In the early phase of PD, DA agonists, monoamine oxidase B (MAO-B) and anticholinergic agents can be used for treatment and later catechol-O-methyltransferase inhibitors can be combined with levodopa to increase its half-life in order to delay its adverse effects, but in the long term, they no longer have sustained efficacy [13]. This evidence concerns the gene MAOB and Parkinson disease.