GCNT1 (Glucosaminyl (N-Acetyl) Transferase 1): GCNT1 is a gene that encodes an enzyme involved in the biosynthesis of mucins, essential components of mucus. It plays a role in modifying glycoproteins, affecting cell signalling and immune function. Altered GCNT1 activity has been associated with conditions such as cystic fibrosis and certain cancers.