The QQ-plot of observed versus expected p-values presented in Figure 1 demonstrates that there was no appreciable inflation of the test statistic in the analyzed sample, as the mean chi-square was very close to 1.0 (1.005) and lambda was 1.0. Our smallest p-value (6.7E-07) did not reach the threshold for genome-wide statistical significance (i.e., 5.0E-08). The 20 most significant results are presented in Table 3. These top hits contain one SNP in an ADHD candidate gene (SLC9A9) with an associated significance level (6.4E-6) comparable to that observed in other studies.
