Glucosaminyl (N-Acetyl) Transferase 2, I-Branching Enzyme (I Blood Group); Ii Blood Group; NACGT1; GCNT5; IGNT; II; Glucosaminyl (N-Acetyl) Transferase 2, I-Branching Enzyme (Ii Blood Group); N-Acetyllactosaminide Beta-1,6-N-Acetylglucosaminyl-Transferase; Glucosaminyl (N-Acetyl) Transferase 2, I-Branching Enzyme; I Beta-1,6-N-Acetylglucosaminyltransferase; Beta-1,6-N-Acetylglucosaminyltransferase 2; Glucosaminyl (N-Acetyl) Transferase 5; N-Acetylglucosaminyltransferase

This gene encodes the enzyme responsible for formation of the blood group I antigen. The i and I antigens are distinguished by linear and branched poly-N-acetyllactosaminoglycans, respectively. The encoded protein is the I-branching enzyme, a beta-1,6-N-acetylglucosaminyltransferase responsible for the conversion of fetal i antigen to adult I antigen in erythrocytes during embryonic development. Mutations in this gene have been associated with adult i blood group phenotype. Alternatively spliced transcript variants encoding different isoforms have been described.