DCDC2 and nephronophthisis: Because oligogenic inheritance has been reported for ciliopathies, and mutations in human DCDC2 have been linked to nephronophthisis-related ciliopathies (NPHP-RC), we generated double mutants of rpi-1 with ciliopathy gene ortholog mutants (Nephronophthisis, Bardet Biedl syndrome and Meckel–Gruber syndrome) to investigate the genetic interactions (Hoefele et al., 2007; Schueler et al., 2015).