N-Acetylgalactosamine (GalNAc) is an amino sugar derivative of galactose used as a targeting ligand in investigational antisense oligonucleotides and siRNA therapies targeted to the liver, where it binds to the asialoglycoprotein receptors on hepatocytes. 
 

⇒   Ulashchik, E. A., Martynenko-Makaev, Y. V., Akhlamionok, T. P., Melnik, D. M., Shmanai, V. V., & Zatsepin, T. S. (2021). Synthesis of galNAc-oligonucleotide conjugates using galNAc phosphoramidite and triple-galNAc CPG solid support. Design and Delivery of SiRNA Therapeutics, 101-118. DOI