In addition, we did a meta-analysis of 6874 PD patients including 51 GCH1 carriers from 6 studies to evaluate the potential association between the GCH1 deleterious variants and AAO of the patients, which demonstrated that the GCH1 deleterious variants could modify the AAO in PD patients (more than 6 years ahead). The gene discussed is GCH1; the disease is Parkinson disease.