APOE ε2 Allele Is Associated with Larger Regional Cortical Thicknesses and Volumes

Abstract

Background: The protective effect of the apolipoprotein E (APOE) Ε2 allele against Alzheimer’s disease (AD) is controversial. Objective: Our purpose was to clarify if the Ε2 allele affects regional cortical thicknesses and volumes. Methods: Regional cortical thicknesses and volumes were measured with an automated pipeline in 109 subjects with mild cognitive impairment, 114 AD patients and 105 age-matched healthy controls. Results: In the mild cognitive impairment group, the Ε2 carriers had thicker regional cortices at the transverse temporal cortex and parahippocampal gyrus than the subjects with Ε3/Ε3, and a larger cerebral gray matter and smaller lateral ventricles than the Ε3/Ε3 and Ε4 carriers. In the AD group, the Ε2 carriers had significantly thicker entorhinal and transverse temporal cortices, a larger whole cerebral gray matter, and smaller lateral ventricles than the subjects with the Ε3/Ε3 genotype, and a significantly thicker entorhinal cortex and larger cerebral gray matter than Ε4 carriers. No APOE2 effect was found in the control group. Conclusion: The APOE Ε2 allele is associated with larger regional cortical thicknesses and volumes in mild cognitive impairment and AD.