“…Given the pleiotropic effects Abbreviations: BH4, tetrahydrobiopterin; NO, nitric oxide; NOS, nitric oxide synthase; GTP-CH1, guanosine triphosphate cyclohydrolase 1; DRD, DOPA-responsive dystonia; hph-1, hyperphenylalaninemia 1; WT, wild-type; hph, homozygous hph-1; DOPAC, deuterium-labelled 3,4-dihydroxyphenylacetic acid; 5-HIAA, 5-hydroxyindoleacetic acid; 5-HTP, 5-hydroxytryptophan; HVA, homovanillic acid; VMA, Vanillylmandelic acid; DHBA, dihydroxybenzylamine; DA, dopamine; 5-HT, serotonin; NA, noradrenaline; MHPG, 3-methoxy-4-hydroxyphenylglycol; EZM, elevated zero maze; SAP, stretched-attend posture; MB, marble burying; TST, tailsuspension test; FST, forced swim test; ANOVA, analysis of variance; SEM, standard error of the mean; EPM, elevated plus maze. disorder characterised by dystonia-related gait problems (Romstad et al, 2003). Besides this classical clinical manifestation, studies report increased prevalence of anxiety and major depression in DRD patients (Hahn et al, 2001;Van Hove et al, 2006;TrenderGerhard et al, 2009;Tadic et al, 2012).…”