It was found that cytokine-cytokine receptor interaction, graft-versus-host disease, inflammatory bowel disease, lipid and atherosclerosis, human immunodeficiency virus type 1 infection, GnRH signaling pathway, sphingolipid signaling pathway, cell cycle, TNF signaling pathway, FOXO signaling pathway, etc. played an important role in T2DM. The gene discussed is GNRH1; the disease is type 2 diabetes mellitus.