PRPF31 and retinitis pigmentosa 1: The coding sequence of PRPF31 is only 1.5 kb, well within the limits of current gene therapy vectors, and a PRPF31 heterozygous knockout mouse is available for study, although it only develops very late onset retinal degeneration which may be more characteristic of age-related macular degeneration than RP(Farkas et al., 2014).