RP1L1 (RP1 like 1) is a photoreceptor cilium component essential for photoreceptor cell differentiation and maintenance 1. The protein plays a critical role in the organization of outer segments in both rod and cone photoreceptors, contributing to photoreceptor connecting cilium structure and axoneme assembly 1. RP1L1 pathogenic variants cause inherited photoreceptor diseases through disruption of ciliary function, though the exact molecular mechanisms remain unclear 1. The gene is primarily associated with two distinct retinal dystrophies: occult macular dystrophy (OMD), a cone degeneration characterized by progressive visual acuity loss with normal fundus appearance, and retinitis pigmentosa, a rod-predominant disease 21. Dominant mutations in RP1L1 have been identified in familial OMD cases, with structural changes detected in outer nuclear and photoreceptor layers via optical coherence tomography 2. In large-scale genetic studies, RP1L1 variants account for significant proportions of inherited eye diseases, with the gene ranking among the top causative genes for retinitis pigmentosa in Japanese populations and showing a 5.88% de novo mutation rate 34. Recent studies suggest RP1L1 may also contribute to age-related macular degeneration susceptibility and have complex interactions with other photoreceptor proteins that could modify disease phenotypes 51.