Vanicek et al. found significant differences in the expression of 5-HT transporters in the anterior cingulate cortex and hippocampus of ADHD patients compared to the normal population, indicating that the coupling ability of 5-HT transporters in the anterior cingulate cortex and hippocampus may have been altered [41]. The gene discussed is SLC6A4; the disease is attention deficit-hyperactivity disorder.