CRB1 and retinitis pigmentosa 1: Crb2Chx10Cre and Crb2CrxCre cell-specific knockout mice (which lack Crb2 in retinal progenitor and photoreceptor cells, respectively) and Crb1Crb2F/+Chx10Cre double-knockout mice (which lack Crb1 and have a 50% reduction in Crb2 levels) develop an early-onset RP phenotype (Alves et al., 2013a,b, 2014a; Pellissier et al., 2013).