SPAG6 and male infertility: Disruption of SPAG6, the mouse PF16 orthologue, results in male infertility, due to loss of sperm motility [11]; and also to hydrocephalus, which is likely due to abnormal ciliary motility in epithelial cells in the brain cavities, as motile cilia are required to direct the correct flow of cerebrospinal fluid [12].