PKD2L1 and Kidney Cyst: Although no mutations in the PKD2L1 gene have been identified in patients suffering from polycystic kidney disease to date and Pkd2l1 knock-out mice do not develop kidney cysts (Delling et al., 2013), polycystin-2L1 has attracted particular attention because it has been shown to act as a Ca2+ channel in primary cilia (DeCaen et al., 2013; Delling et al., 2013).