APOE and Alzheimer disease: Therefore, to explore our results in greater depth, we divided our sample set regarding APOE ε4 status in each group of subjects as follows: patients with AD APOE ε4 carriers (n = 19; 58%), patients with AD APOE ε4 non-carriers (n = 14; 42%), control APOE ε4 carriers (n = 3; 10%), and control APOE ε4 non-carriers (n = 27; 90%).