CCDC15 is a centriolar protein that plays a critical role in centriole assembly, maintenance, and length regulation. 1 CCDC15 localizes to the centriole inner scaffold, a key subcompartment controlling centriole size and architectural integrity. 1 The protein functions by recruiting essential centriolar components, including the inner scaffold protein POC1B and the distal SFI1/Centrin-2 complex, to centrioles. 1 CCDC15 depletion impairs centriole structural integrity and length, leading to defective cilium formation, maintenance, and compromised Hedgehog signaling responses. 1 In spermatozoa, CCDC15 colocalizes with centrin at both proximal and distal centrioles, underscoring its specialized role in reproductive cell centrosomes. 2 Beyond ciliogenesis, CCDC15 has emerged as a prognostically relevant biomarker in non-small cell lung cancer and shows altered expression in active systemic lupus erythematosus. 3, 4 Additionally, CCDC15 variants are associated with C-reactive protein levels, linking the gene to inflammatory and cardiometabolic pathways. 5 These findings position CCDC15 as essential for maintaining centriolar architecture and primary cilium function, with potential implications for ciliopathies and inflammatory diseases.