APOE Affects the Volume and Shape of the Amygdala and the Hippocampus in Mild Cognitive Impairment and Alzheimer’s Disease: Age Matters

© 2015 - IOS Press and the authors. All rights reserved. This paper examines how age intervenes in the effects of APOE ε4 allele on the volume and shape morphometrics of the hippocampus and the amygdala in mild cognitive impairment (MCI) and Alzheimer's disease. We evaluate the structural morphological differences between ε4 carriers and non-carriers in two age-dependent subgroups; younger than 75 years (Young- Old) and older than 80 years (Very-Old). While we show that the four structures of interest atrophy significantly in the ε4 carriers, relative to the non-carriers, of the Young-Old group, this effect is not observed in their Very-Old counterparts.Tthe structures in the right hemisphere are found to be more affected by the APOE genotype than those in the left hemisphere and we identify the relevant regions in which significant atrophy occurs to be parts of the basolateral, centromedial, and lateral nucleus subregions of the amygdala and the CA1 and subiculum subregions of the hippocampus. We also observe that the APOE genotype only affects MCI patients that deteriorated to dementia within 3 years while leaving their "non-converting" counterparts unaffected.