@article {7463, title = {Fine mapping of QT interval regions in global populations refines previously identified QT interval loci and identifies signals unique to African and Hispanic descent populations.}, journal = {Heart Rhythm}, volume = {14}, year = {2017}, month = {2017 Apr}, pages = {572-580}, abstract = {

BACKGROUND: The electrocardiographically measured QT interval (QT) is heritable and its prolongation is an established risk factor for several cardiovascular diseases. Yet, most QT genetic studies have been performed in European ancestral populations, possibly reducing their global relevance.

OBJECTIVE: To leverage diversity and improve biological insight, we fine mapped 16 of the 35 previously identified QT loci (46\%) in populations of African American (n = 12,410) and Hispanic/Latino (n = 14,837) ancestry.

METHODS: Racial/ethnic-specific multiple linear regression analyses adjusted for heart rate and clinical covariates were examined separately and in combination after inverse-variance weighted trans-ethnic meta-analysis.

RESULTS: The 16 fine-mapped QT loci included on the Illumina Metabochip represented 21 independent signals, of which 16 (76\%) were significantly (P-value<=9.1{\texttimes}10(-5)) associated with QT. Through sequential conditional analysis we also identified three trans-ethnic novel SNPs at ATP1B1, SCN5A-SCN10A, and KCNQ1 and three Hispanic/Latino-specific novel SNPs at NOS1AP and SCN5A-SCN10A (two novel SNPs) with evidence of associations with QT independent of previous identified GWAS lead SNPs. Linkage disequilibrium patterns helped to narrow the region likely to contain the functional variants at several loci, including NOS1AP, USP50-TRPM7, and PRKCA, although intervals surrounding SLC35F1-PLN and CNOT1 remained broad in size (>100 kb). Finally, bioinformatics-based functional characterization suggested a regulatory function in cardiac tissues for the majority of independent signals that generalized and the novel SNPs.

CONCLUSION: Our findings suggest that a majority of identified SNPs implicate gene regulatory dysfunction in QT prolongation, that the same loci influence variation in QT across global populations, and that additional, novel, population-specific QT signals exist.

}, issn = {1556-3871}, doi = {10.1016/j.hrthm.2016.12.021}, author = {Avery, Christy L and Wassel, Christina L and Richard, Melissa A and Highland, Heather M and Bien, Stephanie and Zubair, Niha and Soliman, Elsayed Z and Fornage, Myriam and Bielinski, Suzette J and Tao, Ran and Seyerle, Amanda A and Shah, Sanjiv J and Lloyd-Jones, Donald M and Buyske, Steven and Rotter, Jerome I and Post, Wendy S and Rich, Stephen S and Hindorff, Lucia A and Jeff, Janina M and Shohet, Ralph V and Sotoodehnia, Nona and Lin, Dan Yu and Whitsel, Eric A and Peters, Ulrike and Haiman, Christopher A and Crawford, Dana C and Kooperberg, Charles and North, Kari E} } @article {7798, title = {Discovery, fine-mapping, and conditional analyses of genetic variants associated with C-reactive protein in multiethnic populations using the Metabochip in the Population Architecture using Genomics and Epidemiology (PAGE) study.}, journal = {Hum Mol Genet}, volume = {27}, year = {2018}, month = {2018 Aug 15}, pages = {2940-2953}, abstract = {

C-reactive protein (CRP) is a circulating biomarker indicative of systemic inflammation. We aimed to evaluate genetic associations with CRP levels among non-European-ancestry populations through discovery, fine-mapping and conditional analyses. A total of 30~503 non-European-ancestry participants from 6 studies participating in the Population Architecture using Genomics and Epidemiology study had serum high-sensitivity CRP measurements and \~{}200~000 single nucleotide polymorphisms (SNPs) genotyped on the Metabochip. We evaluated the association between each SNP and log-transformed CRP levels using multivariate linear regression, with additive genetic models adjusted for age, sex, the first four principal components of genetic ancestry, and study-specific factors. Differential linkage disequilibrium patterns between race/ethnicity groups were used to fine-map regions associated with CRP levels. Conditional analyses evaluated for multiple independent signals within genetic regions. One hundred and sixty-three unique variants in 12 loci in overall or race/ethnicity-stratified Metabochip-wide scans reached a Bonferroni-corrected P-value <2.5E-7. Three loci have no (HACL1, OLFML2B) or only limited (PLA2G6) previous associations with CRP levels. Six loci had different top hits in race/ethnicity-specific versus overall analyses. Fine-mapping refined the signal in six loci, particularly in HNF1A. Conditional analyses provided evidence for secondary signals in LEPR, IL1RN and HNF1A, and for multiple independent signals in CRP and APOE. We identified novel variants and loci associated with CRP levels, generalized known CRP associations to a multiethnic study population, refined association signals at several loci and found evidence for multiple independent signals at several well-known loci. This study demonstrates the benefit of conducting inclusive genetic association studies in large multiethnic populations.

}, issn = {1460-2083}, doi = {10.1093/hmg/ddy211}, author = {Kocarnik, Jonathan M and Richard, Melissa and Graff, Misa and Haessler, Jeffrey and Bien, Stephanie and Carlson, Chris and Carty, Cara L and Reiner, Alexander P and Avery, Christy L and Ballantyne, Christie M and LaCroix, Andrea Z and Assimes, Themistocles L and Barbalic, Maja and Pankratz, Nathan and Tang, Weihong and Tao, Ran and Chen, Dongquan and Talavera, Gregory A and Daviglus, Martha L and Chirinos-Medina, Diana A and Pereira, Rocio and Nishimura, Katie and B{\r u}zkov{\'a}, Petra and Best, Lyle G and Ambite, Jose Luis and Cheng, Iona and Crawford, Dana C and Hindorff, Lucia A and Fornage, Myriam and Heiss, Gerardo and North, Kari E and Haiman, Christopher A and Peters, Ulrike and Le Marchand, Lo{\"\i}c and Kooperberg, Charles} }