Increased BBB permeability facilitates endothelin-1 (ET-1) and plasminogen activator inhibitor 1 (PAI-1) extravasation and interaction with their respective receptors in the stress-processing pathways, predisposing to PTSD (Kurihara et al., 2000; Jiang et al., 2016; Chen et al., 2017a; Bouarab et al., 2021). The gene discussed is EDN1; the disease is post-traumatic stress disorder.