ARC and attention deficit-hyperactivity disorder: In the current study, we assemble five ADHD and control CNV data sets from the United Kingdom, Ireland, Northern Europe, United States of America and Canada.10 Our aim was to test the hypothesis that ADHD-associated CNVs show enrichment for gene sets that have been: (a) implicated by SNVs in the most recent, largest schizophrenia and autism de novo exome-sequencing studies20, 21, 22, 23 and (b) selected for function involving ARC, NMDAR and FMRP targets.