Yoshino H, et al. - The frequency of guanosine triphosphate cyclohydrolase I (GCH1) mutations and clinical symptoms in patients with clinically diagnosed Parkinson’s disease (PD) and dopa-responsive dystonia (DRD) was examined in this analysis. The Sanger method was used to screen entire exons in 268 subjects with PD and 26 subjects with DRD, with the examinations of brain magnetic resonance imaging scans, striatal dopamine transporter scans, and [123I] metaiodobenzylguanidine (MIBG) myocardiac scintigraphy scans. The results obtained from the study illustrated the clinical characteristics of PD and DRD patients due to GCH1 mutations. Researchers reported that PD patients with GCH1 mutations also had different symptoms from those seen in typical PD. Heterogeneous clinical symptoms were found in patients with GCH1 mutations.