In the case of a patient with multiple-site embolism, genetic fibrinolytic disorder (specifically PAI-1 4G/5G and MTHFR C677T mutations), and unique characteristics of anticoagulation therapy, it is crucial to prioritize early screening for viral infections (EBV/CMV) and hypercoagulable-related genetic factors to elucidate the etiology and thrombotic propensity. This evidence concerns the gene MTHFR and viral infectious disease.