CCL2, CCL22, CCL15, and CXCL2 were significantly higher in case post than in case–control pre, while CCL25 and CXCL12 were significantly lower in case post than in case–control pre, indicating those up- and downregulated chemokines were potential markers for PTSD onset. The gene discussed is CXCL12; the disease is post-traumatic stress disorder.