-effects of these medication should be well considered. Management of GS includes health education, complication evaluation and regular follow-up. Annual evaluation by a nephrologist is recommended. Extra evaluation and treatment depend on special conditions, such as pregnancy, perioperative or growth period. Antenatal diagnosis for GS is technically feasible but not recommend due to the benign prognosis in the majority of patients. In general, this expert consensus statement aims to establish an initial framework for the better diagnosis, treatment and management of Chinese patients with GS.