Gitelman's syndrome (GS) is an autosomal recessive renal tubular disorder characterized by hypokalaemic metabolic alkalosis, hypomagnesaemia and hypocalciuria [1]. The electrolyte disturbances resemble those observed in chronic administration of thiazide diuretics. GS usually results from inactivating mutations of the SLC12A3 gene encoding the thiazide-sensitive Na+–Cl- cotransporter (NCCT) on the apical membrane of distal convoluted tubule (DCT) cells [2,3]. Loss of NCCT function leads to decreased Na+ and Cl- reabsorption in the DCT. The initial clinical presentation of GS includes transient episodes of muscle weakness and tetany, usually in children or young adults [4]. Some patients are completely asymptomatic. Although the neuromuscular manifestations are common and the hypomagnesaemia present in GS can also precipitate neuromuscular symptoms, to the best of our knowledge, profound hypokalaemia complicated by paralysis is rarely seen as the presenting feature in patients with GS [5]. With the paralytic presentation, GS may be misdiagnosed as hypokalaemic periodic paralysis (HPP) such as thyrotoxic periodic paralysis or familial periodic paralysis due to acute shift of K+ into cells, leading to improper management [6]. Furthermore, the documented mutations in the thiazide-sensitive NCCT responsible for GS have been not reported in Chinese patients. In this report, we describe a Chinese male who manifested with acute hypokalaemic paralysis resulting from GS caused by one novel NCCT mutation N426K, and another already known NCCT mutation T163M, respectively.
