MPO (R = −0.566, p = 0.044) and MMP-9 (R = −0.441, p = 0.05) were negatively correlated and TIMP-1 (R = 0.367, p = 0.089) was marginally positively correlated with duration of PTSD illness (see Figure 3). The gene discussed is MMP9; the disease is post-traumatic stress disorder.