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- Mishra, A., et al.
(author)
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Stroke genetics informs drug discovery and risk prediction across ancestries
- 2022
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 611, s. 115-123
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Journal article (peer-reviewed)abstract
- Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry(1,2). Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis(3), and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach(4), we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry(5). Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.
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- Jaworek, T., et al.
(author)
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Contribution of Common Genetic Variants to Risk of Early-Onset Ischemic Stroke
- 2022
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 99:16
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Journal article (peer-reviewed)abstract
- Background and Objectives Current genome-wide association studies of ischemic stroke have focused primarily on late-onset disease. As a complement to these studies, we sought to identify the contribution of common genetic variants to risk of early-onset ischemic stroke. Methods We performed a meta-analysis of genome-wide association studies of early-onset stroke (EOS), ages 18-59 years, using individual-level data or summary statistics in 16,730 cases and 599,237 nonstroke controls obtained across 48 different studies. We further compared effect sizes at associated loci between EOS and late-onset stroke (LOS) and compared polygenic risk scores (PRS) for venous thromboembolism (VTE) between EOS and LOS. Results We observed genome-wide significant associations of EOS with 2 variants in ABO, a known stroke locus. These variants tag blood subgroups O1 and A1, and the effect sizes of both variants were significantly larger in EOS compared with LOS. The odds ratio (OR) for rs529565, tagging O1, was 0.88 (95% confidence interval [CI]: 0.85-0.91) in EOS vs 0.96 (95% CI: 0.92-1.00) in LOS, and the OR for rs635634, tagging A1, was 1.16 (1.11-1.21) for EOS vs 1.05 (0.99-1.11) in LOS; p-values for interaction = 0.001 and 0.005, respectively. Using PRSs, we observed that greater genetic risk for VTE, another prothrombotic condition, was more strongly associated with EOS compared with LOS (p = 0.008). Discussion The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with EOS than with LOS, supporting a stronger role of prothrombotic factors in EOS.
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- Valdes-Marquez, E., et al.
(author)
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Relative effects of LDL-C on ischemic stroke and coronary disease A Mendelian randomization study
- 2019
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 92:11
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Journal article (peer-reviewed)abstract
- Objective To examine the causal relevance of lifelong differences in low-density lipoprotein cholesterol (LDL-C) for ischemic stroke (IS) relative to that for coronary heart disease (CHD) using a Mendelian randomization approach. We undertook a 2-sample Mendelian randomization, based on summary data, to estimate the causal relevance of LDL-C for risk of IS and CHD. Information from 62 independent genetic variants with genome-wide significant effects on LDL-C levels was used to estimate the causal effects of LDL-C for IS and IS subtypes (based on 12,389 IS cases from METASTROKE) and for CHD (based on 60,801 cases from CARDIoGRAMplusC4D). We then assessed the effects of LDL-C on IS and CHD for heterogeneity. A 1 mmol/L higher genetically determined LDL-C was associated with a 50% higher risk of CHD (odds ratio [OR] 1.49, 95% confidence interval [CI] 1.32-1.68, p = 1.1 x 10(-8)). By contrast, the causal effect of LDL-C was much weaker for IS (OR 1.12, 95% CI 0.96-1.30, p = 0.14; p for heterogeneity = 2.6 x 10(-3)) and, in particular, for cardioembolic stroke (OR 1.06, 95% CI 0.84-1.33, p = 0.64; p for heterogeneity = 8.6 x 10(-3)) when compared with that for CHD. In contrast with the consistent effects of LDL-C-lowering therapies on IS and CHD, genetic variants that confer lifelong LDL-C differences show a weaker effect on IS than on CHD. The relevance of etiologically distinct IS subtypes may contribute to the differences observed.
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4. |
- Pulit, SL, et al.
(author)
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Loci associated with ischaemic stroke and its subtypes (SiGN): a genome-wide association study.
- 2016
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In: The Lancet. Neurology. - 1474-4465. ; 15:2, s. 174-84
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Journal article (peer-reviewed)abstract
- The discovery of disease-associated loci through genome-wide association studies (GWAS) is the leading genetic approach to the identification of novel biological pathways underlying diseases in humans. Until recently, GWAS in ischaemic stroke have been limited by small sample sizes and have yielded few loci associated with ischaemic stroke. We did a large-scale GWAS to identify additional susceptibility genes for stroke and its subtypes.To identify genetic loci associated with ischaemic stroke, we did a two-stage GWAS. In the first stage, we included 16851 cases with state-of-the-art phenotyping data and 32473 stroke-free controls. Cases were aged 16 to 104 years, recruited between 1989 and 2012, and subtypes of ischaemic stroke were recorded by centrally trained and certified investigators who used the web-based protocol, Causative Classification of Stroke (CCS). We constructed case-control strata by identifying samples that were genotyped on nearly identical arrays and were of similar genetic ancestral background. We cleaned and imputed data by use of dense imputation reference panels generated from whole-genome sequence data. We did genome-wide testing to identify stroke-associated loci within each stratum for each available phenotype, and we combined summary-level results using inverse variance-weighted fixed-effects meta-analysis. In the second stage, we did in-silico lookups of 1372 single nucleotide polymorphisms identified from the first stage GWAS in 20941 cases and 364736 unique stroke-free controls. The ischaemic stroke subtypes of these cases had previously been established with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system, in accordance with local standards. Results from the two stages were then jointly analysed in a final meta-analysis.We identified a novel locus (G allele at rs12122341) at 1p13.2 near TSPAN2 that was associated with large artery atherosclerosis-related stroke (first stage odds ratio [OR] 1·21, 95% CI 1·13-1·30, p=4·50×10(-8); joint OR 1·19, 1·12-1·26, p=1·30×10(-9)). Our results also supported robust associations with ischaemic stroke for four other loci that have been reported in previous studies, including PITX2 (first stage OR 1·39, 1·29-1·49, p=3·26×10(-19); joint OR 1·37, 1·30-1·45, p=2·79×10(-32)) and ZFHX3 (first stage OR 1·19, 1·11-1·27, p=2·93×10(-7); joint OR 1·17, 1·11-1·23, p=2·29×10(-10)) for cardioembolic stroke, and HDAC9 (first stage OR 1·29, 1·18-1·42, p=3·50×10(-8); joint OR 1·24, 1·15-1·33, p=4·52×10(-9)) for large artery atherosclerosis stroke. The 12q24 locus near ALDH2, which has previously been associated with all ischaemic stroke but not with any specific subtype, exceeded genome-wide significance in the meta-analysis of small artery stroke (first stage OR 1·20, 1·12-1·28, p=6·82×10(-8); joint OR 1·17, 1·11-1·23, p=2·92×10(-9)). Other loci associated with stroke in previous studies, including NINJ2, were not confirmed.Our results suggest that all ischaemic stroke-related loci previously implicated by GWAS are subtype specific. We identified a novel gene associated with large artery atherosclerosis stroke susceptibility. Follow-up studies will be necessary to establish whether the locus near TSPAN2 can be a target for a novel therapeutic approach to stroke prevention. In view of the subtype-specificity of the associations detected, the rich phenotyping data available in the Stroke Genetics Network (SiGN) are likely to be crucial for further genetic discoveries related to ischaemic stroke.US National Institute of Neurological Disorders and Stroke, National Institutes of Health.
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7. |
- Petersson, M., et al.
(author)
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Patient-Reported Symptom Severity in a Nationwide Myasthenia Gravis Cohort Cross-sectional Analysis of the Swedish GEMG Study
- 2021
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 97:14
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Journal article (peer-reviewed)abstract
- Background and Objectives To describe myasthenia gravis activities of daily living (MG-ADL) in relation to clinical characteristics in a large Swedish nationwide cohort. Methods In a cross-sectional prevalence cohort study, the Genes and Environment in Myasthenia Gravis study, performed from November 2018 through August 2019, patients with myasthenia gravis (MG) were invited to submit an extensive 106-item life environment questionnaire, including the MG-ADL score. Patients were classified into early-onset MG (EOMG, <50 years), late-onset MG (LOMG, >= 50 years), or thymoma-associated MG (TAMG). Comparisons of disease-specific characteristics were made between subgroups, sexes, and different MG-ADL scores. Results A total of 1,077 patients were included, yielding a 74% response rate: 505 (47%) were classified as EOMG, 520 (48%) LOMG, and 45 (4%) TAMG. Mean age at inclusion was 64.3 years (SD 15.7) and mean disease duration was 14.6 years (SD 14.0). Complete MG-ADL scores (n = 1,035) ranged from 0p to 18p, where 26% reported a score of 0p. Higher MG-ADL scores were associated with female sex, obesity, and diagnostic delay (odds ratio [OR] 1.62, 1.72, and 1.69; p(adj) = 0.017, 0.013, and 0.008) and inversely correlated with high educational attainment (OR 0.59; p(adj) = 0.02), but not with age at inclusion, disease subtype, or disease duration. Almost half of the population (47%) reported MG-ADL >= 3p, corresponding to an unsatisfactory symptom state. Discussion In this nationwide study, comprising more than 40% of the prevalent MG population in Sweden, almost half of the patients reported current disease symptoms associated with an unsatisfactory symptom state, indicating the need for improved treatment options.
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- Appleton, Jason Philip, et al.
(author)
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The TOS2 study: An international multi-centre audit assessing the standard of neurological examination
- 2015
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In: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 86:11
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Conference paper (peer-reviewed)abstract
- Having previously demonstrated that in-patients referred to neurology at two UK hospitals were not fully examined prior to referral, we designed an audit with 80% power to detect a 10% increase in tendon hammer or ophthalmoscope use following an educational intervention. In-patients referred to neurology over a 4 month period in the UK, Jordan, Sweden and the United Arab Emirates were asked whether they recalled examination with a Tendon hammer, Ophthalmoscope and Stethoscope since admission. Results were disseminated to local medical teams and data were collected for a further 4 months. Pre and post-intervention data were available for 11 centres with 407 and 391 patients in each arm. 264 patients (64.86%) recalled examination with a tendon hammer preintervention, which significantly improved to 298 (76.21%) (p
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10. |
- Ilinca, A., et al.
(author)
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MAP3K6 Mutations in a Neurovascular Disease Causing Stroke, Cognitive Impairment, and Tremor
- 2021
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In: Neurology-Genetics. - : Ovid Technologies (Wolters Kluwer Health). - 2376-7839. ; 7:1
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Journal article (peer-reviewed)abstract
- Objective To describe a possible novel genetic mechanism for cerebral small vessel disease (cSVD) and stroke. Methods We studied a Swedish kindred with ischemic stroke and intracerebral hemorrhage, tremor, dysautonomia, and mild cognitive decline. Members were examined clinically, radiologically, and by histopathology. Genetic workup included whole-exome sequencing (WES) and whole-genome sequencing (WGS) and intrafamilial cosegregation analyses. Results Fifteen family members were examined clinically. Twelve affected individuals had white matter hyperintensities and 1 or more of (1) stroke episodes, (2) clinically silent lacunar ischemic lesions, and (3) cognitive dysfunction. All affected individuals had tremor and/or atactic gait disturbance. Mild symmetric basal ganglia calcifications were seen in 3 affected members. Postmortem examination of 1 affected member showed pathologic alterations in both small and large arteries the brain. Skin biopsies of 3 affected members showed extracellular amorphous deposits within the subepidermal zone, which may represent degenerated arterioles. WES or WGS did not reveal any potentially disease-causing variants in known genes for cSVDs or idiopathic basal ganglia calcification, but identified 1 heterozygous variant, NM_004672.4 MAP3K6 c.322G>A p.(Asp108Asn), that cosegregated with the disease in this large family. MAP3K6 has known functions in angiogenesis and affects vascular endothelial growth factor expression, which may be implicated in cerebrovascular disease. Conclusions Our data strongly suggest the MAP3K6 variant to be causative for this novel disease phenotype, but the absence of functional data and the present lack of additional families with this disease and MAP3K6 mutations still limit the formal evidence for the variant's pathogenicity.
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11. |
- Ilinca, A., et al.
(author)
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Whole-Exome Sequencing in 22 Young Ischemic Stroke Patients With Familial Clustering of Stroke
- 2020
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 51:4, s. 1056-1063
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Journal article (peer-reviewed)abstract
- Backgrounds and Purpose-Although new methods for genetic analyses are rapidly evolving, there are currently knowledge gaps in how to detect Mendelian forms of stroke. Methods-We performed whole-exome sequencing in 22 probands, under 56 years at their first ischemic stroke episode, from multi-incident stroke families. With the use of a comprehensive stroke-gene panel, we searched for variants in stroke-related genes. The probands' clinical stroke subtype was related to clinical characteristics previously associated with pathogenic variants in these genes. Relatives were genotyped in 7 families to evaluate stroke-gene variants of unknown significance. In 2 larger families with embolic stroke of unknown source, whole-exome sequencing was performed in additional members to examine the possibility of identifying new stroke genes. Results-Six of 22 probands carried pathogenic or possibly pathogenic variants in genes reported to be associated with their stroke subtype. A known pathogenic variant in NOTCH3 and a possibly pathogenic variant in ACAD9 gene were identified. A novel JAK2:c.3188G>A (p.Arg1063His) mutation was seen in a proband with embolic stroke of undetermined source and prothrombotic status. However, penetrance in the family was incomplete. COL4A2:c.3368A>G (p.Glu1123Gly) was detected in 2 probands but did not cosegregate with the disease in their families. Whole-exome sequencing in multiple members of 2 pedigrees with embolic stroke of undetermined source revealed possibly pathogenic variants in genes not previously associated with stroke, GPR142:c.148C>G (p.Leu50Val), and PTPRN2:c.2416A>G (p.Ile806Val); LRRC1 c.808A>G (p.Ile270Val), SLC7A10c.1294dupG (p.Val432fs), IKBKB: c.1070C>T (p.Ala357Val), and OXGR1 c.392G>A (p.Arg131His), respectively. Conclusions-Screening with whole-exome sequencing using a comprehensive stroke-gene panel may identify rare monogenic forms of stroke, but careful evaluation of clinical characteristics and potential pathogenicity of novel variants remain important. In our study, the majority of individuals with familial aggregation of stroke lacked any identified genetic causes.
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13. |
- Appleton, Jason Philip, et al.
(author)
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Improving the likelihood of neurology patients being examined using patient feedback
- 2015
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In: BMJ Quality Improvement Reports. - : BMJ. - 2050-1315. ; 4:1
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Journal article (peer-reviewed)abstract
- We aimed to establish whether recall of elements of the neurological examination can be improved by use of a simple patient assessment score. In a previous study we demonstrated that in-patients referred to neurology at two United Kingdom (UK) hospitals were not fully examined prior to referral; we therefore designed a larger quality improvement report with 80% power to detect a 10% increase in tendon hammer or ophthalmoscope use following an educational intervention. In-patients referred to neurology over a four month period (in hospitals in the UK (10), Jordan (1), Sweden (2), and the United Arab Emirates (1)) were asked whether they recalled being examined with a tendon hammer (T), ophthalmoscope (O), and stethoscope (S) since admission. The results were disseminated to local medical teams using various techniques (including Grand Round presentations, email, posters, discounted equipment). Data were then collected for a further four month period post-intervention. Pre-intervention and post-intervention data were available for 11 centres with 407 & 391 patients in each arm respectively. Median age of patients was 51 (range 13-100) and 49 (range 16-95) years respectively, with 44.72% and 44.76% being male in each group. 264 patients (64.86%) recalled being examined with a tendon hammer in the pre-intervention arm, which significantly improved to 298 (76.21%) (p<0.001). Only 119 patients (29.24%) recollected examination with an ophthalmoscope pre-intervention, which significantly improved to 149 (38.11%)(p=0.009). The majority of patients (321 (78.87%)) pre-intervention recalled examination with a stethoscope, which significantly improved to 330 (84.4%) to a lesser extent (p=0.045). Results indicate that most patients are not fully examined prior to neurology referral yet a simple assessment score and educational intervention can improve recall of elements of the neurological examination and thus the likelihood of patients being examined neurologically. This is the largest and - to our knowledge - only study to assess this issue. This has implications for national neurological educators.
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14. |
- Delp, Johannes, et al.
(author)
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Neurotoxicity and underlying cellular changes of 21 mitochondrial respiratory chain inhibitors
- 2021
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In: Archives of Toxicology. - : Springer. - 0340-5761 .- 1432-0738. ; 95:2, s. 591-615
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Journal article (peer-reviewed)abstract
- Inhibition of complex I of the mitochondrial respiratory chain (cI) by rotenone and methyl-phenylpyridinium (MPP +) leads to the degeneration of dopaminergic neurons in man and rodents. To formally describe this mechanism of toxicity, an adverse outcome pathway (AOP:3) has been developed that implies that any inhibitor of cI, or possibly of other parts of the respiratory chain, would have the potential to trigger parkinsonian motor deficits. We used here 21 pesticides, all of which are described in the literature as mitochondrial inhibitors, to study the general applicability of AOP:3 or of in vitro assays that are assessing its activation. Five cI, three complex II (cII), and five complex III (cIII) inhibitors were characterized in detail in human dopaminergic neuronal cell cultures. The NeuriTox assay, examining neurite damage in LUHMES cells, was used as in vitro proxy of the adverse outcome (AO), i.e., of dopaminergic neurodegeneration. This test provided data on whether test compounds were unspecific cytotoxicants or specifically neurotoxic, and it yielded potency data with respect to neurite degeneration. The pesticide panel was also examined in assays for the sequential key events (KE) leading to the AO, i.e., mitochondrial respiratory chain inhibition, mitochondrial dysfunction, and disturbed proteostasis. Data from KE assays were compared to the NeuriTox data (AO). The cII-inhibitory pesticides tested here did not appear to trigger the AOP:3 at all. Some of the cI/cIII inhibitors showed a consistent AOP activation response in all assays, while others did not. In general, there was a clear hierarchy of assay sensitivity: changes of gene expression (biomarker of neuronal stress) correlated well with NeuriTox data; mitochondrial failure (measured both by a mitochondrial membrane potential-sensitive dye and a respirometric assay) was about 10-260 times more sensitive than neurite damage (AO); cI/cIII activity was sometimes affected at > 1000 times lower concentrations than the neurites. These data suggest that the use of AOP:3 for hazard assessment has a number of caveats: (i) specific parkinsonian neurodegeneration cannot be easily predicted from assays of mitochondrial dysfunction; (ii) deriving a point-of-departure for risk assessment from early KE assays may overestimate toxicant potency.
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- Malik, Rainer, et al.
(author)
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Low-frequency and common genetic variation in ischemic stroke : The METASTROKE collaboration
- 2016
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In: Neurology. - 1526-632X. ; 86:13, s. 26-1217
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate the influence of common and low-frequency genetic variants on the risk of ischemic stroke (all IS) and etiologic stroke subtypes.METHODS: We meta-analyzed 12 individual genome-wide association studies comprising 10,307 cases and 19,326 controls imputed to the 1000 Genomes (1 KG) phase I reference panel. We selected variants showing the highest degree of association (p < 1E-5) in the discovery phase for replication in Caucasian (13,435 cases and 29,269 controls) and South Asian (2,385 cases and 5,193 controls) samples followed by a transethnic meta-analysis. We further investigated the p value distribution for different bins of allele frequencies for all IS and stroke subtypes.RESULTS: We showed genome-wide significance for 4 loci: ABO for all IS, HDAC9 for large vessel disease (LVD), and both PITX2 and ZFHX3 for cardioembolic stroke (CE). We further refined the association peaks for ABO and PITX2. Analyzing different allele frequency bins, we showed significant enrichment in low-frequency variants (allele frequency <5%) for both LVD and small vessel disease, and an enrichment of higher frequency variants (allele frequency 10% and 30%) for CE (all p < 1E-5).CONCLUSIONS: Our findings suggest that the missing heritability in IS subtypes can in part be attributed to low-frequency and rare variants. Larger sample sizes are needed to identify the variants associated with all IS and stroke subtypes.
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- Phillips, S. P., et al.
(author)
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Systematic review of methods used to study the intersecting impact of sex and social locations on health outcomes
- 2020
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In: SSM - Population Health. - : Elsevier BV. - 2352-8273. ; 12
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Research review (peer-reviewed)abstract
- Purpose: Independent health impacts of sex or social circumstances are well-studied, particularly among older adults. Less theorized or examined is how combinations or intersections of these underpin differential health effects. Nevertheless, and often without naming it as such, an intersectional framework aligns with studies of social determinants of health, life-course epidemiology and eco-epidemiology. In this systematic review we examined and aimed to identify research methods used to operationalize, whether intentionally or inadvertently, interconnected effects of sex and social locations on health outcomes for 45+ year olds.Methods: Using broad search terms, numerous databases, and following Prisma guidelines, 732 of 9214 papers initially identified, met inclusion criteria for full review.Results: Of the 501 papers included after full review, methods used in considering intersections of sex and social circumstances/location(s) included regression (112 of 365 papers), growth curves (7 of 22), multilevel (15 of 25), decomposition (6 of 9), mediation (10 of 17), structural equation modelling (23 of 25), and other (2 of 3). Most (n = 157) approximated intersectional analyses by including interaction terms or sex-stratifying results.Discussion: Few authors used the inherent strength of some study methods to examine intersecting traits. As even fewer began with an intersectionality framework their subsequent failure to deliver cannot be faulted, despite many studies including data and methodologies that would support intersectional analyses. There appeared to be a gap, not in analytic potential but rather in theorizing that differential distributions of social locations describe heterogeneity within the categories 'men' and 'women' that can underlie differential, gendered effects on older adults' health. While SEM, mediation and decomposition analyses emerged as particularly robust methods, the unexpected outcome was finding how few researchers consider intersectionality as a potential predictor of health.
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17. |
- Söderholm, M, et al.
(author)
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Exome array analysis of ischaemic stroke : results from a southern Swedish study
- 2016
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In: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 23:12, s. 1722-1728
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Journal article (peer-reviewed)abstract
- BACKGROUND AND PURPOSE: Genome-wide association (GWA) studies have identified a few risk loci for ischaemic stroke, but these variants explain only a small part of the genetic contribution to the disease. Coding variants associated with amino acid substitutions or premature termination of protein synthesis could have a large effect on disease risk. We performed an exome array analysis for ischaemic stroke.METHODS: Patients with ischaemic stroke (n = 2385) and control subjects (n = 6077) from three Swedish studies were genotyped with the Illumina HumanOmniExpressExome BeadChip. Single-variant association analysis and gene-based tests were performed of exome variants with minor allele frequency of < 5%. A separate GWA analysis was also performed, based on 700 000 genotyped common markers and subsequent imputation.RESULTS: No exome variant or gene was significantly associated with all ischaemic stroke after Bonferroni correction (all P > 1.8 × 10(-6) for single-variant and >4.15 × 10(-6) for gene-based analysis). The strongest association in single-variant analysis was found for a missense variant in the DNAH11 gene (rs143362381; P = 5.01 × 10(-6) ). In gene-based tests, the strongest association was for the ZBTB20 gene (P = 7.9 × 10(-5) ). The GWA analysis showed that the sample was homogenous (median genomic inflation factor = 1.006). No genome-wide significant association with overall ischaemic stroke risk was found. However, previously reported associations for the PITX2 and ZFHX3 gene loci with cardioembolic stroke subtype were replicated (P = 7 × 10(-15) and 6 × 10(-3) ).CONCLUSIONS: This exome array analysis did not identify any single variants or genes reaching the pre-defined significance level for association with ischaemic stroke. Further studies on exome variants should be performed in even larger, well-defined and subtyped samples.
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