DRD5 and attention deficit-hyperactivity disorder: Finally, we note that genes associated with ADHD susceptibility, such as DRD5 that encodes dopamine receptor 5 (Manor et al., 2004) and SLC6A3 that encodes dopamine transporter 1 (Faraone et al., 2014), are both located in close proximity to the SLC7A11 located on chromosome 4.