ORCID Profile
0000-0002-0053-2002
Current Organisations
Massachusetts General Hospital
,
Harvard Medical School
,
Broad Institute
,
Brigham and Women's Hospital
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Publisher: Elsevier BV
Date: 08-2018
Publisher: American Medical Association (AMA)
Date: 04-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 27-09-2017
DOI: 10.1212/WNL.0000000000004560
Abstract: To determine whether common variants in familial cerebral small vessel disease (SVD) genes confer risk of sporadic cerebral SVD. We meta-analyzed genotype data from in iduals of European ancestry to determine associations of common single nucleotide polymorphisms (SNPs) in 6 familial cerebral SVD genes ( COL4A1 , COL4A2 , NOTCH3 , HTRA1 , TREX1 , and CECR1 ) with intracerebral hemorrhage (ICH) (deep, lobar, all 1,878 cases, 2,830 controls) and ischemic stroke (IS) (lacunar, cardioembolic, large vessel disease, all 19,569 cases, 37,853 controls). We applied data quality filters and set statistical significance thresholds accounting for linkage disequilibrium and multiple testing. A locus in COL4A2 was associated (significance threshold p 3.5 × 10 −4 ) with both lacunar IS (lead SNP rs9515201: odds ratio [OR] 1.17, 95% confidence interval [CI] 1.11–1.24, p = 6.62 × 10 −8 ) and deep ICH (lead SNP rs4771674: OR 1.28, 95% CI 1.13–1.44, p = 5.76 × 10 −5 ). A SNP in HTRA1 was associated (significance threshold p 5.5 × 10 −4 ) with lacunar IS (rs79043147: OR 1.23, 95% CI 1.10–1.37, p = 1.90 × 10 −4 ) and less robustly with deep ICH. There was no clear evidence for association of common variants in either COL4A2 or HTRA1 with non-SVD strokes or in any of the other genes with any stroke phenotype. These results provide evidence of shared genetic determinants and suggest common pathophysiologic mechanisms of distinct ischemic and hemorrhagic cerebral SVD stroke phenotypes, offering new insights into the causal mechanisms of cerebral SVD.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2012
DOI: 10.1161/STROKEAHA.111.632075
Abstract: Ischemic stroke (IS) shares many common risk factors with coronary artery disease (CAD). We hypothesized that genetic variants associated with myocardial infarction (MI) or CAD may be similarly involved in the etiology of IS. To test this hypothesis, we evaluated whether single-nucleotide polymorphisms (SNPs) at 11 different loci recently associated with MI or CAD through genome-wide association studies were associated with IS. Meta-analyses of the associations between the 11 MI-associated SNPs and IS were performed using 6865 cases and 11 395 control subjects recruited from 9 studies. SNPs were either genotyped directly or imputed in a few cases a surrogate SNP in high linkage disequilibrium was chosen. Logistic regression was performed within each study to obtain study-specific βs and standard errors. Meta-analysis was conducted using an inverse variance weighted approach assuming a random effect model. Despite having power to detect odds ratio of 1.09–1.14 for overall IS and 1.20–1.32 for major stroke subtypes, none of the SNPs were significantly associated with overall IS and/or stroke subtypes after adjusting for multiple comparisons. Our results suggest that the major common loci associated with MI risk do not have effects of similar magnitude on overall IS but do not preclude moderate associations restricted to specific IS subtypes. Disparate mechanisms may be critical in the development of acute ischemic coronary and cerebrovascular events.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 26-02-2019
Publisher: Springer Science and Business Media LLC
Date: 03-12-2018
DOI: 10.1038/S41467-018-07340-5
Abstract: Carotid artery intima media thickness (cIMT) and carotid plaque are measures of subclinical atherosclerosis associated with ischemic stroke and coronary heart disease (CHD). Here, we undertake meta-analyses of genome-wide association studies (GWAS) in 71,128 in iduals for cIMT, and 48,434 in iduals for carotid plaque traits. We identify eight novel susceptibility loci for cIMT, one independent association at the previously-identified PINX1 locus, and one novel locus for carotid plaque. Colocalization analysis with nearby vascular expression quantitative loci (cis-eQTLs) derived from arterial wall and metabolic tissues obtained from patients with CHD identifies candidate genes at two potentially additional loci, ADAMTS9 and LOXL4 . LD score regression reveals significant genetic correlations between cIMT and plaque traits, and both cIMT and plaque with CHD, any stroke subtype and ischemic stroke. Our study provides insights into genes and tissue-specific regulatory mechanisms linking atherosclerosis both to its functional genomic origins and its clinical consequences in humans.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 16-01-2019
DOI: 10.1212/WNL.0000000000006851
Abstract: To explore genetic and lifestyle risk factors of MRI-defined brain infarcts (BI) in large population-based cohorts. We performed meta-analyses of genome-wide association studies (GWAS) and examined associations of vascular risk factors and their genetic risk scores (GRS) with MRI-defined BI and a subset of BI, namely, small subcortical BI (SSBI), in 18 population-based cohorts (n = 20,949) from 5 ethnicities (3,726 with BI, 2,021 with SSBI). Top loci were followed up in 7 population-based cohorts (n = 6,862 1,483 with BI, 630 with SBBI), and we tested associations with related phenotypes including ischemic stroke and pathologically defined BI. The mean prevalence was 17.7% for BI and 10.5% for SSBI, steeply rising after age 65. Two loci showed genome-wide significant association with BI: FBN2, p = 1.77 × 10 −8 and LINC00539/ZDHHC20, p = 5.82 × 10 −9 . Both have been associated with blood pressure (BP)–related phenotypes, but did not replicate in the smaller follow-up s le or show associations with related phenotypes. Age- and sex-adjusted associations with BI and SSBI were observed for BP traits ( p value for BI, p [BI] = 9.38 × 10 −25 p [SSBI] = 5.23 × 10 −14 for hypertension), smoking ( p [BI] = 4.4 × 10 −10 p [SSBI] = 1.2 × 10 −4 ), diabetes ( p [BI] = 1.7 × 10 −8 p [SSBI] = 2.8 × 10 −3 ), previous cardiovascular disease ( p [BI] = 1.0 × 10 −18 p [SSBI] = 2.3 × 10 −7 ), stroke ( p [BI] = 3.9 × 10 −69 p [SSBI] = 3.2 × 10 −24 ), and MRI-defined white matter hyperintensity burden ( p [BI] = 1.43 × 10 −157 p [SSBI] = 3.16 × 10 −106 ), but not with body mass index or cholesterol. GRS of BP traits were associated with BI and SSBI ( p ≤ 0.0022), without indication of directional pleiotropy. In this multiethnic GWAS meta-analysis, including over 20,000 population-based participants, we identified genetic risk loci for BI requiring validation once additional large datasets become available. High BP, including genetically determined, was the most significant modifiable, causal risk factor for BI.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2013
DOI: 10.1161/STROKEAHA.113.001857
Abstract: Meta-analyses of extant genome-wide data illustrate the need to focus on subtypes of ischemic stroke for gene discovery. The National Institute of Neurological Disorders and Stroke SiGN (Stroke Genetics Network) contributes substantially to meta-analyses that focus on specific subtypes of stroke. The National Institute of Neurological Disorders and Stroke SiGN includes ischemic stroke cases from 24 genetic research centers: 13 from the United States and 11 from Europe. Investigators harmonize ischemic stroke phenotyping using the Web-based causative classification of stroke system, with data entered by trained and certified adjudicators at participating genetic research centers. Through the Center for Inherited Diseases Research, the Network plans to genotype 10 296 carefully phenotyped stroke cases using genome-wide single nucleotide polymorphism arrays and adds to these another 4253 previously genotyped cases, for a total of 14 549 cases. To maximize power for subtype analyses, the study allocates genotyping resources almost exclusively to cases. Publicly available studies provide most of the control genotypes. Center for Inherited Diseases Research–generated genotypes and corresponding phenotypes will be shared with the scientific community through the US National Center for Biotechnology Information database of Genotypes and Phenotypes, and brain MRI studies will be centrally archived. The Stroke Genetics Network, with its emphasis on careful and standardized phenotyping of ischemic stroke and stroke subtypes, provides an unprecedented opportunity to uncover genetic determinants of ischemic stroke.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2019
DOI: 10.1212/WNL.0000000000008007
Abstract: To describe the relationship between intraventricular hemorrhage (IVH) expansion and long-term outcome and to use this relationship to select and validate clinically relevant thresholds of IVH expansion in 2 separate intracerebral hemorrhage (ICH) populations. We used fractional polynomial analysis to test linear and nonlinear models of 24-hour IVH volume change and clinical outcome with data from the Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT (PREDICT)-ICH study. The primary outcome was poor clinical outcome (modified Rankin Scale [mRS] score 4–6) at 90 days. We derived dichotomous thresholds from the selected model and calculated diagnostic accuracy measures. We validated all thresholds in an independent single-center ICH cohort (Massachusetts General Hospital). Of the 256 patients from PREDICT, 127 (49.6%) had an mRS score of 4 to 6. Twenty-four–hour IVH volume change and poor outcome fit a nonlinear relationship, in which minimal increases in IVH were associated with a high probability of an mRS score of 4 to 6. IVH expansion ≥1 mL (n = 53, sensitivity 33%, specificity 92%, adjusted odds ratio [aOR] 2.68, 95% confidence interval [CI] 1.11–6.46) and development of any new IVH (n = 74, sensitivity 43%, specificity 85%, aOR 2.53, 95% CI 1.22–5.26) strongly predicted poor outcome at 90 days. The dichotomous thresholds reproduced well in a validation cohort of 169 patients. IVH expansion as small as 1 mL or any new IVH is strongly predictive of poor outcome. These findings may assist clinicians with bedside prognostication and could be incorporated into definitions of hematoma expansion to inform future ICH treatment trials.
Publisher: Springer Science and Business Media LLC
Date: 12-03-2018
Publisher: Wiley
Date: 03-2017
DOI: 10.1002/ANA.24840
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2015
Publisher: Wiley
Date: 19-10-2016
DOI: 10.1002/ANA.24780
Abstract: In observational epidemiologic studies, higher plasma high‐density lipoprotein cholesterol (HDL‐C) has been associated with increased risk of intracerebral hemorrhage (ICH). DNA sequence variants that decrease cholesteryl ester transfer protein ( CETP ) gene activity increase plasma HDL‐C as such, medicines that inhibit CETP and raise HDL‐C are in clinical development. Here, we test the hypothesis that CETP DNA sequence variants associated with higher HDL‐C also increase risk for ICH. We performed 2 candidate‐gene analyses of CETP . First, we tested in idual CETP variants in a discovery cohort of 1,149 ICH cases and 1,238 controls from 3 studies, followed by replication in 1,625 cases and 1,845 controls from 5 studies. Second, we constructed a genetic risk score comprised of 7 independent variants at the CETP locus and tested this score for association with HDL‐C as well as ICH risk. Twelve variants within CETP demonstrated nominal association with ICH, with the strongest association at the rs173539 locus (odds ratio [OR] = 1.25, standard error [SE] = 0.06, p = 6.0 × 10 −4 ) with no heterogeneity across studies ( I 2 = 0%). This association was replicated in patients of European ancestry ( p = 0.03). A genetic score of CETP variants found to increase HDL‐C by ∼2.85mg/dl in the Global Lipids Genetics Consortium was strongly associated with ICH risk (OR = 1.86, SE = 0.13, p = 1.39 × 10 −6 ). Genetic variants in CETP associated with increased HDL‐C raise the risk of ICH. Given ongoing therapeutic development in CETP inhibition and other HDL‐raising strategies, further exploration of potential adverse cerebrovascular outcomes may be warranted. Ann Neurol 2016 :730–740
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 26-01-2021
DOI: 10.1161/CIRCULATIONAHA.120.047633
Abstract: Clinically recognized atrial fibrillation (AF) is associated with higher risk of complications, including ischemic stroke, cognitive decline, heart failure, myocardial infarction, and death. It is increasingly recognized that AF frequently is undetected until complications such as stroke or heart failure occur. Hence, the public and clinicians have an intense interest in detecting AF earlier. However, the most appropriate strategies to detect undiagnosed AF (sometimes referred to as subclinical AF) and the prognostic and therapeutic implications of AF detected by screening are uncertain. Our report summarizes the National Heart, Lung, and Blood Institute’s virtual workshop focused on identifying key research priorities related to AF screening. Global experts reviewed major knowledge gaps and identified critical research priorities in the following areas: (1) role of opportunistic screening (2) AF as a risk factor, risk marker, or both (3) relationship between AF burden detected with long-term monitoring and outcomes/treatments (4) designs of potential randomized trials of systematic AF screening with clinically relevant outcomes and (5) role of AF screening after ischemic stroke. Our report aims to inform and catalyze AF screening research that will advance innovative, resource-efficient, and clinically relevant studies in erse populations to improve the diagnosis, management, and prognosis of patients with undiagnosed AF.
Publisher: Springer Science and Business Media LLC
Date: 03-06-2019
DOI: 10.1038/S41588-019-0449-0
Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-07-2021
DOI: 10.1212/WNL.0000000000012227
Abstract: To test the genetic contribution of rare missense variants in COL4A1 and COL4A2 in which common variants are genetically associated with sporadic intracerebral hemorrhage (ICH), we performed rare variant analysis in multiple sequencing data for the risk for sporadic ICH. We performed sequencing across 559 Kbp at 13q34 including COL4A1 and COL4A2 among 2,133 in iduals (1,055 ICH cases 1,078 controls) in United States–based and 1,381 in iduals (192 ICH cases 1,189 controls) from Scotland-based cohorts, followed by sequence annotation, functional impact prediction, genetic association testing, and in silico thermodynamic modeling. We identified 107 rare nonsynonymous variants in sporadic ICH, of which 2 missense variants, rs138269346 (COL4A1 I110T ) and rs201716258 (COL4A2 H203L ), were predicted to be highly functional and occurred in multiple ICH cases but not in controls from the United States–based cohort. The minor allele of rs201716258 was also present in Scottish patients with ICH, and rs138269346 was observed in 2 ICH-free controls with a history of hypertension and myocardial infarction. Rs138269346 was nominally associated with nonlobar ICH risk ( p = 0.05), but not with lobar ICH ( p = 0.08), while associations between rs201716258 and ICH subtypes were nonsignificant ( p 0.12). Both variants were considered pathogenic based on minor allele frequency ( .00035 in European populations), predicted functional impact (deleterious or probably damaging), and in silico modeling studies (substantially altered physical length and thermal stability of collagen). We identified rare missense variants in COL4A1 / A2 in association with sporadic ICH. Our annotation and simulation studies suggest that these variants are highly functional and may represent targets for translational follow-up.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2019
DOI: 10.1161/CIRCGEN.118.002338
Abstract: Genome-wide association studies have identified multiple loci associated with stroke. However, the specific stroke subtypes affected, and whether loci influence both ischemic and hemorrhagic stroke, remains unknown. For loci associated with stroke, we aimed to infer the combination of stroke subtypes likely to be affected, and in doing so assess the extent to which such loci have homogeneous effects across stroke subtypes. We performed Bayesian multinomial regression in 16 664 stroke cases and 32 792 controls of European ancestry to determine the most likely combination of stroke subtypes affected for loci with published genome-wide stroke associations, using model selection. Cases were subtyped under 2 commonly used stroke classification systems, TOAST (Trial of Org 10172 Acute Stroke Treatment) and causative classification of stroke. All in iduals had genotypes imputed to the Haplotype Reference Consortium 1.1 Panel. Sixteen loci were considered for analysis. Seven loci influenced both hemorrhagic and ischemic stroke, 3 of which influenced ischemic and hemorrhagic subtypes under both TOAST and causative classification of stroke. Under causative classification of stroke, 4 loci influenced both small vessel stroke and intracerebral hemorrhage. An EDNRA locus demonstrated opposing effects on ischemic and hemorrhagic stroke. No loci were predicted to influence all stroke subtypes in the same direction, and only one locus (12q24) was predicted to influence all ischemic stroke subtypes. Heterogeneity in the influence of stroke-associated loci on stroke subtypes is pervasive, reflecting differing causal pathways. However, overlap exists between hemorrhagic and ischemic stroke, which may reflect shared pathobiology predisposing to small vessel arteriopathy. Stroke is a complex, heterogeneous disorder requiring tailored analytic strategies to decipher genetic mechanisms.
Location: United States of America
Start Date: 2018
End Date: 2021
Funder: Medical Research Council
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