Acquired Gitelman syndrome in a primary Sjögren syndrome patient with a SLC12A3 heterozygous mutation: A case report and literature review.

Acquired Gitelman's syndrome (GS) associated with Sjögren syndrome (SS) is rare. A 50-year-old woman was admitted to our department because of nausea, acratia and sicca complex. Laboratory tests after admission showed renal failure, hypokalaemia, metabolic alkalosis, hypomagnesaemia and hypocalciuria, all of which met the diagnostic criteria for GS. Diagnostic evaluation identified primary SS as the cause of the acquired GS. Light microscopy of the renal tissue from the patient showed severe membranoproliferative glomerunephritis and tubulointerstitial nephritis. Immunohistochemical staining of the renal tissue showed the absence of sodium-chloride co-transporter (NCCT) in distal convoluted tubules. Genetic analysis of chromosomal DNA extracted from the patient's peripheral blood showed SLC12A3 gene heterozygous mutation. The reported case was comprehensively analyzed on the basis of the clinical features, and laboratory, pathological and genetic test findings. The patient has achieved a complete remission after meticulous care and appropriate treatment.