Among 547 patients with ischemic stroke and 350 controls, matrix‐assisted laser desorption/ionization time of flight mass spectrometry was used to examine eight variants arising from four different genes, including MMP‐1 (rs1799750), MMP‐2 (rs243865, rs2285053, rs2241145), MMP‐9 (rs17576), and MMP‐12 (rs660599, rs2276109, and rs652438). The gene discussed is MMP9; the disease is ischemic stroke.