Estimates of theta ERO energy of the TFROI were calculated using the S-transform algorithm for 1,064 case-control subjects, producing a mean score of 3.58 ± 1.12 μV and range of 0.86 μV to 8.05 μV. For the two subject classes, cases (N = 640) and controls (N = 424), the means were 3.47 ± 1.12 μV and 3.76 ± 1.11 μV, respectively (P = 3.1 × 10−5). After stringent data cleaning and quality control, GWAS was performed on theta ERO data for 951,071 SNPs, with age, sex and PCs 1 and 2 included as covariates. The quantile-quantile plot of association results for individual SNPs is presented in Figure 3. No strong deviation is observed from the expected distribution of P-values, although some dispersion is evident at the extreme tail. The genomic inflation factor (λ) is 1.0 (corresponding median chi-squared statistic is 0.94), indicating no biased inflation of the test statistic or population stratification artifacts.
