Specifically, we investigated regional associations between the ApoE ε4 genotype and longitudinal changes in glucose uptake, measured using FDG PET, over a median 72-month follow-up period in 48 subjects with MCI (24 ApoE ε4 carriers and 24 non-carriers) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Here, APOE is linked to early-onset autosomal dominant Alzheimer disease.