DAO and schizophrenia: For example, transcripts encoding the cadherin Fat2, which plays an important role in cerebellum development, the amino acid oxidase Dao, which may be involved in schizophrenia, the tryptophan hydroxylase 2 (Tph2), which is responsible for the biosynthesis of serotonin, the dopamine β-hydroxylase (Dbh), which converts dopamine to norepinephrine, the inhibitory neurotransmitter Gabra6 and the neurotransmitter transporters Slc6a2, Slc6a4 and Slc6a5 were expressed predominantly in the brainstem.