The APOE4 effect: Structural brain differences in Alzheimer's disease according to the age at symptom onset.

Our results show that APOE genotype has a significant effect on GM integrity as a function of age of disease onset. Specifically, while LOAD APOE4 genotype is mostly associated with increased medial temporal and parietal atrophy compared to -LOAD, for EOAD APOE4 might have a more specific effect on subcortical (mammillary body) structures. The findings suggest that APOE genotype needs to be taken into account when classifying patients by age at onset.