transient tyrosinemia of the newborn (Monarch Disease Ontology id MONDO_0018083) is a benign disorder of tyrosine metabolism detected upon newborn screening and often observed in premature infants. It shows no clinical symptoms. It is characterized by tyrosinemia, moderate hyperphenylalaninemia, and tyrosiluria that usually resolve after 2 months of age. Also known as: transient neonatal tyrosinemia, transient tyrosinemia of the neonate.