Radial spoke head protein 9 homolog is a protein that in humans is encoded by the RSPH9 gene. Function This gene encodes a protein thought to be a component of the radial spoke head in motile cilia and flagellawhich then releases antibodies . Clinical significance Mutation in this gene are associated with primary ciliary dyskinesia. References Further reading External links GeneReviews/NCBI/NIH/UW entry on Primary Ciliary Dyskinesia