RAB28 is a farnesylated small GTPase that plays critical roles in ciliary function and retinal photoreceptor maintenance. The protein is essential for outer segment phagocytosis (OSP) by retinal pigment epithelium cells, specifically regulating both dawn and dusk peaks of cone outer segment disc shedding and phagocytosis 1. RAB28 requires proper ciliary localization for function, with its delivery to outer segments dependent on phosphodiesterase 6 δ-subunit (PDE6D) and the BBSome complex 23. Loss of RAB28 function severely impairs cone photoreceptor survival while having less pronounced effects on rods 2. The protein also regulates extracellular vesicle production at ciliary membranes and affects visual cycle function by modulating retinoid metabolism 13. Pathogenic variants in RAB28 cause autosomal recessive cone-rod dystrophy 18 (CRD18), characterized by progressive central vision loss, macular hyperpigmentation, and severely attenuated electroretinographic responses 45. The disease phenotype includes outer nuclear layer loss, photoreceptor outer segment thinning, and RPE atrophy, with minimal progression over time 5. Some variants may also be associated with postaxial polydactyly, suggesting broader ciliary dysfunction 6.