APOE and early-onset autosomal dominant Alzheimer disease: The APOE is the prime suspect as it is associated with a shorter lifespan41 and with other ‘killers’ in the population such as heart disease and stroke.42–44 It has been reported that APOE-ɛ4ɛ4 carriers have an age at onset of Alzheimer’s disease of about 16 years earlier than APOE-ɛ4 non-carriers, and that the frequency of APOE-ɛ4 reduces with age from ∼0.18 in the general population to 0.1 in the age group 85+.37 Despite this reduced APOE-ɛ4 frequency in the very old (85+), Alzheimer’s disease prevalence is higher in this latter age group.