When examining the genetic overlap of disease in RP, we found that in those 43 genes that are only known to cause RP, there was enrichment not only of genes in the phototransduction and retinoid pathways, but also of genes involved in mRNA splicing, such as Prpf3, Prpf4, Prpf8, and Prpf31 (Table 4). The gene discussed is PRPF4; the disease is retinitis pigmentosa 1.