To evaluate the topographic specificity of the significant findings of KCNJ6 SNPs with the theta ERO phenotype at Fz, we investigated the association of SNPs in KCNJ6 with theta ERO power at the central midline (Cz) and parietal midline (Pz) channels. The association analysis results for Cz and Pz for KCNJ6 SNPs did not reach genome-wide significance levels, nor yield as many P-values < 1 × 10−4 as Fz. There are 15 SNPs with P-values < 1 × 10−4 for Fz while there is only one for Cz and none for Pz. The most significant SNP for Fz, rs2835872, was also most significant for Cz (6.00 × 10-5). The SNP with the lowest P-value for Pz, rs2835850, (P = 1.10 × 10−4), reached genome-wide significance for Fz. This suggests that the theta oscillations in all three regions shared a genetic determinant in KCNJ6, and that the frontal channel shows the strongest signal.
