Renal phenotype in Bardet-Biedl Syndrome: a combined defect of urinary concentration and dilution is associated with defective urinary AQP2 and UMOD excretion.

Renal phenotype in Bardet-Biedl Syndrome: a combined defect of urinary concentration and dilution is associated with defective urinary AQP2 and UMOD excretion. Am J Physiol Renal Physiol. 2016 Aug 3;:ajprenal.00224.2016 Authors: Zacchia M, Zacchia E, Zona E, Capolongo G, Raiola I, Rinaldi L, Trepiccione F, Ingrosso D, Perna A, Di Iorio V, Simonelli F, Moe OW, Capasso G Abstract The renal phenotype in Bardet-Biedl syndrome (BBS) is highly variable. The present study describes renal findings in 41 BBS patients and analyzes the pathogenesis of hyposthenuria, the most common renal dysfunction. 5/41 patients (12%) showed an estimated glomerular filtration rate <60ml/min/1.73m2. Urine protein and urine albumin-to-creatinine ratio were over 200 and 30 mg/g in 9/24 and 7/23 patients respectively. 4/41 patients showed no renal anomalies on ultrasound. 20/34 patients had hyposthenuria in the absence of renal insufficiency. In all 8 of the hyposthenuric patients studied, dDAVP failed to elevate urine osmolality (Uosm), suggesting a nephrogenic origin. Interestingly, water loading (WL) did not result in a significant reduction of Uosm, indicating combined concentrating and diluting defects. DDAVP infusion induced a significant increase of plasma Factor VIII and von Willebrand Factor levels, supporting normal function of the type 2 vasopressin receptor at least in endothelial cells. While urinary aquaporin 2 (u-AQP2) abundance was not differen...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research