Polβ gene expression in PBMCs did not differ between PTSD patients and controls (U = 221.0, p = 0.861, Cohen’s r = 0.03), and in the entire cohort, there were no associations with PTSD symptoms (rS = 0.15, p = 0.454), depressive symptoms (rS = 0.12, p = 0.551), somatic symptoms (rS = -0.03, p = 0.895), and lifetime traumatic event exposure (rS = − 0.21, p = 0.281). This evidence concerns the gene POLB and post-traumatic stress disorder.