MAO-A and MAO-B inhibitor drugs are primarily prescribed for the control of emotional behavior (e.g. depression and anxiety disorders) and neurodegenerative diseases (e.g. Parkinson’s disease, Alzheimer’s, and possibly amyotrophic lateral sclerosis and Huntington’s diseases) (Bortolato et al., 2008; Dlugos et al., 2009; Bortolato and Shih, 2011; Youdim et al., 2006; Al-Nuaimi et al., 2012; Tripathi et al., 2018). The gene discussed is MAOA; the disease is Parkinson disease.