The function of ENSG00000183833 (CFAP91, cilia and flagella associated protein 91) is as follows. Involved in sperm flagellum axonemal organization and function (PubMed:12223483, PubMed:32161152). May regulate cilium motility through its role in the assembly of the axonemal radial spokes (By similarity). {ECO:0000250|UniProtKB:A8IH47, ECO:0000269|PubMed:12223483, ECO:0000269|PubMed:32161152}.