@article {6574, title = {Meta-analysis in more than 17,900 cases of ischemic stroke reveals a novel association at 12q24.12.}, journal = {Neurology}, volume = {83}, year = {2014}, month = {2014 Aug 19}, pages = {678-85}, abstract = {

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 {\texttimes} 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.

}, keywords = {Brain Ischemia, Cerebral Hemorrhage, Chromosomes, Human, Pair 12, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Humans, Polymorphism, Single Nucleotide, Risk, Stroke}, issn = {1526-632X}, doi = {10.1212/WNL.0000000000000707}, author = {Kilarski, Laura L and Achterberg, Sefanja and Devan, William J and Traylor, Matthew and Malik, Rainer and Lindgren, Arne and Pare, Guillame and Sharma, Pankaj and Slowik, Agniesczka and Thijs, Vincent and Walters, Matthew and Worrall, Bradford B and Sale, Mich{\`e}le M and Algra, Ale and Kappelle, L Jaap and Wijmenga, Cisca and Norrving, Bo and Sandling, Johanna K and R{\"o}nnblom, Lars and Goris, An and Franke, Andre and Sudlow, Cathie and Rothwell, Peter M and Levi, Christopher and Holliday, Elizabeth G and Fornage, Myriam and Psaty, Bruce and Gretarsdottir, Solveig and Thorsteinsdottir, Unnar and Seshadri, Sudha and Mitchell, Braxton D and Kittner, Steven and Clarke, Robert and Hopewell, Jemma C and Bis, Joshua C and Boncoraglio, Giorgio B and Meschia, James and Ikram, M Arfan and Hansen, Bjorn M and Montaner, Joan and Thorleifsson, Gudmar and Stefanson, Kari and Rosand, Jonathan and de Bakker, Paul I W and Farrall, Martin and Dichgans, Martin and Markus, Hugh S and Bevan, Steve} } @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 {6864, title = {Common variation in COL4A1/COL4A2 is associated with sporadic cerebral small vessel disease.}, journal = {Neurology}, volume = {84}, year = {2015}, month = {2015 Mar 3}, pages = {918-26}, abstract = {

OBJECTIVES: We hypothesized that common variants in the collagen genes COL4A1/COL4A2 are associated with sporadic forms of cerebral small vessel disease.

METHODS: We conducted meta-analyses of existing genotype data among individuals of European ancestry to determine associations of 1,070 common single nucleotide polymorphisms (SNPs) in the COL4A1/COL4A2 genomic region with the following: intracerebral hemorrhage and its subtypes (deep, lobar) (1,545 cases, 1,485 controls); ischemic stroke and its subtypes (cardioembolic, large vessel disease, lacunar) (12,389 cases, 62,004 controls); and white matter hyperintensities (2,733 individuals with ischemic stroke and 9,361 from population-based cohorts with brain MRI data). We calculated a statistical significance threshold that accounted for multiple testing and linkage disequilibrium between SNPs (p < 0.000084).

RESULTS: Three intronic SNPs in COL4A2 were significantly associated with deep intracerebral hemorrhage (lead SNP odds ratio [OR] 1.29, 95\% confidence interval [CI] 1.14-1.46, p = 0.00003; r(2) > 0.9 between SNPs). Although SNPs associated with deep intracerebral hemorrhage did not reach our significance threshold for association with lacunar ischemic stroke (lead SNP OR 1.10, 95\% CI 1.03-1.18, p = 0.0073), and with white matter hyperintensity volume in symptomatic ischemic stroke patients (lead SNP OR 1.07, 95\% CI 1.01-1.13, p = 0.016), the direction of association was the same. There was no convincing evidence of association with white matter hyperintensities in population-based studies or with non-small vessel disease cerebrovascular phenotypes.

CONCLUSIONS: Our results indicate an association between common variation in the COL4A2 gene and symptomatic small vessel disease, particularly deep intracerebral hemorrhage. These findings merit replication studies, including in ethnic groups of non-European ancestry.

}, keywords = {Cerebral Small Vessel Diseases, Collagen Type IV, Genetic Association Studies, Genetic Variation, Humans, Polymorphism, Single Nucleotide}, issn = {1526-632X}, doi = {10.1212/WNL.0000000000001309}, author = {Rannikmae, Kristiina and Davies, Gail and Thomson, Pippa A and Bevan, Steve and Devan, William J and Falcone, Guido J and Traylor, Matthew and Anderson, Christopher D and Battey, Thomas W K and Radmanesh, Farid and Deka, Ranjan and Woo, Jessica G and Martin, Lisa J and Jimenez-Conde, Jordi and Selim, Magdy and Brown, Devin L and Silliman, Scott L and Kidwell, Chelsea S and Montaner, Joan and Langefeld, Carl D and Slowik, Agnieszka and Hansen, Bjorn M and Lindgren, Arne G and Meschia, James F and Fornage, Myriam and Bis, Joshua C and Debette, Stephanie and Ikram, Mohammad A and Longstreth, Will T and Schmidt, Reinhold and Zhang, Cathy R and Yang, Qiong and Sharma, Pankaj and Kittner, Steven J and Mitchell, Braxton D and Holliday, Elizabeth G and Levi, Christopher R and Attia, John and Rothwell, Peter M and Poole, Deborah L and Boncoraglio, Giorgio B and Psaty, Bruce M and Malik, Rainer and Rost, Natalia and Worrall, Bradford B and Dichgans, Martin and Van Agtmael, Tom and Woo, Daniel and Markus, Hugh S and Seshadri, Sudha and Rosand, Jonathan and Sudlow, Cathie L M} }