RP2 and Usher syndrome: This includes many disease genes associated with a retinal ciliopathy phenotype, including Joubert disease genes Ahi1, Arl13b, Pde6b, Tmem138, and Tmem231; Bardet-Biedl disease genes Arl6, Bbs12, Bbs5, Bbs9, Ift74, Lztfl1, and Trim32; Senior-Loken syndrome gene Iqcb1; retinitis pigmentosa disease genes Arl3, Nek2, Rp2, and Topors; Leber congenital amaurosis disease gene Lca5 and; Usher syndrome gene Iqcb1 (Figure 3A).