PKD2 and Joubert syndrome and related disorders: Although the causative genes of ADPKD, PKD1 and PKD2 genes encoding polycystin1 (PC1) and polycystin2 (PC2), respectively (100, 101), are different from those of JSRD, multiple cysts are also observed in NPH of JSRD patients, indicating that tolvaptan could be used for the treatment of NPH.