Crigler-Najjar syndrome type 2 (Monarch Disease Ontology entry MONDO_0011725) can be described as follows. Type 2 Crigler-Najjar syndrome (CNS2) is a hereditary disorder of bilirubin metabolism characterized by unconjugated hyperbilirubinemia due to reduced and inducible activity of hepatic bilirubin glucuronosyltransferase (GT). CNS2 is a milder form of CNS than CNS1. Also known as: Arias syndrome, UGT deficiency type 2, bilirubin uridinediphosphate glucuronosyltransferase deficiency type 2, bilirubin-UGT deficiency type 2, hereditary unconjugated hyperbilirubinemia type 2.