scholarly journals Association of common genetic variants with brain microbleeds

Neurology ◽  
2020 ◽  
Vol 95 (24) ◽  
pp. e3331-e3343 ◽  
Author(s):  
Maria J. Knol ◽  
Dongwei Lu ◽  
Matthew Traylor ◽  
Hieab H.H. Adams ◽  
José Rafael J. Romero ◽  
...  

ObjectiveTo identify common genetic variants associated with the presence of brain microbleeds (BMBs).MethodsWe performed genome-wide association studies in 11 population-based cohort studies and 3 case–control or case-only stroke cohorts. Genotypes were imputed to the Haplotype Reference Consortium or 1000 Genomes reference panel. BMBs were rated on susceptibility-weighted or T2*-weighted gradient echo MRI sequences, and further classified as lobar or mixed (including strictly deep and infratentorial, possibly with lobar BMB). In a subset, we assessed the effects of APOE ε2 and ε4 alleles on BMB counts. We also related previously identified cerebral small vessel disease variants to BMBs.ResultsBMBs were detected in 3,556 of the 25,862 participants, of which 2,179 were strictly lobar and 1,293 mixed. One locus in the APOE region reached genome-wide significance for its association with BMB (lead single nucleotide polymorphism rs769449; odds ratio [OR]any BMB [95% confidence interval (CI)] 1.33 [1.21–1.45]; p = 2.5 × 10−10). APOE ε4 alleles were associated with strictly lobar (OR [95% CI] 1.34 [1.19–1.50]; p = 1.0 × 10−6) but not with mixed BMB counts (OR [95% CI] 1.04 [0.86–1.25]; p = 0.68). APOE ε2 alleles did not show associations with BMB counts. Variants previously related to deep intracerebral hemorrhage and lacunar stroke, and a risk score of cerebral white matter hyperintensity variants, were associated with BMB.ConclusionsGenetic variants in the APOE region are associated with the presence of BMB, most likely due to the APOE ε4 allele count related to a higher number of strictly lobar BMBs. Genetic predisposition to small vessel disease confers risk of BMB, indicating genetic overlap with other cerebral small vessel disease markers.

2015 ◽  
Vol 36 (1) ◽  
pp. 158-171 ◽  
Author(s):  
Christof Haffner ◽  
Rainer Malik ◽  
Martin Dichgans

Cerebral small vessel disease (SVD) is among the most frequent causes of both stroke and dementia. There is a growing list of genes known to be implicated in Mendelian forms of SVD. Also, genome-wide association studies have identified common variants at a number of genetic loci that are associated with manifestations of SVD, among them loci for white matter hyperintensities, small vessel stroke, and deep intracerebral hemorrhage. Driven by these discoveries and new animal models substantial progress has been made in elucidating the molecular, cellular, and physiologic mechanisms underlying SVD. A major theme emerging from these studies is the extracellular matrix (ECM). Recent findings include a role of structural constituents of the ECM such as type IV collagens in hereditary and sporadic SVD, the sequestration of proteins with a known role in ECM maintenance into aggregates of NOTCH3, and altered signaling through molecules known to interact with the ECM. Here, we review recent progress in the identification of genes involved in SVD and discuss mechanistic concepts with a particular focus on the ECM.


Acta Naturae ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 4-15 ◽  
Author(s):  
L. A. Dobrynina ◽  
M. R. Zabitova ◽  
L. A. Kalashnikova ◽  
E. V. Gnedovskaya ◽  
M. A. Piradov

Hypertension (HT) and its cerebral complications are extremely vexing medical and social problems. Despite the obvious association between hypertension and the clinical and neuroimaging features of cerebral microangiopathy (CMA) (also known as cerebral small vessel disease), the causal links between them remain ambiguous. Besides, antihypertensive therapy as the only way to manage these patients does not always prevent brain damage. Knowledge about the key factors and mechanisms involved in HT and CMA development is important for predicting the risk of cerebral complications and developing new approaches to their prevention and treatment. At present, genome-wide association studies and other approaches are used to investigate the common hereditary mechanisms of HT and CMA development, which will explain a large number of CMA cases not associated with hypertension, lack of a correlation between HT severity and the degree of cerebral injury, and failure of antihypertensive therapy to prevent CMA progression. Epigenetic markers likely play a modulating role in the development of these diseases.


2021 ◽  
Author(s):  
Stéphanie Debette ◽  
Marie-Gabrielle Duperron ◽  
Maria Knol ◽  
Quentin Le Grand ◽  
Tavia Evans ◽  
...  

Abstract Perivascular space burden (PVS) is an emerging and possibly the earliest magnetic resonance imaging (MRI)-marker of cerebral small vessel disease (cSVD), a leading cause of stroke and dementia. Its molecular underpinnings are unknown. Genome-wide and whole-exome association studies in 40,095 participants (21 population-based cohorts, 66.3±8.6 years) revealed 24 genome-wide significant PVS risk loci. These showed association with white matter PVS already at age 20, suggesting an important role of early-life factors. PVS loci were enriched in genes causing early-onset leukodystrophies and genes expressed in fetal brain endothelial cells. Mendelian randomization analyses supported causal associations of high blood pressure with basal ganglia (BG) and hippocampal PVS, and of BG PVS with stroke. Transcriptome-wide association studies suggest causal implication of 11 genes, to prioritize for experimental follow-up as putative biotargets for cSVD. Two-thirds of PVS loci point to novel pathways, involving extracellular matrix, membrane transport, and developmental processes, with enrichment in targets of existing drugs for vascular/cognitive disorders.


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Forrest Lowe ◽  
Souvik Sen ◽  
Hamdi S Adam ◽  
Ryan Demmer ◽  
Bruce A Wasserman ◽  
...  

Background: Prior studies have shown the association between periodontal disease, lacunar strokes and cognitive impairment. Using the Atherosclerosis Risk in Communities (ARIC) cohort study we investigated the relationship between periodontal disease (PD) and the development of MRI verified small vessel disease. Methods: Using the ARIC database data we extracted data for 1143 (mean age 77 years, 76% white, 24% African-American and 45% male) participants assessed for PD (N=800) versus periodontal health (N=343). These participants were assessed for small vessel disease on 3T MRI as measured by the log of white matter hyperintensity volume (WMHV). WMHV were derived from a semiautomated segmentation of FLAIR images. Student t-test was then used to evaluate the relationship between small vessel disease as the log of WMHV in subjects with PD or periodontal health. Based on WMHV the patients were grouped into quartiles and the association of PD with WMHV were tested using the group in periodontal health and lowest quartile of WMHV as the reference groups. Multinomial logistic regression was used to compute crude and adjusted odds ratio (OR) for the higher quartiles of WMHV compared to the reference quartile. Results: There was a significant increase in the presence of small vessel disease measured as log WMHV in the PD cohort as compared to periodontal health cohort with p= 0.023 on Independent Sample t-est. Based on WMHV the subjects were grouped into quartiles 0-6.41, >6.41-11.56, >11.56-21.36 and >21.36 cu mm3). PD was associated with only the highest quartile of WMHV on univariate (crude OR 1.77, 95% CI 1.23-2.56) and multivariable (adjusted OR 1.61, 95% CI 1.06-2.44) analyses. The later was adjusted for age, race, gender, hypertension, diabetes and smoking. Conclusion: Based on this prospective cohort there is data to suggest that PD may be associated with cerebral small vessel disease. Maintaining proper dental health may decrease future risk for the associated lacunar strokes and vascular cognitive impairment.


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Dorothee Schoemaker ◽  
Yesica Zuluaga ◽  
Lina Velilla ◽  
Carolina Ospina ◽  
Francisco Lopera ◽  
...  

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary cerebral small vessel disease (cSVD) linked to NOTCH3 mutations and leading to the early onset of stroke and vascular cognitive impairment. Neuroimaging features of CADASIL include extensive white matter hyperintensity, lacunes, cerebral microbleeds and enlarged perivascular spaces. Researchers from the Rotterdam study recently proposed a MRI-based cSVD Score reflecting the overall burden of cerebrovascular injury (Yilmaz et al., 2018). Here, we explored the relevance of this cSVD Score in distinguishing CADASIL subjects from non-carriers and its relationships to cognition. We evaluated 26 NOTCH3 mutation carriers and 25 non-carriers from large Colombian families. Of the CADASIL subjects, 4 had previous strokes (symptomatic) and 22 had no history of strokes (asymptomatic). All subjects underwent a 3T MRI and a neuropsychological evaluation. Structural MRI markers of cSVD, as well as the cSVD Score, were quantified in each subject following established protocols. Demographic, cognitive and neuroimaging features across groups are presented in Table 1. The cSVD Score significantly differed between groups, after adjusting for age (Figure 1-A). In CADASIL subjects, the cSVD Score was negatively related to performance in Memory, Processing Speed, Executive Function, after accounting for age and education (Figure 1-B). These results suggest that the cSVD Score could be a useful marker of disease severity in CADASIL. Longitudinal studies are now needed to determine if this score allows predicting clinical outcomes in CADASIL, such as stroke or dementia.


2019 ◽  
Vol 20 (3) ◽  
pp. 776 ◽  
Author(s):  
Michael Thrippleton ◽  
Gordon Blair ◽  
Maria Valdes-Hernandez ◽  
Andreas Glatz ◽  
Scott Semple ◽  
...  

A protocol for evaluating ultrasmall superparamagnetic particles of iron oxide (USPIO) uptake and elimination in cerebral small vessel disease patients was developed and piloted. B1-insensitive R1 measurement was evaluated in vitro. Twelve participants with history of minor stroke were scanned at 3-T MRI including structural imaging, and R1 and R2* mapping. Participants were scanned (i) before and (ii) after USPIO (ferumoxytol) infusion, and again at (iii) 24–30 h and (iv) one month. Absolute and blood-normalised changes in R1 and R2* were measured in white matter (WM), deep grey matter (GM), white matter hyperintensity (WMH) and stroke lesion regions. R1 measurements were accurate across a wide range of values. R1 (p < 0.05) and R2* (p < 0.01) mapping detected increases in relaxation rate in all tissues immediately post-USPIO and at 24–30 h. R2* returned to baseline at one month. Blood-normalised R1 and R2* changes post-infusion and at 24–30 h were similar, and were greater in GM versus WM (p < 0.001). Narrower distributions were seen with R2* than for R1 mapping. R1 and R2* changes were correlated at 24–30 h (p < 0.01). MRI relaxometry permits quantitative evaluation of USPIO uptake; R2* appears to be more sensitive to USPIO than R1. Our data are explained by intravascular uptake alone, yielding estimates of cerebral blood volume, and did not support parenchymal uptake. Ferumoxytol appears to be eliminated at 1 month. The approach should be valuable in future studies to quantify both blood-pool USPIO and parenchymal uptake associated with inflammatory cells or blood-brain barrier leak.


2019 ◽  
Vol 25 (10) ◽  
pp. 2455-2467 ◽  
Author(s):  
Tim B. Bigdeli ◽  
◽  
Giulio Genovese ◽  
Penelope Georgakopoulos ◽  
Jacquelyn L. Meyers ◽  
...  

Abstract Schizophrenia is a common, chronic and debilitating neuropsychiatric syndrome affecting tens of millions of individuals worldwide. While rare genetic variants play a role in the etiology of schizophrenia, most of the currently explained liability is within common variation, suggesting that variation predating the human diaspora out of Africa harbors a large fraction of the common variant attributable heritability. However, common variant association studies in schizophrenia have concentrated mainly on cohorts of European descent. We describe genome-wide association studies of 6152 cases and 3918 controls of admixed African ancestry, and of 1234 cases and 3090 controls of Latino ancestry, representing the largest such study in these populations to date. Combining results from the samples with African ancestry with summary statistics from the Psychiatric Genomics Consortium (PGC) study of schizophrenia yielded seven newly genome-wide significant loci, and we identified an additional eight loci by incorporating the results from samples with Latino ancestry. Leveraging population differences in patterns of linkage disequilibrium, we achieve improved fine-mapping resolution at 22 previously reported and 4 newly significant loci. Polygenic risk score profiling revealed improved prediction based on trans-ancestry meta-analysis results for admixed African (Nagelkerke’s R2 = 0.032; liability R2 = 0.017; P < 10−52), Latino (Nagelkerke’s R2 = 0.089; liability R2 = 0.021; P < 10−58), and European individuals (Nagelkerke’s R2 = 0.089; liability R2 = 0.037; P < 10−113), further highlighting the advantages of incorporating data from diverse human populations.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 1528-1528
Author(s):  
Heena Desai ◽  
Anh Le ◽  
Ryan Hausler ◽  
Shefali Verma ◽  
Anurag Verma ◽  
...  

1528 Background: The discovery of rare genetic variants associated with cancer have a tremendous impact on reducing cancer morbidity and mortality when identified; however, rare variants are found in less than 5% of cancer patients. Genome wide association studies (GWAS) have identified hundreds of common genetic variants significantly associated with a number of cancers, but the clinical utility of individual variants or a polygenic risk score (PRS) derived from multiple variants is still unclear. Methods: We tested the ability of polygenic risk score (PRS) models developed from genome-wide significant variants to differentiate cases versus controls in the Penn Medicine Biobank. Cases for 15 different cancers and cancer-free controls were identified using electronic health record billing codes for 11,524 European American and 5,994 African American individuals from the Penn Medicine Biobank. Results: The discriminatory ability of the 15 PRS models to distinguish their respective cancer cases versus controls ranged from 0.68-0.79 in European Americans and 0.74-0.93 in African Americans. Seven of the 15 cancer PRS trended towards an association with their cancer at a p<0.05 (Table), and PRS for prostate, thyroid and melanoma were significantly associated with their cancers at a bonferroni corrected p<0.003 with OR 1.3-1.6 in European Americans. Conclusions: Our data demonstrate that common variants with significant associations from GWAS studies can distinguish cancer cases versus controls for some cancers in an unselected biobank population. Given the small effects, future studies are needed to determine how best to incorporate PRS with other risk factors in the precision prediction of cancer risk. [Table: see text]


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