The monoamine oxidase A gene (MAOA), located on the X-chromosome, encodes an enzyme that metabolizes monoamine neurotransmitters, including dopamine, norepinephrine, and serotonin (Shih & Thompson, 1999). The MAOA gene has a polymorphism in the promoter (regulatory) region (MAOA-LPR) that affects gene activity (Sabol, Hu, & Hamer, 1998). The low-activity variant has been implicated in increased sensitivity to environmental stressors (Meyer-Lindenberg et al., 2006).
