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1.  Association between neuropathology and brain volume in the Framingham Heart Study 
Studies of clinical and community cohorts have shown that antemortem imaging measures of hippocampal volume have correlated with postmortem Alzheimer's pathology. Fewer studies have examined the relationship between both Alzheimer's and cerebrovascular pathology, and antemortem brain imaging. The aim of this study was to correlate antemortem brain magnetic resonance imaging (MRI) volumes with postmortem brain pathology (both Alzheimer-related and cerebrovascular) in a community-derived cohort from the Framingham Heart Study (FHS). Participants (n=59) from the FHS were included if they were enrolled in the brain autopsy program and underwent antemortem clinical evaluation, neuropsychological testing and brain MRI. Cortical neurofibrillary tangle pathology correlated with lower total cerebral brain (beta±SE=−0.04±0.01, p=0.004) and hippocampal volumes (beta±SE=−0.03±0.02, p=0.044) and larger temporal horns (log-transformed, beta±SE=0.05±0.01, p=0.001). Similar findings were seen between total/cortical neuritic plaques and total cerebral brain and temporal horn volume. White matter hyperintensities (also log-transformed) were best predicted by the presence of deep nuclei microinfarcts (beta±SE=0.53±0.21, p=0.016), whereas hippocampal volume was significantly decreased in the presence of hippocampal sclerosis (beta±SE =−1.23±0.30, p<0.001). This study showed that volumetric MRI measures correlated with postmortem Alzheimer-related and cerebrovascular neuropathology in this community-derived cohort, confirming that these MRI measures are important antemortem surrogates for these dementia-related pathologies.
doi:10.1097/WAD.0000000000000032
PMCID: PMC4139422  PMID: 24614264
2.  Insulin-like growth factor-1 and risk of Alzheimer dementia and brain atrophy 
Neurology  2014;82(18):1613-1619.
Objective:
To relate serum insulin-like growth factor-1 (IGF-1) to risk of Alzheimer disease (AD) dementia and to brain volumes in a dementia-free community sample spanning middle and older ages.
Methods:
Dementia-free Framingham participants from generation 1 (n = 789, age 79 ± 4 years, 64% women) and generation 2 (n = 2,793, age 61 ± 9 years, 55% women; total = 3,582, age 65 ± 11 years, 57% women) had serum IGF-1 measured in 1990–1994 and 1998–2001, respectively, and were followed prospectively for incident dementia and AD dementia. Brain MRI was obtained in stroke- and dementia-free survivors of both generations 1 (n = 186) and 2 (n = 1,867) during 1999–2005. Baseline IGF-1 was related to risk of incident dementia using Cox models and to total brain and hippocampal volumes using linear regression in multivariable models adjusted for age, sex, APOE ε4, plasma homocysteine, waist-hip ratio, and physical activity.
Results:
Mean IGF-1 levels were 144 ± 60 μg/L in generation 1 and 114 ± 37 μg/L in generation 2. We observed 279 cases of incident dementia (230 AD dementia) over a mean follow-up of 7.4 ± 3.1 years. Persons with IGF-1 in the lowest quartile had a 51% greater risk of AD dementia (hazard ratio = 1.51, 95% confidence interval: 1.14–2.00; p = 0.004). Among persons without dementia, higher IGF-1 levels were associated with greater total brain volumes (β/SD increment in IGF-1 was 0.55 ± 0.24, p = 0.025; and 0.26 ± 0.06, p < 0.001, for generations 1 and 2, respectively).
Conclusion:
Lower serum levels of IGF-1 are associated with an increased risk of developing AD dementia and higher levels with greater brain volumes even among middle-aged community-dwelling participants free of stroke and dementia. Higher levels of IGF-1 may protect against subclinical and clinical neurodegeneration.
doi:10.1212/WNL.0000000000000382
PMCID: PMC4013812  PMID: 24706014
3.  Parental longevity is associated with cognition and brain ageing in middle-aged offspring 
Age and Ageing  2013;43(3):358-363.
Background: offspring of long-lived individuals have lower risk for dementia. We examined the relation between parental longevity and cognition and subclinical markers of brain ageing in community-dwelling adult offspring.
Methods: offspring participants with both parents in the Framingham Heart Study, aged ≥55 years and dementia-free underwent baseline and repeat neuropsychological (NP) testing and brain magnetic resonance imaging (MRI). Parental longevity was defined as having at least one parent survive to age ≥85 years. To test the association between parental longevity and measures of cognition and brain volumes, we used multivariable linear and logistic regression adjusting for age, sex, education and time to NP testing or brain MRI.
Results: of 728 offspring (mean age 66 years, 54% women), 407 (56%) had ≥1 parent achieve longevity. In cross-sectional analysis, parental longevity was associated with better scores on attention (beta 0.21 ± 0.08, P = 0.006) and a lower odds of extensive white matter hyperintensity on brain MRI (odds ratio 0.59, 95% CI: 0.38, 0.92, P = 0.019). The association with white matter hyperintensity was no longer significant in models adjusted for cardiovascular risk factors and disease. In longitudinal analysis (6.7 ± 1.7 years later), offspring with parental longevity had slower decline in attention (0.18 ± 0.08, P = 0.038), executive function (beta 0.19 ± 0.09, P = 0.031) and visual memory (beta −0.18 ± 0.08, P = 0.023), and less increase in temporal horn volume (beta −0.25 ± 0.09, P = 0.005). The associations persisted in fully adjusted models.
Conclusion: parental longevity is associated with better brain ageing in middle-aged offspring.
doi:10.1093/ageing/aft175
PMCID: PMC4001170  PMID: 24212919
brain ageing; brain imaging; cognition; longevity; neuropsychological testing; older people; parental longevity
4.  Risk Factors, Stroke Prevention Treatments, and Prevalence of Cerebral Microbleeds in the Framingham Heart Study 
Background and purpose
Cerebral microbleeds (CMBs) are associated with increased risk of stroke and poor cognition. Vascular risk factors and medications used for stroke prevention may increase the risk of CMB. We examined the prevalence of CMB and the association of these risk factors with CMB, postulating that risk factors for cerebral amyloid angiopathy would be associated with lobar CMB and markers of hypertensive vasculopathy with deep CMB.
Methods
We include 1,965 Framingham Original and Offspring participants (age 66.5±11.0years; 54%women) and evaluated the age- and sex-specific prevalence of CMB. We related various vascular and genetic (APOE) risk factors and medication use to presence of CMB overall and stratified by brain location (deep, lobar or mixed).
Results
CMBs were observed in 8.8% of participants, being mostly lobar (63%). CMB prevalence increased with age (p<0.0001) and was higher in men (p<0.001). Hypertension increased risk of any CMB, and in deep and mixed locations (p<0.05), and low total cholesterol and APOE ε4 increased risk of lobar CMB (p<0.05). Statin use increased risk of lobar and mixed location CMB (p<0.05). The latter association was not affected by adjustment for cholesterol levels, or concomitant medication use.
Conclusions
We observed the expected association of hypertension with deep CMB and low cholesterol and APOEε4 with lobar CMB. Additionally, statin use was independently associated with CMB risk. This potential adverse effect of statin use needs to be examined in other cohorts.
doi:10.1161/STROKEAHA.114.004130
PMCID: PMC4048617  PMID: 24713533
5.  Common genetic variants influence human subcortical brain structures 
Hibar, Derrek P. | Stein, Jason L. | Renteria, Miguel E. | Arias-Vasquez, Alejandro | Desrivières, Sylvane | Jahanshad, Neda | Toro, Roberto | Wittfeld, Katharina | Abramovic, Lucija | Andersson, Micael | Aribisala, Benjamin S. | Armstrong, Nicola J. | Bernard, Manon | Bohlken, Marc M. | Boks, Marco P. | Bralten, Janita | Brown, Andrew A. | Chakravarty, M. Mallar | Chen, Qiang | Ching, Christopher R. K. | Cuellar-Partida, Gabriel | den Braber, Anouk | Giddaluru, Sudheer | Goldman, Aaron L. | Grimm, Oliver | Guadalupe, Tulio | Hass, Johanna | Woldehawariat, Girma | Holmes, Avram J. | Hoogman, Martine | Janowitz, Deborah | Jia, Tianye | Kim, Sungeun | Klein, Marieke | Kraemer, Bernd | Lee, Phil H. | Olde Loohuis, Loes M. | Luciano, Michelle | Macare, Christine | Mather, Karen A. | Mattheisen, Manuel | Milaneschi, Yuri | Nho, Kwangsik | Papmeyer, Martina | Ramasamy, Adaikalavan | Risacher, Shannon L. | Roiz-Santiañez, Roberto | Rose, Emma J. | Salami, Alireza | Sämann, Philipp G. | Schmaal, Lianne | Schork, Andrew J. | Shin, Jean | Strike, Lachlan T. | Teumer, Alexander | van Donkelaar, Marjolein M. J. | van Eijk, Kristel R. | Walters, Raymond K. | Westlye, Lars T. | Whelan, Christopher D. | Winkler, Anderson M. | Zwiers, Marcel P. | Alhusaini, Saud | Athanasiu, Lavinia | Ehrlich, Stefan | Hakobjan, Marina M. H. | Hartberg, Cecilie B. | Haukvik, Unn K. | Heister, Angelien J. G. A. M. | Hoehn, David | Kasperaviciute, Dalia | Liewald, David C. M. | Lopez, Lorna M. | Makkinje, Remco R. R. | Matarin, Mar | Naber, Marlies A. M. | McKay, D. Reese | Needham, Margaret | Nugent, Allison C. | Pütz, Benno | Royle, Natalie A. | Shen, Li | Sprooten, Emma | Trabzuni, Daniah | van der Marel, Saskia S. L. | van Hulzen, Kimm J. E. | Walton, Esther | Wolf, Christiane | Almasy, Laura | Ames, David | Arepalli, Sampath | Assareh, Amelia A. | Bastin, Mark E. | Brodaty, Henry | Bulayeva, Kazima B. | Carless, Melanie A. | Cichon, Sven | Corvin, Aiden | Curran, Joanne E. | Czisch, Michael | de Zubicaray, Greig I. | Dillman, Allissa | Duggirala, Ravi | Dyer, Thomas D. | Erk, Susanne | Fedko, Iryna O. | Ferrucci, Luigi | Foroud, Tatiana M. | Fox, Peter T. | Fukunaga, Masaki | Gibbs, J. Raphael | Göring, Harald H. H. | Green, Robert C. | Guelfi, Sebastian | Hansell, Narelle K. | Hartman, Catharina A. | Hegenscheid, Katrin | Heinz, Andreas | Hernandez, Dena G. | Heslenfeld, Dirk J. | Hoekstra, Pieter J. | Holsboer, Florian | Homuth, Georg | Hottenga, Jouke-Jan | Ikeda, Masashi | Jack, Clifford R. | Jenkinson, Mark | Johnson, Robert | Kanai, Ryota | Keil, Maria | Kent, Jack W. | Kochunov, Peter | Kwok, John B. | Lawrie, Stephen M. | Liu, Xinmin | Longo, Dan L. | McMahon, Katie L. | Meisenzahl, Eva | Melle, Ingrid | Mohnke, Sebastian | Montgomery, Grant W. | Mostert, Jeanette C. | Mühleisen, Thomas W. | Nalls, Michael A. | Nichols, Thomas E. | Nilsson, Lars G. | Nöthen, Markus M. | Ohi, Kazutaka | Olvera, Rene L. | Perez-Iglesias, Rocio | Pike, G. Bruce | Potkin, Steven G. | Reinvang, Ivar | Reppermund, Simone | Rietschel, Marcella | Romanczuk-Seiferth, Nina | Rosen, Glenn D. | Rujescu, Dan | Schnell, Knut | Schofield, Peter R. | Smith, Colin | Steen, Vidar M. | Sussmann, Jessika E. | Thalamuthu, Anbupalam | Toga, Arthur W. | Traynor, Bryan J. | Troncoso, Juan | Turner, Jessica A. | Valdés Hernández, Maria C. | van ’t Ent, Dennis | van der Brug, Marcel | van der Wee, Nic J. A. | van Tol, Marie-Jose | Veltman, Dick J. | Wassink, Thomas H. | Westman, Eric | Zielke, Ronald H. | Zonderman, Alan B. | Ashbrook, David G. | Hager, Reinmar | Lu, Lu | McMahon, Francis J. | Morris, Derek W. | Williams, Robert W. | Brunner, Han G. | Buckner, Randy L. | Buitelaar, Jan K. | Cahn, Wiepke | Calhoun, Vince D. | Cavalleri, Gianpiero L. | Crespo-Facorro, Benedicto | Dale, Anders M. | Davies, Gareth E. | Delanty, Norman | Depondt, Chantal | Djurovic, Srdjan | Drevets, Wayne C. | Espeseth, Thomas | Gollub, Randy L. | Ho, Beng-Choon | Hoffmann, Wolfgang | Hosten, Norbert | Kahn, René S. | Le Hellard, Stephanie | Meyer-Lindenberg, Andreas | Müller-Myhsok, Bertram | Nauck, Matthias | Nyberg, Lars | Pandolfo, Massimo | Penninx, Brenda W. J. H. | Roffman, Joshua L. | Sisodiya, Sanjay M. | Smoller, Jordan W. | van Bokhoven, Hans | van Haren, Neeltje E. M. | Völzke, Henry | Walter, Henrik | Weiner, Michael W. | Wen, Wei | White, Tonya | Agartz, Ingrid | Andreassen, Ole A. | Blangero, John | Boomsma, Dorret I. | Brouwer, Rachel M. | Cannon, Dara M. | Cookson, Mark R. | de Geus, Eco J. C. | Deary, Ian J. | Donohoe, Gary | Fernández, Guillén | Fisher, Simon E. | Francks, Clyde | Glahn, David C. | Grabe, Hans J. | Gruber, Oliver | Hardy, John | Hashimoto, Ryota | Hulshoff Pol, Hilleke E. | Jönsson, Erik G. | Kloszewska, Iwona | Lovestone, Simon | Mattay, Venkata S. | Mecocci, Patrizia | McDonald, Colm | McIntosh, Andrew M. | Ophoff, Roel A. | Paus, Tomas | Pausova, Zdenka | Ryten, Mina | Sachdev, Perminder S. | Saykin, Andrew J. | Simmons, Andy | Singleton, Andrew | Soininen, Hilkka | Wardlaw, Joanna M. | Weale, Michael E. | Weinberger, Daniel R. | Adams, Hieab H. H. | Launer, Lenore J. | Seiler, Stephan | Schmidt, Reinhold | Chauhan, Ganesh | Satizabal, Claudia L. | Becker, James T. | Yanek, Lisa | van der Lee, Sven J. | Ebling, Maritza | Fischl, Bruce | Longstreth, W. T. | Greve, Douglas | Schmidt, Helena | Nyquist, Paul | Vinke, Louis N. | van Duijn, Cornelia M. | Xue, Luting | Mazoyer, Bernard | Bis, Joshua C. | Gudnason, Vilmundur | Seshadri, Sudha | Ikram, M. Arfan | Martin, Nicholas G. | Wright, Margaret J. | Schumann, Gunter | Franke, Barbara | Thompson, Paul M. | Medland, Sarah E.
Nature  2015;520(7546):224-229.
The highly complex structure of the human brain is strongly shaped by genetic influences1. Subcortical brain regions form circuits with cortical areas to coordinate movement2, learning, memory3 and motivation4, and altered circuits can lead to abnormal behaviour and disease2. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume5 and intracranial volume6. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10−33; 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability inhuman brain development, and may help to determine mechanisms of neuropsychiatric dysfunction.
doi:10.1038/nature14101
PMCID: PMC4393366  PMID: 25607358
6.  Circulating Brain‐Derived Neurotrophic Factor Concentrations and the Risk of Cardiovascular Disease in the Community 
Background
Brain‐derived neurotrophic factor (BDNF) is a pleiotropic peptide involved in maintaining endothelial integrity. It is unknown if circulating BDNF levels are associated with risk of cardiovascular disease (CVD).
Methods and Results
We prospectively investigated the association of circulating BDNF levels with cardiovascular events and mortality in 3687 participants (mean age 65 years, 2068 women) from the Framingham Heart Study (FHS). Using a common nonsynonomous single nucleotide polymorphism (SNP) in the BDNF gene (rs6265), we then performed a Mendelian randomization experiment in the CARDIoGRAM (Coronary ARtery DIsease Genome‐Wide Replication And Meta‐Analysis) consortium (>22 000 coronary artery disease [CAD] cases, >60 000 controls) to investigate whether SNP rs6265 was associated with CAD in CARDIoGRAM and, if so, whether the effect estimate differed from that predicted based on FHS data. On follow‐up (median 8.9 years), 467 individuals (261 women) in FHS experienced a CVD event, and 835 (430 women) died. In multivariable‐adjusted Cox regression, serum BDNF was associated inversely with CVD risk (hazard ratio [HR] per 1‐SD increase 0.88, 95% CI 0.80 to 0.97, P=0.01) and with mortality (HR 0.87, 95% CI 0.80 to 0.93, P=0.0002). SNP rs6265 was associated with BDNF concentrations (0.772 ng/mL increase per minor allele copy) in FHS. In CARDIoGRAM, SNP rs6265 was associated with CAD (odds ratio 0.957, 95% CI 0.923 to 0.992), a magnitude consistent with the predicted effect (HR per minor allele copy 0.99, 95% CI 0.98 to 1.0; P=0.06 for difference between predicted and observed effect).
Conclusion
Higher serum BDNF is associated with a decreased risk of CVD and mortality. Mendelian randomization suggests a causal protective role of BDNF in the pathogenesis of CVD.
doi:10.1161/JAHA.114.001544
PMCID: PMC4392437  PMID: 25762803
cardiovascular disease; growth factors; Mendelian randomization; mortality; risk factors
7.  Mutation of FOXC1 and PITX2 induces cerebral small-vessel disease 
The Journal of Clinical Investigation  2014;124(11):4877-4881.
Patients with cerebral small-vessel disease (CSVD) exhibit perturbed end-artery function and have an increased risk for stroke and age-related cognitive decline. Here, we used targeted genome-wide association (GWA) analysis and defined a CSVD locus adjacent to the forkhead transcription factor FOXC1. Moreover, we determined that the linked SNPs influence FOXC1 transcript levels and demonstrated that patients as young as 1 year of age with altered FOXC1 function exhibit CSVD. MRI analysis of patients with missense and nonsense mutations as well as FOXC1-encompassing segmental duplication and deletion revealed white matter hyperintensities, dilated perivascular spaces, and lacunar infarction. In a zebrafish model, overexpression or morpholino-induced suppression of foxc1 induced cerebral hemorrhage. Inhibition of foxc1 perturbed platelet-derived growth factor (Pdgf) signaling, impairing neural crest migration and the recruitment of mural cells, which are essential for vascular stability. GWA analysis also linked the FOXC1-interacting transcription factor PITX2 to CSVD, and both patients with PITX2 mutations and murine Pitx2–/– mutants displayed brain vascular phenotypes. Together, these results extend the genetic etiology of stroke and demonstrate an increasing developmental basis for human cerebrovascular disease.
doi:10.1172/JCI75109
PMCID: PMC4347243  PMID: 25250569
8.  Circulating biomarkers that predict incident dementia 
Dementia is currently diagnosed based on clinical symptoms and signs, but significant brain damage has already occurred by the time a clinical diagnosis of dementia is made, and it is increasingly recognized that this may be too late for any effective intervention. It would therefore be of great public health and preventive value to define a variety of biomarkers that could permit early detection of persons at a higher risk for developing dementia, and specifically dementia due to Alzheimer’s disease. Nevertheless, for the purpose of large-scale screening, circulating biomarkers are more appropriate because they are less invasive than lumbar puncture, less costly than brain amyloid imaging and can be easily assessed repeatedly in a primary care clinic setting. In this brief review we will review a number of candidate molecules implicated as possible predictors of dementia risk. These candidates include markers of vascular injury, metabolic and inflammatory states, amyloid and tau pathway markers, measures of neural degeneration and repair efforts, and other molecules that might contribute to anatomical and functional changes characteristic of dementia and Alzheimer’s disease.
doi:10.1186/alzrt235
PMCID: PMC4056619  PMID: 25031629
9.  Midlife Cardiovascular Risk Impacts Executive Function: Framingham Offspring Study 
Introduction
Novel error scores and traditional indices of executive function (EF) were related to cardiovascular risk factors (CVRF) measured 10–15 years earlier.
Methods
From 1991–1995, the Framingham Stroke Risk Profile (FSRP), a composite score of cardiovascular risk, was ascertained in 1755 Framingham Offspring participants (54% women, mean age= 54 ± 9 years). Participants were administered EF tests: FAS and Animals Fluency tests, Trail Making Test B (TrB), and Digit Span-Backwards (DS-B) in 2005–2009. Linear and logistic regression were used to relate the FSRP and its components to both error responses and traditional scores.
Results
Consistent with previous findings, the FSRP and the individual components diabetes and sex were associated with several traditional measures of EF. Of interest were relationships between the FSRP score and TrB Total Errors (p=0.04), DS-B % Total Errors (p=0.02) and DS-B Capacity Score (p=0.03), and prevalent CVD related to making FAS Perseverations in the 75th percentile (p=0.03). By comparison, FSRP and CVD were not related to the traditional DS-B or FAS scores. Additionally, age was associated with higher Animals % Total Errors and % Perseverations among ApoE4+ individuals and with higher TrB Total Errors among ApoE4− individuals.
Conclusion
For those middle-aged and healthy, including those ApoE4+, CVRF are related to impairments in EF as ascertained by novel errors as well as traditional measures.
doi:10.1097/WAD.0b013e3182a715bc
PMCID: PMC3945114  PMID: 23995818
Neuropsychological assessment; Executive function; Mild cognitive impairment; ApolipoproteinE allele 4
10.  Shared genetic susceptibility to ischemic stroke and coronary artery disease – a genome-wide analysis of common variants 
Summary
Background and Purpose
Ischemic stroke (IS) and coronary artery disease (CAD) share several risk factors and each have a substantial heritability. We conducted a genome-wide analysis to evaluate the extent of shared genetic determination of the two diseases.
Methods
Genome-wide association data were obtained from the METASTROKE, CARDIoGRAM, and C4D consortia. We first analyzed common variants reaching a nominal threshold of significance (p<0.01) for CAD for their association with IS and vice versa. We then examined specific overlap across phenotypes for variants that reached a high threshold of significance. Finally, we conducted a joint meta-analysis on the combined phenotype of IS or CAD. Corresponding analyses were performed restricted to the 2,167 individuals with the ischemic large artery stroke (LAS) subtype.
Results
Common variants associated with CAD at p<0.01 were associated with a significant excess risk for IS and for LAS and vice versa. Among the 42 known genome-wide significant loci for CAD, three and five loci were significantly associated with IS and LAS, respectively. In the joint meta-analyses, 15 loci passed genome-wide significance (p<5×10-8) for the combined phenotype of IS or CAD and 17 loci passed genome-wide significance for LAS or CAD. Since these loci had prior evidence for genome-wide significance for CAD we specifically analyzed the respective signals for IS and LAS and found evidence for association at chr12q24/SH2B3 (pIS=1.62×10-07) and ABO (pIS =2.6×10-4) as well as at HDAC9 (pLAS=2.32×10-12), 9p21 (pLAS =3.70×10-6), RAI1-PEMT-RASD1 (pLAS =2.69×10-5), EDNRA (pLAS =7.29×10-4), and CYP17A1-CNNM2-NT5C2 (pLAS =4.9×10-4).
Conclusions
Our results demonstrate substantial overlap in the genetic risk of ischemic stroke and particularly the large artery stroke subtype with coronary artery disease.
doi:10.1161/STROKEAHA.113.002707
PMCID: PMC4112102  PMID: 24262325
11.  APOE genotype modifies the relationship between midlife vascular risk factors and later cognitive decline 
Vascular risk factors have been associated with cognitive decline, however, it remains unclear whether apolipoprotein E (APOE) genotype modifies this relationship. We aimed to further elucidate these relationships and extend previous findings by examining data from a more comprehensive cognitive assessment than used in prior studies. 1,436 participants from the prospective Framingham Offspring Cohort Study underwent health examination from 1991-1995, followed by a baseline neuropsychological assessment (1999-2003) and a repeat neuropsychological assessment approximately eight years later (2004-2009). Multivariate linear regression analyses were performed to examine the relationship between midlife vascular risk factors, presence of the APOE ε4 allele, and cognitive change. APOE genotype significantly modified the associations between both midlife hypertension and cardiovascular disease and decline in language abilities as well as midlife diabetes and decline in verbal memory, attention, and visuospatial abilities. Associations between increased midlife vascular risk burden and greater cognitive decline were observed among APOE ε4 carriers but not non-carriers. The present findings revealed a subgroup at increased risk for cognitive decline (APOE ε4 carriers with midlife exposure to vascular risk factors) and suggest that treatment of vascular risk factors during midlife may reduce the risk of cognitive impairment later in life, particularly among APOE ε4 carriers.
doi:10.1016/j.jstrokecerebrovasdis.2013.03.013
PMCID: PMC3849195  PMID: 23601373
Apolipoprotein E; Cognition; Vascular Risk; Aging; Diabetes; Hypertension; Cardiovascular Disease
12.  Defining MCI in the Framingham Heart Study Offspring: Education vs. WRAT-based norms 
Alzheimer disease and associated disorders  2013;27(4):10.1097/WAD.0b013e31827bde32.
Introduction
Psychometric definitions of mild cognitive impairment (MCI) typically use cut-off levels set at 1.5 standard deviations below age- and education-adjusted norms, assuming that the education adjustment accounts for premorbid abilities. However, non-cognitive factors impact educational attainment, potentially leading to incorrect categorization as MCI. We examined whether using an adjustment based on reading performance (Wide Range Achievement Test [WRAT] Reading) improved MCI diagnostic accuracy.
Methods
935 Framingham Offspring (mean age 72 ± 5) underwent tests of Memory, Executive Function, Abstraction, Language, and Visuospatial Function as part of a neuropsychological test battery. Domain-specific test scores were regressed onto age and WRAT score, or education, to define MCI. Survival analyses were used to relate baseline MCI to incident dementia.
Results
The two MCI definitions differed most for the lowest and highest education groups. The WRAT definition was more strongly associated with incident dementia for all five tests. MCI-level Abstraction performance was associated with incident dementia using the WRAT definition (HR = 3.20, p = .033), but not the education definition (HR = 1.19, p = .814).
Discussion
The WRAT should be considered along with the standard measure of years of education, as it may be a better surrogate marker of premorbid abilities.
doi:10.1097/WAD.0b013e31827bde32
PMCID: PMC3626741  PMID: 23314066
Mild cognitive impairment; premorbid abilities; neuropsychological assessment; Alzheimer's disease; longitudinal
13.  Serum BDNF and VEGF levels are associated with Risk of Stroke and Vascular Brain Injury: Framingham Study 
Stroke; a journal of cerebral circulation  2013;44(10):10.1161/STROKEAHA.113.001447.
Background and Purpose
BDNF, a major neurotrophin and VEGF, an endothelial growth factor have a documented role in neurogenesis, angiogenesis and neuronal survival. In animal experiments they impact infarct size and functional motor recovery after an ischemic brain lesion. We sought to examine the association of serum BDNF and VEGF with the risk of clinical stroke or subclinical vascular brain injury in a community-based sample.
Methods
In 3440 stroke/TIA-free FHS participants (mean age 65±11yrs, 56%W), we related baseline BDNF and logVEGF to risk of incident stroke/TIA. In a subsample with brain MRI and with neuropsychological (NP) tests available (N=1863 and 2104, respectively; mean age 61±9yrs, 55%W, in each) we related baseline BDNF and logVEGF to log-white matter hyperintensity volume (lWMHV) on brain MRI, and to visuospatial memory and executive function tests.
Results
During a median follow-up of 10 years, 193 participants experienced incident stroke/TIA. In multivariable analyses adjusted for age-, sex- and traditional stroke risk factors, lower BDNF and higher logVEGF levels were associated with an increased risk of incident stroke/TIA (HR comparing BDNF Q1 versus Q2–4:1.47, 95%CI:1.09–2.00, p=0.012; and HR/SD increase in logVEGF:1.21, 95%CI:1.04–1.40, p=0.012). Persons with higher BDNF levels had less lWMHV (β±SE=−0.05±0.02; p=0.025), and better visual memory (β±SE=0.18±0.07; p=0.005).
Conclusions
Lower serum BDNF and higher VEGF concentrations were associated with increased risk of incident stroke/TIA. Higher levels of BDNF were also associated with less white matter hyperintensity and better visual memory. Our findings suggest that circulating BDNF and VEGF levels modify risk of clinical and subclinical vascular brain injury.
doi:10.1161/STROKEAHA.113.001447
PMCID: PMC3873715  PMID: 23929745
BDNF; VEGF; Risk; Stroke; Brain MRI; Subclinical
14.  Brain Imaging and Cognitive Predictors of Stroke and Alzheimer Disease in the Framingham Heart Study 
Background and purpose
Exposure to vascular risk factors has a gradual deleterious effect on brain MRI and cognitive measures. We explored whether a pattern of these measures exists that predicts stroke and Alzheimer’s disease (AD) risk.
Methods
A cognitive battery was administered to 1,679 dementia and stroke-free Framingham Offspring (age>55; mean=65.7±7.0) between 1999 and 2004; participants were also free of other neurological conditions that could affect cognition and >90% also had brain MRI examination. We related cognitive and MRI measures to risks of incident stroke and AD during up to 10 years of follow-up. As a secondary analysis, we explored these associations in the FHS Original cohort (mean age 67.5±7.3 and 84.8±3.3 at the cognitive assessment and MRI examination, respectively).
Results
A total of 55 Offspring participants sustained strokes and 31 developed AD. Offspring who scored <1.5 standard-deviations below predicted mean scores, for age and education, on an executive function test, had a higher risk of future stroke (HR=2.27;95%CI:1.06–4.85) and AD (3.60;95%CI:1.52–8.52); additional cognitive tests also predicted AD. Participants with low (<20%ile) total brain volume and high (>20%ile) white matter hyperintensity volume had a higher risk of stroke (HR=1.97;95%CI:1.03–3.77 and HR=2.74;95%CI:1.51–5.00, respectively) but not AD. Hippocampal volume at the bottom quintile predicted AD in the Offspring and Original cohorts (HR=4.41;95%CI:2.00–9.72 and HR=2.37;95%CI:1.12–5.00, respectively). A stepwise increase in stroke risk was apparent with increasing numbers of these cognitive and imagingmarkers.
Conclusions
Specific patterns of cognitive and brain structural measures observed even in early aging predict stroke risk and may serve as biomarkers for risk prediction.
doi:10.1161/STROKEAHA.113.000947
PMCID: PMC3974341  PMID: 23920020
stroke; Alzheimer’s disease; cognitive function; brain MRI
15.  A Multi-Ethnic Meta-Analysis of Genome-Wide Association Studies in Over 100,000 Subjects Identifies 23 Fibrinogen-Associated Loci but no Strong Evidence of a Causal Association between Circulating Fibrinogen and Cardiovascular Disease 
Sabater-Lleal, Maria | Huang, Jie | Chasman, Daniel | Naitza, Silvia | Dehghan, Abbas | Johnson, Andrew D | Teumer, Alexander | Reiner, Alex P | Folkersen, Lasse | Basu, Saonli | Rudnicka, Alicja R | Trompet, Stella | Mälarstig, Anders | Baumert, Jens | Bis, Joshua C. | Guo, Xiuqing | Hottenga, Jouke J | Shin, So-Youn | Lopez, Lorna M | Lahti, Jari | Tanaka, Toshiko | Yanek, Lisa R | Oudot-Mellakh, Tiphaine | Wilson, James F | Navarro, Pau | Huffman, Jennifer E | Zemunik, Tatijana | Redline, Susan | Mehra, Reena | Pulanic, Drazen | Rudan, Igor | Wright, Alan F | Kolcic, Ivana | Polasek, Ozren | Wild, Sarah H | Campbell, Harry | Curb, J David | Wallace, Robert | Liu, Simin | Eaton, Charles B. | Becker, Diane M. | Becker, Lewis C. | Bandinelli, Stefania | Räikkönen, Katri | Widen, Elisabeth | Palotie, Aarno | Fornage, Myriam | Green, David | Gross, Myron | Davies, Gail | Harris, Sarah E | Liewald, David C | Starr, John M | Williams, Frances M.K. | Grant, P.J. | Spector, Timothy D. | Strawbridge, Rona J | Silveira, Angela | Sennblad, Bengt | Rivadeneira, Fernando | Uitterlinden, Andre G | Franco, Oscar H | Hofman, Albert | van Dongen, Jenny | Willemsen, G | Boomsma, Dorret I | Yao, Jie | Jenny, Nancy Swords | Haritunians, Talin | McKnight, Barbara | Lumley, Thomas | Taylor, Kent D | Rotter, Jerome I | Psaty, Bruce M | Peters, Annette | Gieger, Christian | Illig, Thomas | Grotevendt, Anne | Homuth, Georg | Völzke, Henry | Kocher, Thomas | Goel, Anuj | Franzosi, Maria Grazia | Seedorf, Udo | Clarke, Robert | Steri, Maristella | Tarasov, Kirill V | Sanna, Serena | Schlessinger, David | Stott, David J | Sattar, Naveed | Buckley, Brendan M | Rumley, Ann | Lowe, Gordon D | McArdle, Wendy L | Chen, Ming-Huei | Tofler, Geoffrey H | Song, Jaejoon | Boerwinkle, Eric | Folsom, Aaron R. | Rose, Lynda M. | Franco-Cereceda, Anders | Teichert, Martina | Ikram, M Arfan | Mosley, Thomas H | Bevan, Steve | Dichgans, Martin | Rothwell, Peter M. | Sudlow, Cathie L M | Hopewell, Jemma C. | Chambers, John C. | Saleheen, Danish | Kooner, Jaspal S. | Danesh, John | Nelson, Christopher P | Erdmann, Jeanette | Reilly, Muredach P. | Kathiresan, Sekar | Schunkert, Heribert | Morange, Pierre-Emmanuel | Ferrucci, Luigi | Eriksson, Johan G | Jacobs, David | Deary, Ian J | Soranzo, Nicole | Witteman, Jacqueline CM | de Geus, Eco JC | Tracy, Russell P. | Hayward, Caroline | Koenig, Wolfgang | Cucca, Francesco | Jukema, J Wouter | Eriksson, Per | Seshadri, Sudha | Markus, Hugh S. | Watkins, Hugh | Samani, Nilesh J | Wallaschofski, Henri | Smith, Nicholas L. | Tregouet, David | Ridker, Paul M. | Tang, Weihong | Strachan, David P. | Hamsten, Anders | O’Donnell, Christopher J.
Circulation  2013;128(12):10.1161/CIRCULATIONAHA.113.002251.
Background
Estimates of the heritability of plasma fibrinogen concentration, an established predictor of cardiovascular disease (CVD), range from 34 to 50%. Genetic variants so far identified by genome-wide association (GWA) studies only explain a small proportion (< 2%) of its variation.
Methods and Results
We conducted a meta-analysis of 28 GWA studies, including more than 90,000 subjects of European ancestry, the first GWA meta-analysis of fibrinogen levels in 7 African Americans studies totaling 8,289 samples, and a GWA study in Hispanic-Americans totaling 1,366 samples. Evaluation for association of SNPs with clinical outcomes included a total of 40,695 cases and 85,582 controls for coronary artery disease (CAD), 4,752 cases and 24,030 controls for stroke, and 3,208 cases and 46,167 controls for venous thromboembolism (VTE). Overall, we identified 24 genome-wide significant (P<5×10−8) independent signals in 23 loci, including 15 novel associations, together accounting for 3.7% of plasma fibrinogen variation. Gene-set enrichment analysis highlighted key roles in fibrinogen regulation for the three structural fibrinogen genes and pathways related to inflammation, adipocytokines and thyrotrophin-releasing hormone signaling. Whereas lead SNPs in a few loci were significantly associated with CAD, the combined effect of all 24 fibrinogen-associated lead SNPs was not significant for CAD, stroke or VTE.
Conclusion
We identify 23 robustly associated fibrinogen loci, 15 of which are new. Clinical outcome analysis of these loci does not support a causal relationship between circulating levels of fibrinogen and CAD, stroke or VTE.
doi:10.1161/CIRCULATIONAHA.113.002251
PMCID: PMC3842025  PMID: 23969696
Fibrinogen; cardiovascular disease; genome-wide association study
16.  Relations of arterial stiffness and endothelial function to brain aging in the community 
Neurology  2013;81(11):984-991.
Objective:
To determine the association of arterial stiffness and pressure pulsatility, which can damage small vessels in the brain, with vascular and Alzheimer-type brain aging.
Methods:
Stroke- and dementia-free Framingham Offspring Study participants (n = 1,587, 61 ± 9 years, 45% male) underwent study of tonometric arterial stiffness and endothelial function (1998–2001) and brain MRI and cognition (1999–2002). We related carotid-femoral pulse wave velocity (CFPWV), mean arterial and central pulse pressure, and endothelial function to vascular brain aging by MRI (total cerebral brain volume [TCBV], white matter hyperintensity volume, silent cerebral infarcts) and vascular and Alzheimer-type cognitive aging (Trails B minus Trails A and logical memory-delayed recall, respectively).
Results:
Higher CFPWV was associated with lower TCBV, greater white matter hyperintensity volume, and greater prevalence of silent cerebral infarcts (all p < 0.05). Each SD greater CFPWV was associated with lower TCBV equivalent to 1.2 years of brain aging. Mean arterial and central pulse pressure were associated with greater white matter hyperintensity volume (p = 0.005) and lower TCBV (p = 0.02), respectively, and worse verbal memory (both p < 0.05). Associations of tonometry variables with TCBV and white matter hyperintensity volume were stronger among those aged 65 years and older vs those younger than 65 years (p < 0.10 for interaction). Brachial artery endothelial function was unrelated to MRI measures (all p > 0.05).
Conclusions:
Greater arterial stiffness and pressure pulsatility are associated with brain aging, MRI vascular insults, and memory deficits typically seen in Alzheimer dementia. Future investigations are warranted to evaluate the potential impact of prevention and treatment of unfavorable arterial hemodynamics on neurocognitive outcomes.
doi:10.1212/WNL.0b013e3182a43e1c
PMCID: PMC3888200  PMID: 23935179
18.  Meta-analysis in more than 17,900 cases of ischemic stroke reveals a novel association at 12q24.12 
Neurology  2014;83(8):678-685.
Objectives:
To perform a genome-wide association study (GWAS) using the Immunochip array in 3,420 cases of ischemic stroke and 6,821 controls, followed by a meta-analysis with data from more than 14,000 additional ischemic stroke cases.
Methods:
Using the Immunochip, we genotyped 3,420 ischemic stroke cases and 6,821 controls. After imputation we meta-analyzed the results with imputed GWAS data from 3,548 cases and 5,972 controls recruited from the ischemic stroke WTCCC2 study, and with summary statistics from a further 8,480 cases and 56,032 controls in the METASTROKE consortium. A final in silico “look-up” of 2 single nucleotide polymorphisms in 2,522 cases and 1,899 controls was performed. Associations were also examined in 1,088 cases with intracerebral hemorrhage and 1,102 controls.
Results:
In an overall analysis of 17,970 cases of ischemic stroke and 70,764 controls, we identified a novel association on chromosome 12q24 (rs10744777, odds ratio [OR] 1.10 [1.07–1.13], p = 7.12 × 10−11) with ischemic stroke. The association was with all ischemic stroke rather than an individual stroke subtype, with similar effect sizes seen in different stroke subtypes. There was no association with intracerebral hemorrhage (OR 1.03 [0.90–1.17], p = 0.695).
Conclusion:
Our results show, for the first time, a genetic risk locus associated with ischemic stroke as a whole, rather than in a subtype-specific manner. This finding was not associated with intracerebral hemorrhage.
doi:10.1212/WNL.0000000000000707
PMCID: PMC4150131  PMID: 25031287
19.  APOE genotype and MRI markers of cerebrovascular disease 
Neurology  2013;81(3):292-300.
Objective:
We aimed to examine the association of APOE ε genotype with MRI markers of cerebrovascular disease (CVD): white matter hyperintensities, brain infarcts, and cerebral microbleeds.
Methods:
We performed a systematic review and meta-analysis of 42 cross-sectional or longitudinal studies identified in PubMed from 1966 to June 2012 (n = 29,965). This included unpublished data from 3 population-based studies: 3C-Dijon, Framingham Heart Study, and Sydney Memory and Ageing Study. When necessary, authors were contacted to provide effect estimates for the meta-analysis.
Results:
APOE ε4 carrier status and APOE ε44 genotype were associated with increasing white matter hyperintensity burden (sample size–weighted z score meta-analysis [meta]-p = 0.0034 and 0.0030) and presence of cerebral microbleeds (meta odds ratio [OR] = 1.24, 95% confidence interval [CI] [1.07, 1.43], p = 0.004, and 1.87 [1.26, 2.78], p = 0.002), especially lobar. APOE ε2 carrier status was associated with increasing white matter hyperintensity load (z score meta-p = 0.00053) and risk of brain infarct (meta OR = 1.41[1.09, 1.81], p = 0.008).
Conclusions:
APOE ε4 and APOE ε2 were associated with increasing burden in MRI markers for both hemorrhagic and ischemic CVD. While the association of APOE ε4 with an increased burden of CVD could be partly contributing to the relationship between APOE ε4 and AD, APOE ε2 was associated with MRI markers of CVD in the opposite direction compared to AD.
doi:10.1212/WNL.0b013e31829bfda4
PMCID: PMC3770168  PMID: 23858411
20.  Lexical retrieval in discourse: An early indicator of Alzheimer's dementia 
Clinical linguistics & phonetics  2013;27(12):905-921.
We examined the progression of lexical-retrieval deficits in individuals with neuropathologically determined Alzheimer's disease (AD; n = 23) and a comparison group without criteria for AD (n = 24) to determine whether linguistic changes were a significant marker of the disease. Our participants underwent multiple administrations of a neuropsychological battery, with initial administration occurring on average 16 years prior to death. The battery included the Boston Naming Test (BNT), a letter fluency task (FAS), and written description of the Cookie Theft Picture (CTP).
Repeated measures analysis revealed that the AD-group showed progressively greater decline in FAS and CTP lexical performance than the comparison group. Cross-sectional time-specific group comparisons indicated that the CTP differentiated performance between the two groups at 7–9 years prior to death and FAS and BNT only at 2–4 years. These results suggest that lexical-retrieval deficits in written discourse serve as an early indicator of AD.
doi:10.3109/02699206.2013.815278
PMCID: PMC4095845  PMID: 23985011
discourse; naming; early markers; neuropathology; Alzheimer's disease
21.  Associations of NINJ2 Sequence Variants with Incident Ischemic Stroke in the Cohorts for Heart and Aging in Genomic Epidemiology (CHARGE) Consortium 
PLoS ONE  2014;9(6):e99798.
Background
Stroke, the leading neurologic cause of death and disability, has a substantial genetic component. We previously conducted a genome-wide association study (GWAS) in four prospective studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and demonstrated that sequence variants near the NINJ2 gene are associated with incident ischemic stroke. Here, we sought to fine-map functional variants in the region and evaluate the contribution of rare variants to ischemic stroke risk.
Methods and Results
We sequenced 196 kb around NINJ2 on chromosome 12p13 among 3,986 European ancestry participants, including 475 ischemic stroke cases, from the Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, and Framingham Heart Study. Meta-analyses of single-variant tests for 425 common variants (minor allele frequency [MAF] ≥ 1%) confirmed the original GWAS results and identified an independent intronic variant, rs34166160 (MAF = 0.012), most significantly associated with incident ischemic stroke (HR = 1.80, p = 0.0003). Aggregating 278 putatively-functional variants with MAF≤ 1% using count statistics, we observed a nominally statistically significant association, with the burden of rare NINJ2 variants contributing to decreased ischemic stroke incidence (HR = 0.81; p = 0.026).
Conclusion
Common and rare variants in the NINJ2 region were nominally associated with incident ischemic stroke among a subset of CHARGE participants. Allelic heterogeneity at this locus, caused by multiple rare, low frequency, and common variants with disparate effects on risk, may explain the difficulties in replicating the original GWAS results. Additional studies that take into account the complex allelic architecture at this locus are needed to confirm these findings.
doi:10.1371/journal.pone.0099798
PMCID: PMC4069013  PMID: 24959832
22.  Serum Brain-Derived Neurotrophic Factor and the Risk for Dementia 
JAMA neurology  2014;71(1):55-61.
IMPORTANCE
In animal studies, brain-derived neurotrophic factor (BDNF) has been shown to impact neuronal survival and function and improve synaptic plasticity and long-term memory. Circulating BDNF levels increase with physical activity and caloric restriction, thus BDNF may mediate some of the observed associations between lifestyle and the risk for dementia. Some prior studies showed lower circulating BDNF in persons with Alzheimer disease (AD) compared with control participants; however, it remains uncertain whether reduced levels precede dementia onset.
OBJECTIVE
To examine whether higher serum BDNF levels in cognitively healthy adults protect against the future risk for dementia and AD and to identify potential modifiers of this association.
DESIGN, SETTING, AND PARTICIPANTS
Framingham Study original and offspring participants were followed up from 1992 and 1998, respectively, for up to 10 years. We used Cox models to relate BDNF levels to the risk for dementia and AD and adjusted for potential confounders. We also ran sensitivity analyses stratified by sex, age, and education, as well as related BDNF genetic variants to AD risk. This community-based, prospective cohort study involved 2131 dementia-free participants aged 60 years and older (mean [SD] age, 72 [7] years; 56% women).
MAIN OUTCOMES AND MEASURES
Ten-year incidence of dementia and AD.
RESULTS
During follow-up, 140 participants developed dementia, 117 of whom had AD. Controlling for age and sex, each standard-deviation increment in BDNF was associated with a 33% lower risk for dementia and AD (P = .006 and P = .01, respectively) and these associations persisted after additional adjustments. Compared with the bottom quintile, BDNF levels in the top quintile were associated with less than half the risk for dementia and AD (hazard ratio, 0.49; 95%CI, 0.28–0.85; P = .01; and hazard ratio, 0.46; 95%CI, 0.24–0.86; P = .02, respectively). These associations were apparent only among women, persons aged 80 years and older, and those with college degrees (hazard ratios for AD: 0.65, [95%CI, 0.50–0.85], P = .001; 0.63 [95%CI, 0.47–0.85], P = .002; and 0.27 [95%CI, 0.11–0.65], P = .003, respectively). Brain-derived neurotrophic factor genetic variants were not associated with AD risk.
CONCLUSIONS AND RELEVANCE
Higher serum BDNF levels may protect against future occurrence of dementia and AD. Our findings suggest a role for BDNF in the biology and possibly in the prevention of dementia and AD, especially in select subgroups of women and older and more highly educated persons.
doi:10.1001/jamaneurol.2013.4781
PMCID: PMC4056186  PMID: 24276217
23.  Gene-Wide Analysis Detects Two New Susceptibility Genes for Alzheimer's Disease 
Escott-Price, Valentina | Bellenguez, Céline | Wang, Li-San | Choi, Seung-Hoan | Harold, Denise | Jones, Lesley | Holmans, Peter | Gerrish, Amy | Vedernikov, Alexey | Richards, Alexander | DeStefano, Anita L. | Lambert, Jean-Charles | Ibrahim-Verbaas, Carla A. | Naj, Adam C. | Sims, Rebecca | Jun, Gyungah | Bis, Joshua C. | Beecham, Gary W. | Grenier-Boley, Benjamin | Russo, Giancarlo | Thornton-Wells, Tricia A. | Denning, Nicola | Smith, Albert V. | Chouraki, Vincent | Thomas, Charlene | Ikram, M. Arfan | Zelenika, Diana | Vardarajan, Badri N. | Kamatani, Yoichiro | Lin, Chiao-Feng | Schmidt, Helena | Kunkle, Brian | Dunstan, Melanie L. | Vronskaya, Maria | Johnson, Andrew D. | Ruiz, Agustin | Bihoreau, Marie-Thérèse | Reitz, Christiane | Pasquier, Florence | Hollingworth, Paul | Hanon, Olivier | Fitzpatrick, Annette L. | Buxbaum, Joseph D. | Campion, Dominique | Crane, Paul K. | Baldwin, Clinton | Becker, Tim | Gudnason, Vilmundur | Cruchaga, Carlos | Craig, David | Amin, Najaf | Berr, Claudine | Lopez, Oscar L. | De Jager, Philip L. | Deramecourt, Vincent | Johnston, Janet A. | Evans, Denis | Lovestone, Simon | Letenneur, Luc | Hernández, Isabel | Rubinsztein, David C. | Eiriksdottir, Gudny | Sleegers, Kristel | Goate, Alison M. | Fiévet, Nathalie | Huentelman, Matthew J. | Gill, Michael | Brown, Kristelle | Kamboh, M. Ilyas | Keller, Lina | Barberger-Gateau, Pascale | McGuinness, Bernadette | Larson, Eric B. | Myers, Amanda J. | Dufouil, Carole | Todd, Stephen | Wallon, David | Love, Seth | Rogaeva, Ekaterina | Gallacher, John | George-Hyslop, Peter St | Clarimon, Jordi | Lleo, Alberto | Bayer, Anthony | Tsuang, Debby W. | Yu, Lei | Tsolaki, Magda | Bossù, Paola | Spalletta, Gianfranco | Proitsi, Petra | Collinge, John | Sorbi, Sandro | Garcia, Florentino Sanchez | Fox, Nick C. | Hardy, John | Naranjo, Maria Candida Deniz | Bosco, Paolo | Clarke, Robert | Brayne, Carol | Galimberti, Daniela | Scarpini, Elio | Bonuccelli, Ubaldo | Mancuso, Michelangelo | Siciliano, Gabriele | Moebus, Susanne | Mecocci, Patrizia | Zompo, Maria Del | Maier, Wolfgang | Hampel, Harald | Pilotto, Alberto | Frank-García, Ana | Panza, Francesco | Solfrizzi, Vincenzo | Caffarra, Paolo | Nacmias, Benedetta | Perry, William | Mayhaus, Manuel | Lannfelt, Lars | Hakonarson, Hakon | Pichler, Sabrina | Carrasquillo, Minerva M. | Ingelsson, Martin | Beekly, Duane | Alvarez, Victoria | Zou, Fanggeng | Valladares, Otto | Younkin, Steven G. | Coto, Eliecer | Hamilton-Nelson, Kara L. | Gu, Wei | Razquin, Cristina | Pastor, Pau | Mateo, Ignacio | Owen, Michael J. | Faber, Kelley M. | Jonsson, Palmi V. | Combarros, Onofre | O'Donovan, Michael C. | Cantwell, Laura B. | Soininen, Hilkka | Blacker, Deborah | Mead, Simon | Mosley, Thomas H. | Bennett, David A. | Harris, Tamara B. | Fratiglioni, Laura | Holmes, Clive | de Bruijn, Renee F. A. G. | Passmore, Peter | Montine, Thomas J. | Bettens, Karolien | Rotter, Jerome I. | Brice, Alexis | Morgan, Kevin | Foroud, Tatiana M. | Kukull, Walter A. | Hannequin, Didier | Powell, John F. | Nalls, Michael A. | Ritchie, Karen | Lunetta, Kathryn L. | Kauwe, John S. K. | Boerwinkle, Eric | Riemenschneider, Matthias | Boada, Mercè | Hiltunen, Mikko | Martin, Eden R. | Schmidt, Reinhold | Rujescu, Dan | Dartigues, Jean-François | Mayeux, Richard | Tzourio, Christophe | Hofman, Albert | Nöthen, Markus M. | Graff, Caroline | Psaty, Bruce M. | Haines, Jonathan L. | Lathrop, Mark | Pericak-Vance, Margaret A. | Launer, Lenore J. | Van Broeckhoven, Christine | Farrer, Lindsay A. | van Duijn, Cornelia M. | Ramirez, Alfredo | Seshadri, Sudha | Schellenberg, Gerard D. | Amouyel, Philippe | Williams, Julie
PLoS ONE  2014;9(6):e94661.
Background
Alzheimer's disease is a common debilitating dementia with known heritability, for which 20 late onset susceptibility loci have been identified, but more remain to be discovered. This study sought to identify new susceptibility genes, using an alternative gene-wide analytical approach which tests for patterns of association within genes, in the powerful genome-wide association dataset of the International Genomics of Alzheimer's Project Consortium, comprising over 7 m genotypes from 25,580 Alzheimer's cases and 48,466 controls.
Principal Findings
In addition to earlier reported genes, we detected genome-wide significant loci on chromosomes 8 (TP53INP1, p = 1.4×10−6) and 14 (IGHV1-67 p = 7.9×10−8) which indexed novel susceptibility loci.
Significance
The additional genes identified in this study, have an array of functions previously implicated in Alzheimer's disease, including aspects of energy metabolism, protein degradation and the immune system and add further weight to these pathways as potential therapeutic targets in Alzheimer's disease.
doi:10.1371/journal.pone.0094661
PMCID: PMC4055488  PMID: 24922517
24.  Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer’s disease 
Lambert, Jean-Charles | Ibrahim-Verbaas, Carla A | Harold, Denise | Naj, Adam C | Sims, Rebecca | Bellenguez, Céline | Jun, Gyungah | DeStefano, Anita L | Bis, Joshua C | Beecham, Gary W | Grenier-Boley, Benjamin | Russo, Giancarlo | Thornton-Wells, Tricia A | Jones, Nicola | Smith, Albert V | Chouraki, Vincent | Thomas, Charlene | Ikram, M Arfan | Zelenika, Diana | Vardarajan, Badri N | Kamatani, Yoichiro | Lin, Chiao-Feng | Gerrish, Amy | Schmidt, Helena | Kunkle, Brian | Dunstan, Melanie L | Ruiz, Agustin | Bihoreau, Marie-Thérèse | Choi, Seung-Hoan | Reitz, Christiane | Pasquier, Florence | Hollingworth, Paul | Ramirez, Alfredo | Hanon, Olivier | Fitzpatrick, Annette L | Buxbaum, Joseph D | Campion, Dominique | Crane, Paul K | Baldwin, Clinton | Becker, Tim | Gudnason, Vilmundur | Cruchaga, Carlos | Craig, David | Amin, Najaf | Berr, Claudine | Lopez, Oscar L | De Jager, Philip L | Deramecourt, Vincent | Johnston, Janet A | Evans, Denis | Lovestone, Simon | Letenneur, Luc | Morón, Francisco J | Rubinsztein, David C | Eiriksdottir, Gudny | Sleegers, Kristel | Goate, Alison M | Fiévet, Nathalie | Huentelman, Matthew J | Gill, Michael | Brown, Kristelle | Kamboh, M Ilyas | Keller, Lina | Barberger-Gateau, Pascale | McGuinness, Bernadette | Larson, Eric B | Green, Robert | Myers, Amanda J | Dufouil, Carole | Todd, Stephen | Wallon, David | Love, Seth | Rogaeva, Ekaterina | Gallacher, John | St George-Hyslop, Peter | Clarimon, Jordi | Lleo, Alberto | Bayer, Anthony | Tsuang, Debby W | Yu, Lei | Tsolaki, Magda | Bossù, Paola | Spalletta, Gianfranco | Proitsi, Petroula | Collinge, John | Sorbi, Sandro | Sanchez-Garcia, Florentino | Fox, Nick C | Hardy, John | Deniz Naranjo, Maria Candida | Bosco, Paolo | Clarke, Robert | Brayne, Carol | Galimberti, Daniela | Mancuso, Michelangelo | Matthews, Fiona | Moebus, Susanne | Mecocci, Patrizia | Zompo, Maria Del | Maier, Wolfgang | Hampel, Harald | Pilotto, Alberto | Bullido, Maria | Panza, Francesco | Caffarra, Paolo | Nacmias, Benedetta | Gilbert, John R | Mayhaus, Manuel | Lannfelt, Lars | Hakonarson, Hakon | Pichler, Sabrina | Carrasquillo, Minerva M | Ingelsson, Martin | Beekly, Duane | Alvarez, Victoria | Zou, Fanggeng | Valladares, Otto | Younkin, Steven G | Coto, Eliecer | Hamilton-Nelson, Kara L | Gu, Wei | Razquin, Cristina | Pastor, Pau | Mateo, Ignacio | Owen, Michael J | Faber, Kelley M | Jonsson, Palmi V | Combarros, Onofre | O’Donovan, Michael C | Cantwell, Laura B | Soininen, Hilkka | Blacker, Deborah | Mead, Simon | Mosley, Thomas H | Bennett, David A | Harris, Tamara B | Fratiglioni, Laura | Holmes, Clive | de Bruijn, Renee F A G | Passmore, Peter | Montine, Thomas J | Bettens, Karolien | Rotter, Jerome I | Brice, Alexis | Morgan, Kevin | Foroud, Tatiana M | Kukull, Walter A | Hannequin, Didier | Powell, John F | Nalls, Michael A | Ritchie, Karen | Lunetta, Kathryn L | Kauwe, John S K | Boerwinkle, Eric | Riemenschneider, Matthias | Boada, Mercè | Hiltunen, Mikko | Martin, Eden R | Schmidt, Reinhold | Rujescu, Dan | Wang, Li-san | Dartigues, Jean-François | Mayeux, Richard | Tzourio, Christophe | Hofman, Albert | Nöthen, Markus M | Graff, Caroline | Psaty, Bruce M | Jones, Lesley | Haines, Jonathan L | Holmans, Peter A | Lathrop, Mark | Pericak-Vance, Margaret A | Launer, Lenore J | Farrer, Lindsay A | van Duijn, Cornelia M | Van Broeckhoven, Christine | Moskvina, Valentina | Seshadri, Sudha | Williams, Julie | Schellenberg, Gerard D | Amouyel, Philippe
Nature genetics  2013;45(12):1452-1458.
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.
doi:10.1038/ng.2802
PMCID: PMC3896259  PMID: 24162737
25.  Genome-Wide Meta-Analysis of Homocysteine and Methionine Metabolism Identifies Five One Carbon Metabolism Loci and a Novel Association of ALDH1L1 with Ischemic Stroke 
PLoS Genetics  2014;10(3):e1004214.
Circulating homocysteine levels (tHcy), a product of the folate one carbon metabolism pathway (FOCM) through the demethylation of methionine, are heritable and are associated with an increased risk of common diseases such as stroke, cardiovascular disease (CVD), cancer and dementia. The FOCM is the sole source of de novo methyl group synthesis, impacting many biological and epigenetic pathways. However, the genetic determinants of elevated tHcy (hyperhomocysteinemia), dysregulation of methionine metabolism and the underlying biological processes remain unclear. We conducted independent genome-wide association studies and a meta-analysis of methionine metabolism, characterized by post-methionine load test tHcy, in 2,710 participants from the Framingham Heart Study (FHS) and 2,100 participants from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial, and then examined the association of the identified loci with incident stroke in FHS. Five genes in the FOCM pathway (GNMT [p = 1.60×10−63], CBS [p = 3.15×10−26], CPS1 [p = 9.10×10−13], ALDH1L1 [p = 7.3×10−13] and PSPH [p = 1.17×10−16]) were strongly associated with the difference between pre- and post-methionine load test tHcy levels (ΔPOST). Of these, one variant in the ALDH1L1 locus, rs2364368, was associated with incident ischemic stroke. Promoter analyses reveal genetic and epigenetic differences that may explain a direct effect on GNMT transcription and a downstream affect on methionine metabolism. Additionally, a genetic-score consisting of the five significant loci explains 13% of the variance of ΔPOST in FHS and 6% of the variance in VISP. Association between variants in FOCM genes with ΔPOST suggest novel mechanisms that lead to differences in methionine metabolism, and possibly the epigenome, impacting disease risk. These data emphasize the importance of a concerted effort to understand regulators of one carbon metabolism as potential therapeutic targets.
Author Summary
Elevated homocysteine (tHcy) is strongly associated with risk for common disorders such as stroke, cardiovascular disease and Alzheimer disease. Lowering tHcy levels has proven to have variable success in reducing clinical risk, so the question remains, “Are we correctly targeting these disorders by lowering tHcy?” Understanding folate one-carbon metabolism pathway (FOCM) genetic variation will aid us in developing new targets for therapy. The FOCM is essential in regulation of the epigenome, which controls genes in ways beyond nucleotide sequence. We present data generated from stroke-only and general populations where we identify strong association of genetic risk factors for variation in one-carbon metabolism function, characterized by the post-methionine load test. We show that GNMT harbors genetic and epigenetic differences that influence gene function, which may have downstream effects on the epigenome of the cell, affecting disease risk. We developed a genetic risk score that predicts post-methionine load homocysteine levels that may be useful in clinic. Finally, we identified a novel association between ischemic stroke and ALDH1L1, which emphasizes the clinical importance of this work. Our results highlight the importance of a concerted effort to target the FOCM (beyond tHcy) and parallel pathways in future pharmacogenetic work using the genetic variation we describe here.
doi:10.1371/journal.pgen.1004214
PMCID: PMC3961178  PMID: 24651765

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