The AD group did not significantly differ with respect to the presence of APOE4 alleles from the MCI group (p = 0.765), but had significantly lower MMSE scores (compared with CU group, p = 1.24 × 10−90; MCI group, p = 1.61 × 10−40) and a different presence of APOE4 alleles compared with the CU group (p = 0.014). The gene discussed is APOE; the disease is Alzheimer disease.