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1.  Identification of Nine Novel Loci Associated with White Blood Cell Subtypes in a Japanese Population 
PLoS Genetics  2011;7(6):e1002067.
White blood cells (WBCs) mediate immune systems and consist of various subtypes with distinct roles. Elucidation of the mechanism that regulates the counts of the WBC subtypes would provide useful insights into both the etiology of the immune system and disease pathogenesis. In this study, we report results of genome-wide association studies (GWAS) and a replication study for the counts of the 5 main WBC subtypes (neutrophils, lymphocytes, monocytes, basophils, and eosinophils) using 14,792 Japanese subjects enrolled in the BioBank Japan Project. We identified 12 significantly associated loci that satisfied the genome-wide significance threshold of P<5.0×10−8, of which 9 loci were novel (the CDK6 locus for the neutrophil count; the ITGA4, MLZE, STXBP6 loci, and the MHC region for the monocyte count; the SLC45A3-NUCKS1, GATA2, NAALAD2, ERG loci for the basophil count). We further evaluated associations in the identified loci using 15,600 subjects from Caucasian populations. These WBC subtype-related loci demonstrated a variety of patterns of pleiotropic associations within the WBC subtypes, or with total WBC count, platelet count, or red blood cell-related traits (n = 30,454), which suggests unique and common functional roles of these loci in the processes of hematopoiesis. This study should contribute to the understanding of the genetic backgrounds of the WBC subtypes and hematological traits.
Author Summary
White blood cells (WBCs) are blood cells that mediate immune systems and defend the body against foreign microorganisms. It is well known that WBCs consist of various subtypes of cells with distinct roles, although the genetic background of each of the WBC subtypes has yet to be examined. In this study, we report genome-wide association studies (GWAS) for the 5 main WBC subtypes (neutrophils, lymphocytes, monocytes, basophils, and eosinophils) using 14,792 Japanese subjects. We identified 12 significantly associated genetic loci, and 9 of them were novel. Evaluation of the associations of these identified loci in cohorts of Caucasian populations demonstrated both ethnically common and divergent genetic backgrounds of the WBC subtypes. These loci also indicated a variety of patterns of pleiotropic associations within the hematological traits, including the other WBC subtypes, total WBC count, platelet count, or red blood cell-related traits, which suggests unique and common functional roles of these loci in the processes of hematopoiesis.
doi:10.1371/journal.pgen.1002067
PMCID: PMC3128095  PMID: 21738478
2.  Multiple loci influence erythrocyte phenotypes in the CHARGE Consortium 
Nature genetics  2009;41(11):1191-1198.
Erythrocyte measures are heritable and have important health implications, yet their genetic determinants are largely unknown. We performed genome-wide association analyses in 24,167 European-ancestry individuals for six erythrocyte traits and identified associations at 23 loci (P values 5×10-8 to 1×10-57). Replication testing in an independent set of 9,456 European-ancestry individuals showed strong evidence of association in all 23 loci in meta-analysis of the discovery and replication cohorts. Our findings include previously identified loci (HBS1L/MYB, HFE, TMPRSS6, TFR2, SPTA1) and novel associations (EPO, TFRC, SH2B3, and 15 other loci). This study has identified novel determinants of erythrocyte traits, offering insight into common variants underlying variation in erythrocyte measures.
doi:10.1038/ng.466
PMCID: PMC2778265  PMID: 19862010
3.  A variational Bayes discrete mixture test for rare variant association 
Genetic epidemiology  2014;38(1):21-30.
Recently, many statistical methods have been proposed to test for associations between rare genetic variants and complex traits. Most of these methods test for association by aggregating genetic variations within a predefined region, such as a gene. Although there is evidence that “aggregate” tests are more powerful than the single marker test, these tests generally ignore neutral variants and therefore are unable to identify specific variants driving the association with phenotype. We propose a novel aggregate rare-variant test that explicitly models a fraction of variants as neutral, tests associations at the gene-level, and infers the rare-variants driving the association. Simulations show that in the practical scenario where there are many variants within a given region of the genome with only a fraction causal our approach has greater power compared to other popular tests such as the Sequence Kernel Association Test (SKAT), the Weighted Sum Statistic (WSS), and the collapsing method of Morris and Zeggini (MZ). Our algorithm leverages a fast variational Bayes approximate inference methodology to scale to exome-wide analyses, a significant computational advantage over exact inference model selection methodologies. To demonstrate the efficacy of our methodology we test for associations between von Willebrand Factor (VWF) levels and VWF missense rare-variants imputed from the National Heart, Lung, and Blood Institute’s Exome Sequencing project into 2,487 African Americans within the VWF gene. Our method suggests that a relatively small fraction (~10%) of the imputed rare missense variants within VWF are strongly associated with lower VWF levels in African Americans.
PMCID: PMC4030763  PMID: 24482836
Exome sequencing study; approximate inference; von Willebrand Factor genetics
4.  Systematic evaluation of coding variation identifies a candidate causal variant in TM6SF2 influencing total cholesterol and myocardial infarction risk 
Nature genetics  2014;46(4):345-351.
Blood lipid levels are heritable, treatable risk factors for cardiovascular disease. We systematically assessed genome-wide coding variation to identify novel lipid genes, fine-map known lipid loci, and evaluate whether low frequency variants with large effect exist. Using an exome array, we genotyped 80,137 coding variants in 5,643 Norwegians. We followed up 18 variants in 4,666 Norwegians to identify 10 loci with coding variants associated with a lipid trait (P < 5×10−8). One coding variant in TM6SF2 (p.Glu167Lys), residing in a GWAS locus for lipid levels, modifies total cholesterol levels and is associated with myocardial infarction. Transient overexpression and knockdown of TM6SF2 in mouse produces alteration in serum lipid profiles consistent with the association observed in humans, identifying TM6SF2 as the functional gene at a large GWAS locus previously known as NCAN/CILP2/PBX4 or 19p13. This study demonstrates that systematic assessment of coding variation can quickly point to a candidate causal gene.
doi:10.1038/ng.2926
PMCID: PMC4169222  PMID: 24633158
5.  Loci influencing blood pressure identified using a cardiovascular gene-centric array 
Ganesh, Santhi K. | Tragante, Vinicius | Guo, Wei | Guo, Yiran | Lanktree, Matthew B. | Smith, Erin N. | Johnson, Toby | Castillo, Berta Almoguera | Barnard, John | Baumert, Jens | Chang, Yen-Pei Christy | Elbers, Clara C. | Farrall, Martin | Fischer, Mary E. | Franceschini, Nora | Gaunt, Tom R. | Gho, Johannes M.I.H. | Gieger, Christian | Gong, Yan | Isaacs, Aaron | Kleber, Marcus E. | Leach, Irene Mateo | McDonough, Caitrin W. | Meijs, Matthijs F.L. | Mellander, Olle | Molony, Cliona M. | Nolte, Ilja M. | Padmanabhan, Sandosh | Price, Tom S. | Rajagopalan, Ramakrishnan | Shaffer, Jonathan | Shah, Sonia | Shen, Haiqing | Soranzo, Nicole | van der Most, Peter J. | Van Iperen, Erik P.A. | Van Setten, Jessica | Vonk, Judith M. | Zhang, Li | Beitelshees, Amber L. | Berenson, Gerald S. | Bhatt, Deepak L. | Boer, Jolanda M.A. | Boerwinkle, Eric | Burkley, Ben | Burt, Amber | Chakravarti, Aravinda | Chen, Wei | Cooper-DeHoff, Rhonda M. | Curtis, Sean P. | Dreisbach, Albert | Duggan, David | Ehret, Georg B. | Fabsitz, Richard R. | Fornage, Myriam | Fox, Ervin | Furlong, Clement E. | Gansevoort, Ron T. | Hofker, Marten H. | Hovingh, G. Kees | Kirkland, Susan A. | Kottke-Marchant, Kandice | Kutlar, Abdullah | LaCroix, Andrea Z. | Langaee, Taimour Y. | Li, Yun R. | Lin, Honghuang | Liu, Kiang | Maiwald, Steffi | Malik, Rainer | Murugesan, Gurunathan | Newton-Cheh, Christopher | O'Connell, Jeffery R. | Onland-Moret, N. Charlotte | Ouwehand, Willem H. | Palmas, Walter | Penninx, Brenda W. | Pepine, Carl J. | Pettinger, Mary | Polak, Joseph F. | Ramachandran, Vasan S. | Ranchalis, Jane | Redline, Susan | Ridker, Paul M. | Rose, Lynda M. | Scharnag, Hubert | Schork, Nicholas J. | Shimbo, Daichi | Shuldiner, Alan R. | Srinivasan, Sathanur R. | Stolk, Ronald P. | Taylor, Herman A. | Thorand, Barbara | Trip, Mieke D. | van Duijn, Cornelia M. | Verschuren, W. Monique | Wijmenga, Cisca | Winkelmann, Bernhard R. | Wyatt, Sharon | Young, J. Hunter | Boehm, Bernhard O. | Caulfield, Mark J. | Chasman, Daniel I. | Davidson, Karina W. | Doevendans, Pieter A. | FitzGerald, Garret A. | Gums, John G. | Hakonarson, Hakon | Hillege, Hans L. | Illig, Thomas | Jarvik, Gail P. | Johnson, Julie A. | Kastelein, John J.P. | Koenig, Wolfgang | März, Winfried | Mitchell, Braxton D. | Murray, Sarah S. | Oldehinkel, Albertine J. | Rader, Daniel J. | Reilly, Muredach P. | Reiner, Alex P. | Schadt, Eric E. | Silverstein, Roy L. | Snieder, Harold | Stanton, Alice V. | Uitterlinden, André G. | van der Harst, Pim | van der Schouw, Yvonne T. | Samani, Nilesh J. | Johnson, Andrew D. | Munroe, Patricia B. | de Bakker, Paul I.W. | Zhu, Xiaofeng | Levy, Daniel | Keating, Brendan J. | Asselbergs, Folkert W.
Human Molecular Genetics  2013;22(16):3394-3395.
doi:10.1093/hmg/ddt177
PMCID: PMC3888295
6.  Genetic variation associated with circulating monocyte count in the eMERGE Network 
Human Molecular Genetics  2013;22(10):2119-2127.
With white blood cell count emerging as an important risk factor for chronic inflammatory diseases, genetic associations of differential leukocyte types, specifically monocyte count, are providing novel candidate genes and pathways to further investigate. Circulating monocytes play a critical role in vascular diseases such as in the formation of atherosclerotic plaque. We performed a joint and ancestry-stratified genome-wide association analyses to identify variants specifically associated with monocyte count in 11 014 subjects in the electronic Medical Records and Genomics Network. In the joint and European ancestry samples, we identified novel associations in the chromosome 16 interferon regulatory factor 8 (IRF8) gene (P-value = 2.78×10(−16), β = −0.22). Other monocyte associations include novel missense variants in the chemokine-binding protein 2 (CCBP2) gene (P-value = 1.88×10(−7), β = 0.30) and a region of replication found in ribophorin I (RPN1) (P-value = 2.63×10(−16), β = −0.23) on chromosome 3. The CCBP2 and RPN1 region is located near GATA binding protein2 gene that has been previously shown to be associated with coronary heart disease. On chromosome 9, we found a novel association in the prostaglandin reductase 1 gene (P-value = 2.29×10(−7), β = 0.16), which is downstream from lysophosphatidic acid receptor 1. This region has previously been shown to be associated with monocyte count. We also replicated monocyte associations of genome-wide significance (P-value = 5.68×10(−17), β = −0.23) at the integrin, alpha 4 gene on chromosome 2. The novel IRF8 results and further replications provide supporting evidence of genetic regions associated with monocyte count.
doi:10.1093/hmg/ddt010
PMCID: PMC3633369  PMID: 23314186
7.  Loci influencing blood pressure identified using a cardiovascular gene-centric array 
Ganesh, Santhi K. | Tragante, Vinicius | Guo, Wei | Guo, Yiran | Lanktree, Matthew B. | Smith, Erin N. | Johnson, Toby | Castillo, Berta Almoguera | Barnard, John | Baumert, Jens | Chang, Yen-Pei Christy | Elbers, Clara C. | Farrall, Martin | Fischer, Mary E. | Franceschini, Nora | Gaunt, Tom R. | Gho, Johannes M.I.H. | Gieger, Christian | Gong, Yan | Isaacs, Aaron | Kleber, Marcus E. | Leach, Irene Mateo | McDonough, Caitrin W. | Meijs, Matthijs F.L. | Mellander, Olle | Molony, Cliona M. | Nolte, Ilja M. | Padmanabhan, Sandosh | Price, Tom S. | Rajagopalan, Ramakrishnan | Shaffer, Jonathan | Shah, Sonia | Shen, Haiqing | Soranzo, Nicole | van der Most, Peter J. | Van Iperen, Erik P.A. | Van Setten, Jessic A. | Vonk, Judith M. | Zhang, Li | Beitelshees, Amber L. | Berenson, Gerald S. | Bhatt, Deepak L. | Boer, Jolanda M.A. | Boerwinkle, Eric | Burkley, Ben | Burt, Amber | Chakravarti, Aravinda | Chen, Wei | Cooper-DeHoff, Rhonda M. | Curtis, Sean P. | Dreisbach, Albert | Duggan, David | Ehret, Georg B. | Fabsitz, Richard R. | Fornage, Myriam | Fox, Ervin | Furlong, Clement E. | Gansevoort, Ron T. | Hofker, Marten H. | Hovingh, G. Kees | Kirkland, Susan A. | Kottke-Marchant, Kandice | Kutlar, Abdullah | LaCroix, Andrea Z. | Langaee, Taimour Y. | Li, Yun R. | Lin, Honghuang | Liu, Kiang | Maiwald, Steffi | Malik, Rainer | Murugesan, Gurunathan | Newton-Cheh, Christopher | O'Connell, Jeffery R. | Onland-Moret, N. Charlotte | Ouwehand, Willem H. | Palmas, Walter | Penninx, Brenda W. | Pepine, Carl J. | Pettinger, Mary | Polak, Joseph F. | Ramachandran, Vasan S. | Ranchalis, Jane | Redline, Susan | Ridker, Paul M. | Rose, Lynda M. | Scharnag, Hubert | Schork, Nicholas J. | Shimbo, Daichi | Shuldiner, Alan R. | Srinivasan, Sathanur R. | Stolk, Ronald P. | Taylor, Herman A. | Thorand, Barbara | Trip, Mieke D. | van Duijn, Cornelia M. | Verschuren, W. Monique | Wijmenga, Cisca | Winkelmann, Bernhard R. | Wyatt, Sharon | Young, J. Hunter | Boehm, Bernhard O. | Caulfield, Mark J. | Chasman, Daniel I. | Davidson, Karina W. | Doevendans, Pieter A. | FitzGerald, Garret A. | Gums, John G. | Hakonarson, Hakon | Hillege, Hans L. | Illig, Thomas | Jarvik, Gail P. | Johnson, Julie A. | Kastelein, John J.P. | Koenig, Wolfgang | März, Winfried | Mitchell, Braxton D. | Murray, Sarah S. | Oldehinkel, Albertine J. | Rader, Daniel J. | Reilly, Muredach P. | Reiner, Alex P. | Schadt, Eric E. | Silverstein, Roy L. | Snieder, Harold | Stanton, Alice V. | Uitterlinden, André G. | van der Harst, Pim | van der Schouw, Yvonne T. | Samani, Nilesh J. | Johnson, Andrew D. | Munroe, Patricia B. | de Bakker, Paul I.W. | Zhu, Xiaofeng | Levy, Daniel | Keating, Brendan J. | Asselbergs, Folkert W.
Human Molecular Genetics  2013;22(8):1663-1678.
Blood pressure (BP) is a heritable determinant of risk for cardiovascular disease (CVD). To investigate genetic associations with systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP) and pulse pressure (PP), we genotyped ∼50 000 single-nucleotide polymorphisms (SNPs) that capture variation in ∼2100 candidate genes for cardiovascular phenotypes in 61 619 individuals of European ancestry from cohort studies in the USA and Europe. We identified novel associations between rs347591 and SBP (chromosome 3p25.3, in an intron of HRH1) and between rs2169137 and DBP (chromosome1q32.1 in an intron of MDM4) and between rs2014408 and SBP (chromosome 11p15 in an intron of SOX6), previously reported to be associated with MAP. We also confirmed 10 previously known loci associated with SBP, DBP, MAP or PP (ADRB1, ATP2B1, SH2B3/ATXN2, CSK, CYP17A1, FURIN, HFE, LSP1, MTHFR, SOX6) at array-wide significance (P < 2.4 × 10−6). We then replicated these associations in an independent set of 65 886 individuals of European ancestry. The findings from expression QTL (eQTL) analysis showed associations of SNPs in the MDM4 region with MDM4 expression. We did not find any evidence of association of the two novel SNPs in MDM4 and HRH1 with sequelae of high BP including coronary artery disease (CAD), left ventricular hypertrophy (LVH) or stroke. In summary, we identified two novel loci associated with BP and confirmed multiple previously reported associations. Our findings extend our understanding of genes involved in BP regulation, some of which may eventually provide new targets for therapeutic intervention.
doi:10.1093/hmg/dds555
PMCID: PMC3657476  PMID: 23303523
8.  Effects of Rare and Common Blood Pressure Gene Variants on Essential Hypertension: Results from the FBPP, CLUE and ARIC Studies 
Circulation research  2012;112(2):318-326.
Rationale
Hypertension (HTN) affects ~30% of adults in industrialized countries and is the major risk factor for cardiovascular disease.
Objective
We sought to study the genetic effect of coding and conserved non-coding variants in syndromic HTN genes on systolic (SBP) and diastolic (DBP) blood pressure to assess their overall impact on essential hypertension (EH).
Methods and Results
We resequenced 11 genes (AGT, CYP11B1, CYP17A1, HSD11B2, NR3C1, NR3C2, SCNN1A, SCNN1B, SCNN1G, WNK1 and WNK4) in 560 European (EA) and African (AA) ancestry GenNet participants with extreme SBP. We investigated genetic associations of 2,535 variants with BP in 19,997 EAs and 6,069 AAs in three types of analyses. First, we studied the combined effects of all variants in GenNet. Second, we studied 1000 Genomes imputed polymorphic variants in 9,747 EA and 3,207 AA ARIC subjects. Lastly, we genotyped 37 missense and common noncoding variants in 6,591 EAs and 6,521 individuals (3,659 EA/2,862 AA) from the CLUE and FBPP studies. None of the variants individually reached significant false-discovery rates (FDR≤0.05) for SBP and DBP. However, upon pooling all coding and non-coding variants we identified at least 5 loci (AGT, CYP11B1, NR3C2, SCNN1G and WNK1), with higher association at evolutionary conserved sites.
Conclusions
Both rare and common variants at these genes affect BP in the general population with modest effects sizes (<0.05 standard deviation units) and much larger sample sizes are required to assess the impact of individual genes. Collectively, conserved noncoding variants affect BP to a greater extent than missense mutations.
doi:10.1161/CIRCRESAHA.112.276725
PMCID: PMC3548950  PMID: 23149595
essential hypertension; blood pressure; population genetics; sequencing; genotype
9.  Genetics of coronary artery calcification among African Americans, a meta-analysis 
BMC Medical Genetics  2013;14:75.
Background
Coronary heart disease (CHD) is the major cause of death in the United States. Coronary artery calcification (CAC) scores are independent predictors of CHD. African Americans (AA) have higher rates of CHD but are less well-studied in genomic studies. We assembled the largest AA data resource currently available with measured CAC to identify associated genetic variants.
Methods
We analyzed log transformed CAC quantity (ln(CAC + 1)), for association with ~2.5 million single nucleotide polymorphisms (SNPs) and performed an inverse-variance weighted meta-analysis on results for 5,823 AA from 8 studies. Heritability was calculated using family studies. The most significant SNPs among AAs were evaluated in European Ancestry (EA) CAC data; conversely, the significance of published SNPs for CAC/CHD in EA was queried within our AA meta-analysis.
Results
Heritability of CAC was lower in AA (~30%) than previously reported for EA (~50%). No SNP reached genome wide significance (p < 5E-08). Of 67 SNPs with p < 1E-05 in AA there was no evidence of association in EA CAC data. Four SNPs in regions previously implicated in CAC/CHD (at 9p21 and PHACTR1) in EA reached nominal significance for CAC in AA, with concordant direction. Among AA, rs16905644 (p = 4.08E-05) had the strongest association in the 9p21 region.
Conclusions
While we observed substantial heritability for CAC in AA, we failed to identify loci for CAC at genome-wide significant levels despite having adequate power to detect alleles with moderate to large effects. Although suggestive signals in AA were apparent at 9p21 and additional CAC and CAD EA loci, overall the data suggest that even larger samples and an ethnic specific focus will be required for GWAS discoveries for CAC in AA populations.
doi:10.1186/1471-2350-14-75
PMCID: PMC3733595  PMID: 23870195
Atherosclerosis; Coronary artery calcium; Genetics; Meta-analysis; African-American
10.  Genetic determinants of the ankle-brachial index: A meta-analysis of a cardiovascular candidate gene 50K SNP panel in the candidate gene association resource (CARe) consortium 
Atherosclerosis  2012;222(1):138-147.
Background
Candidate gene association studies for peripheral artery disease (PAD), including subclinical disease assessed with the ankle-brachial index (ABI), have been limited by the modest number of genes examined. We conducted a two stage meta-analysis of ~50,000 SNPs across ~2100 candidate genes to identify genetic variants for ABI.
Methods and results
We studied subjects of European ancestry from 8 studies (n = 21,547, 55% women, mean age 44–73 years) and African American ancestry from 5 studies (n = 7267, 60% women, mean age 41–73 years) involved in the candidate gene association resource (CARe) consortium. In each ethnic group, additive genetic models were used (with each additional copy of the minor allele corresponding to the given beta) to test each SNP for association with continuous ABI (excluding ABI > 1.40) and PAD (defined as ABI < 0.90) using linear or logistic regression with adjustment for known PAD risk factors and population stratification. We then conducted a fixed-effects inverse-variance weighted meta-analyses considering a p < 2 × 10−6 to denote statistical significance.
Results
In the European ancestry discovery meta-analyses, rs2171209 in SYTL3 (β = −0.007, p = 6.02 × 10−7) and rs290481 in TCF7L2 (β = −0.008, p = 7.01 × 10−7) were significantly associated with ABI. None of the SNP associations for PAD were significant, though a SNP in CYP2B6 (p = 4.99 × 10−5) was among the strongest associations. These 3 genes are linked to key PAD risk factors (lipoprotein(a), type 2 diabetes, and smoking behavior, respectively). We sought replication in 6 population-based and 3 clinical samples (n = 15,440) for rs290481 and rs2171209. However, in the replication stage (rs2171209, p = 0.75; rs290481, p = 0.19) and in the combined discovery and replication analysis the SNP–ABI associations were no longer significant (rs2171209, p = 1.14 × 10−3; rs290481, p = 8.88 × 10−5). In African Americans, none of the SNP associations for ABI or PAD achieved an experiment-wide level of significance.
Conclusions
Genetic determinants of ABI and PAD remain elusive. Follow-up of these preliminary findings may uncover important biology given the known gene-risk factor associations. New and more powerful approaches to PAD gene discovery are warranted.
doi:10.1016/j.atherosclerosis.2012.01.039
PMCID: PMC3596171  PMID: 22361517
Ankle brachial index; Peripheral artery disease; Genetics; Candidate gene array; Meta-analysis; Ethnicity
11.  Genome-Wide Association Study of Retinopathy in Individuals without Diabetes 
PLoS ONE  2013;8(2):e54232.
Background
Mild retinopathy (microaneurysms or dot-blot hemorrhages) is observed in persons without diabetes or hypertension and may reflect microvascular disease in other organs. We conducted a genome-wide association study (GWAS) of mild retinopathy in persons without diabetes.
Methods
A working group agreed on phenotype harmonization, covariate selection and analytic plans for within-cohort GWAS. An inverse-variance weighted fixed effects meta-analysis was performed with GWAS results from six cohorts of 19,411 Caucasians. The primary analysis included individuals without diabetes and secondary analyses were stratified by hypertension status. We also singled out the results from single nucleotide polymorphisms (SNPs) previously shown to be associated with diabetes and hypertension, the two most common causes of retinopathy.
Results
No SNPs reached genome-wide significance in the primary analysis or the secondary analysis of participants with hypertension. SNP, rs12155400, in the histone deacetylase 9 gene (HDAC9) on chromosome 7, was associated with retinopathy in analysis of participants without hypertension, −1.3±0.23 (beta ± standard error), p = 6.6×10−9. Evidence suggests this was a false positive finding. The minor allele frequency was low (∼2%), the quality of the imputation was moderate (r2 ∼0.7), and no other common variants in the HDAC9 gene were associated with the outcome. SNPs found to be associated with diabetes and hypertension in other GWAS were not associated with retinopathy in persons without diabetes or in subgroups with or without hypertension.
Conclusions
This GWAS of retinopathy in individuals without diabetes showed little evidence of genetic associations. Further studies are needed to identify genes associated with these signs in order to help unravel novel pathways and determinants of microvascular diseases.
doi:10.1371/journal.pone.0054232
PMCID: PMC3564946  PMID: 23393555
12.  A genome-wide association study identifies a region at chromosome 12 as a potential susceptibility locus for restenosis after percutaneous coronary intervention 
Human Molecular Genetics  2011;20(23):4748-4757.
Percutaneous coronary intervention (PCI) has become an effective therapy to treat obstructive coronary artery diseases (CAD). However, one of the major drawbacks of PCI is the occurrence of restenosis in 5–25% of all initially treated patients. Restenosis is defined as the re-narrowing of the lumen of the blood vessel, resulting in renewed symptoms and the need for repeated intervention. To identify genetic variants that are associated with restenosis, a genome-wide association study (GWAS) was conducted in 295 patients who developed restenosis (cases) and 571 who did not (controls) from the GENetic Determinants of Restenosis (GENDER) study. Analysis of ∼550 000 single nucleotide polymorphisms (SNPs) in GENDER was followed by a replication phase in three independent case–control populations (533 cases and 3067 controls). A potential susceptibility locus for restenosis at chromosome 12, including rs10861032 (Pcombined = 1.11 × 10−7) and rs9804922 (Pcombined = 1.45 × 10−6), was identified in the GWAS and replication phase. In addition, both SNPs were also associated with coronary events (rs10861032, Padditive = 0.005; rs9804922, Padditive = 0.023) in a trial based cohort set of elderly patients with (enhanced risk of) CAD (PROSPER) and all-cause mortality in PROSPER (rs10861032, Padditive = 0.007; rs9804922, Padditive = 0.013) and GENDER (rs10861032, Padditive = 0.005; rs9804922, Padditive = 0.023). Further analysis suggests that this locus could be involved in regulatory functions.
doi:10.1093/hmg/ddr389
PMCID: PMC3209827  PMID: 21878436
14.  Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure 
Wain, Louise V | Verwoert, Germaine C | O’Reilly, Paul F | Shi, Gang | Johnson, Toby | Johnson, Andrew D | Bochud, Murielle | Rice, Kenneth M | Henneman, Peter | Smith, Albert V | Ehret, Georg B | Amin, Najaf | Larson, Martin G | Mooser, Vincent | Hadley, David | Dörr, Marcus | Bis, Joshua C | Aspelund, Thor | Esko, Tõnu | Janssens, A Cecile JW | Zhao, Jing Hua | Heath, Simon | Laan, Maris | Fu, Jingyuan | Pistis, Giorgio | Luan, Jian’an | Arora, Pankaj | Lucas, Gavin | Pirastu, Nicola | Pichler, Irene | Jackson, Anne U | Webster, Rebecca J | Zhang, Feng | Peden, John F | Schmidt, Helena | Tanaka, Toshiko | Campbell, Harry | Igl, Wilmar | Milaneschi, Yuri | Hotteng, Jouke-Jan | Vitart, Veronique | Chasman, Daniel I | Trompet, Stella | Bragg-Gresham, Jennifer L | Alizadeh, Behrooz Z | Chambers, John C | Guo, Xiuqing | Lehtimäki, Terho | Kühnel, Brigitte | Lopez, Lorna M | Polašek, Ozren | Boban, Mladen | Nelson, Christopher P | Morrison, Alanna C | Pihur, Vasyl | Ganesh, Santhi K | Hofman, Albert | Kundu, Suman | Mattace-Raso, Francesco US | Rivadeneira, Fernando | Sijbrands, Eric JG | Uitterlinden, Andre G | Hwang, Shih-Jen | Vasan, Ramachandran S | Wang, Thomas J | Bergmann, Sven | Vollenweider, Peter | Waeber, Gérard | Laitinen, Jaana | Pouta, Anneli | Zitting, Paavo | McArdle, Wendy L | Kroemer, Heyo K | Völker, Uwe | Völzke, Henry | Glazer, Nicole L | Taylor, Kent D | Harris, Tamara B | Alavere, Helene | Haller, Toomas | Keis, Aime | Tammesoo, Mari-Liis | Aulchenko, Yurii | Barroso, Inês | Khaw, Kay-Tee | Galan, Pilar | Hercberg, Serge | Lathrop, Mark | Eyheramendy, Susana | Org, Elin | Sõber, Siim | Lu, Xiaowen | Nolte, Ilja M | Penninx, Brenda W | Corre, Tanguy | Masciullo, Corrado | Sala, Cinzia | Groop, Leif | Voight, Benjamin F | Melander, Olle | O’Donnell, Christopher J | Salomaa, Veikko | d’Adamo, Adamo Pio | Fabretto, Antonella | Faletra, Flavio | Ulivi, Sheila | Del Greco, M Fabiola | Facheris, Maurizio | Collins, Francis S | Bergman, Richard N | Beilby, John P | Hung, Joseph | Musk, A William | Mangino, Massimo | Shin, So-Youn | Soranzo, Nicole | Watkins, Hugh | Goel, Anuj | Hamsten, Anders | Gider, Pierre | Loitfelder, Marisa | Zeginigg, Marion | Hernandez, Dena | Najjar, Samer S | Navarro, Pau | Wild, Sarah H | Corsi, Anna Maria | Singleton, Andrew | de Geus, Eco JC | Willemsen, Gonneke | Parker, Alex N | Rose, Lynda M | Buckley, Brendan | Stott, David | Orru, Marco | Uda, Manuela | van der Klauw, Melanie M | Zhang, Weihua | Li, Xinzhong | Scott, James | Chen, Yii-Der Ida | Burke, Gregory L | Kähönen, Mika | Viikari, Jorma | Döring, Angela | Meitinger, Thomas | Davies, Gail | Starr, John M | Emilsson, Valur | Plump, Andrew | Lindeman, Jan H | ’t Hoen, Peter AC | König, Inke R | Felix, Janine F | Clarke, Robert | Hopewell, Jemma C | Ongen, Halit | Breteler, Monique | Debette, Stéphanie | DeStefano, Anita L | Fornage, Myriam | Mitchell, Gary F | Smith, Nicholas L | Holm, Hilma | Stefansson, Kari | Thorleifsson, Gudmar | Thorsteinsdottir, Unnur | Samani, Nilesh J | Preuss, Michael | Rudan, Igor | Hayward, Caroline | Deary, Ian J | Wichmann, H-Erich | Raitakari, Olli T | Palmas, Walter | Kooner, Jaspal S | Stolk, Ronald P | Jukema, J Wouter | Wright, Alan F | Boomsma, Dorret I | Bandinelli, Stefania | Gyllensten, Ulf B | Wilson, James F | Ferrucci, Luigi | Schmidt, Reinhold | Farrall, Martin | Spector, Tim D | Palmer, Lyle J | Tuomilehto, Jaakko | Pfeufer, Arne | Gasparini, Paolo | Siscovick, David | Altshuler, David | Loos, Ruth JF | Toniolo, Daniela | Snieder, Harold | Gieger, Christian | Meneton, Pierre | Wareham, Nicholas J | Oostra, Ben A | Metspalu, Andres | Launer, Lenore | Rettig, Rainer | Strachan, David P | Beckmann, Jacques S | Witteman, Jacqueline CM | Erdmann, Jeanette | van Dijk, Ko Willems | Boerwinkle, Eric | Boehnke, Michael | Ridker, Paul M | Jarvelin, Marjo-Riitta | Chakravarti, Aravinda | Abecasis, Goncalo R | Gudnason, Vilmundur | Newton-Cheh, Christopher | Levy, Daniel | Munroe, Patricia B | Psaty, Bruce M | Caulfield, Mark J | Rao, Dabeeru C | Tobin, Martin D | Elliott, Paul | van Duijn, Cornelia M
Nature genetics  2011;43(10):1005-1011.
Numerous genetic loci influence systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans 1-3. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N=74,064) and follow-up studies (N=48,607), we identified at genome-wide significance (P= 2.7×10-8 to P=2.3×10-13) four novel PP loci (at 4q12 near CHIC2/PDGFRAI, 7q22.3 near PIK3CG, 8q24.12 in NOV, 11q24.3 near ADAMTS-8), two novel MAP loci (3p21.31 in MAP4, 10q25.3 near ADRB1) and one locus associated with both traits (2q24.3 near FIGN) which has recently been associated with SBP in east Asians. For three of the novel PP signals, the estimated effect for SBP was opposite to that for DBP, in contrast to the majority of common SBP- and DBP-associated variants which show concordant effects on both traits. These findings indicate novel genetic mechanisms underlying blood pressure variation, including pathways that may differentially influence SBP and DBP.
doi:10.1038/ng.922
PMCID: PMC3445021  PMID: 21909110
15.  Genetic association analysis highlights new loci that modulate hematological trait variation in Caucasians and African Americans 
Human genetics  2010;129(3):307-317.
Red blood cell, white blood cell, and platelet measures, including their count, sub-type and volume, are important diagnostic and prognostic clinical parameters for several human diseases. To identify novel loci associated with hematological traits, and compare the architecture of these phenotypes between ethnic groups, the CARe Project genotyped 49,094 single nucleotide polymorphisms (SNPs) that capture variation in ~2,100 candidate genes in DNA of 23,439 Caucasians and 7,112 African Americans from five population-based cohorts. We found strong novel associations between erythrocyte phenotypes and the glucose-6 phosphate dehydrogenase (G6PD) A-allele in African Americans (rs1050828, P < 2.0 × 10−13, T-allele associated with lower red blood cell count, hemoglobin, and hematocrit, and higher mean corpuscular volume), and between platelet count and a SNP at the tropomyosin-4 (TPM4) locus (rs8109288, P = 3.0 × 10−7 in Caucasians; P = 3.0 × 10−7 in African Americans, T-allele associated with lower platelet count). We strongly replicated many genetic associations to blood cell phenotypes previously established in Caucasians. A common variant of the α-globin (HBA2-HBA1) locus was associated with red blood cell traits in African Americans, but not in Caucasians (rs1211375, P < 7 × 10−8, A-allele associated with lower hemoglobin, mean corpuscular hemoglobin, and mean corpuscular volume). Our results show similarities but also differences in the genetic regulation of hematological traits in European- and African-derived populations, and highlight the role of natural selection in shaping these differences.
doi:10.1007/s00439-010-0925-1
PMCID: PMC3442357  PMID: 21153663
16.  Combined admixture mapping and association analysis identifies a novel blood pressure genetic locus on 5p13: contributions from the CARe consortium 
Human Molecular Genetics  2011;20(11):2285-2295.
Admixture mapping based on recently admixed populations is a powerful method to detect disease variants with substantial allele frequency differences in ancestral populations. We performed admixture mapping analysis for systolic blood pressure (SBP) and diastolic blood pressure (DBP), followed by trait-marker association analysis, in 6303 unrelated African-American participants of the Candidate Gene Association Resource (CARe) consortium. We identified five genomic regions (P< 0.001) harboring genetic variants contributing to inter-individual BP variation. In follow-up association analyses, correcting for all tests performed in this study, three loci were significantly associated with SBP and one significantly associated with DBP (P< 10−5). Further analyses suggested that six independent single-nucleotide polymorphisms (SNPs) contributed to the phenotypic variation observed in the admixture mapping analysis. These six SNPs were examined for replication in multiple, large, independent studies of African-Americans [Women's Health Initiative (WHI), Maywood, Genetic Epidemiology Network of Arteriopathy (GENOA) and Howard University Family Study (HUFS)] as well as one native African sample (Nigerian study), with a total replication sample size of 11 882. Meta-analysis of the replication set identified a novel variant (rs7726475) on chromosome 5 between the SUB1 and NPR3 genes, as being associated with SBP and DBP (P< 0.0015 for both); in meta-analyses combining the CARe samples with the replication data, we observed P-values of 4.45 × 10−7 for SBP and 7.52 × 10−7 for DBP for rs7726475 that were significant after accounting for all the tests performed. Our study highlights that admixture mapping analysis can help identify genetic variants missed by genome-wide association studies because of drastically reduced number of tests in the whole genome.
doi:10.1093/hmg/ddr113
PMCID: PMC3090198  PMID: 21422096
17.  New gene functions in megakaryopoiesis and platelet formation 
Gieger, Christian | Radhakrishnan, Aparna | Cvejic, Ana | Tang, Weihong | Porcu, Eleonora | Pistis, Giorgio | Serbanovic-Canic, Jovana | Elling, Ulrich | Goodall, Alison H. | Labrune, Yann | Lopez, Lorna M. | Mägi, Reedik | Meacham, Stuart | Okada, Yukinori | Pirastu, Nicola | Sorice, Rossella | Teumer, Alexander | Voss, Katrin | Zhang, Weihua | Ramirez-Solis, Ramiro | Bis, Joshua C. | Ellinghaus, David | Gögele, Martin | Hottenga, Jouke-Jan | Langenberg, Claudia | Kovacs, Peter | O’Reilly, Paul F. | Shin, So-Youn | Esko, Tõnu | Hartiala, Jaana | Kanoni, Stavroula | Murgia, Federico | Parsa, Afshin | Stephens, Jonathan | van der Harst, Pim | van der Schoot, C. Ellen | Allayee, Hooman | Attwood, Antony | Balkau, Beverley | Bastardot, François | Basu, Saonli | Baumeister, Sebastian E. | Biino, Ginevra | Bomba, Lorenzo | Bonnefond, Amélie | Cambien, François | Chambers, John C. | Cucca, Francesco | D’Adamo, Pio | Davies, Gail | de Boer, Rudolf A. | de Geus, Eco J. C. | Döring, Angela | Elliott, Paul | Erdmann, Jeanette | Evans, David M. | Falchi, Mario | Feng, Wei | Folsom, Aaron R. | Frazer, Ian H. | Gibson, Quince D. | Glazer, Nicole L. | Hammond, Chris | Hartikainen, Anna-Liisa | Heckbert, Susan R. | Hengstenberg, Christian | Hersch, Micha | Illig, Thomas | Loos, Ruth J. F. | Jolley, Jennifer | Khaw, Kay Tee | Kühnel, Brigitte | Kyrtsonis, Marie-Christine | Lagou, Vasiliki | Lloyd-Jones, Heather | Lumley, Thomas | Mangino, Massimo | Maschio, Andrea | Leach, Irene Mateo | McKnight, Barbara | Memari, Yasin | Mitchell, Braxton D. | Montgomery, Grant W. | Nakamura, Yusuke | Nauck, Matthias | Navis, Gerjan | Nöthlings, Ute | Nolte, Ilja M. | Porteous, David J. | Pouta, Anneli | Pramstaller, Peter P. | Pullat, Janne | Ring, Susan M. | Rotter, Jerome I. | Ruggiero, Daniela | Ruokonen, Aimo | Sala, Cinzia | Samani, Nilesh J. | Sambrook, Jennifer | Schlessinger, David | Schreiber, Stefan | Schunkert, Heribert | Scott, James | Smith, Nicholas L. | Snieder, Harold | Starr, John M. | Stumvoll, Michael | Takahashi, Atsushi | Tang, W. H. Wilson | Taylor, Kent | Tenesa, Albert | Thein, Swee Lay | Tönjes, Anke | Uda, Manuela | Ulivi, Sheila | van Veldhuisen, Dirk J. | Visscher, Peter M. | Völker, Uwe | Wichmann, H.-Erich | Wiggins, Kerri L. | Willemsen, Gonneke | Yang, Tsun-Po | Zhao, Jing Hua | Zitting, Paavo | Bradley, John R. | Dedoussis, George V. | Gasparini, Paolo | Hazen, Stanley L. | Metspalu, Andres | Pirastu, Mario | Shuldiner, Alan R. | van Pelt, L. Joost | Zwaginga, Jaap-Jan | Boomsma, Dorret I. | Deary, Ian J. | Franke, Andre | Froguel, Philippe | Ganesh, Santhi K. | Jarvelin, Marjo-Riitta | Martin, Nicholas G. | Meisinger, Christa | Psaty, Bruce M. | Spector, Timothy D. | Wareham, Nicholas J. | Akkerman, Jan-Willem N. | Ciullo, Marina | Deloukas, Panos | Greinacher, Andreas | Jupe, Steve | Kamatani, Naoyuki | Khadake, Jyoti | Kooner, Jaspal S. | Penninger, Josef | Prokopenko, Inga | Stemple, Derek | Toniolo, Daniela | Wernisch, Lorenz | Sanna, Serena | Hicks, Andrew A. | Rendon, Augusto | Ferreira, Manuel A. | Ouwehand, Willem H. | Soranzo, Nicole
Nature  2011;480(7376):201-208.
Platelets are the second most abundant cell type in blood and are essential for maintaining haemostasis. Their count and volume are tightly controlled within narrow physiological ranges, but there is only limited understanding of the molecular processes controlling both traits. Here we carried out a high-powered meta-analysis of genome-wide association studies (GWAS) in up to 66,867 individuals of European ancestry, followed by extensive biological and functional assessment. We identified 68 genomic loci reliably associated with platelet count and volume mapping to established and putative novel regulators of megakaryopoiesis and platelet formation. These genes show megakaryocyte-specific gene expression patterns and extensive network connectivity. Using gene silencing in Danio rerio and Drosophila melanogaster, we identified 11 of the genes as novel regulators of blood cell formation. Taken together, our findings advance understanding of novel gene functions controlling fate-determining events during megakaryopoiesis and platelet formation, providing a new example of successful translation of GWAS to function.
doi:10.1038/nature10659
PMCID: PMC3335296  PMID: 22139419
18.  Genome-Wide Association Study of White Blood Cell Count in 16,388 African Americans: the Continental Origins and Genetic Epidemiology Network (COGENT) 
PLoS Genetics  2011;7(6):e1002108.
Total white blood cell (WBC) and neutrophil counts are lower among individuals of African descent due to the common African-derived “null” variant of the Duffy Antigen Receptor for Chemokines (DARC) gene. Additional common genetic polymorphisms were recently associated with total WBC and WBC sub-type levels in European and Japanese populations. No additional loci that account for WBC variability have been identified in African Americans. In order to address this, we performed a large genome-wide association study (GWAS) of total WBC and cell subtype counts in 16,388 African-American participants from 7 population-based cohorts available in the Continental Origins and Genetic Epidemiology Network. In addition to the DARC locus on chromosome 1q23, we identified two other regions (chromosomes 4q13 and 16q22) associated with WBC in African Americans (P<2.5×10−8). The lead SNP (rs9131) on chromosome 4q13 is located in the CXCL2 gene, which encodes a chemotactic cytokine for polymorphonuclear leukocytes. Independent evidence of the novel CXCL2 association with WBC was present in 3,551 Hispanic Americans, 14,767 Japanese, and 19,509 European Americans. The index SNP (rs12149261) on chromosome 16q22 associated with WBC count is located in a large inter-chromosomal segmental duplication encompassing part of the hydrocephalus inducing homolog (HYDIN) gene. We demonstrate that the chromosome 16q22 association finding is most likely due to a genotyping artifact as a consequence of sequence similarity between duplicated regions on chromosomes 16q22 and 1q21. Among the WBC loci recently identified in European or Japanese populations, replication was observed in our African-American meta-analysis for rs445 of CDK6 on chromosome 7q21 and rs4065321 of PSMD3-CSF3 region on chromosome 17q21. In summary, the CXCL2, CDK6, and PSMD3-CSF3 regions are associated with WBC count in African American and other populations. We also demonstrate that large inter-chromosomal duplications can result in false positive associations in GWAS.
Author Summary
Although recent genome-wide association studies have identified common genetic variants associated with total white blood cell (WBC) and WBC sub-type counts in European and Japanese ancestry populations, whether these or other loci account for differences in WBC count among African Americans is unknown. By examining >16,000 African Americans, we show that, in addition to the previously identified Duffy Antigen Receptor for Chemokines (DARC) locus on chromosome 1, another variant, rs9131, and other nearby variants on human chromosome 4 are associated with total WBC count in African Americans. The variants span the CXCL2 gene, which encodes an inflammatory mediator involved in WBC production and migration. We show that the association is not restricted to African Americans but is also present in independent samples of European Americans, Hispanic Americans, and Japanese. This finding is potentially important because WBC mediate or have altered counts in a variety of acute and chronic disorders.
doi:10.1371/journal.pgen.1002108
PMCID: PMC3128101  PMID: 21738479
19.  Multiple Loci Are Associated with White Blood Cell Phenotypes 
Nalls, Michael A. | Couper, David J. | Tanaka, Toshiko | van Rooij, Frank J. A. | Chen, Ming-Huei | Smith, Albert V. | Toniolo, Daniela | Zakai, Neil A. | Yang, Qiong | Greinacher, Andreas | Wood, Andrew R. | Garcia, Melissa | Gasparini, Paolo | Liu, Yongmei | Lumley, Thomas | Folsom, Aaron R. | Reiner, Alex P. | Gieger, Christian | Lagou, Vasiliki | Felix, Janine F. | Völzke, Henry | Gouskova, Natalia A. | Biffi, Alessandro | Döring, Angela | Völker, Uwe | Chong, Sean | Wiggins, Kerri L. | Rendon, Augusto | Dehghan, Abbas | Moore, Matt | Taylor, Kent | Wilson, James G. | Lettre, Guillaume | Hofman, Albert | Bis, Joshua C. | Pirastu, Nicola | Fox, Caroline S. | Meisinger, Christa | Sambrook, Jennifer | Arepalli, Sampath | Nauck, Matthias | Prokisch, Holger | Stephens, Jonathan | Glazer, Nicole L. | Cupples, L. Adrienne | Okada, Yukinori | Takahashi, Atsushi | Kamatani, Yoichiro | Matsuda, Koichi | Tsunoda, Tatsuhiko | Tanaka, Toshihiro | Kubo, Michiaki | Nakamura, Yusuke | Yamamoto, Kazuhiko | Kamatani, Naoyuki | Stumvoll, Michael | Tönjes, Anke | Prokopenko, Inga | Illig, Thomas | Patel, Kushang V. | Garner, Stephen F. | Kuhnel, Brigitte | Mangino, Massimo | Oostra, Ben A. | Thein, Swee Lay | Coresh, Josef | Wichmann, H.-Erich | Menzel, Stephan | Lin, JingPing | Pistis, Giorgio | Uitterlinden, André G. | Spector, Tim D. | Teumer, Alexander | Eiriksdottir, Gudny | Gudnason, Vilmundur | Bandinelli, Stefania | Frayling, Timothy M. | Chakravarti, Aravinda | van Duijn, Cornelia M. | Melzer, David | Ouwehand, Willem H. | Levy, Daniel | Boerwinkle, Eric | Singleton, Andrew B. | Hernandez, Dena G. | Longo, Dan L. | Soranzo, Nicole | Witteman, Jacqueline C. M. | Psaty, Bruce M. | Ferrucci, Luigi | Harris, Tamara B. | O'Donnell, Christopher J. | Ganesh, Santhi K.
PLoS Genetics  2011;7(6):e1002113.
White blood cell (WBC) count is a common clinical measure from complete blood count assays, and it varies widely among healthy individuals. Total WBC count and its constituent subtypes have been shown to be moderately heritable, with the heritability estimates varying across cell types. We studied 19,509 subjects from seven cohorts in a discovery analysis, and 11,823 subjects from ten cohorts for replication analyses, to determine genetic factors influencing variability within the normal hematological range for total WBC count and five WBC subtype measures. Cohort specific data was supplied by the CHARGE, HeamGen, and INGI consortia, as well as independent collaborative studies. We identified and replicated ten associations with total WBC count and five WBC subtypes at seven different genomic loci (total WBC count—6p21 in the HLA region, 17q21 near ORMDL3, and CSF3; neutrophil count—17q21; basophil count- 3p21 near RPN1 and C3orf27; lymphocyte count—6p21, 19p13 at EPS15L1; monocyte count—2q31 at ITGA4, 3q21, 8q24 an intergenic region, 9q31 near EDG2), including three previously reported associations and seven novel associations. To investigate functional relationships among variants contributing to variability in the six WBC traits, we utilized gene expression- and pathways-based analyses. We implemented gene-clustering algorithms to evaluate functional connectivity among implicated loci and showed functional relationships across cell types. Gene expression data from whole blood was utilized to show that significant biological consequences can be extracted from our genome-wide analyses, with effect estimates for significant loci from the meta-analyses being highly corellated with the proximal gene expression. In addition, collaborative efforts between the groups contributing to this study and related studies conducted by the COGENT and RIKEN groups allowed for the examination of effect homogeneity for genome-wide significant associations across populations of diverse ancestral backgrounds.
Author Summary
WBC traits are highly variable, moderately heritable, and commonly assayed as part of clinical complete blood count (CBC) examinations. The counts of constituent cell subtypes comprising the WBC count measure are assayed as part of a standard clinical WBC differential test. In this study we employed meta-analytic techniques and identified ten associations with WBC measures at seven genomic loci in a large sample set of over 31,000 participants. Cohort specific data was supplied by the CHARGE, HeamGen, and INGI consortia, as well as independent collaborative studies. We confirm previous associations of WBC traits with three loci and identified seven novel loci. We also utilize a number of additional analytic methods to infer the functional relatedness of independently implicated loci across WBC phenotypes, as well as investigate direct functional consequences of these loci through analyses of genomic variation affecting the expression of proximal genes in samples of whole blood. In addition, subsequent collaborative efforts with studies of WBC traits in African-American and Japanese cohorts allowed for the investigation of the effects of these genomic variants across populations of diverse continental ancestries.
doi:10.1371/journal.pgen.1002113
PMCID: PMC3128114  PMID: 21738480
20.  Time course analysis of gene expression identifies multiple genes with differential expression in patients with in-stent restenosis 
BMC Medical Genomics  2011;4:20.
Background
The vascular disease in-stent restenosis (ISR) is characterized by formation of neointima and adverse inward remodeling of the artery after injury by coronary stent implantation. We hypothesized that the analysis of gene expression in peripheral blood mononuclear cells (PBMCs) would demonstrate differences in transcript expression between individuals who develop ISR and those who do not.
Methods and Results
We determined and investigated PBMC gene expression of 358 patients undergoing an index procedure to treat in de novo coronary artery lesions with bare metallic stents, using a novel time-varying intercept model to optimally assess the time course of gene expression across a time course of blood samples. Validation analyses were conducted in an independent sample of 97 patients with similar time-course blood sampling and gene expression data. We identified 47 probesets with differential expression, of which 36 were validated upon independent replication testing. The genes identified have varied functions, including some related to cellular growth and metabolism, such as the NAB2 and LAMP genes.
Conclusions
In a study of patients undergoing bare metallic stent implantation, we have identified and replicated differential gene expression in peripheral blood mononuclear cells, studied across a time series of blood samples. The genes identified suggest alterations in cellular growth and metabolism pathways, and these results provide the basis for further specific functional hypothesis generation and testing of the mechanisms of ISR.
doi:10.1186/1755-8794-4-20
PMCID: PMC3053213  PMID: 21356094
21.  Genome-wide association study of blood pressure and hypertension 
Nature genetics  2009;41(6):677-687.
Blood pressure (BP) is a major cardiovascular disease risk factor. To date, few variants associated with inter-individual BP variation have been identified. A genome-wide association study of systolic (SBP), diastolic BP (DBP), and hypertension in the CHARGE Consortium (n=29,136) identified 13 SNPs for SBP, 20 for DBP, and 10 for hypertension at p <4×10-7. The top 10 loci for SBP and DBP were incorporated into a risk score; mean BP and prevalence of hypertension increased in relation to number of risk alleles carried. When 10 CHARGE SNPs for each trait were meta-analyzed jointly with the Global BPgen Consortium (n=34,433), four CHARGE loci attained genome-wide significance (p<5×10-8) for SBP (ATP2B1, CYP17A1, PLEKHA7, SH2B3), six for DBP (ATP2B1, CACNB2, CSK/ULK3, SH2B3, TBX3/TBX5, ULK4), and one for hypertension (ATP2B1). Identifying novel BP genes advances our understanding of BP regulation and highlights potential drug targets for the prevention or treatment of hypertension.
doi:10.1038/ng.384
PMCID: PMC2998712  PMID: 19430479
22.  Positional identification of variants of Adamts16 linked to inherited hypertension 
Human Molecular Genetics  2009;18(15):2825-2838.
A previously reported blood pressure (BP) quantitative trait locus on rat Chromosome 1 was isolated in a short congenic segment spanning 804.6 kb. The 804.6 kb region contained only two genes, LOC306664 and LOC306665. LOC306664 is predicted to translate into A Disintegrin-like and Metalloproteinase with Thrombospondin Motifs-16 (Adamts16). LOC306665 is a novel gene. All predicted exons of both LOC306664 and LOC306665 were sequenced. Non-synonymous variants were identified in only one of these genes, LOC306664. These variants were naturally existing polymorphisms among inbred, outbred and wild rats. The full-length rat transcript of Adamts16 was detected in multiple tissues. Similar to ADAMTS16 in humans, expression of Adamts16 was prominent in the kidney. Renal transcriptome analysis suggested that a network of genes related to BP was differential between congenic and S rats. These genes were also differentially expressed between kidney cell lines with or without knock-down of Adamts16. Adamts16 is conserved between rats and humans. It is a candidate gene within the homologous region on human Chromosome 5, which is linked to systolic and diastolic BP in the Quebec Family Study. Multiple variants, including an Ala to Pro variant in codon 90 (rs2086310) of human ADAMTS16, were associated with human resting systolic BP (SBP). Replication study in GenNet confirmed the association of two variants of ADAMTS16 with SBP, including rs2086310. Overall, our report represents a high resolution positional cloning and translational study for Adamts16 as a candidate gene controlling BP.
doi:10.1093/hmg/ddp218
PMCID: PMC2706685  PMID: 19423552
23.  Detection of Venous Thromboembolism by Proteomic Serum Biomarkers 
PLoS ONE  2007;2(6):e544.
Background
Available blood assays for venous thromboembolism (VTE) suffer from diminished specificity. Compared with single marker tests, such as D-dimer, a multi-marker strategy may improve diagnostic ability. We used direct mass spectrometry (MS) analysis of serum from patients with VTE to determine whether protein expression profiles would predict diagnosis.
Methods and Results
We developed a direct MS and computational approach to the proteomic analysis of serum. Using this new method, we analyzed serum from inpatients undergoing radiographic evaluation for VTE. In a balanced cohort of 76 patients, a neural network-based prediction model was built using a training subset of the cohort to first identify proteomic patterns of VTE. The proteomic patterns were then validated in a separate group of patients within the cohort. The model yielded a sensitivity of 68% and specificity of 89%, which exceeded the specificity of D-dimer assay tested by latex agglutination, ELISA, and immunoturbimetric methods (sensitivity/specificity of 63.2%/60.5%, 97.4%/21.1%, 97.4%/15.8%, respectively). We validated differences in protein expression between patients with and without VTE using more traditional gel-based analysis of the same serum samples.
Conclusion
Protein expression analysis of serum using direct MS demonstrates potential diagnostic utility for VTE. This pilot study is the first such direct MS study to be applied to a cardiovascular disease. Differences in protein expression were identified and subsequently validated in a separate group of patients. The findings in this initial cohort can be evaluated in other independent cohorts, including patients with inflammatory conditions and chronic (but not acute) VTE, for the diagnosis of VTE.
doi:10.1371/journal.pone.0000544
PMCID: PMC1891085  PMID: 17579716

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