Besides, neutrophil has proved to be a critical source of matrix metalloproteinase‐9 (MMP‐9) within 24 h of AIS, while MMP‐9 is closely related to blood–brain barrier destruction, brain tissue edema, hemorrhagic transformation, and neurological impairment after AIS (Castellanos et al., 2003; Montaner et al., 2001). The gene discussed is MMP9; the disease is androgen insensitivity syndrome.