There were no significant differences in the methylation of CpG1 (U = 4353.5; p = 0.214), CpG2 (U = 4247.0; p = 0.131) or CpG3 (U = 4718.0; p = 0.740) sites between the patients with PTSD and control subjects; however, to check for an association between CpG methylation and HNF1A polymorphisms due to differences in the distribution of HNF1A-AS1 rs7953249 genotypes between the two diagnostic groups, analysis was performed separately in the PTSD patients and control subjects. This evidence concerns the gene HNF1A and post-traumatic stress disorder.