The -2518A/G (rs1024611) polymorphism is located in the distal regulatory region of the MCP-1 gene relative to the major transcriptional start site of the gene that can influence the transcriptional activity of MCP-1 and contributes to susceptibility to multiple sclerosis, Alzheimer's disease, and major depressive disorder [18–21]. The gene discussed is CCL2; the disease is major depressive disorder.