Since N-acetylaspartate plays multiple roles in brain homeostasis (including regulation of brain fluid balance and acts as a precursor for the neuronal dipeptide N-Acetylaspartylglutamate) [19,20,21,22], the aim of this study is to investigate the possible causative relationship between Cathepsin B and PD, analyzing the role of N-acetylaspartate as a mediator. The gene discussed is CTSB; the disease is Parkinson disease.