OBJECTIVE
Some individuals avoid Alzheimer's disease (AD) pathology as they age, or retain cognition despite substantial pathology, suggesting mechanisms of resistance or resilience to neurodegeneration. Educational attainment (EA) is associated with reduced risk of cognitive decline, although the underlying mechanisms remain unclear. We investigated whether genome-wide polygenic scores (GPS) based on cognitive and non-cognitive components of EA, reflecting intelligence and behavioral/social traits, respectively, show differential associations with AD diagnosis and neuropathology.
METHODS
Associations between GPS for cognitive and non-cognitive components of EA and AD outcomes were examined across four cohorts: two cohorts included living participants with biomarker assessments (BioHermes-1, n = 770; Alzheimer's Disease Neuroimaging Initiative [ADNI], n = 1,361), and two included postmortem neuropathological evaluations (Religious Orders Study and Rush Memory and Aging Project [ROSMAP], n = 841; Brain for Dementia Research [BDR], n = 511). Outcomes included clinical diagnosis, amyloid status, plasma neurodegenerative biomarkers, and neuropathological measurements.
RESULTS
We found a significant negative association between cognitive EA GPS and clinical diagnosis of AD across all four cohorts and with Braak stage in ROSMAP and BDR cohorts. In contrast, the GPS for non-cognitive component of EA showed no significant association with AD diagnosis, neurodegenerative plasma biomarkers or amyloid positron emission tomography (PET) status and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) scores.
INTERPRETATION
These results suggest a brain maintenance mechanism that supports the brain's ability to resist to changes in neuronal integrity. This indicates that interventions focused on increasing EA solely by additional years of schooling are unlikely to affect AD incidence, whereas alternative approaches targeting the cognitive component of EA (intelligence) may offer greater potential for prevention. ANN NEUROL 2026.
G. Leonenko, K. Mavromati, Lynn Hughes et al.· Annals of Neurology· 0 citations
Copy-number variants (CNVs) are major contributors to human disease. In Alzheimer disease (AD), APP duplications cause autosomal-dominant forms, but the role of CNVs in non-monogenic AD remains poorly characterized. We analyzed rare CNVs (frequency <1%) from 22,319 exomes (4,150 early-onset AD [EOAD, ≤65 years], 8,519 late-onset AD [LOAD], 9,650 unaffected control subjects) using harmonized calling and quality control. After identifying 17 individuals with a pathogenic CNV, we performed exome-wide and gene-set burden analyses. EOAD-affected individuals showed increased burdens of rare CNVs affecting coding genes, particularly deletions in AD-related genes. Integrated loss-of-function (LoF) analysis gathering short truncating variants with deletions showed that ABCA1 (odds ratio [OR] = 5.77 [95% confidence interval 2.25; 17.06], p = 0.0002) and ABCA7 deletions contribute to this deletion burden (OR = 2.29 [1.44; 3.65], p = 0.0006), while CTSB LoF alleles appear as candidates (OR = 5.03 [1.50; 20.71], p = 0.0089). We then performed exome-wide gene-level dosage analysis and highlighted 18 genes across five loci with a false discovery rate of <10%, including the 22q11.21 central region, where deletions were restricted to EOAD (including one de novo event) and duplications were enriched in control individuals, with intermediate frequencies in LOAD. We narrowed this locus to the SCARF2-KLHL22-MED15 region after integrating short truncating variants. Replication in 33,977 affected individuals and 362,322 control subjects confirmed association for 22q11.21 dosage with exome-wide significance (ORSCARF2 = 0.34 [0.21; 0.53]; mega-p value = 5.52 × 10-7). SCARF2 overexpression significantly increased amyloid-β uptake, congruent with duplication-associated decreased AD risk. We conclude that rare coding CNVs in a proportion of AD-associated genes and 22q11.21 deletions, including some found in DiGeorge syndrome, increase AD risk. Conversely, we identify 22q11.21 duplication as a strong AD-risk-decreasing factor.
O. Quenez, Catherine Schramm, K. Cassinari et al.· American Journal of Human Ge...· 1 citation
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