Any retinitis pigmentosa in which the cause of the disease is a mutation in the PRPF4 gene. The disease is retinitis pigmentosa 70 (Monarch Disease Ontology entry MONDO_0014400). Also known as: PRPF4 retinitis pigmentosa, RP70, retinitis pigmentosa caused by mutation in PRPF4, retinitis pigmentosa type 70.