After infusion of Option (a FDA-approved microbubble UCA) into the urinary bladder (Fig. 4, Video S1 and Video S2), we found that all (4/4, 100%) Robo2 mosaic mutant mice with hydronephrosis displayed VUR (Fig. 4A–H, Video S3). The gene discussed is ROBO2; the disease is hydronephrosis.