SLC6A3 and attention deficit-hyperactivity disorder: For instance, several studies have reported an increased density of DAT in children and adults diagnosed with ADHD (Cheon et al., 2003; Krause et al., 2003) and meta-analytic studies have found significant associations between the 10r allele of the DAT1 and ADHD (Yang et al., 2007; Gizer et al., 2009; although see Rommelse et al., 2008 for contradictory results).