Studies have found the significant interaction of SCD and APOE ε4, in which SCD APOE ε4 carriers performed worse on the episodic memory and showed smaller left hippocampal volumes [18], while other studies have not observed the differences associated with APOE ε4 statue in glucose metabolism and medial temporal lobe atrophy in SCD [19]. The gene discussed is APOE; the disease is Schnyder corneal dystrophy.