@article {684, title = {A prospective study of venous thromboembolism in relation to factor V Leiden and related factors.}, journal = {Blood}, volume = {99}, year = {2002}, month = {2002 Apr 15}, pages = {2720-5}, abstract = {

The aim of this study was to examine the occurrence of venous thromboembolism (VTE) in relation to factor V-related risk factors. Using a nested case-control design combining 2 population-based prospective studies, we measured factor V Leiden, HR2 haplotype, activated protein C (APC) resistance, and plasma factor V antigen in 335 participants who developed VTE during 8 years of follow-up and 688 controls. The overall odds ratio (OR) of VTE was 3.67 (95\% CI, 2.20-6.12) in participants carrying factor V Leiden compared with noncarriers. APC resistance measured after predilution with factor V-deficient plasma conferred an OR of 2.58 (95\% CI, 1.62-4.10). All 3 participants homozygous for the HR2 haplotype had a VTE, and the OR of VTE for homozygosity was estimated to be 5.5 (95\% CI, 2.45-12.5). Carriers of the HR2 haplotype otherwise were not at increased risk of VTE overall (OR = 1.05; 95\% CI, 0.64-1.72), but double heterozygotes for HR2 and factor V Leiden carried an OR of idiopathic VTE of 16.3 (95\% CI, 1.7-159) compared with noncarriers. Factor V antigen also was not associated with VTE overall, but for participants with the combination of high factor V antigen plus factor V Leiden the OR of idiopathic VTE was 11.5 (95\% CI, 4.2-31.4). In the general population, APC resistance and factor V Leiden were important VTE risk factors; homozygosity for the HR2 haplotype may be a risk factor but was rare; otherwise, HR2 haplotype and factor V antigen were not risk factors except in carriers of factor V Leiden.

}, keywords = {Activated Protein C Resistance, Aged, Cohort Studies, Continental Population Groups, Factor V, Genotype, Haplotypes, Humans, Incidence, Longitudinal Studies, Middle Aged, Odds Ratio, Prospective Studies, Risk Factors, Thromboembolism, Venous Thrombosis}, issn = {0006-4971}, doi = {10.1182/blood.v99.8.2720}, author = {Folsom, Aaron R and Cushman, Mary and Tsai, Michael Y and Aleksic, Nena and Heckbert, Susan R and Boland, Lori L and Tsai, Albert W and Yanez, N David and Rosamond, Wayne D} } @article {893, title = {Beta2-adrenergic receptor genetic variants and risk of sudden cardiac death.}, journal = {Circulation}, volume = {113}, year = {2006}, month = {2006 Apr 18}, pages = {1842-8}, abstract = {

BACKGROUND: Sympathetic activation influences the risk of ventricular arrhythmias and sudden cardiac death (SCD), mediated in part by the beta2-adrenergic receptor (B2AR). We investigated whether variation in the B2AR gene is associated with SCD risk.

METHODS AND RESULTS: In this study, 4441 white and 808 black Cardiovascular Health Study (CHS) participants were followed up prospectively for SCD and genotyped for B2AR Gly16Arg and Gln27Glu polymorphisms. The study was replicated in 155 case and 144 control white subjects in a population-based case-control study of SCD, the Cardiac Arrest Blood Study (CABS). In CHS, Gly16 and Gln27 allele frequencies were 62.4\% and 57.1\% among white and 50.1\% and 81.4\% among black participants. Over a median follow-up of 11.1 years, 156 and 39 SCD events occurred in white and black participants, respectively. The Gln27Glu variant was associated with SCD risk (P=0.008 for general model). SCD risk was higher in Gln27 homozygous participants than in Glu27 carriers (ethnicity-adjusted hazard ratio [HR], 1.56; 95\% confidence interval [CI], 1.17 to 2.09; P=0.003). The increased risk did not differ significantly between white (HR, 1.62; 95\% CI, 1.18 to 2.23) and black (HR, 1.23; 95\% CI, 0.61 to 2.48) participants, although the confidence interval was wide in blacks. In the CABS replication study, Gln27 homozygous participants similarly had higher SCD risk than Glu27 carriers (odds ratio, 1.64; 95\% CI, 1.02 to 2.63; P=0.040). Gly16Arg was not associated with SCD risk in either study.

CONCLUSIONS: Gln27 homozygous individuals have an increased risk of SCD in 2 study populations. Our findings suggest that B2AR plays a role in SCD in humans. Study of genetic variation within the B2AR gene may help identify those at increased SCD risk.

}, keywords = {African Continental Ancestry Group, Aged, Case-Control Studies, Death, Sudden, Cardiac, European Continental Ancestry Group, Female, Gene Frequency, Genetic Predisposition to Disease, Genetic Variation, Glutamine, Haplotypes, Homozygote, Humans, Male, Polymorphism, Single Nucleotide, Receptors, Adrenergic, beta-2, Reproducibility of Results}, issn = {1524-4539}, doi = {10.1161/CIRCULATIONAHA.105.582833}, author = {Sotoodehnia, Nona and Siscovick, David S and Vatta, Matteo and Psaty, Bruce M and Tracy, Russell P and Towbin, Jeffrey A and Lemaitre, Rozenn N and Rea, Thomas D and Durda, J Peter and Chang, Joel M and Lumley, Thomas S and Kuller, Lewis H and Burke, Gregory L and Heckbert, Susan R} } @article {1226, title = {Independent susceptibility markers for atrial fibrillation on chromosome 4q25.}, journal = {Circulation}, volume = {122}, year = {2010}, month = {2010 Sep 07}, pages = {976-84}, abstract = {

BACKGROUND: Genetic variants on chromosome 4q25 are associated with atrial fibrillation (AF). We sought to determine whether there is more than 1 susceptibility signal at this locus.

METHODS AND RESULTS: Thirty-four haplotype-tagging single-nucleotide polymorphisms (SNPs) at the 4q25 locus were genotyped in 790 case and 1177 control subjects from Massachusetts General Hospital and tested for association with AF. We replicated SNPs associated with AF after adjustment for the most significantly associated SNP in 5066 case and 30 661 referent subjects from the German Competence Network for Atrial Fibrillation, Atherosclerosis Risk In Communities Study, Cleveland Clinic Lone AF Study, Cardiovascular Health Study, and Rotterdam Study. All subjects were of European ancestry. A multimarker risk score composed of SNPs that tagged distinct AF susceptibility signals was constructed and tested for association with AF, and all results were subjected to meta-analysis. The previously reported SNP, rs2200733, was most significantly associated with AF (minor allele odds ratio 1.80, 95\% confidence interval 1.50 to 2.15, P=1.2 x 10(-20)) in the discovery sample. Adjustment for rs2200733 genotype revealed 2 additional susceptibility signals marked by rs17570669 and rs3853445. A graded risk of AF was observed with an increasing number of AF risk alleles at SNPs that tagged these 3 susceptibility signals.

CONCLUSIONS: We identified 2 novel AF susceptibility signals on chromosome 4q25. Consideration of multiple susceptibility signals at chromosome 4q25 identifies individuals with an increased risk of AF and may localize regulatory elements at the locus with biological relevance in the pathogenesis of AF.

}, keywords = {Aged, Aged, 80 and over, Atrial Fibrillation, Chromosome Mapping, Chromosomes, Human, Pair 4, European Continental Ancestry Group, Female, Genetic Markers, Genetic Predisposition to Disease, Haplotypes, Humans, Male, Middle Aged, Polymorphism, Single Nucleotide, Risk Factors}, issn = {1524-4539}, doi = {10.1161/CIRCULATIONAHA.109.886440}, author = {Lubitz, Steven A and Sinner, Moritz F and Lunetta, Kathryn L and Makino, Seiko and Pfeufer, Arne and Rahman, Rosanna and Veltman, Caroline E and Barnard, John and Bis, Joshua C and Danik, Stephan P and Sonni, Akshata and Shea, Marisa A and Del Monte, Federica and Perz, Siegfried and M{\"u}ller, Martina and Peters, Annette and Greenberg, Steven M and Furie, Karen L and van Noord, Charlotte and Boerwinkle, Eric and Stricker, Bruno H C and Witteman, Jacqueline and Smith, Jonathan D and Chung, Mina K and Heckbert, Susan R and Benjamin, Emelia J and Rosand, Jonathan and Arking, Dan E and Alonso, Alvaro and K{\"a}{\"a}b, Stefan and Ellinor, Patrick T} } @article {6598, title = {Evidence of heterogeneity by race/ethnicity in genetic determinants of QT interval.}, journal = {Epidemiology}, volume = {25}, year = {2014}, month = {2014 Nov}, pages = {790-8}, abstract = {

BACKGROUND: QT interval (QT) prolongation is an established risk factor for ventricular tachyarrhythmia and sudden cardiac death. Previous genome-wide association studies in populations of the European descent have identified multiple genetic loci that influence QT, but few have examined these loci in ethnically diverse populations.

METHODS: Here, we examine the direction, magnitude, and precision of effect sizes for 21 previously reported SNPs from 12 QT loci, in populations of European (n = 16,398), African (n = 5,437), American Indian (n = 5,032), Hispanic (n = 1,143), and Asian (n = 932) descent as part of the Population Architecture using Genomics and Epidemiology (PAGE) study. Estimates obtained from linear regression models stratified by race/ethnicity were combined using inverse-variance weighted meta-analysis. Heterogeneity was evaluated using Cochran{\textquoteright}s Q test.

RESULTS: Of 21 SNPs, 7 showed consistent direction of effect across all 5 populations, and an additional 9 had estimated effects that were consistent across 4 populations. Despite consistent direction of effect, 9 of 16 SNPs had evidence (P < 0.05) of heterogeneity by race/ethnicity. For these 9 SNPs, linkage disequilibrium plots often indicated substantial variation in linkage disequilibrium patterns among the various racial/ethnic groups, as well as possible allelic heterogeneity.

CONCLUSIONS: These results emphasize the importance of analyzing racial/ethnic groups separately in genetic studies. Furthermore, they underscore the possible utility of trans-ethnic studies to pinpoint underlying casual variants influencing heritable traits such as QT.

}, keywords = {Aged, Continental Population Groups, Electrocardiography, Female, Genetic Predisposition to Disease, Haplotypes, Humans, Long QT Syndrome, Male, Middle Aged, Phenotype, Polymorphism, Single Nucleotide, Quantitative Trait Loci, Quantitative Trait, Heritable, Risk Factors}, issn = {1531-5487}, doi = {10.1097/EDE.0000000000000168}, author = {Seyerle, Amanda A and Young, Alicia M and Jeff, Janina M and Melton, Phillip E and Jorgensen, Neal W and Lin, Yi and Carty, Cara L and Deelman, Ewa and Heckbert, Susan R and Hindorff, Lucia A and Jackson, Rebecca D and Martin, Lisa W and Okin, Peter M and Perez, Marco V and Psaty, Bruce M and Soliman, Elsayed Z and Whitsel, Eric A and North, Kari E and Laston, Sandra and Kooperberg, Charles and Avery, Christy L} }