In the no-PTSD control group, MMP-2 exhibited a notable positive correlation with the PSSI-5 increased arousal and reactivity domain (rho = 0.53), indicating that higher MMP-2 levels were associated with increased hypervigilance and irritability, even in the absence of a PTSD diagnosis (see Figure 3). The gene discussed is MMP2; the disease is post-traumatic stress disorder.