CFAP206 (cilia and flagella associated protein 206) is a microtubule-docking adapter essential for motile ciliary and flagellar structure and function. Functionally, CFAP206 localizes to the basal body and axoneme of motile cilia 1, where it serves as a critical component for radial spoke assembly and positioning. The protein is required for establishing and maintaining radial spokes—T-shaped ciliary complexes that transduce regulatory signals from the ciliary center to outer dynein arms 2. In the respiratory epithelium, CFAP206 regulates ciliary beat frequency; knockout Xenopus larvae demonstrated enhanced beat frequency but reduced mucociliary clearance 1. Clinically, CFAP206 deficiency causes male infertility through severe flagellar dysfunction. A homozygous frameshift mutation in CFAP206 was identified in an infertile man with multiple morphological abnormalities of the flagella (MMAF) phenotype, accompanied by absence of radial spoke proteins WDR66 and RSPH1 3. Cfap206 knockout mice exhibited complete male infertility with structural and ultrastructural flagellar defects and intracytoplasmic sperm injection (ICSI) failures 3. Additionally, Cfap206 mutant mice displayed hydrocephalus and impaired mucociliary clearance without laterality defects, suggesting CFAP206 as a candidate gene for primary ciliary dyskinesia caused by radial spoke defects 1.