APOE and Alzheimer disease: In addition, the genotyping results confirmed that the frequency of the GSTO1*C allele count as well as the homozygote genotype GSTO1*C were higher in platelet study cohorts, especially in APOE ε4 allele–negative AD patients (OR = 5.2; p = 2.9E−5) and in APOE ε4 allele–negative MCI patients (OR = 2.2; p = 0.022) compared to controls (Table S2).