UQCC2 and attention deficit-hyperactivity disorder: Nine of those genes were highlighted in our study, three of which showing association with rare variants related to the severity of ADHD symptoms (KIF11, WAC, and CRBN) and six carrying common genetic variants that are associated with ADHD (MANBA, UQCC2, HIVEP2, FOPX1, KANSL1, and AUH).