This study will evaluate the safety and efficacy of a recombinant adeno-associated virus vector expressing a human RPGR-ORF15 gene (rAAV2tYF-GRK1-RPGR) in patients with X-linked retinitis pigmentosa caused by RPGR-ORF15 mutations. Approximately 15 participants will be enrolled and 3 dose levels will be evaluated in a dose-escalation format.