Associations between APOE-TOMM40 '523 haplotypes and limbic system white matter microstructure
- PMID: 40201595
- PMCID: PMC11973251
- DOI: 10.1002/dad2.70099
Associations between APOE-TOMM40 '523 haplotypes and limbic system white matter microstructure
Abstract
Introduction: We assessed associations between apolipoprotein E Translocase of Outer Mitochondrial Membrane 40 (APOE-TOMM40)-'523 haplotypes and white matter microstructure (WMM) across limbic tracts important for memory and cognition in non-Hispanic Black and White individuals.
Methods: Linear regression models, stratified by APOE and racialized groups, assessed associations between TOMM40-'523-S and limbic tract WMM free-water (FW) and free-water-corrected fractional anisotropy (FAFWcorr).
Results: Black-ε4+-one-'523-S carriers had lower FW in the cingulum and inferior longitudinal fasciculus compared to Black-ε4+-no-'523-S carriers. Additionally, Black-ε4+-one-'523-S carriers had lower FW in the cingulum, uncinate, and fornix, and higher FAFWcorr in the uncinate compared to Black-ε4+-'523-S/S carriers. White-ε3/ε3-'523-S/S carriers had lower FAFWcorr in the cingulum and inferior temporal gyrus compared to White-ε3/ε3-no-'523-S carriers, and lower FAFWcorr in the cingulum compared to White-ε3/ε3-one-'523-S carriers.
Discussion: This supports prior work that '523-S is associated with abnormal aging in White-ε3/ε3 carriers, but is potentially risk-mitigating in Black-ε4+ carriers, while suggesting a differential effect by racialized background of APOE on WMM.
Highlights: White matter microstructure (WMM) across limbic tracts important for cognition was measured by diffusion MRI.Black apolipoprotein E (APOE) ε4+ carriers with one copy of TOMM40-'523-S had normal aging WMM metrics across several tracts, including the cingulum bundle, uncinate fasciculus, fornix, and inferior longitudinal fasciculus.White APOE ε3/ε3 carriers with two copies of TOMM40-'523-S had abnormal aging WMM metrics in the cingulum bundle and inferior temporal gyrus.APOE associations with aging may differ in racialized groups due to TOMM40-'523-S copy number.
Keywords: APOE; Alzheimer's disease (AD); Minority Aging Research Study; Rush Memory and Aging Project; TOMM40; aging; diffusion magnetic resonance imaging (dMRI); free water corrected metrics; genetic risk factors; limbic system tracts; white matter microstructure (WMM).
© 2025 The Author(s). Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.
Conflict of interest statement
Dr. Lisa Barnes (co‐author) serves as the Deputy Editor of “Alzheimer's & Dementia.” Dr. Timothy Hohman (co‐author) serves as the Deputy Editor for “Alzheimer's & Dementia: Translational Research and Clinical Intervention,” Senior Associate Editor for “Alzheimer's & Dementia,” and served on the Scientific Advisory Board for “Vivid Genomics.” No other competing interests were declared by the authors. Author disclosures are available in the supporting information.
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