CRB1 and retinitis pigmentosa: crb mutant PRCs show light-induced degeneration (Johnson et al., 2002) and a human homolog of Crb (CRB1) has been linked to the retinal degenerative diseases, retinitis pigmentosa (RP12) and Leber congenital amaurosis (LCA8) (den Hollander et al., 1999, Richard et al., 2006; den Hollander et al., 2008; Bujakowska et al., 2012; Pellikka and Tepass 2017).