These authors showed the efficacy of a fully complementary U1 snRNA to overcome the exon skipping caused by a mutation at +3 position in intron 10 (c.1245+3A>T) of the retinitis pigmentosa GTPase regulator (RPGR) gene, which origins an X-linked form of RP. Here, RPGR is linked to retinitis pigmentosa 1.