Genetic influence of apolipoprotein E4 genotype on hippocampal morphometry: An N = 725 surface-based Alzheimer's disease neuroimaging initiative study.
The apolipoprotein E (APOE) e4 allele is the most prevalent genetic risk factor for Alzheimer's disease (AD). Hippocampal volumes are generally smaller in AD patients carrying the e4 allele compared to e4 noncarriers. Here we examined the effect of APOE e4 on hippocampal morphometry in a large imaging database-the Alzheimer's Disease Neuroimaging Initiative (ADNI). We automatically segmented and constructed hippocampal surfaces from the baseline MR images of 725 subjects with known APOE genotype information including 167 with AD, 354 with mild cognitive impairment (MCI), and 204 normal controls. High-order correspondences between hippocampal surfaces were enforced across subjects with a novel inverse consistent surface fluid registration method. Multivariate statistics consisting of multivariate tensor-based morphometry (mTBM) and radial distance were computed for surface deformation analysis. Using Hotelling's T(2) test, we found significant morphological deformation in APOE e4 carriers relative to noncarriers in the entire cohort as well as in the nondemented (pooled MCI and control) subjects, affecting the left hippocampus more than the right, and this effect was more pronounced in e4 homozygotes than heterozygotes. Our findings are consistent with previous studies that showed e4 carriers exhibit accelerated hippocampal atrophy; we extend these findings to a novel measure of hippocampal morphometry. Hippocampal morphometry has significant potential as an imaging biomarker of early stage AD.
School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, Arizona.
Jie
J
Shi
Natasha
N
Leporé
Boris A
BA
Gutman
Paul M
PM
Thompson
Leslie C
LC
Baxter
Richard J
RJ
Caselli
Yalin
Y
Wang
D000368:Aged; D000544:Alzheimer Disease / Q000235:genetics* / Q000473:pathology*; D053329:Apolipoprotein E2 / Q000235:genetics; D053318:Apolipoprotein E3 / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics*; D060825:Cognitive Dysfunction / Q000235:genetics* / Q000473:pathology*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D007839:Functional Laterality; D006579:Heterozygote; D006624:Hippocampus / Q000473:pathology*; D006720:Homozygote; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D015999:Multivariate Analysis
D053329:Apolipoprotein E2; D053318:Apolipoprotein E3; D053327:Apolipoprotein E4
APOE e4; Alzheimer's disease; MRI; hippocampus; multivariate tensor-based morphometry