First, it allows for prediction of disease progression in conjunction with clinical parameters (sex, hypertension, urological event), as demonstrated by the PROPKD score.4 Second, genetic analysis enables detection of ADPKD phenocopies and excludes PKD1/2-negative patients from potentially harmful treatment, given that studies on tolvaptan in ADPKD phenocopies are lacking. This evidence concerns the gene PKD1 and autosomal dominant polycystic kidney disease.