In patients with ADHD, a polymorphism of the DRD4 gene, which is associated with decreased functional activity of the dopamine D4-receptor (Asghari et al., 1995), was related to altered performance on tasks with an inhibitory component (Langley et al., 2004; Bellgrove et al., 2005), impaired performance on the Stroop task (Loo et al., 2008), and reduced prefrontal cortical thickness (Shaw et al., 2007). The gene discussed is DRD4; the disease is attention deficit-hyperactivity disorder.