Many previous studies have shown that the APOE e4 genotype affects cognition, brain volume, glucose metabolism and amyloid deposition. However, these studies were conducted separately, and few studies simultaneously investigated the effects of the APOE e4 genotype on cognition, brain volume, glucose metabolism and amyloid deposition in Alzheimer disease (AD). The purpose of this study is to simultaneously investigate the association of the APOE e4 genotype with cognition, brain volume, glucose metabolism and amyloid deposition in patients with AD.

This is a cross-sectional study of 69 subjects with Alzheimer’s disease (AD). All subjects were divided into carriers and noncarriers of the ε4 allele. Forty APOE ε4 carriers and 29 APOE ε4 non-carriers underwent neuropsychological, structural magnetic resonance imaging, 18F-fluorodeoxyglucose positron emission tomography scans (18F-FDG-PET) and 18F-Florbetaben amyloid positron emission tomography scans (amyloid PET). Analysis of covariance (ANCOVA) was conducted to compare the differences on cognition, brain volume, glucose metabolism and amyloid deposition between APOE ε4 carriers and non-carriers after controlling demographics.

APOE ε4 carriers had 50% lower scores of SVLT_delayed recall compared to non-carriers (0.88 ± 1.65 vs 1.76 ± 1.75). However, APOE ε4 carriers performed better on other cognitive tests than non- carriers (K-BNT (11.04 ± 2.55 vs 9.66 ± 2.82), RCFT (25.73 ± 8.56 vs 20.15 ± 10.82), and Stroop test_color response (48.28 ± 26.33 vs 31.56 ± 27.03)). APOE ε4 carriers had slightly smaller hippocampal volume than non-carriers (3.09 ± 0.38 vs 3.32 ± 0.38), but greater total brain cortical thickness (1.45 ± 1.55 vs 1.37 ± 1.24).

We found that APOE e4 genotype is associated with cognition, brain volume in AD, suggesting that APOE e4 genotype can play a very important role in the underlying pathogenesis of AD.