APOE and Alzheimer disease: A recent study using the A/T/N system showed that participants with A+ were twice as often APOE ε4 carriers than participants without A+.31 In line with some previous studies, carriage of APOE ε4 was related to AR-AD and preclinical AD according to Dubois, as well as stage 1 and stage 2 according to NIA-AA and asymptomatic at risk for Alzheimer disease according to IWG-2 criteria.