However, the positive association between cortical superficial siderosis with APOE ε2, but not APOE ε4, shown in a study in cerebral amyloid angiopathy patients is interesting and may suggest that the underlying pathophysiologic mechanism giving rise to cortical superficial siderosis differs from that giving rise to CMBs in cerebral amyloid angiopathy (Shoamanesh et al., 2014). The gene discussed is APOE; the disease is cerebral amyloid angiopathy.