Anti-AN antibodies enable researchers to detect and measure the AN antigen in biological samples. This target is a reported synonym of the PAX6 gene, which encodes paired box 6. This protein is known to function in organ morphogenesis and astrocyte differentiation, among other biological roles. The human version of AN has a canonical amino acid length of 422 residues and a protein mass of 46.7 kilodaltons, although 3 isoforms have been identified. It is reported to be localized in the nucleus of cells and notably expressed in the rectum, duodenum, colon, cerebellum, and appendix. AN is a member of the Paired homeobox protein family.