Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele.

Genetic discoveries of Alzheimer’s disease are the drivers of our understanding, and together with polygenetic risk stratification can contribute towards planning of feasible and efficient preventive and curative clinical trials. We first perform a large genetic association study by merging all available case-control datasets and by-proxy study results (discovery n = 409,435 and validation size n = 58,190). Here, we add six variants associated with Alzheimer’s disease risk (near APP, CHRNE, PRKD3/NDUFAF7, PLCG2 and two exonic variants in the SHARPIN gene). Assessment of the polygenic risk score and stratifying by APOE reveal a 4 to 5.5 years difference in median age at onset of Alzheimer’s disease patients in APOE ɛ4 carriers. Because of this study, the underlying mechanisms of APP can be studied to refine the amyloid cascade and the polygenic risk score provides a tool to select individuals at high risk of Alzheimer’s disease.

We study theoretically the linear conductance of a quantum dot connected to ferromagnetic leads. The dot level is split due to a non-collinear magnetic field or intrinsic magnetization. The system is studied in the non-interacting approximation, where an exact solution is given, and, furthermore, with Coulomb correlations in the weak tunneling limit. For the non-interacting case, we find an anti-resonance for a particular direction of the applied field, non-collinear to the parallel magnetization directions of the leads. The anti-resonance is destroyed by the correlations, giving rise to an interaction induced enhancement of the conductance. The angular dependence of the conductance is thus distinctly different for the interacting and non-interacting cases when the magnetizations of the leads are parallel. However, for anti-parallel lead magnetizations the interactions do not alter the angle dependence significantly.

Aims In observational studies, type-2 diabetes is associated with increased risk of dementia; however, the causal nature of this association remains unanswered. In an unselected nationwide study of all Danes, we wanted to test whether type-2 diabetes is associated with dementia subtypes, and to test whether potential associations are of a causal nature. Methods In the current study of nationwide observational registry data in all Danes above the age of 65 years (n = 784 434) combined with genetic consortia data on 213 370 individuals, we investigated the associations between type-2 diabetes and Alzheimer's disease, vascular dementia, unspecified dementia and all-cause dementia, and whether observational associations were of a causal nature by applying a two-sample Mendelian randomisation strategy. We addressed key biases inherent in Mendelian randomisation approaches. Results Important confounders (age, ethnicity, size of community, region, civil status and education level) were captured on all 784 434 individuals and adjusted for in the models. Multifactorial adjusted hazard ratios were 1.13 (1.06–1.21) for Alzheimer's disease, 1.98 (1.83–2.14) for vascular dementia, 1.53 (1.48–1.59) for unspecified dementia and 1.48 (1.44–1.53) for all-cause dementia in persons with type-2 diabetes v. without. Results were similar for men and women. The two-sample Mendelian randomisation estimate for the association between the genetic instrument and Alzheimer's disease was 1.04 (0.98–1.10), consistent with sensitivity estimates, addressing pleiotropy, measurement bias and weak instrument bias. Conclusions In a nationwide study of all Danes above the age of 65 years, we show that type-2 diabetes is associated with major subtypes of dementia – with particularly strong associations for vascular dementia and unspecified dementia – the two types of dementia with the most obvious vascular pathologies. Although the present two-sample Mendelian randomisation approach using genetic consortia data suggests that type-2 diabetes is not a direct cause of Alzheimer's disease, we were unable to test the causal nature of type-2 diabetes for vascular dementia and unspecified dementia, because no publicly available genetic consortia data yet exist for these dementia endpoints. The causal nature of type-2 diabetes for dementia with vascular pathologies is pivotal questions to solve for future public health recommendations and therapeutic advice.

Introduction Increased plasma levels of C‐reactive protein (CRP) in midlife are associated with increased risk of Alzheimer's disease (AD), whereas in older age the opposite association is observed. Whether genetically determined CRP is associated with AD remains unclear. Methods A total of 111,242 White individuals from the Copenhagen General Population Study and the Copenhagen City Heart Study were included. Plasma levels of CRP and four regulatory genetic variants in the CRP gene were determined. Results For CRP percentile group 1 to 5 (lowest plasma CRP) versus the 50 to 75 group (reference), the hazard ratio for AD was 1.69 (95% confidence interval 1.29–2.16). Genetically low CRP was associated with increased risk of AD in individuals with body mass index ≤25 kg/m2 (P = 4 × 10−6). Discussion Low plasma levels of CRP at baseline were associated with high risk of AD in individuals from the general population. These observational findings were supported by genetic studies.

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.

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IMPORTANCEThe APOE ε2 and APOE ε4 alleles are the strongest protective and risk-increasing, respectively, genetic variants for late-onset Alzheimer disease (AD). However, the mechanisms linking APOE to AD-particularly the apoE protein's role in AD pathogenesis and how this is affected by APOE variants-remain poorly understood. Identifying missense variants in addition to APOE ε2 and APOE ε4 could provide critical new insights, but given the low frequency of additional missense variants, AD genetic cohorts have previously been too small to interrogate this question robustly. OBJECTIVE To determine whether rare missense variants on APOE are associated with AD risk.DESIGN, SETTING, AND PARTICIPANTS Association with case-control status was tested in a sequenced discovery sample (stage 1) and followed up in several microarray imputed cohorts as well as the UK Biobank whole-exome sequencing resource using a proxy-AD phenotype (stages 2 and 3). This study combined case-control, family-based, population-based, and longitudinal AD-related cohorts that recruited referred and volunteer participants. Stage 1 included 37 409 nonunique participants of European or admixed European ancestry, with 11 868 individuals with AD and 11 934 controls passing analysis inclusion criteria. In stages 2 and 3, 475 473 participants were considered across 8 cohorts, of which 84 513 individuals with AD and proxy-AD and 328 372 controls passed inclusion criteria. Selection criteria were cohort specific, and this study was performed a posteriori on individuals who were genotyped. Among the available genotypes, 76 195 were excluded. All data were retrieved between September 2015 and November 2021 and analyzed between April and November 2021. MAIN OUTCOMES AND MEASURESIn primary analyses, the AD risk associated with each missense variant was estimated, as appropriate, with either linear mixed-model regression or logistic regression. In secondary analyses, associations were estimated with age at onset using linear mixed-model regression and risk of conversion to AD using competing-risk regression.RESULTS A total of 544 384 participants were analyzed in the primary case-control analysis; 312 476 (57.4%) were female, and the mean (SD; range) age was 64.9 (15.2; 40-110) years. Two missense variants were associated with a 2-fold to 3-fold decreased AD risk: APOE ε4 (R251G) (odds ratio, 0.44; 95% CI, 0.33-0.59; P = 4.7 × 10 −8 ) and APOE ε3 (V236E) (odds ratio, 0.37; 95% CI, 0.25-0.56; P = 1.9 × 10 −6 ). Additionally, the cumulative incidence of AD in carriers of these variants was found to grow more slowly with age compared with noncarriers. CONCLUSIONS AND RELEVANCEIn this genetic association study, a novel variant associated with AD was identified: R251G always coinherited with ε4 on the APOE gene, which mitigates the ε4-associated AD risk. The protective effect of the V236E variant, which is always coinherited with ε3 on the APOE gene, was also confirmed. The location of these variants confirms that the carboxyl-terminal portion of apoE plays an impo...