@article {6548, title = {Associations of NINJ2 sequence variants with incident ischemic stroke in the Cohorts for Heart and Aging in Genomic Epidemiology (CHARGE) consortium.}, journal = {PLoS One}, volume = {9}, year = {2014}, month = {2014}, pages = {e99798}, abstract = {

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.

}, keywords = {Cell Adhesion Molecules, Neuronal, European Continental Ancestry Group, Female, Genetic Association Studies, Genetic Heterogeneity, Humans, Introns, Ischemia, Male, Myocardial Infarction, Polymorphism, Single Nucleotide, Prospective Studies, Sequence Analysis, DNA}, issn = {1932-6203}, doi = {10.1371/journal.pone.0099798}, author = {Bis, Joshua C and DeStefano, Anita and Liu, Xiaoming and Brody, Jennifer A and Choi, Seung Hoan and Verhaaren, Benjamin F J and Debette, Stephanie and Ikram, M Arfan and Shahar, Eyal and Butler, Kenneth R and Gottesman, Rebecca F and Muzny, Donna and Kovar, Christie L and Psaty, Bruce M and Hofman, Albert and Lumley, Thomas and Gupta, Mayetri and Wolf, Philip A and van Duijn, Cornelia and Gibbs, Richard A and Mosley, Thomas H and Longstreth, W T and Boerwinkle, Eric and Seshadri, Sudha and Fornage, Myriam} } @article {6297, title = {Multilocus genetic risk score associates with ischemic stroke in case-control and prospective cohort studies.}, journal = {Stroke}, volume = {45}, year = {2014}, month = {2014 Feb}, pages = {394-402}, abstract = {

BACKGROUND AND PURPOSE: Genome-wide association studies have revealed multiple common variants associated with known risk factors for ischemic stroke (IS). However, their aggregate effect on risk is uncertain. We aimed to generate a multilocus genetic risk score (GRS) for IS based on genome-wide association studies data from clinical-based samples and to establish its external validity in prospective population-based cohorts.

METHODS: Three thousand five hundred forty-eight clinic-based IS cases and 6399 controls from the Wellcome Trust Case Control Consortium 2 were used for derivation of the GRS. Subjects from the METASTROKE consortium served as a replication sample. The validation sample consisted of 22 751 participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium. We selected variants that had reached genome-wide significance in previous association studies on established risk factors for IS.

RESULTS: A combined GRS for atrial fibrillation, coronary artery disease, hypertension, and systolic blood pressure significantly associated with IS both in the case-control samples and in the prospective population-based studies. Subjects in the top quintile of the combined GRS had >2-fold increased risk of IS compared with subjects in the lowest quintile. Addition of the combined GRS to a simple model based on sex significantly improved the prediction of IS in the combined clinic-based samples but not in the population-based studies, and there was no significant improvement in net reclassification.

CONCLUSIONS: A multilocus GRS based on common variants for established cardiovascular risk factors was significantly associated with IS both in clinic-based samples and in the general population. However, the improvement in clinical risk prediction was found to be small.

}, keywords = {Adult, Aged, Aged, 80 and over, Atrial Fibrillation, Blood Pressure, Brain Ischemia, Case-Control Studies, Cohort Studies, Coronary Artery Disease, Female, Genetic Predisposition to Disease, Genetic Variation, Genome-Wide Association Study, Humans, Hypertension, Male, Middle Aged, Multilocus Sequence Typing, Polymorphism, Single Nucleotide, Population, Prospective Studies, Reproducibility of Results, Risk Assessment, Risk Factors, Sex Factors, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.113.002938}, author = {Malik, Rainer and Bevan, Steve and Nalls, Michael A and Holliday, Elizabeth G and Devan, William J and Cheng, Yu-Ching and Ibrahim-Verbaas, Carla A and Verhaaren, Benjamin F J and Bis, Joshua C and Joon, Aron Y and de Stefano, Anita L and Fornage, Myriam and Psaty, Bruce M and Ikram, M Arfan and Launer, Lenore J and van Duijn, Cornelia M and Sharma, Pankaj and Mitchell, Braxton D and Rosand, Jonathan and Meschia, James F and Levi, Christopher and Rothwell, Peter M and Sudlow, Cathie and Markus, Hugh S and Seshadri, Sudha and Dichgans, Martin} } @article {6683, title = {Multiethnic genome-wide association study of cerebral white matter hyperintensities on MRI.}, journal = {Circ Cardiovasc Genet}, volume = {8}, year = {2015}, month = {2015 Apr}, pages = {398-409}, abstract = {

BACKGROUND: The burden of cerebral white matter hyperintensities (WMH) is associated with an increased risk of stroke, dementia, and death. WMH are highly heritable, but their genetic underpinnings are incompletely characterized. To identify novel genetic variants influencing WMH burden, we conducted a meta-analysis of multiethnic genome-wide association studies.

METHODS AND RESULTS: We included 21 079 middle-aged to elderly individuals from 29 population-based cohorts, who were free of dementia and stroke and were of European (n=17 936), African (n=1943), Hispanic (n=795), and Asian (n=405) descent. WMH burden was quantified on MRI either by a validated automated segmentation method or a validated visual grading scale. Genotype data in each study were imputed to the 1000 Genomes reference. Within each ethnic group, we investigated the relationship between each single-nucleotide polymorphism and WMH burden using a linear regression model adjusted for age, sex, intracranial volume, and principal components of ancestry. A meta-analysis was conducted for each ethnicity separately and for the combined sample. In the European descent samples, we confirmed a previously known locus on chr17q25 (P=2.7{\texttimes}10(-19)) and identified novel loci on chr10q24 (P=1.6{\texttimes}10(-9)) and chr2p21 (P=4.4{\texttimes}10(-8)). In the multiethnic meta-analysis, we identified 2 additional loci, on chr1q22 (P=2.0{\texttimes}10(-8)) and chr2p16 (P=1.5{\texttimes}10(-8)). The novel loci contained genes that have been implicated in Alzheimer disease (chr2p21 and chr10q24), intracerebral hemorrhage (chr1q22), neuroinflammatory diseases (chr2p21), and glioma (chr10q24 and chr2p16).

CONCLUSIONS: We identified 4 novel genetic loci that implicate inflammatory and glial proliferative pathways in the development of WMH in addition to previously proposed ischemic mechanisms.

}, keywords = {Aged, Aged, 80 and over, Chromosomes, Human, Continental Population Groups, Female, Genetic Loci, Genome-Wide Association Study, Humans, Male, Meta-Analysis as Topic, Middle Aged, Models, Genetic, Stroke, White Matter}, issn = {1942-3268}, doi = {10.1161/CIRCGENETICS.114.000858}, author = {Verhaaren, Benjamin F J and Debette, Stephanie and Bis, Joshua C and Smith, Jennifer A and Ikram, M Kamran and Adams, Hieab H and Beecham, Ashley H and Rajan, Kumar B and Lopez, Lorna M and Barral, Sandra and van Buchem, Mark A and van der Grond, Jeroen and Smith, Albert V and Hegenscheid, Katrin and Aggarwal, Neelum T and de Andrade, Mariza and Atkinson, Elizabeth J and Beekman, Marian and Beiser, Alexa S and Blanton, Susan H and Boerwinkle, Eric and Brickman, Adam M and Bryan, R Nick and Chauhan, Ganesh and Chen, Christopher P L H and Chouraki, Vincent and de Craen, Anton J M and Crivello, Fabrice and Deary, Ian J and Deelen, Joris and De Jager, Philip L and Dufouil, Carole and Elkind, Mitchell S V and Evans, Denis A and Freudenberger, Paul and Gottesman, Rebecca F and Gu{\dh}nason, Vilmundur and Habes, Mohamad and Heckbert, Susan R and Heiss, Gerardo and Hilal, Saima and Hofer, Edith and Hofman, Albert and Ibrahim-Verbaas, Carla A and Knopman, David S and Lewis, Cora E and Liao, Jiemin and Liewald, David C M and Luciano, Michelle and van der Lugt, Aad and Martinez, Oliver O and Mayeux, Richard and Mazoyer, Bernard and Nalls, Mike and Nauck, Matthias and Niessen, Wiro J and Oostra, Ben A and Psaty, Bruce M and Rice, Kenneth M and Rotter, Jerome I and von Sarnowski, Bettina and Schmidt, Helena and Schreiner, Pamela J and Schuur, Maaike and Sidney, Stephen S and Sigurdsson, Sigurdur and Slagboom, P Eline and Stott, David J M and van Swieten, John C and Teumer, Alexander and T{\"o}glhofer, Anna Maria and Traylor, Matthew and Trompet, Stella and Turner, Stephen T and Tzourio, Christophe and Uh, Hae-Won and Uitterlinden, Andr{\'e} G and Vernooij, Meike W and Wang, Jing J and Wong, Tien Y and Wardlaw, Joanna M and Windham, B Gwen and Wittfeld, Katharina and Wolf, Christiane and Wright, Clinton B and Yang, Qiong and Zhao, Wei and Zijdenbos, Alex and Jukema, J Wouter and Sacco, Ralph L and Kardia, Sharon L R and Amouyel, Philippe and Mosley, Thomas H and Longstreth, W T and DeCarli, Charles C and van Duijn, Cornelia M and Schmidt, Reinhold and Launer, Lenore J and Grabe, Hans J and Seshadri, Sudha S and Ikram, M Arfan and Fornage, Myriam} } @article {6861, title = {White Matter Lesion Progression: Genome-Wide Search for Genetic Influences.}, journal = {Stroke}, volume = {46}, year = {2015}, month = {2015 Nov}, pages = {3048-57}, abstract = {

BACKGROUND AND PURPOSE: White matter lesion (WML) progression on magnetic resonance imaging is related to cognitive decline and stroke, but its determinants besides baseline WML burden are largely unknown. Here, we estimated heritability of WML progression, and sought common genetic variants associated with WML progression in elderly participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium.

METHODS: Heritability of WML progression was calculated in the Framingham Heart Study. The genome-wide association study included 7773 elderly participants from 10 cohorts. To assess the relative contribution of genetic factors to progression of WML, we compared in 7 cohorts risk models including demographics, vascular risk factors plus single-nucleotide polymorphisms that have been shown to be associated cross-sectionally with WML in the current and previous association studies.

RESULTS: A total of 1085 subjects showed WML progression. The heritability estimate for WML progression was low at 6.5\%, and no single-nucleotide polymorphisms achieved genome-wide significance (P<5{\texttimes}10(-8)). Four loci were suggestive (P<1{\texttimes}10(-5)) of an association with WML progression: 10q24.32 (rs10883817, P=1.46{\texttimes}10(-6)); 12q13.13 (rs4761974, P=8.71{\texttimes}10(-7)); 20p12.1 (rs6135309, P=3.69{\texttimes}10(-6)); and 4p15.31 (rs7664442, P=2.26{\texttimes}10(-6)). Variants that have been previously related to WML explained only 0.8\% to 11.7\% more of the variance in WML progression than age, vascular risk factors, and baseline WML burden.

CONCLUSIONS: Common genetic factors contribute little to the progression of age-related WML in middle-aged and older adults. Future research on determinants of WML progression should focus more on environmental, lifestyle, or host-related biological factors.

}, keywords = {Adult, Aged, Cohort Studies, Disease Progression, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Leukoencephalopathies, Male, Middle Aged, Prospective Studies, White Matter}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.115.009252}, author = {Hofer, Edith and Cavalieri, Margherita and Bis, Joshua C and DeCarli, Charles and Fornage, Myriam and Sigurdsson, Sigurdur and Srikanth, Velandai and Trompet, Stella and Verhaaren, Benjamin F J and Wolf, Christiane and Yang, Qiong and Adams, Hieab H H and Amouyel, Philippe and Beiser, Alexa and Buckley, Brendan M and Callisaya, Michele and Chauhan, Ganesh and de Craen, Anton J M and Dufouil, Carole and van Duijn, Cornelia M and Ford, Ian and Freudenberger, Paul and Gottesman, Rebecca F and Gudnason, Vilmundur and Heiss, Gerardo and Hofman, Albert and Lumley, Thomas and Martinez, Oliver and Mazoyer, Bernard and Moran, Chris and Niessen, Wiro J and Phan, Thanh and Psaty, Bruce M and Satizabal, Claudia L and Sattar, Naveed and Schilling, Sabrina and Shibata, Dean K and Slagboom, P Eline and Smith, Albert and Stott, David J and Taylor, Kent D and Thomson, Russell and T{\"o}glhofer, Anna M and Tzourio, Christophe and van Buchem, Mark and Wang, Jing and Westendorp, Rudi G J and Windham, B Gwen and Vernooij, Meike W and Zijdenbos, Alex and Beare, Richard and Debette, Stephanie and Ikram, M Arfan and Jukema, J Wouter and Launer, Lenore J and Longstreth, W T and Mosley, Thomas H and Seshadri, Sudha and Schmidt, Helena and Schmidt, Reinhold} }