Notable serum peptide/protein changes (levels up or down in the two comparative groups) observed in panel I [shaded] with respect to post-traumatic neurological issues include GRM4 (glutamate receptor-4) and PCLO (protein Piccolo) which were previously suggested as biomarkers for major depression and possibly PTSD [36–38]. The gene discussed is PCLO; the disease is post-traumatic stress disorder.