@article {1343, title = {Genetic variants of the NOTCH3 gene in the elderly and magnetic resonance imaging correlates of age-related cerebral small vessel disease.}, journal = {Brain}, volume = {134}, year = {2011}, month = {2011 Nov}, pages = {3384-97}, abstract = {

Cerebral small vessel disease-related brain lesions such as white matter lesions and lacunes are common findings of magnetic resonance imaging in the elderly. These lesions are thought to be major contributors to disability in old age, and risk factors that include age and hypertension have been established. The radiological, histopathologic and clinical phenotypes of age-related cerebral small vessel disease remarkably resemble autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy, which is caused by mutations in NOTCH3. We hypothesized that genetic variations in NOTCH3 also play a role in age-related cerebral small vessel disease. We directly sequenced all 33 exons, the promoter and 3{\textquoteright}-untranslated region of NOTCH3 in 195 participants with either coalescent white matter lesions or lacunes and compared the results to 82 randomly selected participants with no focal changes on magnetic resonance images in the Austrian Stroke Prevention Study. We detected nine common and 33 rare single nucleotide polymorphisms, of which 20 were novel. All common single nucleotide polymorphisms were genotyped in the entire cohort (n = 888), and four of them, rs1043994, rs10404382, rs10423702 and rs1043997, were associated significantly with both the presence and progression of white matter lesions. The association was confined to hypertensives, a result which we replicated in the Cohorts for Heart and Ageing Research in Genomic Epidemiology Consortium on an independent sample of 4773 stroke-free hypertensive elderly individuals of European descent (P = 0.04). The 33 rare single nucleotide polymorphisms were scattered over the NOTCH3 gene with three being located in the promoter region, 24 in exons (18 non-synonymous), three in introns and three in the 3{\textquoteright}-untranslated region. None of the single nucleotide polymorphisms affected a cysteine residue. Sorting Intolerant From Tolerant, PolyPhen2 analyses and protein structure simulation consistently predicted six of the non-synonymous single nucleotide polymorphisms (H170R, P496L, V1183M, L1518M, D1823N and V1952M) to be functional, with four being exclusively or mainly detected in subjects with severe white matter lesions. In four individuals with rare non-synonymous single nucleotide polymorphisms, we noted anterior temporal lobe hyperintensity, hyperintensity in the external capsule, lacunar infarcts or subcortical lacunar lesions. None of the observed abnormalities were specific to cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy. This is the first comprehensive study investigating (i) the frequency of NOTCH3 variations in community-dwelling elderly and (ii) their effect on cerebral small vessel disease related magnetic resonance imaging phenotypes. We show that the NOTCH3 gene is highly variable with both common and rare single nucleotide polymorphisms spreading across the gene, and that common variants at the NOTCH3 gene increase the risk of age-related white matter lesions in hypertensives. Additional investigations are required to explore the biological mechanisms underlying the observed association.

}, keywords = {Aged, Aged, 80 and over, Alleles, Brain, Cerebral Small Vessel Diseases, Exons, Female, Follow-Up Studies, Genetic Association Studies, Genotype, Humans, Hypertension, Magnetic Resonance Imaging, Male, Middle Aged, Phenotype, Promoter Regions, Genetic, Prospective Studies, Receptor, Notch3, Receptors, Notch}, issn = {1460-2156}, doi = {10.1093/brain/awr252}, author = {Schmidt, Helena and Zeginigg, Marion and Wiltgen, Marco and Freudenberger, Paul and Petrovic, Katja and Cavalieri, Margherita and Gider, Pierre and Enzinger, Christian and Fornage, Myriam and Debette, Stephanie and Rotter, Jerome I and Ikram, Mohammad A and Launer, Lenore J and Schmidt, Reinhold} } @article {6864, title = {Common variation in COL4A1/COL4A2 is associated with sporadic cerebral small vessel disease.}, journal = {Neurology}, volume = {84}, year = {2015}, month = {2015 Mar 3}, pages = {918-26}, abstract = {

OBJECTIVES: We hypothesized that common variants in the collagen genes COL4A1/COL4A2 are associated with sporadic forms of cerebral small vessel disease.

METHODS: We conducted meta-analyses of existing genotype data among individuals of European ancestry to determine associations of 1,070 common single nucleotide polymorphisms (SNPs) in the COL4A1/COL4A2 genomic region with the following: intracerebral hemorrhage and its subtypes (deep, lobar) (1,545 cases, 1,485 controls); ischemic stroke and its subtypes (cardioembolic, large vessel disease, lacunar) (12,389 cases, 62,004 controls); and white matter hyperintensities (2,733 individuals with ischemic stroke and 9,361 from population-based cohorts with brain MRI data). We calculated a statistical significance threshold that accounted for multiple testing and linkage disequilibrium between SNPs (p < 0.000084).

RESULTS: Three intronic SNPs in COL4A2 were significantly associated with deep intracerebral hemorrhage (lead SNP odds ratio [OR] 1.29, 95\% confidence interval [CI] 1.14-1.46, p = 0.00003; r(2) > 0.9 between SNPs). Although SNPs associated with deep intracerebral hemorrhage did not reach our significance threshold for association with lacunar ischemic stroke (lead SNP OR 1.10, 95\% CI 1.03-1.18, p = 0.0073), and with white matter hyperintensity volume in symptomatic ischemic stroke patients (lead SNP OR 1.07, 95\% CI 1.01-1.13, p = 0.016), the direction of association was the same. There was no convincing evidence of association with white matter hyperintensities in population-based studies or with non-small vessel disease cerebrovascular phenotypes.

CONCLUSIONS: Our results indicate an association between common variation in the COL4A2 gene and symptomatic small vessel disease, particularly deep intracerebral hemorrhage. These findings merit replication studies, including in ethnic groups of non-European ancestry.

}, keywords = {Cerebral Small Vessel Diseases, Collagen Type IV, Genetic Association Studies, Genetic Variation, Humans, Polymorphism, Single Nucleotide}, issn = {1526-632X}, doi = {10.1212/WNL.0000000000001309}, author = {Rannikmae, Kristiina and Davies, Gail and Thomson, Pippa A and Bevan, Steve and Devan, William J and Falcone, Guido J and Traylor, Matthew and Anderson, Christopher D and Battey, Thomas W K and Radmanesh, Farid and Deka, Ranjan and Woo, Jessica G and Martin, Lisa J and Jimenez-Conde, Jordi and Selim, Magdy and Brown, Devin L and Silliman, Scott L and Kidwell, Chelsea S and Montaner, Joan and Langefeld, Carl D and Slowik, Agnieszka and Hansen, Bjorn M and Lindgren, Arne G and Meschia, James F and Fornage, Myriam and Bis, Joshua C and Debette, Stephanie and Ikram, Mohammad A and Longstreth, Will T and Schmidt, Reinhold and Zhang, Cathy R and Yang, Qiong and Sharma, Pankaj and Kittner, Steven J and Mitchell, Braxton D and Holliday, Elizabeth G and Levi, Christopher R and Attia, John and Rothwell, Peter M and Poole, Deborah L and Boncoraglio, Giorgio B and Psaty, Bruce M and Malik, Rainer and Rost, Natalia and Worrall, Bradford B and Dichgans, Martin and Van Agtmael, Tom and Woo, Daniel and Markus, Hugh S and Seshadri, Sudha and Rosand, Jonathan and Sudlow, Cathie L M} } @article {6688, title = {Genetic overlap between diagnostic subtypes of ischemic stroke.}, journal = {Stroke}, volume = {46}, year = {2015}, month = {2015 Mar}, pages = {615-9}, abstract = {

BACKGROUND AND PURPOSE: Despite moderate heritability, the phenotypic heterogeneity of ischemic stroke has hampered gene discovery, motivating analyses of diagnostic subtypes with reduced sample sizes. We assessed evidence for a shared genetic basis among the 3 major subtypes: large artery atherosclerosis (LAA), cardioembolism, and small vessel disease (SVD), to inform potential cross-subtype analyses.

METHODS: Analyses used genome-wide summary data for 12 389 ischemic stroke cases (including 2167 LAA, 2405 cardioembolism, and 1854 SVD) and 62 004 controls from the Metastroke consortium. For 4561 cases and 7094 controls, individual-level genotype data were also available. Genetic correlations between subtypes were estimated using linear mixed models and polygenic profile scores. Meta-analysis of a combined LAA-SVD phenotype (4021 cases and 51 976 controls) was performed to identify shared risk alleles.

RESULTS: High genetic correlation was identified between LAA and SVD using linear mixed models (rg=0.96, SE=0.47, P=9{\texttimes}10(-4)) and profile scores (rg=0.72; 95\% confidence interval, 0.52-0.93). Between LAA and cardioembolism and SVD and cardioembolism, correlation was moderate using linear mixed models but not significantly different from zero for profile scoring. Joint meta-analysis of LAA and SVD identified strong association (P=1{\texttimes}10(-7)) for single nucleotide polymorphisms near the opioid receptor μ1 (OPRM1) gene.

CONCLUSIONS: Our results suggest that LAA and SVD, which have been hitherto treated as genetically distinct, may share a substantial genetic component. Combined analyses of LAA and SVD may increase power to identify small-effect alleles influencing shared pathophysiological processes.

}, keywords = {Alleles, Atherosclerosis, Cerebral Small Vessel Diseases, Cohort Studies, Data Interpretation, Statistical, Embolism, Genome-Wide Association Study, Genotype, Humans, Ischemia, Linear Models, Meta-Analysis as Topic, Phenotype, Polymorphism, Single Nucleotide, Stroke}, issn = {1524-4628}, doi = {10.1161/STROKEAHA.114.007930}, author = {Holliday, Elizabeth G and Traylor, Matthew and Malik, Rainer and Bevan, Steve and Falcone, Guido and Hopewell, Jemma C and Cheng, Yu-Ching and Cotlarciuc, Ioana and Bis, Joshua C and Boerwinkle, Eric and Boncoraglio, Giorgio B and Clarke, Robert and Cole, John W and Fornage, Myriam and Furie, Karen L and Ikram, M Arfan and Jannes, Jim and Kittner, Steven J and Lincz, Lisa F and Maguire, Jane M and Meschia, James F and Mosley, Thomas H and Nalls, Mike A and Oldmeadow, Christopher and Parati, Eugenio A and Psaty, Bruce M and Rothwell, Peter M and Seshadri, Sudha and Scott, Rodney J and Sharma, Pankaj and Sudlow, Cathie and Wiggins, Kerri L and Worrall, Bradford B and Rosand, Jonathan and Mitchell, Braxton D and Dichgans, Martin and Markus, Hugh S and Levi, Christopher and Attia, John and Wray, Naomi R} } @article {9706, title = {Genetic Complexities of Cerebral Small Vessel Disease, Blood Pressure, and Dementia.}, journal = {JAMA Netw Open}, volume = {7}, year = {2024}, month = {2024 May 01}, pages = {e2412824}, abstract = {

IMPORTANCE: Vascular disease is a treatable contributor to dementia risk, but the role of specific markers remains unclear, making prevention strategies uncertain.

OBJECTIVE: To investigate the causal association between white matter hyperintensity (WMH) burden, clinical stroke, blood pressure (BP), and dementia risk, while accounting for potential epidemiologic biases.

DESIGN, SETTING, AND PARTICIPANTS: This study first examined the association of genetically determined WMH burden, stroke, and BP levels with Alzheimer disease (AD) in a 2-sample mendelian randomization (2SMR) framework. Second, using population-based studies (1979-2018) with prospective dementia surveillance, the genetic association of WMH, stroke, and BP with incident all-cause dementia was examined. Data analysis was performed from July 26, 2020, through July 24, 2022.

EXPOSURES: Genetically determined WMH burden and BP levels, as well as genetic liability to stroke derived from genome-wide association studies (GWASs) in European ancestry populations.

MAIN OUTCOMES AND MEASURES: The association of genetic instruments for WMH, stroke, and BP with dementia was studied using GWASs of AD (defined clinically and additionally meta-analyzed including both clinically diagnosed AD and AD defined based on parental history [AD-meta]) for 2SMR and incident all-cause dementia for longitudinal analyses.

RESULTS: In 2SMR (summary statistics-based) analyses using AD GWASs with up to 75 024 AD cases (mean [SD] age at AD onset, 75.5 [4.4] years; 56.9\% women), larger WMH burden showed evidence for a causal association with increased risk of AD (odds ratio [OR], 1.43; 95\% CI, 1.10-1.86; P = .007, per unit increase in WMH risk alleles) and AD-meta (OR, 1.19; 95\% CI, 1.06-1.34; P = .008), after accounting for pulse pressure for the former. Blood pressure traits showed evidence for a protective association with AD, with evidence for confounding by shared genetic instruments. In the longitudinal (individual-level data) analyses involving 10 699 incident all-cause dementia cases (mean [SD] age at dementia diagnosis, 74.4 [9.1] years; 55.4\% women), no significant association was observed between larger WMH burden and incident all-cause dementia (hazard ratio [HR], 1.02; 95\% CI, 1.00-1.04; P = .07). Although all exposures were associated with mortality, with the strongest association observed for systolic BP (HR, 1.04; 95\% CI, 1.03-1.06; P = 1.9 {\texttimes} 10-14), there was no evidence for selective survival bias during follow-up using illness-death models. In secondary analyses using polygenic scores, the association of genetic liability to stroke, but not genetically determined WMH, with dementia outcomes was attenuated after adjusting for interim stroke.

CONCLUSIONS: These findings suggest that WMH is a primary vascular factor associated with dementia risk, emphasizing its significance in preventive strategies for dementia. Future studies are warranted to examine whether this finding can be generalized to non-European populations.

}, keywords = {Aged, Aged, 80 and over, Alzheimer Disease, Blood Pressure, Cerebral Small Vessel Diseases, Dementia, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Male, Mendelian Randomization Analysis, Prospective Studies, Risk Factors, Stroke}, issn = {2574-3805}, doi = {10.1001/jamanetworkopen.2024.12824}, author = {Sargurupremraj, Muralidharan and Soumar{\'e}, A{\"\i}cha and Bis, Joshua C and Surakka, Ida and J{\"u}rgenson, Tuuli and Joly, Pierre and Knol, Maria J and Wang, Ruiqi and Yang, Qiong and Satizabal, Claudia L and Gudjonsson, Alexander and Mishra, Aniket and Bouteloup, Vincent and Phuah, Chia-Ling and van Duijn, Cornelia M and Cruchaga, Carlos and Dufouil, Carole and Chene, Genevi{\`e}ve and Lopez, Oscar L and Psaty, Bruce M and Tzourio, Christophe and Amouyel, Philippe and Adams, Hieab H and Jacqmin-Gadda, H{\'e}l{\`e}ne and Ikram, Mohammad Arfan and Gudnason, Vilmundur and Milani, Lili and Winsvold, Bendik S and Hveem, Kristian and Matthews, Paul M and Longstreth, W T and Seshadri, Sudha and Launer, Lenore J and Debette, Stephanie} }