@article {5863, title = {Genetic risk factors for ischaemic stroke and its subtypes (the METASTROKE collaboration): a meta-analysis of genome-wide association studies.}, journal = {Lancet Neurol}, volume = {11}, year = {2012}, month = {2012 Nov}, pages = {951-62}, abstract = {

BACKGROUND: Various genome-wide association studies (GWAS) have been done in ischaemic stroke, identifying a few loci associated with the disease, but sample sizes have been 3500 cases or less. We established the METASTROKE collaboration with the aim of validating associations from previous GWAS and identifying novel genetic associations through meta-analysis of GWAS datasets for ischaemic stroke and its subtypes.

METHODS: We meta-analysed data from 15 ischaemic stroke cohorts with a total of 12 389 individuals with ischaemic stroke and 62 004 controls, all of European ancestry. For the associations reaching genome-wide significance in METASTROKE, we did a further analysis, conditioning on the lead single nucleotide polymorphism in every associated region. Replication of novel suggestive signals was done in 13 347 cases and 29 083 controls.

FINDINGS: We verified previous associations for cardioembolic stroke near PITX2 (p=2{\textperiodcentered}8{\texttimes}10(-16)) and ZFHX3 (p=2{\textperiodcentered}28{\texttimes}10(-8)), and for large-vessel stroke at a 9p21 locus (p=3{\textperiodcentered}32{\texttimes}10(-5)) and HDAC9 (p=2{\textperiodcentered}03{\texttimes}10(-12)). Additionally, we verified that all associations were subtype specific. Conditional analysis in the three regions for which the associations reached genome-wide significance (PITX2, ZFHX3, and HDAC9) indicated that all the signal in each region could be attributed to one risk haplotype. We also identified 12 potentially novel loci at p<5{\texttimes}10(-6). However, we were unable to replicate any of these novel associations in the replication cohort.

INTERPRETATION: Our results show that, although genetic variants can be detected in patients with ischaemic stroke when compared with controls, all associations we were able to confirm are specific to a stroke subtype. This finding has two implications. First, to maximise success of genetic studies in ischaemic stroke, detailed stroke subtyping is required. Second, different genetic pathophysiological mechanisms seem to be associated with different stroke subtypes.

FUNDING: Wellcome Trust, UK Medical Research Council (MRC), Australian National and Medical Health Research Council, National Institutes of Health (NIH) including National Heart, Lung and Blood Institute (NHLBI), the National Institute on Aging (NIA), the National Human Genome Research Institute (NHGRI), and the National Institute of Neurological Disorders and Stroke (NINDS).

}, keywords = {Brain Ischemia, Databases, Genetic, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Risk Factors, Stroke}, issn = {1474-4465}, doi = {10.1016/S1474-4422(12)70234-X}, author = {Traylor, Matthew and Farrall, Martin and Holliday, Elizabeth G and Sudlow, Cathie and Hopewell, Jemma C and Cheng, Yu-Ching and Fornage, Myriam and Ikram, M Arfan and Malik, Rainer and Bevan, Steve and Thorsteinsdottir, Unnur and Nalls, Mike A and Longstreth, Wt and Wiggins, Kerri L and Yadav, Sunaina and Parati, Eugenio A and DeStefano, Anita L and Worrall, Bradford B and Kittner, Steven J and Khan, Muhammad Saleem and Reiner, Alex P and Helgadottir, Anna and Achterberg, Sefanja and Fernandez-Cadenas, Israel and Abboud, Sherine and Schmidt, Reinhold and Walters, Matthew and Chen, Wei-Min and Ringelstein, E Bernd and O{\textquoteright}Donnell, Martin and Ho, Weang Kee and Pera, Joanna and Lemmens, Robin and Norrving, Bo and Higgins, Peter and Benn, Marianne and Sale, Michele and Kuhlenb{\"a}umer, Gregor and Doney, Alexander S F and Vicente, Astrid M and Delavaran, Hossein and Algra, Ale and Davies, Gail and Oliveira, Sofia A and Palmer, Colin N A and Deary, Ian and Schmidt, Helena and Pandolfo, Massimo and Montaner, Joan and Carty, Cara and de Bakker, Paul I W and Kostulas, Konstantinos and Ferro, Jose M and van Zuydam, Natalie R and Valdimarsson, Einar and Nordestgaard, B{\o}rge G and Lindgren, Arne and Thijs, Vincent and Slowik, Agnieszka and Saleheen, Danish and Par{\'e}, Guillaume and Berger, Klaus and Thorleifsson, Gudmar and Hofman, Albert and Mosley, Thomas H and Mitchell, Braxton D and Furie, Karen and Clarke, Robert and Levi, Christopher and Seshadri, Sudha and Gschwendtner, Andreas and Boncoraglio, Giorgio B and Sharma, Pankaj and Bis, Joshua C and Gretarsdottir, Solveig and Psaty, Bruce M and Rothwell, Peter M and Rosand, Jonathan and Meschia, James F and Stefansson, Kari and Dichgans, Martin and Markus, Hugh S} } @article {6688, title = {Genetic overlap between diagnostic subtypes of ischemic stroke.}, journal = {Stroke}, volume = {46}, year = {2015}, month = {2015 Mar}, pages = {615-9}, abstract = {

BACKGROUND AND PURPOSE: Despite moderate heritability, the phenotypic heterogeneity of ischemic stroke has hampered gene discovery, motivating analyses of diagnostic subtypes with reduced sample sizes. We assessed evidence for a shared genetic basis among the 3 major subtypes: large artery atherosclerosis (LAA), cardioembolism, and small vessel disease (SVD), to inform potential cross-subtype analyses.

METHODS: Analyses used genome-wide summary data for 12 389 ischemic stroke cases (including 2167 LAA, 2405 cardioembolism, and 1854 SVD) and 62 004 controls from the Metastroke consortium. For 4561 cases and 7094 controls, individual-level genotype data were also available. Genetic correlations between subtypes were estimated using linear mixed models and polygenic profile scores. Meta-analysis of a combined LAA-SVD phenotype (4021 cases and 51 976 controls) was performed to identify shared risk alleles.

RESULTS: High genetic correlation was identified between LAA and SVD using linear mixed models (rg=0.96, SE=0.47, P=9{\texttimes}10(-4)) and profile scores (rg=0.72; 95\% confidence interval, 0.52-0.93). Between LAA and cardioembolism and SVD and cardioembolism, correlation was moderate using linear mixed models but not significantly different from zero for profile scoring. Joint meta-analysis of LAA and SVD identified strong association (P=1{\texttimes}10(-7)) for single nucleotide polymorphisms near the opioid receptor μ1 (OPRM1) gene.

CONCLUSIONS: Our results suggest that LAA and SVD, which have been hitherto treated as genetically distinct, may share a substantial genetic component. Combined analyses of LAA and SVD may increase power to identify small-effect alleles influencing shared pathophysiological processes.

}, keywords = {Alleles, Atherosclerosis, Cerebral Small Vessel Diseases, Cohort Studies, Data Interpretation, Statistical, Embolism, Genome-Wide Association Study, Genotype, Humans, Ischemia, Linear Models, Meta-Analysis as Topic, Phenotype, Polymorphism, Single Nucleotide, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.114.007930}, author = {Holliday, Elizabeth G and Traylor, Matthew and Malik, Rainer and Bevan, Steve and Falcone, Guido and Hopewell, Jemma C and Cheng, Yu-Ching and Cotlarciuc, Ioana and Bis, Joshua C and Boerwinkle, Eric and Boncoraglio, Giorgio B and Clarke, Robert and Cole, John W and Fornage, Myriam and Furie, Karen L and Ikram, M Arfan and Jannes, Jim and Kittner, Steven J and Lincz, Lisa F and Maguire, Jane M and Meschia, James F and Mosley, Thomas H and Nalls, Mike A and Oldmeadow, Christopher and Parati, Eugenio A and Psaty, Bruce M and Rothwell, Peter M and Seshadri, Sudha and Scott, Rodney J and Sharma, Pankaj and Sudlow, Cathie and Wiggins, Kerri L and Worrall, Bradford B and Rosand, Jonathan and Mitchell, Braxton D and Dichgans, Martin and Markus, Hugh S and Levi, Christopher and Attia, John and Wray, Naomi R} } @article {6812, title = {Meta-Analysis of Genome-Wide Association Studies Identifies Genetic Risk Factors for Stroke in African Americans.}, journal = {Stroke}, volume = {46}, year = {2015}, month = {2015 Aug}, pages = {2063-8}, abstract = {

BACKGROUND AND PURPOSE: The majority of genome-wide association studies (GWAS) of stroke have focused on European-ancestry populations; however, none has been conducted in African Americans, despite the disproportionately high burden of stroke in this population. The Consortium of Minority Population Genome-Wide Association Studies of Stroke (COMPASS) was established to identify stroke susceptibility loci in minority populations.

METHODS: Using METAL, we conducted meta-analyses of GWAS in 14 746 African Americans (1365 ischemic and 1592 total stroke cases) from COMPASS, and tested genetic variants with P<10(-6) for validation in METASTROKE, a consortium of ischemic stroke genetic studies in European-ancestry populations. We also evaluated stroke loci previously identified in European-ancestry populations.

RESULTS: The 15q21.3 locus linked with lipid levels and hypertension was associated with total stroke (rs4471613; P=3.9{\texttimes}10(-8)) in African Americans. Nominal associations (P<10(-6)) for total or ischemic stroke were observed for 18 variants in or near genes implicated in cell cycle/mRNA presplicing (PTPRG, CDC5L), platelet function (HPS4), blood-brain barrier permeability (CLDN17), immune response (ELTD1, WDFY4, and IL1F10-IL1RN), and histone modification (HDAC9). Two of these loci achieved nominal significance in METASTROKE: 5q35.2 (P=0.03), and 1p31.1 (P=0.018). Four of 7 previously reported ischemic stroke loci (PITX2, HDAC9, CDKN2A/CDKN2B, and ZFHX3) were nominally associated (P<0.05) with stroke in COMPASS.

CONCLUSIONS: We identified a novel genetic variant associated with total stroke in African Americans and found that ischemic stroke loci identified in European-ancestry populations may also be relevant for African Americans. Our findings support investigation of diverse populations to identify and characterize genetic risk factors, and the importance of shared genetic risk across populations.

}, keywords = {African Americans, Case-Control Studies, Cohort Studies, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Polymorphism, Single Nucleotide, Risk Factors, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.115.009044}, author = {Carty, Cara L and Keene, Keith L and Cheng, Yu-Ching and Meschia, James F and Chen, Wei-Min and Nalls, Mike and Bis, Joshua C and Kittner, Steven J and Rich, Stephen S and Tajuddin, Salman and Zonderman, Alan B and Evans, Michele K and Langefeld, Carl D and Gottesman, Rebecca and Mosley, Thomas H and Shahar, Eyal and Woo, Daniel and Yaffe, Kristine and Liu, Yongmei and Sale, Mich{\`e}le M and Dichgans, Martin and Malik, Rainer and Longstreth, W T and Mitchell, Braxton D and Psaty, Bruce M and Kooperberg, Charles and Reiner, Alexander and Worrall, Bradford B and Fornage, Myriam} } @article {6991, title = {Genome-Wide Association Analysis of Young-Onset Stroke Identifies a Locus on Chromosome 10q25 Near HABP2.}, journal = {Stroke}, volume = {47}, year = {2016}, month = {2016 Feb}, pages = {307-16}, abstract = {

BACKGROUND AND PURPOSE: Although a genetic contribution to ischemic stroke is well recognized, only a handful of stroke loci have been identified by large-scale genetic association studies to date. Hypothesizing that genetic effects might be stronger for early- versus late-onset stroke, we conducted a 2-stage meta-analysis of genome-wide association studies, focusing on stroke cases with an age of onset <60 years.

METHODS: The discovery stage of our genome-wide association studies included 4505 cases and 21 968 controls of European, South-Asian, and African ancestry, drawn from 6 studies. In Stage 2, we selected the lead genetic variants at loci with association P<5{\texttimes}10(-6) and performed in silico association analyses in an independent sample of <=1003 cases and 7745 controls.

RESULTS: One stroke susceptibility locus at 10q25 reached genome-wide significance in the combined analysis of all samples from the discovery and follow-up stages (rs11196288; odds ratio =1.41; P=9.5{\texttimes}10(-9)). The associated locus is in an intergenic region between TCF7L2 and HABP2. In a further analysis in an independent sample, we found that 2 single nucleotide polymorphisms in high linkage disequilibrium with rs11196288 were significantly associated with total plasma factor VII-activating protease levels, a product of HABP2.

CONCLUSIONS: HABP2, which encodes an extracellular serine protease involved in coagulation, fibrinolysis, and inflammatory pathways, may be a genetic susceptibility locus for early-onset stroke.

}, keywords = {Adult, African Continental Ancestry Group, Age of Onset, Aged, Asian Continental Ancestry Group, Brain Ischemia, Chromosomes, Human, Pair 10, Computer Simulation, DNA, Intergenic, European Continental Ancestry Group, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Male, Middle Aged, Odds Ratio, Polymorphism, Single Nucleotide, Serine Endopeptidases, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.115.011328}, author = {Cheng, Yu-Ching and Stanne, Tara M and Giese, Anne-Katrin and Ho, Weang Kee and Traylor, Matthew and Amouyel, Philippe and Holliday, Elizabeth G and Malik, Rainer and Xu, Huichun and Kittner, Steven J and Cole, John W and O{\textquoteright}Connell, Jeffrey R and Danesh, John and Rasheed, Asif and Zhao, Wei and Engelter, Stefan and Grond-Ginsbach, Caspar and Kamatani, Yoichiro and Lathrop, Mark and Leys, Didier and Thijs, Vincent and Metso, Tiina M and Tatlisumak, Turgut and Pezzini, Alessandro and Parati, Eugenio A and Norrving, Bo and Bevan, Steve and Rothwell, Peter M and Sudlow, Cathie and Slowik, Agnieszka and Lindgren, Arne and Walters, Matthew R and Jannes, Jim and Shen, Jess and Crosslin, David and Doheny, Kimberly and Laurie, Cathy C and Kanse, Sandip M and Bis, Joshua C and Fornage, Myriam and Mosley, Thomas H and Hopewell, Jemma C and Strauch, Konstantin and M{\"u}ller-Nurasyid, Martina and Gieger, Christian and Waldenberger, Melanie and Peters, Annette and Meisinger, Christine and Ikram, M Arfan and Longstreth, W T and Meschia, James F and Seshadri, Sudha and Sharma, Pankaj and Worrall, Bradford and Jern, Christina and Levi, Christopher and Dichgans, Martin and Boncoraglio, Giorgio B and Markus, Hugh S and Debette, Stephanie and Rolfs, Arndt and Saleheen, Danish and Mitchell, Braxton D} }