This led in rapid succession to links between polycystic kidney disease and cilia, starting with the link of C. elegans homolog of the PKD1 and PKD2 polycystins, mutated in human polycystic kidney disease, to sensory cilia [11]; the link of IFT-B components to mutations in left-right asymmetry [12]; and the link between the IFT-B complex, the polycystic kidney disease gene tg737 and ciliary assembly [13]. Here, PKD1 is linked to polycystic kidney disease.