For example, a meta-analysis of two randomized controlled trials and four pre-experimental studies with a total of 100 patients with PD undergoing physical exercise showed a significant increase in BDNF blood levels in parallel with improvement of motor symptoms (e.g., improvement in Unified Parkinson’s disease rating scale-Part III (MDS-UPDRS-III)) [49]. The gene discussed is BDNF; the disease is Parkinson disease.