FAM161A is a centrosomal-ciliary protein essential for photoreceptor ciliary structure and function. Primary function: FAM161A localizes to the photoreceptor connecting cilium, basal body, and centriole 1, where it is part of the inner centriole scaffold organized by POC1A-POC1B heterodimers to maintain centriolar integrity 2. Mechanism: FAM161A directly binds microtubules and increases α-tubulin acetylation 1, while its C-terminal UPF0564 domain mediates microtubule association and protein-protein interactions 1. The protein is critical for molecular delivery of outer segment cargo proteins and ciliary organization 3. Disease relevance: Biallelic FAM161A mutations cause autosomal recessive retinitis pigmentosa 28 (RP28), the third most frequently mutated gene in inherited retinal disease cohorts 4. FAM161A deficiency disrupts photoreceptor connecting cilia structure, leading to outer segment collapse and progressive photoreceptor degeneration 35. Clinical significance: Mouse models demonstrate progressive retinal degeneration with photoreceptor cell death 3, though disease progression varies depending on mutation type 5. Gene augmentation therapy using both FAM161A isoforms with appropriate promoter strength shows promise for structural and functional rescue 67.