The prodromal AD group presented an older age (p < 0.001), a highest percentage of amnestic (p = 0.001) and probable (p < 0.001) MCI subtypes, the presence of the APOE ε4 allele (p < 0.001) and lower MMSE scores (p = 0.026), as expected (Table 2). This evidence concerns the gene APOE and Alzheimer disease.