Structural and functional characteristics of urinary tract in offspring of Balkan endemic nephropathy patients

Abstract

Introduction. Balkan endemic nephropathy (BEN) is a familial chronic progressive tubulointerstitial disease of unknown aetiology that occurs with high prevalence in endemic rural environments of Serbia, Bosnia and Herzegovina, Croatia, Bulgaria and Romania. It has been documented only in adults. Objective. The aim of this study was to examine clinical markers of BEN in children and adolescent offspring of BEN patients. Methods. Prospective clinical trial involved two groups of children and adolescents: I consisted of 30 offspring of BEN patients and II of 29 offspring of non-BEN dialysis patients, both of them living in the same South Morava region of Serbia. All of them were healthy at the time of the investigation, not receiving any drugs. The study included personal and family history, physical examination, comprehensive laboratory analyses and renal ultrasound. Blood pressure (BP) was determined by using casual BP and 24 h ABPM in subjects older than 5 years. Urinary proteins were investigated by analysing microalbumin, alfa 1 microglobulin, beta 2 microglobulin and SDS-PAGE electrophoresis. GFR was measured by estimated creatinine clearance and by serum Cystatin C concentrations. Results. There were no statistically significant differences in age, gender, history of urinary tract infections or functional voiding disorders between these two groups. All of the studied subjects had normal BP and GFR. Renal ultrasound was abnormal only in BEN offspring (6.66%) as well as increased urine concentrations of microalbumin (3.3%), alpha 1 microglobulin (10%) and beta 2 microglobulin (13.3%) while low molecular protein (<66,000 D) was prevalent in BEN compared with non- BEN offspring (21.43% vs. 3.7%). Conclusion. Renal abnormalities in offspring of BEN patients may be an early marker of BEN. This has to be confirmed in long term follow-up of a greater number of BEN paediatric offspring.