Another study from the same group on the effect of DRD4 (4R/4 R vs. 2R) gene polymorphism on ReHo and functional connectivity in ADHD patients found that the presence of the DRD4 2R allele had both increased and decreased ReHo bilaterally in the cerebellum and the left angular gyrus, respectively. Here, DRD4 is linked to attention deficit-hyperactivity disorder.