Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. 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 analysis3, 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 approach4, 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 ancestry5. 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.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is caused by mutations in the NOTCH3 gene, affecting the number of cysteines in the extracellular domain of the receptor, causing protein misfolding and receptor aggregation. The pathogenic role of cysteine-sparing NOTCH3 missense mutations in patients with typical clinical CADASIL syndrome is unknown. The aim of this article is to describe these mutations to clarify if any could be potentially pathogenic. Articles on cysteine-sparing NOTCH3 missense mutations in patients with clinical suspicion of CADASIL were reviewed. Mutations were considered potentially pathogenic if patients had: (a) typical clinical CADASIL syndrome; (b) diffuse white matter hyperintensities; (c) the 33 NOTCH3 exons analyzed; (d) mutations that were not polymorphisms; and (e) Granular osmiophilic material (GOM) deposits in the skin biopsy. Twenty-five different mutations were listed. Four fulfill the above criteria: p.R61W; p.R75P; p.D80G; and p.R213K. Patients carrying these mutations had typical clinical CADASIL syndrome and diffuse white matter hyperintensities, mostly without anterior temporal pole involvement. Cysteine-sparing NOTCH3 missense mutations are associated with typical clinical CADASIL syndrome and typical magnetic resonance imaging (MRI) findings, although with less involvement of the anterior temporal lobe. Hence, these mutations should be further studied to confirm their pathological role in CADASIL.

Rationale: Ischemic stroke (IS) is among the leading causes of adult disability. Part of the variability in functional outcome after stroke has been attributed to genetic factors but no locus has been consistently associated with stroke outcome. Objective: Our aim was to identify genetic loci influencing the recovery process using accurate phenotyping to produce the largest genome-wide association study (GWAS) in IS recovery to date. Methods and Results: A 12-cohort, two-phase (discovery-replication and joint) meta-analysis of GWAS included anterior-territory and previously independent IS cases. Functional outcome was recorded using 3-month modified Rankin Scale (mRS). Analyses were adjusted for confounders such as discharge NIHSS. A gene-based burden test was performed. The discovery phase (n=1,225) was followed by open (n=2,482) and stringent joint-analyses (n=1,791). Those cohorts with mRS recorded at timepoints other than 3-month or incomplete data on previous functional status were excluded in the stringent analyses. Novel variants in Pals1-Associated Tight Junction (PATJ) gene were associated with worse functional outcome at 3-month after stroke. The top variant was rs76221407 (G allele, beta=0•40, p=1•70×10 −9). Conclusions: Our results identify a set of common variants in PATJ gene associated with 3month functional outcome at genome-wide significance level. Future studies should examine the role of PATJ in stroke recovery and consider stringent phenotyping to enrich the information captured to unveil additional stroke outcome loci.

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P atients with Ischemic stroke are at high risk of having a new stroke or developing other vascular diseases such as acute myocardial infarction, or vascular death, known as vascular recurrence. A study in the South London Stroke Register described a cumulative risk of vascular recurrence after a first stroke of 8.0% at 1 year and 16.6% at 5 years.1 To reduce vascular recurrence, the most prescribed treatment for secondary prevention of stroke is antiplatelet agents, 2 most widely used are acetylsalicylic acid, clopidogrel, or a combination of both. However 10% to 20% of patients treated with antiplatelet drugs have a new vascular event 3 ; in addition, serious vascular events are reduced only by <25% compared with placebo. 4 Pharmacogenetic studies have evaluated the relationship between genetic variants and high on-treatment platelet reactivity usually assessing platelet aggregation.5 Mega et al 5 found an association between the CYP2C19 reduced-function allele and lower levels of the clopidogrel active metabolite, diminished platelet inhibition, and higher rates of majorBackground and Purpose-Clopidogrel is one of the most used antiplatelet drugs in patients with cardiovascular disease. However, 16% to 50% of patients have a high on-clopidogrel platelet reactivity and an increased risk of ischemic events. The pathogenesis of high on-treatment platelet reactivity in patients with stroke is only partially explained by genetic variations. This study aims to find differentially methylated sites across the genome associated with vascular recurrence in ischemic stroke patients treated with clopidogrel. Methods-From a cohort of 1900 patients with ischemic stroke, we selected 42 patients treated with clopidogrel, including 21 with a recurrent vascular event and 21 without vascular recurrence during the first year of follow-up. Over 480 000 DNA methylation sites were analyzed across the genome. Differentially methylated CpG sites were identified by nonparametric testing using R. Replication analysis was performed in a new cohort of 191 subjects and results were correlated with platelet reactivity in a subset of 90 subjects using light transmission aggregometry. Results-A total of 73 differentially methylated CpG sites (P<1×10 −05) were identified; 3 of them were selected for further replication: cg03548645 (P=1.42×10 , XRCC1). The cg03548645 CpG remained significant in the replication study (P=0.034), a deep analysis of this region revealed another methylation site associated with vascular recurrence, P=0.037. Lower cg03548645 (TRAF3) DNA methylation levels were correlated with an increased platelet aggregation (ρ=−0.29, P=0.0075). observed that lower P2Y12 gene promoter DNA methylation (DNAm) was associated with an increased risk of clopidogrel high on-treatment platelet reactivity in patients with albumin ≤35 g/L, currently smoking, or abusing alcohol, suggesting a potential role for epigenetics in clopidogrel high on-treatment platelet reactivity and vascular events after clopidogrel treatment. Conclusions-Thi...

Stroke is a complex disease and one of the main causes of morbidity and mortality among the adult population. A huge variety of factors is known to influence patient outcome, including demographic variables, comorbidities or genetics. In this review, we expound what is known about the influence of clinical variables and related genetic risk factors on ischemic stroke outcome, focusing on acute and subacute outcome (within 24 to 48 hours after stroke and until day 10, respectively), as they are the first indicators of stroke damage. We searched the PubMed data base for articles that investigated the interaction between clinical variables or genetic factors and acute or subacute stroke outcome. A total of 61 studies were finally included in this review. Regarding the data collected, the variables consistently associated with acute stroke outcome are: glucose levels, blood pressure, presence of atrial fibrillation, prior statin treatment, stroke severity, type of acute treatment performed, severe neurological complications, leukocyte levels, and genetic risk factors. Further research and international efforts are required in this field, which should include genome-wide association studies.

Hemorrhagic transformation is a complication of recombinant tissue-plasminogen activator (rtPA) treatment. The most severe form, parenchymal hematoma, can result in neurological deterioration, disability, and death. Our objective is to identify single nucleotide variations associated with a risk of parenchymal hematoma following thrombolytic therapy in acute ischemic stroke patients. A fixed-effect genome-wide metanalysis was performed combining two-stage Genome Wide Association studies (GWAs) (n = 1,904). The Discovery Stage (3 cohorts) comprised 1,324 ischemic stroke individuals, of whom 5.4% had a parenchymal hematoma. Genetic variants yielding a p-value &lt;1x10−5 were analyzed in the Validation Stage (6 cohorts), formed by 580 ischemic stroke patients with 12.1% hemorrhagic events. All the participants received rtPA; cases were parenchymal hematoma type 1 or 2 as defined by the ECASS criteria. Genome-wide significant findings (p &lt; 5x10−8) were characterized by in-silico functional annotation, gene expression, and DNA regulatory elements. We analyzed 7,989,272 single nucleotide polymorphisms (SNPs) and identified a Genome-wide association locus on chromosome 20 in the Discovery Cohort; functional annotation indicated that the ZBTB46 gene was driving the association for Chrosome 20. The top SNP was rs76484331 in the ZBTB46 gene (p = 2.49x10−8; odds ratio (OR): 11.21; 95% confidence interval (CI): 4.82–26.55). In the Replication Cohort (n = 580), the rs76484331 polymorphism was associated with parenchymal hematoma (p = 0.01), and the overall association after meta-analysis increased (p = 1.61x10−8; OR: 5.84; 95%CI: 3.16–10.76). ZBTB46 codes the Zinc Finger and BTB domain-containing protein 46 that acts as a transcription factor. In-silico studies indicated that ZBTB46 is expressed in brain tissue by neurons and endothelial cells. Moreover, rs76484331 interacts with the promoter sites located at 20q13. In conculsion, we identified single nucleotide variants in the ZBTB46 gene associated with a higher risk of parenchymal hematoma following rtPA treatment.

Background and Purpose— Despite great efforts by pharmacogenetic studies, the causes of aspirin failure to prevent the recurrence of ischemic events remain unclear. Our aim was to study whether epigenetics could be associated with the risk of vascular recurrence in aspirin-treated stroke patients. Methods— We performed an epigenetic joint analysis study in 327 patients treated with aspirin. In the discovery stage, we performed a nested case–control study in 38 matched ischemic stroke patients in whom 450 000 methylation sites were analyzed. Nineteen patients presented vascular recurrence after stroke, and 19 matched patients did not present vascular recurrence during the first year of follow-up. In a second stage, 289 new patients were analyzed by EpiTYPER. Results— The following 3 differentially methylated candidate CpG sites, were identified in the discovery stage and analyzed in the second stage: cg26039762 ( P =9.69×10 −06 , RAF1 ), cg04985020 ( P =3.47×10 −03 , PPM1A ), and cg08419850 ( P =3.47×10 −03 , KCNQ1 ). Joint analysis identified an epigenome-wide association for cg04985020 ( PPM1A ; P =1.78×10 −07 ), with vascular recurrence in patients treated with aspirin. Conclusions— The pattern of differential methylation in PPM1A is associated with vascular recurrence in aspirin-treated stroke patients.