- Interaction of nephrocystin-4 and RPGRIP1 is disrupted by nephronophthisis or Leber congenital amaurosis-associated mutations. Roepman, R., Letteboer, S.J., Arts, H.H., van Beersum, S.E., Lu, X., Krieger, E., Ferreira, P.A., Cremers, F.P. Proc. Natl. Acad. Sci. U.S.A. (2005)