title: NORMOMAGNESEMIC GITELMAN SYNDROME PATIENTS EXHIBIT A STRONGER REACTION TO THIAZIDE THAN HYPOMAGNESEMIC PATIENTS.
abstract: OBJECTIVE
  In recent decades, the thiazide test has been introduced to aid the diagnosis of Gitelman syndrome (GS), but the effect of thiazide in normomagnesemic GS patients is currently unknown. This study was conducted to compare the thiazide test results of normomagnesemic and hypomagnesemic GS patients.
  
  
  METHODS
  Seventeen GS patients with SLC12A3 gene mutations were enrolled, five of whom did not have a history of hypomagnesemia. The clinical data were documented, and SLC12A3 gene screening was performed. The thiazide test was performed in all of the patients and 20 healthy controls. A receiver operating characteristic curve was used to evaluate the sensitivity and specificity of the thiazide test in the diagnosis of GS.
  
  
  RESULTS
  A 7-fold increase in sodium and chloride excretion was observed after thiazide application in healthy controls, and an approximately 2-fold increase was found in the 5 normomagnesemic GS patients; however, there was no change in the 12 hypomagnesemic GS patients. A weaker reaction to thiazide was observed in hypomagnesemic compared with normomagnesemic GS patients. The clearance of chloride in 1 patient was overestimated because of chronic renal function insufficiency (CRI). When a reasonable cutoff value for chloride fractional excretion was selected, the thiazide test was 95% sensitive and 94.1% specific for the diagnosis of GS.
  
  
  CONCLUSIONS
  Hypomagnesemic GS patients exhibited greater sodium-chloride cotransporter dysfunction than normomagnesemic GS patients. When CRI occurs, the chloride and sodium clearance rates, rather than the fractional excretion, should be used in the evaluation of the thiazide test results.
authors.forename: Lanping
authors.initials: L
authors.lastname: Jiang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Peng
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.forename: Tao
authors.initials: T
authors.lastname: Yuan
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
authors.forename: Ou
authors.initials: O
authors.lastname: Wang
authors.forename: Haiyun
authors.initials: H
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Cai
authors.initials: C
authors.lastname: Yue
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Nie
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xing
authors.forename: Xuemei
authors.initials: X
authors.lastname: Li
authors.forename: Xuewang
authors.initials: X
authors.lastname: Lee
authors.forename: Limeng
authors.initials: L
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002712:Chlorides / Q000652:urine; D005260:Female; D005838:Genotype; D053579:Gitelman Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D006852:Hydrochlorothiazide / Q000008:administration & dosage*; D008274:Magnesium / Q000097:blood* / Q000652:urine; D008275:Magnesium Deficiency / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012964:Sodium / Q000652:urine; D049993:Sodium Chloride Symporter Inhibitors / Q000008:administration & dosage*; D064486:Solute Carrier Family 12, Member 3 / Q000235:genetics
chemical_list: D002712:Chlorides; C578874:SLC12A3 protein, human; D049993:Sodium Chloride Symporter Inhibitors; D064486:Solute Carrier Family 12, Member 3; D006852:Hydrochlorothiazide; D012964:Sodium; D008274:Magnesium