In a more recent case–control study, T2DM patients were more likely to be APOE4+ or have ε3/ε4 genotype compared to controls, especially in those with CHD or cerebral infarction, while the ε2/ε3 genotype was more common in T2DM patients with diabetic nephropathy (28). Here, APOE is linked to type 2 diabetes mellitus.