Whole genome sequencing of 10K patients with acute ischaemic stroke or transient ischaemic attack: design, methods and baseline patient characteristics

Gain-of-function PPM1D mutations attenuate ischemic stroke

Identification of genetic aberrations in stroke, the second leading cause of death worldwide, is of paramount importance for understanding the disease pathogenesis and generating new therapies. Whole-genome sequencing from 10,241 ischemic stroke patients identified eight patients carrying gain-of-function mutations on coding variants in the protein phosphatase magnesium-dependent 1 δ (PPM1D) gene. Patients carrying PPM1D mutations exhibit better stroke-related clinical phenotypes, including improvements in peripheral inflammation, fibrinogen, low-density lipoprotein, cholesterol and plateletcrit level. Experimental brain ischemia in Ppm1d-deficient (Ppm1d-/-) mice resulted in enlarged lesions and pronounced neurological impairments. Spatial transcriptomics revealed a distinct Ppm1d-associated gene expression pattern, indicating disrupted endothelial homeostasis during ischemic brain injury. Proteomic analysis demonstrated that differentially expressed proteins in primary brain endothelial cells from Ppm1d-/- mice were significantly enriched in the peroxisome proliferator-activated receptors (PPARs)-mediated metabolic signaling. Mechanistically, Ppm1d deficiency promoted aberrant fatty acid β-oxidation and increased oxidative stress, which impaired endothelial cell function through the PPARα pathway. A small molecule, T2755, was identified to engage Trp427 and stabilize PPM1D, thereby mitigating ischemic brain injury in mice. Collectively, we find that PPM1D protects against ischemic brain injury and validates its pharmacological stabilizer T2755 as a promising therapy for ischemic stroke. Gain-of-function PPM1D mutations attenuate ischemic cerebral injury. Whole-genome sequencing data of 10,241 ischemic stroke patients from the Third Chinese National Stroke Registry (CNSR-III) identified eight patients with gain-of-function mutations in the protein phosphatase magnesium-dependent 1 δ (PPM1D) gene (17q23.2). These mutation carriers displayed improved peripheral inflammation, decreased fibrinogen, low-density lipoprotein, cholesterol and plateletcrit level. Ppm1d-deficient (Ppm1d-/-) mice exhibited exacerbated stroke outcomes, characterized by enlarged infarct volumes, disrupted cerebrovascular architecture, and enhanced neuro-inflammation. Mechanistically, Ppm1d deficiency induced the disturbance of endothelial fatty acid metabolism involving the PPARα pathway. Through integrated computational modeling, virtual screening, and in vitro validation, T2755 was identified as a small molecule PPM1D stabilizer. Pharmacological PPM1D stabilization with T2755 significantly attenuated ischemic brain injury in murine models.

Impact of Clonal Hematopoiesis of Indeterminate Potential on the Long-Term Risk of Recurrent Stroke in Patients with a High Atherosclerotic Burden

AIMS

Clonal hematopoiesis of indeterminate potential (CHIP), which has recently been shown to be an age-related phenomenon, is associated with cardiovascular diseases, including atherosclerosis and stroke. This study focused on the association between CHIP and short- and long-term stroke recurrence in patients with acute ischemic stroke and intracranial atherosclerotic stenosis (ICAS).

METHODS

This study included 4,699 patients with acute ischemic stroke based on data from the Third China National Stroke Registry (CNSR-III), a nationwide prospective hospital-based registry. The ICAS assessment followed the criteria established by the Warfarin-Aspirin Symptomatic Intracranial Disease Study and Brain Imaging. Atherosclerosis Scores (AS) were used to assess the atherosclerosis burden, as determined by the number and severity of steno-occlusions in the intracranial arteries. The primary outcome was stroke recurrence three months and one year after the event.

RESULTS

Among the 4,699 patients, 3,181 (67.7%) were female, and the median age was 63.0 (55.0-71.0) years. We found that CHIP significantly increased the risk of stroke recurrence at the 1-year follow-up in patients with ICAS (adjusted hazard ratio [HR] 2.71, 95% confidence interval [CI] (1.77-4.16), P for interaction, 0.008).

CONCLUSIONS

Our results revealed that CHIP might have a significant impact on the long-term risk of recurrent stroke, particularly in patients with a higher atherosclerotic burden.

Association between PPAR polymorphisms and neurological functional disability of ischemic stroke

Peroxisome proliferator-activated receptor-γ (PPARγ) plays a protective role against brain injury after stroke in mice. However, the relationship between PPARγ gene polymorphisms and the functional outcome of acute ischemic stroke (AIS) remains unknown. 8822 patients from The Third China National Stroke Registry (CNSR-III) after whole-genome sequencing, two functional single nucleotide polymorphisms(SNPs) in PPARγ, rs1801282 C > G and rs3856806 C > T, were further analysed. The primary outcome was neurological functional disability at three months. Of the 8822 patients, 968 (11.0%) and 3497 (39.6%) were carriers of rs1801282 and rs3856806, respectively. Carriers of rs3856806 showed reduced risks for three-month neurological functional disability (OR, 0.84; 95% CI, 0.73-0.98; p = 0.02) and reduced risks for higher infarct volume (OR 0.90, 95% CI, 0.81-0.99, p = 0.04). They also had a reduced risk of neurological functional disability only in case of lower baseline IL-6 levels (OR 0.64, 95% CI 0.48-0.84, Pinteraction = 0.01). Carriers of rs1801282 had a reduced risk for three-month neurological functional disability (OR 0.77, 95% CI, 0.61-0.99, p = 0.04). Our study suggested that PPARγ polymorphisms are associated with a reduced risk for neurological functional disability and higher infarct volume in AIS. Therefore, PPARγ can be a potential therapeutic target in AIS.

Predicting functional outcome in ischemic stroke patients using genetic, environmental, and clinical factors: a machine learning analysis of population-based prospective cohort study

Ischemic stroke (IS) is a leading cause of adult disability that can severely compromise the quality of life for patients. Accurately predicting the IS functional outcome is crucial for precise risk stratification and effective therapeutic interventions. We developed a predictive model integrating genetic, environmental, and clinical factors using data from 7819 IS patients in the Third China National Stroke Registry. Employing an 80:20 split, we randomly divided the dataset into development and internal validation cohorts. The discrimination and calibration performance of models were evaluated using the area under the receiver operating characteristic curves (AUC) for discrimination and Brier score with calibration curve in the internal validation cohort. We conducted genome-wide association studies (GWAS) in the development cohort, identifying rs11109607 (ANKS1B) as the most significant variant associated with IS functional outcome. We employed principal component analysis to reduce dimensionality on the top 100 significant variants identified by the GWAS, incorporating them as genetic factors in the predictive model. We employed a machine learning algorithm capable of identifying nonlinear relationships to establish predictive models for IS patient functional outcome. The optimal model was the XGBoost model, which outperformed the logistic regression model (AUC 0.818 versus 0.756, P < .05) and significantly improved reclassification efficiency. Our study innovatively incorporated genetic, environmental, and clinical factors for predicting the IS functional outcome in East Asian populations, thereby offering novel insights into IS functional outcome.

Non-O blood types are associated with a greater risk of large artery atherosclerosis stroke and dysregulation of cholesterol metabolism: an observational study

BACKGROUND

Previous research on ABO blood types and stroke has been controversial, predominantly suggesting heightened risk of stroke in non-O blood types. Nonetheless, investigations into the correlation and underlying mechanisms between ABO blood groups and stroke subtypes, especially within Chinese cohorts, remain limited.

METHODS

The ABO blood types of 9,542 ischaemic stroke (IS) patients were inferred using two ABO gene loci (c.261G > del; c.802G > A). The healthy population was derived from the 1000 Genomes Project. Patients were classified by the causative classification system (CCS). Volcano plot and gene ontology (GO) analysis were employed to explore protein differential expression among blood types. Additionally, HT29 and SW480 cell lines with downregulated ABO expression were generated to evaluate its impact on cholesterol uptake and efflux.

RESULTS

A greater proportion of stroke patients had non-O blood types (70.46%) than did healthy individuals (61.54%). Notable differences in blood type distributions were observed among stroke subtypes, with non-O blood type patients mainly classified as having large artery atherosclerosis (LAA). Clinical baseline characteristics, such as the low-density lipoprotein cholesterol level, activated partial thromboplastin time and thrombin time, varied significantly among blood types. A volcano plot revealed 17 upregulated and 42 downregulated proteins in the O blood type. GO term analysis indicated that downregulated proteins were primarily associated with lipid metabolism pathways. In vitro experiments revealed that reducing ABO gene expression decreased cholesterol uptake and increased cholesterol efflux.

CONCLUSIONS

This study revealed that the non-O blood type increased the risk of LAA stroke through cholesterol metabolism.

DNMT3A dysfunction promotes neuroinflammation and exacerbates acute ischemic stroke

Somatic mutations related to clonal hematopoiesis of indeterminate potential (CHIP) are risk factors for stroke. The impact of DNMT3A, the most mutated gene in CHIP, on clinical functional outcomes of acute ischemic stroke (AIS) remains unclear. In a well-characterized cohort of 8524 ischemic stroke patients, we demonstrated that DNMT3A-driven CHIP was significantly associated with neurological disability in these patients. With a stroke mouse model of transient middle cerebral artery occlusion (tMCAO), we demonstrated that DNMT3A protein levels in the brain penumbra increased. The DNMT3A inhibitor RG108 administration amplified neutrophil proliferation in the blood, promoted neutrophil infiltration into the brain penumbra, and exaggerated proinflammatory activation in tMCAO male mice. DNMT3A inhibition also significantly increased infarct volume and worsened neurobehavioral function in tMCAO male mice. In conclusion, DNMT3A somatic mutations are associated with worsened neurological disability in some patients with AIS, potentially through increased neutrophil proliferation and infiltration in the ischemic brain region. These findings suggest a possible mechanism for proinflammatory activation and tissue damage in the affected brain tissue, highlighting the need for further research in this area.

Neglected Mendelian causes of stroke in adult Chinese patients who had an ischaemic stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

Multiple factors play important roles in the occurrence and prognosis of stroke. However, the roles of monogenic variants in all-cause ischaemic stroke have not been systematically investigated. We aim to identify underdiagnosed monogenic stroke in an adult ischaemic stroke/transient ischaemic attack (TIA) cohort (the Third China National Stroke Registry, CNSR-III).

METHODS

Targeted next-generation sequencing for 181 genes associated with stroke was conducted on DNA samples from 10 428 patients recruited through CNSR-III. The genetic and clinical data from electronic health records (EHRs) were reviewed for completion of the diagnostic process. We assessed the percentages of individuals with pathogenic or likely pathogenic (P/LP) variants, and the diagnostic yield of pathogenic variants in known monogenic disease genes with associated phenotypes.

RESULTS

In total, 1953 individuals harboured at least one P/LP variant out of 10 428 patients. Then, 792 (7.6%) individuals (comprising 759 individuals harbouring one P/LP variant in one gene, 29 individuals harbouring two or more P/LP variants in different genes and 4 individuals with two P/LP variants in ABCC6) were predicted to be at risk for one or more monogenic diseases based on the inheritance pattern. Finally, 230 of 792 individuals manifested a clinical phenotype in the EHR data to support the diagnosis of stroke with a monogenic cause. The most diagnosed Mendelian cause of stroke in the cohort was cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. There were no relationships between age or family history and the incidence of first symptomatic monogenic stroke in patients.

CONCLUSION

The rate of monogenic cause of stroke was 2.2% after reviewing the clinical phenotype. Possible reasons that Mendelian causes of stroke may be missed in adult patients who had an ischaemic stroke/TIA include a late onset of stroke symptoms, combination with common vascular risks and the absence of a prominent family history.

Subtype-Specific Association of Mitochondrial DNA Copy Number With Poststroke/TIA Outcomes in 10 241 Patients in China

BACKGROUND

Mitochondrial DNA copy number (mtDNA-CN) is associated with the severity and mortality in patients with stroke, but the associations in different stroke subtypes remain unexplored.

METHODS

We conducted an observational prospective cohort analysis on patients with ischemic stroke or transient ischemic attack enrolled in the Third China National Stroke Registry. We applied logistic models to assess the association of mtDNA-CN with functional outcome (modified Rankin Scale score, 3-6 versus 0-2) and Cox proportional hazard models to assess the association with stroke recurrence (treating mortality as a competing risk) and mortality during a 12-month follow-up, adjusting for sex, age, physical activity, National Institutes of Health Stroke Scale at admission, history of stroke and peripheral artery disease, small artery occlusion, and interleukin-6. Subgroup analyses stratified by age and stroke subtypes were conducted.

RESULTS

The Third China National Stroke Registry enrolled 15 166 patients, of which 10 241 with whole-genome sequencing data were retained (mean age, 62.2 [SD, 11.2] years; 68.8% men). The associations between mtDNA-CN and poststroke/transient ischemic attack outcomes were specific to patients aged ≤65 years, with lower mtDNA-CN significantly associated with stroke recurrence in 12 months (subdistribution hazard ratio, 1.15 per SD lower mtDNA-CN [95% CI, 1.04-1.27]; P=5.2×10-3) and higher all-cause mortality in 3 months (hazard ratio, 2.19 [95% CI, 1.41-3.39]; P=5.0×10-4). Across subtypes, the associations of mtDNA-CN with stroke recurrence were specific to stroke of undetermined cause (subdistribution hazard ratio, 1.28 [95% CI, 1.11-1.48]; P=6.6×10-4). In particular, lower mtDNA-CN was associated with poorer functional outcomes in stroke of undetermined cause patients diagnosed with embolic stroke of undetermined source (odds ratio, 1.53 [95% CI, 1.20-1.94]; P=5.4×10-4), which remained significant after excluding patients with recurrent stroke (odds ratio, 1.49 [95% CI, 1.14-1.94]; P=3.0×10-3).

CONCLUSIONS

Lower mtDNA-CN is associated with higher stroke recurrence rate and all-cause mortality, as well as poorer functional outcome at follow-up, among stroke of undetermined cause, embolic stroke of undetermined source, and younger patients.

Association between clonal hematopoiesis-related gene mutations and unfavorable functional outcome in patients with large-artery atherosclerotic stroke

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) is a phenomenon that characterizes individuals with somatic mutations that are related to hematologic malignancy but without hematologic abnormalities. Presence of CHIP is associated with the atherosclerotic cardiovascular disease through the activation of the interleukin 6 (IL-6) pathway; however, its role on unfavorable functional outcomes in different etiologies of ischemic stroke remains unclear. We aimed to investigate the association between CHIP-related gene mutations and unfavorable functional outcomes of ischemic stroke with different etiologies.

METHODS

We prospectively studied a cohort of 3396 stroke patients with identified etiologies, and identified CHIP and the presence of the IL6R variant (IL6R p.Asp358Ala) by whole-genome sequencing. The IL6R p.Asp358Ala coding mutation was used as a genetic inhibition for IL-6 signaling. The primary outcome was unfavorable functional outcome [(Modified Rankin Scale), mRS 2-6] at 3 months.

RESULTS

Of the 3396 patients, 110 (3.2%) were CHIP carriers and the median age was 62 years (IQR, 54.0-69.0). The CHIP increased the risk of unfavorable functional outcome among patients with hyper-inflammation status of high-sensitivity C-reactive protein (hsCRP) > median levels in patients with large-artery atherosclerosis (LAA) (OR 2.45, 95% CI 1.00-5.98, p = 0.049, pinteraction = 0.01). Presence of IL6R variant (IL6R p.Asp358Ala) could attenuate the risk of unfavorable functional outcome only in patients with CHIP (OR 0.30, 95%CI 0.12-0.76, p = 0.01, pinteraction = 0.02), and especially in LAA patients with CHIP (OR 0.1, 95%CI 0.02-0.42, p = 0.002; pinteraction = 0.001).

CONCLUSION

CHIP is associated with unfavorable functional outcomes in patients with LAA stroke and hyper-inflammation. Genetic IL-6 signaling inhibition might attenuate the risk of unfavorable functional outcomes in CHIP carriers, especially in LAA stroke patients.

Variants within the LPL gene confer susceptility to diabetic kidney disease and rapid decline in kidney function in Chinese patients with type 2 diabetes

AIM

To examine the association between lipoprotein lipase (LPL) polymorphisms and susceptibility to diabetic kidney disease (DKD) and early renal function decline in Chinese patients with type 2 diabetes (T2D).

METHODS

The association of eight LPL single nucleotide polymorphisms (SNPs) with DKD was analysed in 2793 patients with T2D from the third China National Stroke Registry. DKD was defined as either an urine albumin-to-creatinine ratio (UACR) of 30 mg/g or higher at baseline and 3 months, or an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m2 at baseline and 3 months. Rapid decline in kidney function (RDKF) was defined as a reduction in the eGFR of 3 mL/min/1.73 m2 or greater per year. Logistic regression models were used to evaluate the association of LPL SNP and DKD with an additive model.

RESULTS

The SNPs rs285 C>T (OR = 1.40, P = .0154), rs328 C>G (OR = 2.24, P = .0104) and rs3208305 A>T (OR = 1.85, P = .0015) were identified to be significantly associated with DKD defined by eGFR. Among 1241 participants with follow-up data, 441 (35.5%) showed RDKF over a mean follow-up period of 1 year, and the rs285 C allele was associated with higher odds of RDKF (OR = 1.31, 95% CI 1.04-1.66; P = .025) after adjustment for multiple variables.

CONCLUSIONS

These results suggest that LPL-related SNPs are new candidate factors for conferring susceptibility to DKD and may promote rapid loss of renal function in Chinese patients with T2D.

The STROMICS genome study: deep whole-genome sequencing and analysis of 10K Chinese patients with ischemic stroke reveal complex genetic and phenotypic interplay

Ischemic stroke is a leading cause of global mortality and long-term disability. However, there is a paucity of whole-genome sequencing studies on ischemic stroke, resulting in limited knowledge of the interplay between genomic and phenotypic variations among affected patients. Here, we outline the STROMICS design and present the first whole-genome analysis on ischemic stroke by deeply sequencing and analyzing 10,241 stroke patients from China. We identified 135.59 million variants, > 42% of which were novel. Notable disparities in allele frequency were observed between Chinese and other populations for 89 variants associated with stroke risk and 10 variants linked to response to stroke medications. We investigated the population structure of the participants, generating a map of genetic selection consisting of 31 adaptive signals. The adaption of the MTHFR rs1801133-G allele, which links to genetically evaluated VB9 (folate acid) in southern Chinese patients, suggests a gene-specific folate supplement strategy. Through genome-wide association analysis of 18 stroke-related traits, we discovered 10 novel genetic-phenotypic associations and extensive cross-trait pleiotropy at 6 lipid-trait loci of therapeutic relevance. Additionally, we found that the set of loss-of-function and cysteine-altering variants present in the causal gene NOTCH3 for the autosomal dominant stroke disorder CADASIL displayed a broad neuro-imaging spectrum. These findings deepen our understanding of the relationship between the population and individual genetic layout and clinical phenotype among stroke patients, and provide a foundation for future efforts to utilize human genetic knowledge to investigate mechanisms underlying ischemic stroke outcomes, discover novel therapeutic targets, and advance precision medicine.

A pipeline for sample tagging of whole genome bisulfite sequencing data using genotypes of whole genome sequencing

BACKGROUND

In large-scale high-throughput sequencing projects and biobank construction, sample tagging is essential to prevent sample mix-ups. Despite the availability of fingerprint panels for DNA data, little research has been conducted on sample tagging of whole genome bisulfite sequencing (WGBS) data. This study aims to construct a pipeline and identify applicable fingerprint panels to address this problem.

RESULTS

Using autosome-wide A/T polymorphic single nucleotide variants (SNVs) obtained from whole genome sequencing (WGS) and WGBS of individuals from the Third China National Stroke Registry, we designed a fingerprint panel and constructed an optimized pipeline for tagging WGBS data. This pipeline used Bis-SNP to call genotypes from the WGBS data, and optimized genotype comparison by eliminating wildtype homozygous and missing genotypes, and retaining variants with identical genomic coordinates and reference/alternative alleles. WGS-based and WGBS-based genotypes called from identical or different samples were extensively compared using hap.py. In the first batch of 94 samples, the genotype consistency rates were between 71.01%-84.23% and 51.43%-60.50% for the matched and mismatched WGS and WGBS data using the autosome-wide A/T polymorphic SNV panel. This capability to tag WGBS data was validated among the second batch of 240 samples, with genotype consistency rates ranging from 70.61%-84.65% to 49.58%-61.42% for the matched and mismatched data, respectively. We also determined that the number of genetic variants required to correctly tag WGBS data was on the order of thousands through testing six fingerprint panels with different orders for the number of variants. Additionally, we affirmed this result with two self-designed panels of 1351 and 1278 SNVs, respectively. Furthermore, this study confirmed that using the number of genetic variants with identical coordinates and ref/alt alleles, or identical genotypes could not correctly tag WGBS data.

CONCLUSION

This study proposed an optimized pipeline, applicable fingerprint panels, and a lower boundary for the number of fingerprint genetic variants needed for correct sample tagging of WGBS data, which are valuable for tagging WGBS data and integrating multi-omics data for biobanks.

Biomarker and genomic analyses reveal molecular signatures of non-cardioembolic ischemic stroke

Acute ischemic stroke (AIS) is a major cause of disability and mortality worldwide. Non-cardioembolic ischemic stroke (NCIS), which constitutes the majority of AIS cases, is highly heterogeneous, thus requiring precision medicine treatments. This study aimed to investigate the molecular mechanisms underlying NCIS heterogeneity. We integrated data from the Third China National Stroke Registry, including clinical phenotypes, biomarkers, and whole-genome sequencing data for 7695 patients with NCIS. We identified 30 molecular clusters based on 63 biomarkers and explored the comprehensive landscape of biological heterogeneity and subpopulations in NCIS. Dimensionality reduction revealed fine-scale subpopulation structures associated with specific biomarkers. The subpopulations with biomarkers for inflammation, abnormal liver and kidney function, homocysteine metabolism, lipid metabolism, and gut microbiota metabolism were associated with a high risk of unfavorable clinical outcomes, including stroke recurrence, disability, and mortality. Several genes encoding potential drug targets were identified as putative causal genes that drive the clusters, such as CDK10, ERCC3, and CHEK2. We comprehensively characterized the genetic architecture of these subpopulations, identified their molecular signatures, and revealed the potential of the polybiomarkers and polygenic prediction for assessing clinical outcomes. Our study demonstrates the power of large-scale molecular biomarkers and genomics to understand the underlying biological mechanisms of and advance precision medicine for NCIS.

Thirteen-year trends in risk scores predictive values for subsequent stroke in patients with acute ischemic event

INTRODUCTION

A high residual risk of subsequent stroke suggested that the predictive ability of Stroke Prognosis Instrument-II (SPI-II) and Essen Stroke Risk Score (ESRS) may have changed over the years.

AIM

To explore the predictive values of the SPI-II and ESRS for 1-year subsequent stroke risk in a pooled analysis of three consecutive national cohorts in China over 13 years.

RESULTS

In the China National Stroke Registries (CNSRs), 10.7% (5297/50,374) of the patients had a subsequent stroke within 1 year; area under the curve (AUC) of SPI-II and ESRS was .60 (95% confidence interval [CI]: .59-.61) and .58 (95% CI: .57-.59), respectively. For SPI-II, the AUC was .60 (95% CI: .59-.62) in CNSR-I, .60 (95% CI: .59-.62) in CNSR-II, and .58 (95% CI: .56-.59) in CNSR-III over the past 13 years. The declining trend was also found in ESRS scale (CNSR-I: .60 [95% CI: .59-.61]; CNSR-II: .60 [95% CI: .59-.62]; and CNSR-III: .56 [95% CI: .55-.58]).

CONCLUSIONS

The predictive power of the traditional risk scores SPI-II and ESRS was limited and gradually decreased over the past 13 years, thus the scales may not be useful for current clinical practice. Further derivation of risk scales with additional imaging features and biomarkers may be warranted.

Telomere length and stroke recurrence after ischemic stroke and TIA

BACKGROUND AND OBJECTIVE

Shortening telomere length (TL), as an indicator of aging, has been associated with increased risk of cardiovascular disease and incident stroke. However, there are limited data relating to the association between TL and recurrent stroke.

METHODS

Patients from the Third China National Stroke Registry who had whole genome sequencing (WGS) were selected. TL was estimated using TelSeq based on binary sequence alignment/map files derived from WGS data. Cox proportional hazards regression models were performed to assess the association of TL with recurrent stroke.

RESULTS

A total of 8041 patients with ischemic stroke (IS) or transient ischemic attack (TIA) were included. Mean TL was 2.14 ± 0.82 kb. Patients in the lowest tertile of TL had higher incidence of stroke recurrence compared to those in the middle and highest tertile (6.4% vs 5.9% vs 5.2%), but the difference was not longer significant after adjusting for age, sex, cardiovascular risk factors and stroke severity. Similarly, when analyzing TL as a continuous variable, the HR per 1000 bp increase in TL was significant 0.88 (0.79-0.98), but after adjusting for co-variates, was no longer significant (0.91; 95% confidence interval (CI), 0.81-1.02). In patients aged > 65 years, but not in younger patients, after adjusting for co-variates, TL was significantly associated with stroke recurrence. Compared to the lowest tertile, HRs (95% CI) after adjustment for all co-variates for the middle and highest tertiles were 0.78 (0.55-1.10) and 0.67 (0.46-0.98), respectively, with p for trend of 0.03. In analyses using TL as a continuous variable, adjusted HR (95% CI) per 1000 bp increase in TL was 0.80 (0.66-0.96). However, there was no significant interaction between TL and age on risk of stroke recurrence (p for interaction = 0.09).

CONCLUSIONS

In Chinese IS or TIA patients, no independent association was found between TL and risk of stroke recurrence after adjusting for co-variates. We found a possible association in older patients but this needs replicating.

Exome-based gene panel analysis in a cohort of acute juvenile ischemic stroke patients:relevance of NOTCH3 and GLA variants

BACKGROUND

Genetic variants are considered to have a crucial impact on the occurrence of ischemic stroke. In clinical routine, the diagnostic value of next-generation sequencing (NGS) in the medical clarification of acute juvenile stroke has not been investigated so far.

MATERIAL AND METHODS

We analyzed an exome-based gene panel of 349 genes in 172 clinically well-characterized patients with magnetic resonance imaging (MRI)-proven, juvenile (age ≤ 55 years), ischemic stroke admitted to a single comprehensive stroke center.

RESULTS

Monogenetic diseases causing ischemic stroke were observed in five patients (2.9%): In three patients with lacunar stroke (1.7%), we identified pathogenic variants in NOTCH3 causing cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Hence, CADASIL was identified at a frequency of 12.5% in the lacunar stroke subgroup. Further, in two male patients (1.2%) suffering from lacunar and cardioembolic stroke, pathogenic variants in GLA causing Fabry's disease were present. Additionally, genetic variants in monogenetic diseases lacking impact on stroke occurrence, variants of unclear significance (VUS) in monogenetic diseases, and (cardiovascular-) risk genes in ischemic stroke were observed in a total of 15 patients (15.7%).

CONCLUSION

Genetic screening for Fabry's disease in cardioembolic and lacunar stroke as well as CADASIL in lacunar stroke might be beneficial in routine medical work-up of acute juvenile ischemic stroke.

Somatic mutation contributing to clonal haematopoiesis is a risk factor of recurrent stroke in first-ever acute ischaemic stroke: a prospective cohort study

BACKGROUND

Somatic mutation contributes to clonal haematopoiesis of indeterminate potential (CHIP) is related to age and associated with a higher risk of stroke and atherosclerotic cardiovascular disease. Here, we investigated the prognostic significance of CHIP in a large first-ever acute ischaemic stroke (AIS) cohort and explored the underlying mechanisms.

METHODS

We studied a prospective cohort of 6016 patients who had a first-ever AIS in China. Whole-genome sequencing was performed to identify CHIP. High-sensitivity C reactive protein (hs-CRP) levels above 3 mg/L at baseline were defined as hyperinflammation. Recurrent stroke during the 3-month follow-up was the primary outcome.

RESULTS

Among the 6016 patients who had a first-ever AIS, with a median age was 62 years (IQR, 54.0‒70.0), 3.70% were identified as CHIP carriers. The most common mutations occurred in the DNMT3A (30.0%) and TET2 (11.4%) genes. During a follow-up of 3 months, the presence of CHIP was associated with recurrent stroke (HR 1.62, 95% CI 1.04 to 2.51, p=0.03), recurrent ischaemic stroke (HR 1.64, 95% CI 1.04 to 2.58, p=0.03) and combined vascular events (HR 1.58, 95% CI 1.02 to 2.44, p=0.04) after adjusting for hsCRP levels at baseline in patients who had a first-ever AIS. Subgroup analysis demonstrated that CHIP was only associated with recurrent stroke when patients under hyperinflammation (OR 3.10, 95% CI 1.92 to 5.00, p<0.001) but not in those without hyperinflammation (OR 0.18, 95% CI 0.03 to 1.04, p=0.06, P_interaction=0.002).

CONCLUSION

Our results suggest that somatic mutations contributing to CHIP increase the risk of short-term recurrent stroke in patients who had a first-ever AIS. Hyperinflammation may be important in the relationship between CHIP and recurrent stroke.

Stroke Genetics: Discovery, Insight Into Mechanisms, and Clinical Perspectives

Stroke is the second leading cause of death worldwide and a complex, heterogeneous condition. In this review, we provide an overview of the current knowledge on monogenic and multifactorial forms of stroke, highlighting recent insight into the continuum between these. We describe how, in recent years, large-scale genome-wide association studies have enabled major progress in deciphering the genetic basis for stroke and its subtypes, although more research is needed to interpret these findings. We cover the potential of stroke genetics to reveal novel pathophysiological processes underlying stroke, to accelerate the discovery of new therapeutic approaches, and to identify individuals in the population who are at high risk of stroke and could be targeted for tailored preventative interventions.