The results from the GWAS and follow-up analyses implicate several genes influencing theta EROs that were not detected by previous linkage and association studies (Table III). Based on combined P-values, the most significant marker to emerge is rs4907240 located downstream of ARID5A (P = 3.7 × 10−6), with effect sizes of 0.25 ± 0.06 μV and 0.10 ± 0.06 μV for the minor allele in the GWAS and replication, respectively. The protein encoded by ARID5A belongs to a family of diverse proteins with recognized roles in development, tissue-specific gene expression, and cellular growth regulation [Wilsker et al., 2002; Patsialou et al., 2005], although with no reported role in brain development or neuroelectrical activity. In contrast, the next top-ranked SNP, rs13831, is within the 3′ UTR of GNAS1 (estimated coefficients of −0.21 ± 0.05 μV and −0.15 ± 0.05 μV), a locus with a complex, imprinted expression pattern for multiple transcripts, including the G-protein alpha subunit (GSα) involved in the cellular actions of neurotransmitters, autocrine/paracrine factors, and hormones [Bastepe, 2007; Plagge et al., 2008], as well as neuroendocrine secretory protein 55
