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