Sialyltransferase is a type of glycosyltransferase that transfers sialic acid residues to the terminal end of sugar chains, participating in the synthesis of glycoproteins and glycolipids. This family includes multiple subtypes such as ST3Gal, ST6Gal, and ST8Sia, each with specific substrate specificity and tissue expression patterns. These enzymes are primarily located in the Golgi apparatus and are widely present in various cells and tissues. Sialyltransferases play a crucial role in regulating biological processes such as cell adhesion, signal transduction, and immune recognition. The specific expression and mutations of the gene are associated with various diseases, including cancer, neurodegenerative diseases, and congenital metabolic disorders.