Next, we restricted the GWAS analyses to PTSD control subjects with self-reported traumatic experiences. A total of 468 EAs and 933 AAs who did not report any traumatic events were excluded, leaving 1110 EAs and 1833 AAs for analyses. Distribution of different types of trauma exposure in EAs and in AAs is shown in Figure S1 in Supplement 1. In both populations, witnessed someone being badly injured or killed was the most reported trauma experience, followed by seriously physically attacked or assaulted. In EAs, 32% reported one traumatic experience, 23% reported two traumatic experiences, and 45% reported three or more traumatic experiences. The distribution in AAs was very similar (Figure S2 in Supplement 1). In EAs and AAs, 768,784 SNPs and 871,502 SNPs, respectively, passed quality control steps. The threshold of genome-wide significance was 6.50×10−8 for EAs and 5.74×10−8 for AAs. The genomic inflation factor λs were 1.017 and 1.007 for EAs and AAs, respectively. The quartile-quartile plots are shown in Figure 1C, D. Despite restricting the control subjects to trauma exposed subjects, which removed nearly one third of the
