Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the uncontrolled formation and growth of renal cysts due to a mutation occurring in one of the two polycystin genes, PKD1 and PKD2 [1,2] and, much more rarely, by two other recently identified genes, GANAB [3] and PMM2 [4]. The gene discussed is GANAB; the disease is autosomal dominant polycystic kidney disease.