Although data on the risk from COL4A1/2 mutations for future intracerebral hemorrhage or ischemic stroke remain limited, these mutations might increase the intracranial hemorrhagic risk in anticoagulated patients: one patient carrying COL4A1 mutation p.G562E died at age 40 after a spontaneous cerebral hemorrhage while on oral anticoagulation.25,26 The intracranial bleeding risk during IV thrombolysis in patients carrying COL4A1/COL4A2 mutations also needs consideration. The gene discussed is COL4A1; the disease is ischemic stroke.