CATSPER1 and male infertility: The importance of the CCR6 receptor and CatSper channel can be highlighted by the observed reduction in the expression levels of either CCR6 [5] or CatSper [25] or both in sperm from the infertile patients recruited in the current study, indicating that defects in any component of this receptor-channel module with various sperm malfunctions may contribute to different forms of male infertility.