There was a very small difference between the groups in Period 4, where non-ADPKD patients had an higher u-AQP2 excretion rate compared to healthy controls (0.02 [0.01; 0.09] vs. 0.01 [0.00; 0.02], p=0.023). This evidence concerns the gene AQP2 and autosomal dominant polycystic kidney disease.