We included 60 MCI patients with APOE ε3/ε3, 18 MCI patients with APOE ε2/ε3, 73 CN subjects with APOE ε3/ε3, and 36 CN subjects with APOE ε2/ε3 genotypes who had resting‐state functional magnetic resonance imaging data from the Alzheimer's disease Neuroimaging Initiative. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.