GALNT13 (Polypeptide N-Acetylgalactosaminyltransferase 13) is a gene that encodes an enzyme involved in the initiation of O-linked glycosylation—a crucial post-translational modification process. It transfers N-acetylgalactosamine (GalNAc) to specific protein sites within the Golgi apparatus, influencing protein trafficking, secretion, and interactions on the cell surface. GALNT13 plays a significant role in cell signalling, adhesion, and immune response, with its dysregulation associated with diseases such as cancer and metabolic disorders.