At that time, based on studies performed in Caenorhabditis elegans [82,83], an association between structural and/or functional defects in primary cilia of vertebrate epithelia and another cystic kidney disease caused by mutations in PKD1 (ADPKD1) encoding polycystin-1 [84-87] and PKD2 (ADPKD2) encoding polycystin-2 [88], was suggested. Here, PKD2 is linked to cystic kidney disease.