Clinicopathological Features of Gitelman Syndrome with Proteinuria and Renal Dysfunction

Abstract

Introduction. Gitelman syndrome (GS) is a rare renal tubular salt-wasting disorder. Besides kidney electrolytes loss, proteinuria and renal dysfunction were also observed. However, their incidence, risk factors, pathological features, and prognosis were unclear. Methods. We retrospectively reviewed 116 GS patients and analyzed their clinical, genetic, and pathological characteristics. We also systematically reviewed articles on GS with proteinuria and renal dysfunction. Results. Twenty-three GS patients had proteinuria (69.6%) and renal dysfunction (43.5%) with a mean age of 35.3 ±13.2 years and 65.2% were male. Compared to patients without proteinuria or renal dysfunction, these patients had elevated plasma angiotensin II level (440.2±351.7 vs. 253.2±187.4 pg/ml, P=0.031) and three times higher incidence of diabetes. The renal pathology of nine biopsied patients indicated hypertrophy of the juxtaglomerular apparatus (100%), chronic tubulointerstitial changes (66.7%), intrarenal vascular changes (66.7%), and glomerulopathy (55.6%). More extensive renin staining was observed in patients with GS than in the control group with glomerular minor lesion (P<0.001). During a median of 85 months (range, 11-205 months) follow-up for 19 out of the 23 GS-renal patients, the renal function was generally stable, except one died of cancer and one developed end-stage renal disease because of concomitant membranous nephropathy and IgA nephropathy. Conclusion. Proteinuria and renal dysfunction were more common than expected and might indicate glomerulopathy and vascular lesions besides a tubulointerstitial injury in GS. Renal function may maintain stable with effective therapy in most cases.