Provided is a method for predicting probability of ischemic stroke onset. A method for predicting a risk of ischemic stroke onset, the method comprising: a detection step of detecting presence or absence of a RNF213 p.R4810K gene variant in a sample derived from a test subject who does not develop ischemic stroke; and a determination step of determining whether a probability of ischemic stroke onset of the test subject is high or not, based on the presence or absence of the RNF213 p.R4810K gene variant in the detection step, and gender information of the test subject. A genetic marker for predicting a risk of ischemic stroke onset using gender information, comprising a RNF213 p.R4810K gene variant. A biomarker for predicting a risk of ischemic stroke onset using gender information, comprising a polypeptide encoded by a RNF213 p.R4810K gene variant.
