To determine whether the ADHD gene set preferentially contained genes of neurological significance, we first looked for evidence in the literature for prior implication of these genes in neuropsychiatric disorders. An independent, systematic assessment of MEDLINE abstracts, HUGE Navigator, the autism gene database AutsDB and the candidate gene database SchizophreniaGene showed that genes implicated in autism and/or schizophrenia in any of these resources were significantly enriched in ADHD CNV genes (Table 1), but not for other brain-related disorders (Supplementary Table S2). Manual review of literature associated with the 175 genes determined that at least 22 (28 total CNVs) of these genes were previously implicated by genetic studies in various neurological and neuropsychiatric disorders (Tables 2 and 3), including Tourette syndrome (two genes), autism (four genes) and schizophrenia (15 genes). Furthermore, eight of these 22 genes (11 total CNVs) have been very recently identified in structural variation studies carried out on autism and schizophrenia cohorts: A2BP1, PARK2, NKAIN2, DPP6, CNTNAP2, IMMP2L, AUTS2 and GRM7.
