In addition to PTPRD and GRM5, several genes in our ADHD CNV gene set are notable, particularly those eight previously reported to have CNVs in another neuropsychiatric disorder (Tables 2 and 3). The A2BP1 gene, whose protein product binds to the ataxin-2 gene responsible for spinocerebellar ataxia-2, was found overlapping with three rare inherited copy number changes in our ADHD probands, and it was also seen in rare de novo copy number changes involving only this gene in a schizophrenic and an autistic proband. Translocations and CNVs disrupting A2BP1 have been reported in patients with autism, schizophrenia, epilepsy and mental retardation. The PARK2, NKAIN2 and DPP6 genes were found overlapping with separate rare inherited copy number changes in our study as well as in CNVs overlapping only the same respective genes in a schizophrenia study. Genomic deletions of the neurexin superfamily gene, CNTNAP2, were also identified in three individuals with schizophrenia and epilepsy. Allelic variants of the CNTNAP2 gene have been found to be associated with autism in three recent studies. Chromosomal rearrangements of both the CNTNAP2 and IMMP2L genes
