Anti-CFAP251 antibodies are used in the immunodetection of the protein cilia and flagella associated protein 251. In humans, the canonical protein has a reported length of 1149 amino acid residues and a mass of 130 kDa. Its subcellular localization is in the cytoplasm. Up to 3 different isoforms have been reported for this protein. It is notably expressed in many tissues, such as the bronchus and epididymis. CFAP251 is known to be involved in spermatozoa motility. The CFAP251 gene has been associated with the disease, Spermatogenic failure. Synonyms for this target antigen include WD repeat domain 66 and WD repeat-containing protein 66. CFAP251 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.