BBS1 is a core component of the BBSome, a coat complex essential for protein trafficking to primary cilia 1. The BBSome functions as a sorting machinery that directs specific membrane proteins to ciliary membranes through a Rab8-dependent mechanism, wherein BBS1 associates with the guanine nucleotide exchange factor RAB3IP/Rabin8 to facilitate Rab8-GTP activation, promoting carrier vesicle docking and fusion at the ciliary base 1. BBS1 is required for proper BBSome assembly and ciliary localization, and together with LTZL1, regulates smoothened (SMO) trafficking and sonic hedgehog pathway signaling 1. Additionally, BBS1 participates in FGFR2 ciliary trafficking, with mutations impairing receptor localization to cilia 2. Mutations in BBS1 cause Bardet-Biedl syndrome (BBS), a rare autosomal recessive ciliopathy characterized by retinal dystrophy, obesity, polydactyly, renal dysfunction, and hypogonadism 34. Defective BBS1 results in impaired ciliogenesis and ciliary dysfunction, explaining the pleiotropic phenotype 3. BBS1 variants also cause non-syndromic retinitis pigmentosa, highlighting variable disease presentation 5. Renal abnormalities represent life-threatening manifestations that can progress to end-stage kidney failure requiring transplantation 46. BBS1 is among the most common IRD-associated genes in UK populations, with founder variants identified in large cohorts 78.