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Abstract
PURPOSE OF REVIEW Over the past few years, apolipoprotein E (ApoE) receptors, also known as LDL receptor-related proteins, have distinguished themselves as functionally diverse signaling receptors with pivotal roles not only in the vascular system but also in the nervous system and during development. RECENT FINDINGS The expanding roles of ApoE receptors for cellular signal transduction at the same time transcend and integrate their lipid transport roles into a larger biological and clinical context. ApoE receptors are essential for the development of the nervous system, the regulation of synaptic plasticity, neuroprotection and the innervation of the muscle. They also regulate the metabolism of the amyloid precursor protein on multiple levels, implicating them in the pathogenesis of Alzheimer's disease. SUMMARY ApoE, a common ligand for all members of the evolutionarily ancient LDL receptor gene family, is the major genetic modifier of the age of onset of Alzheimer's disease. The underlying molecular mechanisms remain shrouded in mystery, but the numerous critical functions of ApoE receptors within and outside the nervous system that have recently emerged make it likely that these multifunctional signal modulators participate in Alzheimer's disease pathogenesis. This review attempts to summarize the most recent and relevant findings in this area.
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Affiliation(s)
- Joachim Herz
- Department of Molecular Genetics, UT Southwestern, Dallas, Texas 75390-9046, USA.
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53
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Martinelli N, Olivieri O, Shen GQ, Trabetti E, Pizzolo F, Busti F, Friso S, Bassi A, Li L, Hu Y, Pignatti PF, Corrocher R, Wang QK, Girelli D. Additive effect of LRP8/APOER2 R952Q variant to APOE epsilon2/epsilon3/epsilon4 genotype in modulating apolipoprotein E concentration and the risk of myocardial infarction: a case-control study. BMC MEDICAL GENETICS 2009; 10:41. [PMID: 19439088 PMCID: PMC2689206 DOI: 10.1186/1471-2350-10-41] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 05/13/2009] [Indexed: 01/19/2023]
Abstract
BACKGROUND The R952Q variant in the low density lipoprotein receptor-related protein 8 (LRP8)/apolipoprotein E receptor 2 (ApoER2) gene has been recently associated with familial and premature myocardial infarction (MI) by means of genome-wide linkage scan/association studies. We were interested in the possible interaction of the R952Q variant with another established cardiovascular genetic risk factor belonging to the same pathway, namely apolipoprotein E (APOE) epsilon2/epsilon3/epsilon4 genotype, in modulating apolipoprotein E (ApoE) plasma levels and risk of MI. METHODS In the Italian cohort used to confirm the association of the R952Q variant with MI, we assessed lipid profile, apolipoprotein concentrations, and APOE epsilon2/epsilon3/epsilon4 genotype. Complete data were available for a total of 681 subjects in a case-control setting (287 controls and 394 patients with MI). RESULTS Plasma ApoE levels decreased progressively across R952Q genotypes (mean levels +/- SD = RR: 0.045 +/- 0.020, RQ: 0.044 +/- 0.014, QQ: 0.040 +/- 0.008 g/l; P for trend = 0.047). Combination with APOE genotypes revealed an additive effect on ApoE levels, with the highest level observed in RR/non-carriers of the E4 allele (0.046 +/- 0.021 g/l), and the lowest level in QQ/E4 carriers (0.035 +/- 0.009 g/l; P for trend = 0.010). QQ/E4 was also the combined genotype with the most significant association with MI (OR 3.88 with 95%CI 1.08-13.9 as compared with RR/non-carriers E4). CONCLUSION Our data suggest that LRP8 R952Q variant may have an additive effect to APOE epsilon2/epsilon3/epsilon4 genotype in determining ApoE concentrations and risk of MI in an Italian population.
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Affiliation(s)
- Nicola Martinelli
- Department of Clinical and Experimental Medicine, University of Verona, Verona, Italy.
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Hutz JE, Kraja AT, McLeod HL, Province MA. CANDID: a flexible method for prioritizing candidate genes for complex human traits. Genet Epidemiol 2009; 32:779-90. [PMID: 18613097 DOI: 10.1002/gepi.20346] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Genomewide studies and localized candidate gene approaches have become everyday study designs for identifying polymorphisms in genes that influence complex human traits. Yet, in general, the number of significant findings and the need to focus on smaller regions require a prioritization of genes for further study. Some candidate gene identification algorithms have been proposed in recent years to attempt to streamline this prioritization, but many suffer from limitations imposed by the source data or are difficult to use and understand. CANDID is a prioritization algorithm designed to produce impartial, accurate rankings of candidate genes that influence complex human traits. CANDID can use information from publications, protein domain descriptions, cross-species conservation measures, gene expression profiles and protein-protein interactions in its analysis. Additionally, users may supplement these data sources with results from linkage, association and other studies. CANDID was tested on well-known complex trait genes using data from the Online Mendelian Inheritance in Man database. Additionally, CANDID was evaluated in a modeled gene discovery environment, where it ranked genes whose trait associations were published after CANDID's databases were compiled. In all settings, CANDID exhibited high sensitivity and specificity, indicating an improvement upon previously published algorithms. Its accuracy and ease of use make CANDID a highly useful tool in study design and analysis for complex human traits.
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Affiliation(s)
- Janna E Hutz
- Division of Statistical Genomics, Washington University School of Medicine, Saint Louis, Missouri, USA.
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Abstract
Single nucleotide polymorphisms (SNPs) are common DNA sequence variations that occur at single bases within the genome. SNPs have been instrumental in elucidating the genetic basis of common, complex diseases using genome-wide association studies, candidate gene case-control association studies, and genome-wide linkage analyses. A key to these studies is genotyping of SNPs. Various methods for SNP genotyping have been developed. For a particular genotyping project, the choice of method is dependent on the number of SNPs (n) and the number of DNA samples (m) to be genotyped. For a genome-wide or large-scale project with very high n and small m, the Affymetrix SNP GeneChip and Illumina GoldenGate BeadChips assays are the ideal methods. For a project involving a small number of SNPs (small n) and a large population (high m), the TaqMan assay is the preferred technology as it has high throughput and is highly accurate, precise, time-efficient, and cost-effective. Here, we describe the detailed procedures for TaqMan SNP genotyping assay, including preparation of high-quality DNA samples, the operating protocol, clarification of technical issues, and discussion of several cautionary notes.
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Abstract
The antiphospholipid syndrome is a non-inflammatory autoimmune disease characterised by the presence of antiphospholipid antibodies in the plasma of patients with venous or arterial thrombosis or recurrent complications of pregnancy. The strong relation between the presence of antibodies against anionic phospholipids and thrombo-embolic complications is well established, but how the presence of antiphospholipid antibodies results in the observed clinical manifestations remains a mystery. Experimental observations suggest that an altered regulation of platelet function can cause the thrombotic complications observed in the antiphospholipid syndrome. In this review, we will discuss the evidence that the platelet is an important player in the pathogenesis of the antiphospholipid syndrome.
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Affiliation(s)
- RT Urbanus
- Department of Clinical Chemistry and Haematology, University Medical Center, Utrecht, the Netherlands
| | - RHWM Derksen
- Department of Rheumatology and Clinical Immunology, University Medical Center, Utrecht, the Netherlands
| | - PG de Groot
- Department of Clinical Chemistry and Haematology, University Medical Center, Utrecht, the Netherlands
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Seidelmann SB, Kuo C, Pleskac N, Molina J, Sayers S, Li R, Zhou J, Johnson P, Braun K, Chan C, Teupser D, Breslow JL, Wight TN, Tall AR, Welch CL. Athsq1 is an atherosclerosis modifier locus with dramatic effects on lesion area and prominent accumulation of versican. Arterioscler Thromb Vasc Biol 2008; 28:2180-6. [PMID: 18818413 DOI: 10.1161/atvbaha.108.176800] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Susceptibility to atherosclerosis is genetically complex, and modifier genes that do not operate via traditional risk factors are largely unknown. A mouse genetics approach can simplify the genetic analysis and provide tools for mechanistic studies. METHODS AND RESULTS We previously identified atherosclerosis susceptibility QTL (Athsq1) on chromosome 4 acting independently of systemic risk factors. We now report confirmation of this locus in congenic strains carrying the MOLF-derived susceptibility allele in the C57BL/6J-Ldlr(-/-) genetic background. Homozygous congenic mice exhibited up to 4.5-fold greater lesion area compared to noncongenic littermates (P<0.0001). Analysis of extracellular matrix composition revealed prominent accumulation of versican, a presumed proatherogenic matrix component abundant in human lesions but almost absent in the widely-used C57BL/6 murine atherosclerosis model. The results of a bone marrow transplantation experiment suggested that both accelerated lesion development and versican accumulation are mediated, at least in part, by macrophages. Interestingly, comparative mapping revealed that the Athsq1 congenic interval contains the mouse region homologous to a widely-replicated CHD locus on human chromosome 9p21. CONCLUSIONS These studies confirm the proatherogenic activity of a novel gene(s) in the MOLF-derived Athsq1 locus and provide in vivo evidence for a causative role of versican in lesion development.
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Robertson JO, Li W, Silverstein RL, Topol EJ, Smith JD. Deficiency of LRP8 in mice is associated with altered platelet function and prolonged time for in vivo thrombosis. Thromb Res 2008; 123:644-52. [PMID: 18706682 DOI: 10.1016/j.thromres.2008.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 05/22/2008] [Accepted: 07/01/2008] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Our group has previously reported genetic studies associating polymorphisms in the low density lipoprotein receptor related protein 8 (LRP8) gene with myocardial infarction. The aim of this study was to define the role of platelet surface LRP8 in thrombosis. MATERIALS AND METHODS Flow cytometry, aggregometry, intravital microscopy and tail bleeding assays were used to examine platelet function and hemostasis in LRP8-deficient mice and littermate controls. RESULTS We demonstrated that activation of platelets from both LRP8(+/-) and LRP8(-/-) mice was reduced in vitro in response to either ADP or thrombin. In vivo, LRP8-hemizygous and LRP8(-/-) mice demonstrated 200% and 68% increased time for carotid occlusion in response to FeCl(3) injury, respectively. Moreover, lipidated apoE3, a ligand for LRP8, inhibited platelet activation in a dose-dependent fashion. This inhibition was markedly attenuated in LRP8(-/-) but not LRP8(+/-) mice and did not result from membrane cholesterol efflux or a nitric oxide dependent pathway. Tail bleeding times were unaffected in both genotypes. CONCLUSIONS Our results suggest that LRP8 is capable of altering thrombosis without affecting normal hemostasis through mechanisms both dependent on and independent of apoE. This suggests a means whereby clot formation could be affected in humans with LRP8 gene variants.
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Affiliation(s)
- Jason O Robertson
- Department of Cell Biology, Cleveland Clinic, Cleveland, OH; Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, USA
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Molecular genetics of myocardial infarction. Genomic Med 2008; 2:7-22. [PMID: 18704761 DOI: 10.1007/s11568-008-9025-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/28/2008] [Accepted: 07/30/2008] [Indexed: 12/28/2022] Open
Abstract
Myocardial infarction (MI) is an important clinical problem because of its large contribution to mortality. The main causal and treatable risk factors for MI include hypertension, hypercholesterolemia or dyslipidemia, diabetes mellitus, and smoking. In addition to these risk factors, recent studies have shown the importance of genetic factors and interactions between multiple genes and environmental factors. Disease prevention is an important strategy for reducing the overall burden of MI, with the identification of markers for disease risk being key both for risk prediction and for potential intervention to lower the chance of future events. Although genetic linkage analyses of families and sib-pairs as well as candidate gene and genome-wide association studies have implicated several loci and candidate genes in predisposition to coronary heart disease (CHD) or MI, the genes that contribute to genetic susceptibility to these conditions remain to be identified definitively. In this review, we summarize both candidate loci for CHD or MI identified by linkage analyses and candidate genes examined by association studies. We also review in more detail studies that have revealed the association with MI or CHD of polymorphisms in MTHFR, LPL, and APOE by the candidate gene approach and those in LTA and at chromosomal region 9p21.3 by genome-wide scans. Such studies may provide insight into the function of implicated genes as well as into the role of genetic factors in the development of CHD and MI.
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Urbanus RT, Pennings MTT, Derksen RHWM, de Groot PG. Platelet activation by dimeric beta2-glycoprotein I requires signaling via both glycoprotein Ibalpha and apolipoprotein E receptor 2'. J Thromb Haemost 2008; 6:1405-12. [PMID: 18485085 DOI: 10.1111/j.1538-7836.2008.03021.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Dimerization of beta(2)-glycoprotein I (beta(2)-GPI) by autoantibodies is thought to trigger the clinical manifestations observed in the antiphospholipid syndrome. Arterial thrombosis, a frequently occurring clinical manifestation of the antiphospholipid syndrome, is a process in which platelets play a crucial role. Previous work has shown that binding of dimeric beta(2)-GPI to the platelet receptors apolipoprotein E receptor 2' (ApoER2') and glycoprotein Ibalpha (GPIbalpha) mediates increased platelet activation in an in vitro thrombosis model. OBJECTIVE The individual roles of ApoER2' and GPIbalpha in mediating platelet activation by dimeric beta(2)-GPI has hitherto been unclear. In this study, we have determined the roles of either receptor in platelet activation by dimeric beta(2)-GPI. METHODS Platelet activation by dimeric beta(2)-GPI was studied under conditions of flow. Intracellular signaling induced by dimeric beta(2)-GPI was subsequently analyzed by means of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis. RESULTS The increase in platelet deposition onto a fibronectin surface under conditions of flow by dimeric beta(2)-GPI was completely abolished by inhibition of the interaction of dimeric beta(2)-GPI with either GPIbalpha or ApoER2'. Upon platelet stimulation with dimeric beta(2)-GPI, GPIbalpha translocated to the cytoskeleton via the scaffold protein 14-3-3zeta. Concomitantly, ApoER2' dissociated from the adapter protein Disabled1, presumably through phosphorylation of the cytoplasmic tail. Inhibition of one process could not inhibit the other. CONCLUSION We show that dimeric beta(2)-GPI signals via two distinct pathways in platelets, both of which are required for platelet activation. Abrogation of either signal results in loss of activation.
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Affiliation(s)
- R T Urbanus
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, Utrecht, The Netherlands
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Lieb W, Zeller T, Mangino M, Götz A, Braund P, Wenzel JJ, Horn C, Proust C, Linsel-Nitschke P, Amouyel P, Bruse P, Arveiler D, König IR, Ferrières J, Ziegler A, Balmforth AJ, Evans A, Ducimetière P, Cambien F, Hengstenberg C, Stark K, Hall AS, Schunkert H, Blankenberg S, Samani NJ, Erdmann J, Tiret L. Lack of association of genetic variants in the LRP8 gene with familial and sporadic myocardial infarction. J Mol Med (Berl) 2008; 86:1163-70. [PMID: 18592168 DOI: 10.1007/s00109-008-0376-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 05/14/2008] [Accepted: 05/26/2008] [Indexed: 01/06/2023]
Abstract
Coronary artery disease (CAD) and myocardial infarction (MI) have a genetic basis, but the precise genetic underpinning remains controversial. Recently, an association of the LRP8 R952Q polymorphism (rs5174) with familial premature CAD/MI was reported. We analysed rs5174 (or the perfect proxy rs5177) in 1,210 patients with familial MI and 1,015 controls from the German MI Family study, in 1,926 familial CAD (1,377 with MI) patients and 2,938 controls from the Wellcome Trust Case Control Consortium (WTCCC) MI/CAD cohort, in 346 CAD patients and 351 controls from the AtheroGene study and in 295 men with incident CAD and 301 controls from the Prospective Epidemiological Study of MI study and found no evidence for association in any of the populations studied. In the WTCCC and the German MI Family studies, additional single-nucleotide polymorphisms in the LRP8 gene were analysed and displayed no evidence for association either.
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Affiliation(s)
- Wolfgang Lieb
- Medizinische Klinik II, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Hu Y, Li L, Seidelmann SB, Timur AA, Shen PH, Driscoll DJ, Wang QK. Identification of association of common AGGF1 variants with susceptibility for Klippel-Trenaunay syndrome using the structure association program. Ann Hum Genet 2008; 72:636-43. [PMID: 18564129 DOI: 10.1111/j.1469-1809.2008.00458.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Klippel-Trenaunay syndrome (KTS) is a severe congenital disorder characterized by capillary malformations, venous malformations or varicose veins, and hypertrophy of the affected tissues. The angiogenic factor gene AGGF1 was previously identified as a candidate susceptibility gene for KTS, but further genetic studies are needed to firmly establish the genetic relationship between AGGF1 and KTS. We analyzed HapMap data and identified two tagSNPs, rs13155212 and rs7704267 that capture information for all common variants in AGGF1. The two SNPs were genotyped in 173 Caucasian KTS patients and 477 Caucasian non-KTS controls, and both significantly associated with susceptibility for KTS (P= 0.004 and 0.013, respectively). Permutation testing also showed a significant empirical P value for the association (empirical P= 0.006 and 0.015, respectively). To control for potential confounding due to population stratification, the population structure for both cases and controls was characterized by genotyping of 38 ancestry-informative markers (AIMs) and the STRUCTURE program. The association between the AGGF1 SNPs and KTS remained significant after multivariate analysis by incorporating the inferred cluster scores as a covariate or after removal of outlier individuals identified by STRUCTURE. These results suggest that common AGGF1 variants confer risk of KTS.
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Affiliation(s)
- Y Hu
- Center for Cardiovascular Genetics, Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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63
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White TC, Berny MA, Tucker EI, Urbanus RT, de Groot PG, Fernández JA, Griffin JH, Gruber A, McCarty OJT. Protein C supports platelet binding and activation under flow: role of glycoprotein Ib and apolipoprotein E receptor 2. J Thromb Haemost 2008; 6:995-1002. [PMID: 18489431 DOI: 10.1111/j.1538-7836.2008.02979.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Activated protein C (APC) regulates thrombin generation and inhibits apoptosis. Endothelial protein C receptor (EPCR)-bound protein C is activated by thrombomodulin-bound thrombin. APC inactivates coagulation factors (F)Va/VIIIa and generates cytoprotective signaling downstream of protease-activated receptor-1 (PAR-1). Binding of APC to EPCR both modifies and induces PAR-1 signaling, but it is unknown if protein C interacts with cells in an alternative manner. AIM To determine whether platelets possess receptors for protein C that can generate intracellular signals. RESULTS Immobilized protein C or APC supported platelet adhesion, lamellipodia formation and elevation of intracellular Ca(2+). Adhesion of platelets to protein C or APC was inhibited by soluble recombinant apolipoprotein E receptor 2' (ApoER2') and by receptor-associated protein (RAP), an inhibitor of the low-density lipoprotein receptor family. Under shear, surface-bound protein C supported platelet adhesion and aggregation in a glycoprotein (GP)Ibalpha-dependent manner, and adhesion of platelets to immobilized protein C was abrogated by the addition of soluble forms of ApoER2' or RAP. APC bound to purified recombinant ApoER2' or GPIbalpha. CONCLUSIONS Our data demonstrate that activation of platelets with rapid intracellular signaling caused by binding to immobilized protein C or APC occurs via mechanisms that require ApoER2 and GPIbalpha and that APC directly binds to purified ectodomains of the receptors ApoER2 and GPIbalpha. These findings imply that protein C and APC may directly promote cell signaling in other cells by binding to ApoER2 and/or GPIbalpha.
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Affiliation(s)
- T C White
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
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64
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Abdullah KG, Li L, Shen GQ, Hu Y, Yang Y, MacKinlay KG, Topol EJ, Wang QK. Four SNPS on chromosome 9p21 confer risk to premature, familial CAD and MI in an American Caucasian population (GeneQuest). Ann Hum Genet 2008; 72:654-7. [PMID: 18505420 DOI: 10.1111/j.1469-1809.2008.00454.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genome-wide association studies have separately identified four single nucleotide polymorphisms (SNPs) on chromosome 9p21 that confer susceptibility to coronary artery disease (CAD) and myocardial infarction (MI). This study presents the first analysis of these SNPs (rs10757274, rs2383206, rs2383207, and rs10757278) in a premature, familial CAD/MI population (GeneQuest). We performed a case-control analysis of the GeneQuest Caucasian population with 310 cases with premature CAD and MI (average age at onset of 40.3 +/- 5.1) and 560 non-CAD controls to determine if these SNPs are associated with risk of CAD using both the population-based and family-based association study designs. The four SNPs are significantly associated with premature and familial MI and CAD in the GeneQuest Caucasian population (allelic P= 6.61 x 10(-7) to 1.87 x 10(-8)). Sib-TDT analysis showed that three of the four SNPs could confer significant susceptibility to premature CAD and MI. These results indicate that the four SNPs on chromosome 9p21 are also associated with premature, familial CAD.
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Affiliation(s)
- K G Abdullah
- Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, USA
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Abstract
The antiphospholipid antibody syndrome (APS) is characterized by recurrent arterial and venous thrombosis and/or pregnancy in association with antiphospholipid (aPL) antibodies. The pathogenic mechanisms in APS that lead to in vivo injury are incompletely understood. Recent evidence suggests that APL antibodies alter regulation of haemostasis and induce activation of complement. We will discuss the current knowledge on how aPL antibodies trigger increased inflammation and enhanced thrombotic tendency, and thereby lead to tissue damage.
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Affiliation(s)
- J E Salmon
- Department of Medicine, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York 10021, USA.
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Connelly JJ, Shah SH, Doss JF, Gadson S, Nelson S, Crosslin DR, Hale AB, Lou X, Wang T, Haynes C, Seo D, Crossman DC, Mooser V, Granger CB, Jones CJH, Kraus WE, Hauser ER, Gregory SG. Genetic and functional association of FAM5C with myocardial infarction. BMC MEDICAL GENETICS 2008; 9:33. [PMID: 18430236 PMCID: PMC2383879 DOI: 10.1186/1471-2350-9-33] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 04/22/2008] [Indexed: 12/18/2022]
Abstract
Background We previously identified a 40 Mb region of linkage on chromosome 1q in our early onset coronary artery disease (CAD) genome-wide linkage scan (GENECARD) with modest evidence for linkage (n = 420, LOD 0.95). When the data are stratified by acute coronary syndrome (ACS), this modest maximum in the overall group became a well-defined LOD peak (maximum LOD of 2.17, D1S1589/D1S518). This peak overlaps a recently identified inflammatory biomarker (MCP-1) linkage region from the Framingham Heart Study (maximum LOD of 4.27, D1S1589) and a region of linkage to metabolic syndrome from the IRAS study (maximum LOD of 2.59, D1S1589/D1S518). The overlap of genetic screens in independent data sets provides evidence for the existence of a gene or genes for CAD in this region. Methods A peak-wide association screen (457 SNPs) was conducted of a region 1 LOD score down from the peak marker (168–198 Mb) in a linkage peak for acute coronary syndrome (ACS) on chromosome 1, within a family-based early onset coronary artery disease (CAD) sample (GENECARD). Results Polymorphisms were identified within the 'family with sequence similarity 5, member C' gene (FAM5C) that show genetic linkage to and are associated with myocardial infarction (MI) in GENECARD. The association was confirmed in an independent CAD case-control sample (CATHGEN) and strong association with MI was identified with single nucleotide polymorphisms (SNPs) in the 3' end of FAM5C. FAM5C genotypes were also correlated with expression of the gene in human aorta. Expression levels of FAM5C decreased with increasing passage of proliferating aortic smooth muscle cells (SMC) suggesting a role for this molecule in smooth muscle cell proliferation and senescence. Conclusion These data implicate FAM5C alleles in the risk of myocardial infarction and suggest further functional studies of FAM5C are required to identify the gene's contribution to atherosclerosis.
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Affiliation(s)
- Jessica J Connelly
- Department of Medicine and Center for Human Genetics, Duke University Medical Center, Durham, NC, USA.
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Seidelmann SB, Li L, Shen GQ, Topol EJ, Wang QK. Identification of a novel locus for triglyceride on chromosome 1p31-32 in families with premature CAD and MI. J Lipid Res 2008; 49:1034-8. [PMID: 18245017 DOI: 10.1194/jlr.m700576-jlr200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
An increased plasma triglyceride (TG) level is associated with coronary artery disease (CAD) and myocardial infarction (MI) and is a key characteristic of the metabolic syndrome. Here, we used a genome-wide linkage scan to identify a novel genetic locus that influences the plasma TG level. We genotyped 714 persons in 388 multiplex Caucasian families with premature CAD and MI with 408 polymorphic microsatellite markers that cover the entire human genome. The genome-wide scan identified positive linkage for the quantitative TG trait to a novel locus on chromosome 1p31-32 [peak single-point logarithm of odds (LOD) = 3.57, peak multipoint LOD = 3.12]. For single-point linkage analysis, two markers, D1S1728 and D1S551, showed LOD scores of 2.42 and 3.57, respectively. For multipoint linkage analysis, three markers, D1S3736, D1S1728, and D1S551, showed LOD scores of 2.43, 3.03, and 3.12, respectively. No other chromosomal regions showed a LOD score of >2.2. This study identifies a new genetic locus for TG on chromosome 1p31-32. Future studies of the candidate genes at this locus will identify a specific gene influencing the TG, which will provide insights into novel regulatory mechanisms of TG metabolism and may be important for the development of therapies to prevent CAD.
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