The brain’s primary antioxidant, glutathione, is dysregulated in patients with PTSD, [21] and downregulation of the Glutathione-S-Transferase Mu1 & 2 genes, responsible for encoding enzymes involved in conjugation reactions with glutathione, is considered the most reliable blood-based biomarker for PTSD [22]. This evidence concerns the gene HPGDS and post-traumatic stress disorder.