BBS9 is a core structural component of the BBSome complex, an eight-subunit coat complex essential for protein trafficking to primary cilia 1. BBS9 associates with BBS2 and BBS7 through coiled-coil interactions to form a flattened triangular subcomplex architecture 2. The BBSome functions by binding RAB3IP/Rabin8, a guanosine exchange factor for Rab8, facilitating Rab8-GTP localization to cilia and promoting vesicle docking and fusion at the ciliary base 3. BBS9 knockdown in zebrafish and mammalian cells results in reduced cilia number and length, developmental abnormalities in retina and brain, and hydrocephalus 3. Loss-of-function BBS9 mutations cause Bardet-Biedl syndrome, an autosomal recessive disorder characterized by retinopathy, obesity, polydactyly, renal and cardiac malformations, intellectual disability, and hypogonadism 14. BBS9 variants also associate with nonsyndromic craniosynostosis through impaired primary cilia formation in suture osteogenic cells 56. Beyond genetic disease, circRNA derived from BBS9 acts as a miRNA sponge regulating apoptosis in chr7 obstructive pulmonary disease and ferroptosis in lung adenocarcinoma 78. These findings establish BBS9 as critical for ciliogenesis-dependent organ development and potential therapeutic target in ciliopathies and respiratory diseases.