We also performed immunohistochemical staining of four major urate transporters (URAT1, GLUT9, NPT4, and OAT3) in 3 ADPKD kidneys and 1 normal control kidney, which revealed strong expression of all 4 urate transporters along the compressed proximal tubules nearby renal cysts [28] (Additional file 2: Figure S1). This evidence concerns the gene SLC2A9 and cystic kidney disease.