CFAP298 is a highly conserved protein essential for motile cilium function, primarily by mediating cytoplasmic preassembly and stabilization of dynein arm complexes 1. The protein contains a unique ubiquitin-like domain that facilitates interactions between dynein heavy chains, molecular chaperones, and other preassembly factors 1. CFAP298 functions in folding and stabilization of nearly all axonemal dyneins independent of the canonical R2TP complex 2. Beyond dynein assembly, CFAP298 plays a critical role in left-right axis establishment during embryonic development, operating at the level of cilia motility rather than planar cell polarity positioning 3. Mutations in CFAP298 cause primary ciliary dyskinesia 26 with laterality defects including situs inversus and abnormal cardiac positioning 4. Clinically, CFAP298 deficiency results in immotile or poorly beating cilia throughout the body, disrupted cerebrospinal fluid circulation causing spine deformities resembling adolescent idiopathic scoliosis 5, and developmental abnormalities in left-right patterning with altered Nodal, Pitx2, and Lefty1 signaling 3. The protein's specialized architecture and ubiquitin-like domain distinguish it as a critical preassembly factor rather than maintenance factor for ciliary function.