%0 Journal Article %J J Alzheimers Dis %D 2022 %T Investigating Casual Associations Among Gut Microbiota, Metabolites, and Neurodegenerative Diseases: A Mendelian Randomization Study. %A Ning, Jing %A Huang, Shu-Yi %A Chen, Shi-Dong %A Zhang, Ya-Ru %A Huang, Yu-Yuan %A Yu, Jin-Tai %K Alzheimer Disease %K Amyotrophic Lateral Sclerosis %K Gastrointestinal Microbiome %K Genome-Wide Association Study %K Humans %K Mendelian Randomization Analysis %K Neurodegenerative Diseases %K Parkinson Disease %K Risk Factors %K Serotonin %X

BACKGROUND: Recent studies had explored that gut microbiota was associated with neurodegenerative diseases (including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS)) through the gut-brain axis, among which metabolic pathways played an important role. However, the underlying causality remained unclear.

OBJECTIVE: Our study aimed to evaluate potential causal relationships between gut microbiota, metabolites, and neurodegenerative diseases through Mendelian randomization (MR) approach.

METHODS: We selected genetic variants associated with gut microbiota traits (N = 18,340) and gut microbiota-derived metabolites (N = 7,824) from genome-wide association studies. Summary statistics of neurodegenerative diseases were obtained from IGAP (AD, 17,008 cases; 37,154 controls), IPDGC (PD, 37,688 cases; 141,779 controls), and IALSC (ALS, 20,806 cases; 59,804 controls) respectively.

RESULTS: Greater abundance of Ruminococcus (OR, 1.245; 95% CI, 1.103-1.405; p = 0.0004) was found significantly related to higher risk of ALS. Besides, our study found suggestive associations of Actinobacteria, Lactobacillaceae, Faecalibacterium, Ruminiclostridium, and Lachnoclostridium with AD, of Lentisphaerae, Lentisphaeria, Oxalobacteraceae, Victivallales, Bacillales, Eubacteriumhalliigroup, Anaerostipes, and Clostridiumsensustricto1 with PD, and of Lachnospira, Fusicatenibacter, Catenibacterium, and Ruminococcusgnavusgroup with ALS. Our study also revealed suggestive associations between 12 gut microbiome-dependent metabolites and neurodegenerative diseases. Glutamine was related to lower risk of AD. For the serotonin pathway, serotonin was found as a protective factor of PD, while kynurenine as a risk factor for ALS.

CONCLUSION: Our study firstly applied a two-sample MR approach to detect causal relationships among gut microbiota, gut metabolites, and neurodegenerative diseases. Our findings may provide new targets for treatments and may offer valuable insights for further studies on the underlying mechanisms.

%B J Alzheimers Dis %V 87 %P 211-222 %8 2022 %G eng %N 1 %1 https://www.ncbi.nlm.nih.gov/pubmed/35275534?dopt=Abstract %R 10.3233/JAD-215411 %0 Journal Article %J J Alzheimers Dis %D 2022 %T Investigating Causal Relations Between Circulating Metabolites and Alzheimer's Disease: A Mendelian Randomization Study. %A Huang, Shu-Yi %A Yang, Yu-Xiang %A Zhang, Ya-Ru %A Kuo, Kevin %A Li, Hong-Qi %A Shen, Xue-Ning %A Chen, Shi-Dong %A Chen, Ke-Liang %A Dong, Qiang %A Tan, Lan %A Yu, Jin-Tai %K Alzheimer Disease %K Apolipoproteins B %K Cholesterol %K Genome-Wide Association Study %K Glutamine %K Humans %K Mendelian Randomization Analysis %K Polymorphism, Single Nucleotide %K Risk Factors %X

BACKGROUND: Metabolomics is a promising approach that can be used to understand pathophysiological pathways of Alzheimer's disease (AD). However, the causal relationships between metabolism and AD are poorly understood.

OBJECTIVE: We aimed to investigate the causal association between circulating metabolites and risk of AD through two-sample Mendelian randomization (MR) approach.

METHODS: Genetic associations with 123 circulating metabolic traits were utilized as exposures. Summary statistics data from International Genomics of Alzheimer's Project was used in primary analysis, including 21,982 AD cases and 41,944 controls. Validation was performed using family history of AD data from UK Biobank (27,696 cases of maternal AD, 14,338 cases of paternal AD, and 272,244 controls). We utilized inverse-variance weighted method as primary method.

RESULTS: We found significantly increased risks of developing AD per standard deviation increase in the levels of circulating ApoB (odd ratio[OR] = 3.18; 95% confidence interval[CI]: 1.52-6.66, p = 0.0022), glycoprotein acetyls (OR = 1.21; 95% CI: 1.05-1.39, p = 0.0093), total cholesterol (OR = 2.73; 95% CI: 1.41-5.30, p = 0.0030), and low-density lipoprotein (LDL) cholesterol (OR = 2.34; 95% CI: 1.53-3.57, p = 0.0001). Whereas glutamine (OR = 0.81; 95% CI: 0.71-0.92, p = 0.0011) were significantly associated with lower risk of AD. We also detected causal effects of several different composition of LDL fractions on increased AD risk, which has been verified in validation. However, we found no association between circulating high-density lipoprotein cholesterol and AD.

CONCLUSION: Our findings suggest causal effects of circulating glycoprotein acetyls, ApoB, LDL cholesterol, and serum total cholesterol on higher risk of AD, whereas glutamine showed the protective effect.

%B J Alzheimers Dis %V 87 %P 463-477 %8 2022 %G eng %N 1 %1 https://www.ncbi.nlm.nih.gov/pubmed/35275550?dopt=Abstract %R 10.3233/JAD-220050 %0 Journal Article %J J Alzheimers Dis %D 2020 %T Circulating Vitamin D Levels and Alzheimer's Disease: A Mendelian Randomization Study in the IGAP and UK Biobank. %A Wang, Longcai %A Qiao, Yanchun %A Zhang, Haihua %A Zhang, Yan %A Hua, Jiao %A Jin, Shuilin %A Liu, Guiyou %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Biological Specimen Banks %K Cognition Disorders %K Databases, Factual %K Female %K Genome-Wide Association Study %K Humans %K Hydroxycholecalciferols %K Male %K Mendelian Randomization Analysis %K Middle Aged %K Nutritional Status %K United Kingdom %K Vitamin D %K Vitamin D Deficiency %X

Observational studies strongly supported the association of low levels of circulating 25-hydroxyvitamin D (25OHD) and cognitive impairment or dementia in aging populations. However, randomized controlled trials have not shown clear evidence that vitamin D supplementation could improve cognitive outcomes. In fact, some studies reported the association between vitamin D and cognitive impairment based on individuals aged 60 years and over. However, it is still unclear that whether vitamin D levels are causally associated with Alzheimer's disease (AD) risk in individuals aged 60 years and over. Here, we performed a Mendelian randomization (MR) study to investigate the causal association between vitamin D levels and AD using a large-scale vitamin D genome-wide association study (GWAS) dataset and two large-scale AD GWAS datasets from the IGAP and UK Biobank with individuals aged 60 years and over. Our results showed that genetically increased 25OHD levels were significantly associated with reduced AD risk in individuals aged 60 years and over. Hence, our findings in combination with previous literature indicate that maintaining adequate vitamin D status in older people especially aged 60 years and over, may contribute to slow down cognitive decline and forestall AD. Long-term randomized controlled trials are required to test whether vitamin D supplementation may prevent AD in older people especially those aged 60 years and may be recommended as preventive agents.

%B J Alzheimers Dis %V 73 %P 609-618 %8 2020 %G eng %N 2 %1 https://www.ncbi.nlm.nih.gov/pubmed/31815694?dopt=Abstract %R 10.3233/JAD-190713 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Alzheimer's Disease rs11767557 Variant Regulates EPHA1 Gene Expression Specifically in Human Whole Blood. %A Liu, Guiyou %A Zhang, Yan %A Wang, Longcai %A Xu, Jianyong %A Chen, Xiaoyun %A Bao, Yunjuan %A Hu, Yang %A Jin, Shuilin %A Tian, Rui %A Bai, Weiyang %A Zhou, Wenyang %A Wang, Tao %A Han, Zhifa %A Zong, Jian %A Jiang, Qinghua %K Alzheimer Disease %K Case-Control Studies %K China %K Gene Expression %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Humans %K Linkage Disequilibrium %K Polymorphism, Single Nucleotide %K Receptor, EphA1 %K Risk Assessment %X

Large-scale genome-wide association studies have reported EPHA1 rs11767557 variant to be associated with Alzheimer's disease (AD) risk in the European population. However, it is still unclear how this variant functionally contributes to the underlying disease pathogenesis. The rs11767557 variant is located approximately 3 kb upstream of EPHA1 gene. We think that rs11767557 may modify the expression of nearby genes such as EPHA1 and further cause AD risk. Until now, the potential association between rs11767557 and the expression of nearby genes has not been reported in previous studies. Here, we evaluate the potential expression association between rs11767557 and EPHA1 using multiple large-scale eQTLs datasets in human brain tissues and the whole blood. The results show that rs11767557 variant could significantly regulate EPHA1 gene expression specifically in human whole blood. These findings may further provide important supplementary information about the regulating mechanisms of rs11767557 variant in AD risk.

%B J Alzheimers Dis %V 61 %P 1077-1088 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/29332039?dopt=Abstract %R 10.3233/JAD-170468 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Assessment of the Genetic Architecture of Alzheimer's Disease Risk in Rate of Memory Decline. %A Del-Aguila, Jorge L %A Fernández, Maria Victoria %A Schindler, Suzanne %A Ibanez, Laura %A Deming, Yuetiva %A Ma, Shengmei %A Saef, Ben %A Black, Kathleen %A Budde, John %A Norton, Joanne %A Chasse, Rachel %A Harari, Oscar %A Goate, Alison %A Xiong, Chengjie %A Morris, John C %A Cruchaga, Carlos %K Age of Onset %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Dementia %K Disease Progression %K Female %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Heterozygote %K Humans %K Longitudinal Studies %K Male %K Membrane Glycoproteins %K Memory Disorders %K Middle Aged %K Polymorphism, Single Nucleotide %K Receptors, Immunologic %K Risk Assessment %X

Many genetic studies for Alzheimer's disease (AD) have been focused on the identification of common genetic variants associated with AD risk and not on other aspects of the disease, such as age at onset or rate of dementia progression. There are multiple approaches to untangling the genetic architecture of these phenotypes. We hypothesized that the genetic architecture of rate of progression is different than the risk for developing AD dementia. To test this hypothesis, we used longitudinal clinical data from ADNI and the Knight-ADRC at Washington University, and we calculated PRS (polygenic risk score) based on the IGAP study to compare the genetic architecture of AD risk and dementia progression. Dementia progression was measured by the change of Clinical Dementia Rating Sum of Boxes (CDR)-SB per year. Out of the 21 loci for AD risk, no association with the rate of dementia progression was found. The PRS rate was significantly associated with the rate of dementia progression (β= 0.146, p = 0.03). In the case of rare variants, TREM2 (β= 0.309, p = 0.02) was also associated with the rate of dementia progression. TREM2 variant carriers showed a 23% faster rate of dementia compared with non-variant carriers. In conclusion, our results indicate that the recently identified common and rare variants for AD susceptibility have a limited impact on the rate of dementia progression in AD patients.

%B J Alzheimers Dis %V 62 %P 745-756 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29480181?dopt=Abstract %R 10.3233/JAD-170834 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Association of Frontotemporal Dementia GWAS Loci with Late-Onset Alzheimer's Disease in a Northern Han Chinese Population. %A Tan, Chen-Chen %A Wan, Yu %A Tan, Meng-Shan %A Zhang, Wei %A Wang, Zi-Xuan %A Sun, Fu-Rong %A Miao, Dan %A Tan, Lan %A Yu, Jin-Tai %K Age of Onset %K Aged %K Alzheimer Disease %K Apolipoprotein E4 %K Asian Continental Ancestry Group %K Case-Control Studies %K China %K Female %K Frontotemporal Dementia %K Gene Frequency %K Genetic Loci %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Genotype %K Genotyping Techniques %K Humans %K Linkage Disequilibrium %K Male %K Mental Status Schedule %K Polymorphism, Single Nucleotide %X

BACKGROUND: Both Alzheimer's disease (AD) and frontotemporal dementia (FTD) are a class of neurodegenerative diseases. Strong similarities in cerebrospinal fluid biomarker, imaging markers, and disease progression profiles suggest that some or most of the pathophysiology is shared between AD and FTD. A recent large genome-wide association study reported several single nucleotide polymorphisms (SNPs) at the RAB38, RAB38/CTSC, HLA-DRA/HLA-DRB5, and BTNL2 in association with FTD.

OBJECTIVE: To explore whether these SNPs are associated with AD risk.

METHODS: We conducted a case-control study to investigate the association of FTD-associated loci in 2338 Han Chinese subjects.

RESULTS: We observed significant differences in genotype distributions of rs302668 (pc = 0.025), rs9268877 (pc = 0.025), rs9268856 (p <  0.001), and rs1980493 (pc = 0.045) between cases and controls. The SNPs rs16913634 for RAB38/CTSC was unrelated to LOAD risk (p = 0.088).

CONCLUSION: The SNPs rs302668 in RAB38, rs9268877 and rs9268856 polymorphism in HLA-DRA/HLA-DRB5, and rs1980493 polymorphism in BTNL2 might play a role in the susceptibility to late-onset AD in the Han Chinese population.

%B J Alzheimers Dis %V 52 %P 43-50 %8 2016 02 26 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26967218?dopt=Abstract %R 10.3233/JAD-151073 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Genetic Influences on Plasma Homocysteine Levels in African Americans and Yoruba Nigerians. %A Kim, Sungeun %A Nho, Kwangsik %A Ramanan, Vijay K %A Lai, Dongbing %A Foroud, Tatiana M %A Lane, Katie %A Murrell, Jill R %A Gao, Sujuan %A Hall, Kathleen S %A Unverzagt, Frederick W %A Baiyewu, Olusegun %A Ogunniyi, Adesola %A Gureje, Oye %A Kling, Mitchel A %A Doraiswamy, P Murali %A Kaddurah-Daouk, Rima %A Hendrie, Hugh C %A Saykin, Andrew J %K Adaptor Proteins, Signal Transducing %K African Americans %K African Continental Ancestry Group %K Aged %K Aged, 80 and over %K Cohort Studies %K Cystathionine beta-Synthase %K Cytoskeletal Proteins %K Female %K Genetic Variation %K Genome-Wide Association Study %K Heterozygote %K Homocysteine %K Humans %K Indiana %K Longitudinal Studies %K Male %K Nigeria %K Prospective Studies %X

Plasma homocysteine, a metabolite involved in key cellular methylation processes seems to be implicated in cognitive functions and cardiovascular health with its high levels representing a potential modifiable risk factor for Alzheimer's disease (AD) and other dementias. A better understanding of the genetic factors regulating homocysteine levels, particularly in non-white populations, may help in risk stratification analyses of existing clinical trials and may point to novel targets for homocysteine-lowering therapy. To identify genetic influences on plasma homocysteine levels in individuals with African ancestry, we performed a targeted gene and pathway-based analysis using a priori biological information and then to identify new association performed a genome-wide association study. All analyses used combined data from the African American and Yoruba cohorts from the Indianapolis-Ibadan Dementia Project. Targeted analyses demonstrated significant associations of homocysteine and variants within the CBS (Cystathionine beta-Synthase) gene. We identified a novel genome-wide significant association of the AD risk gene CD2AP (CD2-associated protein) with plasma homocysteine levels in both cohorts. Minor allele (T) carriers of identified CD2AP variant (rs6940729) exhibited decreased homocysteine level. Pathway enrichment analysis identified several interesting pathways including the GABA receptor activation pathway. This is noteworthy given the known antagonistic effect of homocysteine on GABA receptors. These findings identify several new targets warranting further investigation in relation to the role of homocysteine in neurodegeneration.

%B J Alzheimers Dis %V 49 %P 991-1003 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26519441?dopt=Abstract %R 10.3233/JAD-150651 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Shared Genetic Etiology between Type 2 Diabetes and Alzheimer's Disease Identified by Bioinformatics Analysis. %A Gao, Lei %A Cui, Zhen %A Shen, Liang %A Ji, Hong-Fang %K Alzheimer Disease %K Apolipoprotein C-I %K Computational Biology %K Databases, Factual %K Diabetes Mellitus, Type 2 %K Female %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Humans %K Lipid Metabolism %K Male %K Polymorphism, Single Nucleotide %X

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are two major health issues, and increasing evidence in recent years supports the close connection between these two diseases. The present study aimed to explore the shared genetic etiology underlying T2D and AD based on the available genome wide association studies (GWAS) data collected through August 2014. We performed bioinformatics analyses based on GWAS data of T2D and AD on single nucleotide polymorphisms (SNPs), gene, and pathway levels, respectively. Six SNPs (rs111789331, rs12721046, rs12721051, rs4420638, rs56131196, and rs66626994) were identified for the first time to be shared genetic factors between T2D and AD. Further functional enrichment analysis found lipid metabolism related pathways to be common between these two disorders. The findings may have important implications for future mechanistic and interventional studies for T2D and AD.

%B J Alzheimers Dis %V 50 %P 13-7 %8 2016 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26639962?dopt=Abstract %R 10.3233/JAD-150580 %0 Journal Article %J Nat Genet %D 2013 %T Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease. %A Lambert, J C %A Ibrahim-Verbaas, C A %A Harold, D %A Naj, A C %A Sims, R %A Bellenguez, C %A DeStafano, A L %A Bis, J C %A Beecham, G W %A Grenier-Boley, B %A Russo, G %A Thorton-Wells, T A %A Jones, N %A Smith, A V %A Chouraki, V %A Thomas, C %A Ikram, M A %A Zelenika, D %A Vardarajan, B N %A Kamatani, Y %A Lin, C F %A Gerrish, A %A Schmidt, H %A Kunkle, B %A Dunstan, M L %A Ruiz, A %A Bihoreau, M T %A Choi, S H %A Reitz, C %A Pasquier, F %A Cruchaga, C %A Craig, D %A Amin, N %A Berr, C %A Lopez, O L %A De Jager, P L %A Deramecourt, V %A Johnston, J A %A Evans, D %A Lovestone, S %A Letenneur, L %A Morón, F J %A Rubinsztein, D C %A Eiriksdottir, G %A Sleegers, K %A Goate, A M %A Fiévet, N %A Huentelman, M W %A Gill, M %A Brown, K %A Kamboh, M I %A Keller, L %A Barberger-Gateau, P %A McGuiness, B %A Larson, E B %A Green, R %A Myers, A J %A Dufouil, C %A Todd, S %A Wallon, D %A Love, S %A Rogaeva, E %A Gallacher, J %A St George-Hyslop, P %A Clarimon, J %A Lleo, A %A Bayer, A %A Tsuang, D W %A Yu, L %A Tsolaki, M %A Bossù, P %A Spalletta, G %A Proitsi, P %A Collinge, J %A Sorbi, S %A Sanchez-Garcia, F %A Fox, N C %A Hardy, J %A Deniz Naranjo, M C %A Bosco, P %A Clarke, R %A Brayne, C %A Galimberti, D %A Mancuso, M %A Matthews, F %A Moebus, S %A Mecocci, P %A Del Zompo, M %A Maier, W %A Hampel, H %A Pilotto, A %A Bullido, M %A Panza, F %A Caffarra, P %A Nacmias, B %A Gilbert, J R %A Mayhaus, M %A Lannefelt, L %A Hakonarson, H %A Pichler, S %A Carrasquillo, M M %A Ingelsson, M %A Beekly, D %A Alvarez, V %A Zou, F %A Valladares, O %A Younkin, S G %A Coto, E %A Hamilton-Nelson, K L %A Gu, W %A Razquin, C %A Pastor, P %A Mateo, I %A Owen, M J %A Faber, K M %A Jonsson, P V %A Combarros, O %A O'Donovan, M C %A Cantwell, L B %A Soininen, H %A Blacker, D %A Mead, S %A Mosley, T H %A Bennett, D A %A Harris, T B %A Fratiglioni, L %A Holmes, C %A de Bruijn, R F %A Passmore, P %A Montine, T J %A Bettens, K %A Rotter, J I %A Brice, A %A Morgan, K %A Foroud, T M %A Kukull, W A %A Hannequin, D %A Powell, J F %A Nalls, M A %A Ritchie, K %A Lunetta, K L %A Kauwe, J S %A Boerwinkle, E %A Riemenschneider, M %A Boada, M %A Hiltuenen, M %A Martin, E R %A Schmidt, R %A Rujescu, D %A Wang, L S %A Dartigues, J F %A Mayeux, R %A Tzourio, C %A Hofman, A %A Nöthen, M M %A Graff, C %A Psaty, B M %A Jones, L %A Haines, J L %A Holmans, P A %A Lathrop, M %A Pericak-Vance, M A %A Launer, L J %A Farrer, L A %A van Duijn, C M %A Van Broeckhoven, C %A Moskvina, V %A Seshadri, S %A Williams, J %A Schellenberg, G D %A Amouyel, P %K Age of Onset %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Case-Control Studies %K Cohort Studies %K Female %K Genetic Loci %K Genetic Predisposition to Disease %K Genome-Wide Association Study %K Humans %K Male %K Middle Aged %K Polymorphism, Single Nucleotide %X

Eleven susceptibility loci for late-onset Alzheimer's disease (LOAD) were identified by previous studies; however, a large portion of the genetic risk for this disease remains unexplained. We conducted a large, two-stage meta-analysis of genome-wide association studies (GWAS) in individuals of European ancestry. In stage 1, we used genotyped and imputed data (7,055,881 SNPs) to perform meta-analysis on 4 previously published GWAS data sets consisting of 17,008 Alzheimer's disease cases and 37,154 controls. In stage 2, 11,632 SNPs were genotyped and tested for association in an independent set of 8,572 Alzheimer's disease cases and 11,312 controls. In addition to the APOE locus (encoding apolipoprotein E), 19 loci reached genome-wide significance (P < 5 × 10(-8)) in the combined stage 1 and stage 2 analysis, of which 11 are newly associated with Alzheimer's disease.

%B Nat Genet %V 45 %P 1452-8 %8 2013 Dec %G eng %N 12 %1 http://www.ncbi.nlm.nih.gov/pubmed/24162737?dopt=Abstract %R 10.1038/ng.2802 %0 Journal Article %J N Engl J Med %D 2013 %T TREM2 variants in Alzheimer's disease. %A Guerreiro, Rita %A Wojtas, Aleksandra %A Bras, Jose %A Carrasquillo, Minerva %A Rogaeva, Ekaterina %A Majounie, Elisa %A Cruchaga, Carlos %A Sassi, Celeste %A Kauwe, John S K %A Younkin, Steven %A Hazrati, Lilinaz %A Collinge, John %A Pocock, Jennifer %A Lashley, Tammaryn %A Williams, Julie %A Lambert, Jean-Charles %A Amouyel, Philippe %A Goate, Alison %A Rademakers, Rosa %A Morgan, Kevin %A Powell, John %A St George-Hyslop, Peter %A Singleton, Andrew %A Hardy, John %K Aged %K Alzheimer Disease %K Animals %K Brain %K Exome %K Genetic Variation %K Genome-Wide Association Study %K Genotype %K Genotyping Techniques %K Heterozygote %K Humans %K Membrane Glycoproteins %K Mice %K Mice, Inbred A %K Mutation %K Receptors, Immunologic %K Risk Factors %K RNA, Messenger %K Sequence Analysis, DNA %X

BACKGROUND: Homozygous loss-of-function mutations in TREM2, encoding the triggering receptor expressed on myeloid cells 2 protein, have previously been associated with an autosomal recessive form of early-onset dementia.

METHODS: We used genome, exome, and Sanger sequencing to analyze the genetic variability in TREM2 in a series of 1092 patients with Alzheimer's disease and 1107 controls (the discovery set). We then performed a meta-analysis on imputed data for the TREM2 variant rs75932628 (predicted to cause a R47H substitution) from three genomewide association studies of Alzheimer's disease and tested for the association of the variant with disease. We genotyped the R47H variant in an additional 1887 cases and 4061 controls. We then assayed the expression of TREM2 across different regions of the human brain and identified genes that are differentially expressed in a mouse model of Alzheimer's disease and in control mice.

RESULTS: We found significantly more variants in exon 2 of TREM2 in patients with Alzheimer's disease than in controls in the discovery set (P=0.02). There were 22 variant alleles in 1092 patients with Alzheimer's disease and 5 variant alleles in 1107 controls (P<0.001). The most commonly associated variant, rs75932628 (encoding R47H), showed highly significant association with Alzheimer's disease (P<0.001). Meta-analysis of rs75932628 genotypes imputed from genomewide association studies confirmed this association (P=0.002), as did direct genotyping of an additional series of 1887 patients with Alzheimer's disease and 4061 controls (P<0.001). Trem2 expression differed between control mice and a mouse model of Alzheimer's disease.

CONCLUSIONS: Heterozygous rare variants in TREM2 are associated with a significant increase in the risk of Alzheimer's disease. (Funded by Alzheimer's Research UK and others.).

%B N Engl J Med %V 368 %P 117-27 %8 2013 Jan 10 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/23150934?dopt=Abstract %R 10.1056/NEJMoa1211851 %0 Journal Article %J PLoS One %D 2010 %T Genetic evidence implicates the immune system and cholesterol metabolism in the aetiology of Alzheimer's disease. %A Jones, Lesley %A Holmans, Peter A %A Hamshere, Marian L %A Harold, Denise %A Moskvina, Valentina %A Ivanov, Dobril %A Pocklington, Andrew %A Abraham, Richard %A Hollingworth, Paul %A Sims, Rebecca %A Gerrish, Amy %A Pahwa, Jaspreet Singh %A Jones, Nicola %A Stretton, Alexandra %A Morgan, Angharad R %A Lovestone, Simon %A Powell, John %A Proitsi, Petroula %A Lupton, Michelle K %A Brayne, Carol %A Rubinsztein, David C %A Gill, Michael %A Lawlor, Brian %A Lynch, Aoibhinn %A Morgan, Kevin %A Brown, Kristelle S %A Passmore, Peter A %A Craig, David %A McGuinness, Bernadette %A Todd, Stephen %A Holmes, Clive %A Mann, David %A Smith, A David %A Love, Seth %A Kehoe, Patrick G %A Mead, Simon %A Fox, Nick %A Rossor, Martin %A Collinge, John %A Maier, Wolfgang %A Jessen, Frank %A Schürmann, Britta %A Heun, Reinhard %A Kölsch, Heike %A van den Bussche, Hendrik %A Heuser, Isabella %A Peters, Oliver %A Kornhuber, Johannes %A Wiltfang, Jens %A Dichgans, Martin %A Frölich, Lutz %A Hampel, Harald %A Hüll, Michael %A Rujescu, Dan %A Goate, Alison M %A Kauwe, John S K %A Cruchaga, Carlos %A Nowotny, Petra %A Morris, John C %A Mayo, Kevin %A Livingston, Gill %A Bass, Nicholas J %A Gurling, Hugh %A McQuillin, Andrew %A Gwilliam, Rhian %A Deloukas, Panos %A Al-Chalabi, Ammar %A Shaw, Christopher E %A Singleton, Andrew B %A Guerreiro, Rita %A Mühleisen, Thomas W %A Nöthen, Markus M %A Moebus, Susanne %A Jöckel, Karl-Heinz %A Klopp, Norman %A Wichmann, H-Erich %A Rüther, Eckhard %A Carrasquillo, Minerva M %A Pankratz, V Shane %A Younkin, Steven G %A Hardy, John %A O'Donovan, Michael C %A Owen, Michael J %A Williams, Julie %K Alzheimer Disease %K Apolipoproteins E %K Cholesterol %K Chromosome Mapping %K Genetic Predisposition to Disease %K Genome, Human %K Genome-Wide Association Study %K Humans %K Immune System %K Polymorphism, Single Nucleotide %X

BACKGROUND: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes.

METHODOLOGY: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset.

PRINCIPAL FINDINGS: We found a significant overrepresentation of association signals in pathways related to cholesterol metabolism and the immune response in both of the two largest genome-wide association studies for LOAD.

SIGNIFICANCE: Processes related to cholesterol metabolism and the innate immune response have previously been implicated by pathological and epidemiological studies of Alzheimer's disease, but it has been unclear whether those findings reflected primary aetiological events or consequences of the disease process. Our independent evidence from two large studies now demonstrates that these processes are aetiologically relevant, and suggests that they may be suitable targets for novel and existing therapeutic approaches.

%B PLoS One %V 5 %P e13950 %8 2010 %G eng %N 11 %1 http://www.ncbi.nlm.nih.gov/pubmed/21085570?dopt=Abstract %R 10.1371/journal.pone.0013950