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606 ABC TRANSPORTER GENES AND RISK OF TYPE 2 DIABETES
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Atherosclerosis Supplements 12, no. 1 (2011) 13–184
606 ABC TRANSPORTER GENES AND RISK OF TYPE 2 DIABETES J. Schou1 , A. Tybjærg-Hansen1,2,3 , B.G. Nordestgaard2,3,4 , R. FrikkeSchmidt1,3 . 1 Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, 2 The Copenhagen City Heart Study, Bispebjerg Hospital, Copenhagen University Hospital, 3 The Copenhagen General Population Study, 4 Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Copenhagen, Denmark Background: ATP-Binding Cassette transporters A1 and G1 (ABCA1 and ABCG1) facilitate efflux of cholesterol from peripheral cells to apolipoprotein A1 and HDL particles, respectively. Decreased efflux of cholesterol in pancreatic beta cells is suggested to impair glucose tolerance in humans and mice, whereas the association with type 2 diabetes is unknown. We tested whether genetic variation in the promoter and coding regions of ABCA1 and ABCG1 predicted risk of type 2 diabetes in the general population. Methods: We resequenced the core promoter and coding region of ABCA1 and ABCG1 in 380 individuals from the Copenhagen City Heart Study (CCHS) with extreme levels of HDL-cholesterol. Twenty eight promoter or coding variants were identified and subsequently genotyped in the CCHS (n = 10,243), and two loss-of-function mutations (N1800H in ABCA1 and −376C>T in ABCG1) were further genotyped in the Copenhagen General Population Study (CGPS, n = 31,072). Results: None of the variants genotyped affected measures of glucose metabolism (blood glucose, hemoglobinA1C), except for two ABCG1 variants that associated with slight increases in hemoglobinA1C (−686G>A, P = 0.02; G327, P = 0.0002). None of the 28 genetic variants predicted increased risk of type 2 diabetes in the CCHS. The two loss-of-function mutations also did not associate with type 2 diabetes in the CGPS (N1800H, P = 0.51; −376C>T, P = 0.72). Conclusion: Genetic variation in ABCA1 and ABCG1 is not associated with increased risk of type 2 diabetes in the general population. These data were obtained in general population samples harboring the largest number (n = 325) of heterozygous carriers of loss-of-function mutations in ABCA1 and ABCG1. 607 APOLIPOPROTEIN E GENE MUTATIONS IN SUBJECTS WITH MIXED HYPERLIPOPROTEINEMIA AND A CLINICAL DIAGNOSIS OF FAMILIAL COMBINED HYPERLIPIDEMIA ´ 2 , A.M. Bea1 , M. Cofan ´ 3 , N. Plana4 , M. Solanas-Barca1 , I. de Castro-Oros ´ E. Ros3 , L. Masana4 , M. Pocov´ı2 , F. Civeira1 , A. Cenarro1 . 1 Instituto Aragones de Ciencias de la Salud, Zaragoza, 2 Universidad de Zaragoza, Zararagoza, 3 4 Hospital Cl´ınic de Barcelona, Barcelona, Hospital Universitari de Sant Joan, Reus, Spain Introduction: Familial combined hyperlipidemia (FCH) is characterized by elevated levels of total cholesterol and triglycerides, vertical transmission of a variable hyperlipidemic phenotype, and high risk of premature cardiovascular disease. FCH is the most common cause of primary mixed hyperlipoproteinemia. An APOE e2/e2 genotype in the presence of mixed hyperlipoproteinemia is diagnostic of familial dysbetalipoproteinemia. However, rare dominant mutations in APOE, which go undetected with the usual genotyping procedure, may also cause dysbetalipoproteinemia. Uncovering such rare APOE variants may change the diagnosis from FCH to dysbetalipoproteinemia. Objectives: To identify APOE mutations associated with dominant mixed hyperlipoproteinemia and to establish their frequency in subjects with a clinical diagnosis of FCH. Methods: We examined 445 unrelated subjects with dominant mixed hyperlipoproteinemia and a clinical diagnosis of FCH and 287 unrelated normolipidemic subjects (control group). Clinical and analytical determinations were done in all of them. DNA was obtained from each subject, and the APOE gene (4 exons and intron-flanking sequences) was sequenced. Results: In addition to common APOE genotypes, two rare functional APOE variants, R136S and DL149, were identified. In the mixed hyperlipoproteinemia group, 9 subjects (2.0%) were carriers of the R136S mutation and 5 subjects (1.1%) were carriers of the DL149 mutation. In the control group, no rare APOE mutations were identified. Conclusion: Rare mutations in the APOE gene, R136S and DL149, were identified in subjects with mixed hyperlipoproteinemia and a clinical diagnosis of FCH, indicating that the APOE gene contributes to this phenotype. 608 HYPOALPHA-HYPOBETALIPOPROTEINEMIA (FAMILIAL COMBINED HYPOLIPIDEMIA) CAUSED BY LOSS OF FUNCTION MUTATIONS OF ANGPTL3 GENE L. Pisciotta1 , E. Di Leo2 , P. Tarugi2 , R. Fresa1 , I. Zavaroni3 , D. Ardigo` 3 , S. Bertolini1 , S. Calandra2 . 1 Department of Internal Medicine, University of Genoa, Genoa, 2 Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, 3 Department of Internal Medicine, University of Parma, Parma, Italy Angiopoietin-like protein 3 (ANGPTL3) is a protein secreted by the liver affecting lipoprotein metabolism. Inactivation of Angptl3 in mice is
Poster presentations
associated with hypotriglyceridemia, while overproduction of Angptl3 causes hypertriglyceridemia. Recently, nonsense mutations in ANGPTL3 gene were found in four siblings with low plasma LDL-C and HDL-C. These lipoprotein changes are due ANGPTL3-mediated inhibition of lipoprotein lipase (LPL) and endothelial lipase (EL). Aim of our study was the analysis of ANGPTL3 gene in a series of subjects with low HDL-C (<5th percentile) associated with hypocholesterolemia and hypotriglyceridemia. In this survey we identified two kindred with loss of function (LOF) ANGTPL3 mutations. Proband D.V. was a 65 year-old female with the following plasma lipid profile: TC 1.87, LDL-C 1.09, HDL-C 0.61, TG 0.37 mmol/L, Apo A-I 58, Apo B 50 mg/dl. She had no clinical features of atherosclerosis. She was homozygous for an intronic mutation (c.1198 +1 g>t), which abolishes the donor splice site of intron 6. Proband’s offspring, heterozygous for the mutation, had a normal lipid profile. Probands M.R. and M.M. were two 59 and 53 year-old brothers, free of cardiovascular diseases, with the following lipid profile: TC 1.88 and 1.91, LDL-C 1.06 and 1.14, HDL-C 0.67 and 0.62, TG 0.35 and 0.33 mmol/L, respectively. They were compound heterozygous for two ANGPTL3 frame-shift mutations: c.55 del A (p.I19L>fs>X40) and c.439–442 del AACT (p.N147X). These observations suggest that individuals with primary hypoalphalipoproteinemia associated with low levels of LDL-C may be homozygous or compound heterozygous for LOF mutations of ANGPTL3. 609 ASSOCIATION OF DIABETES-MELLITUS-RELATED GENETIC VARIANTS WITH CORONARY ARTERY CALCIFICATION 2 3 S. Pechlivanis1 , A. Scherag1 , T.W. Muhleisen ¨ , S. Mohlenkamp ¨ , R. Erbel3 , 1 2 K.-H. Jockel ¨ , M.M. Nothen ¨ , S. Moebus1 , Heinz Nixdorf Recall Study Group. 1 Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, Essen, 2 Department of Genomics, Life & Brain Center, University of Bonn, Bonn, 3 West German Heart Center Essen, University Hospital of Essen, Essen, Germany Objective: To examine the association between diabetes-mellitus (DM)-related single nucleotide polymorphisms (SNPs) and coronary artery calcification (CAC), a valid risk factor for coronary heart disease, in a large population-based cohort. Methods: A custom iSELECT array containing >195,000 SNPs, the CardioMetabochip, has been designed to support large-scale follow-up of putative genetic associations for DM, cardiovascular and other metabolic traits. We selected 59 DM-related SNPs identified through recent large-scale genomewide association analyses for DM (p < 10-4 ) and analysed these 59 SNP in 4,459 participants (992 cases with DM) of the Heinz Nixdorf Recall Study. We applied generalized linear regression models to explore the impact of the diabetes SNPs on CAC. Results: As shown previously (1), the strongest association was observed for the cyclin-dependent kinase inhibitor 2A/2B (CDKN2A/2B) variant rs564398 and quantitative CAC (pnominal =2.26x10-6 ). Fine mapping of this region showed that several other SNPs are strongly associated with CAC (pnominal <10-7 ). We also observed association signals for SNPs located near the Kruppel-like factor 14 (KLF14) on chromosome 7q32.3 and the HLA region on chromosome 6p21.3 with CAC (both pnominal < 0.02). Conclusion: Our study shows that some of the well known diabetes-related genetic variants are associated with CAC even after correcting for diabetes status given that diabetes is associated with CAC. Reference(s) [1] Pechlivanis, S, Scherag, A, Muhleisen, TW, Mohlenkamp, S, Horsthemke, B, Boes, T, Brocker-Preuss, M, Mann, K, Erbel, R, Jockel, KH, Nothen, MM, Moebus, S: Coronary artery calcification and its relationship to validated genetic variants for diabetes mellitus assessed in the Heinz Nixdorf recall cohort. Arterioscler Thromb Vasc Biol 30: 1867–1872, 2010. 610 ACTIVATED LEUKOCYTE CELL ADHESION MOLECULE (ALCAM) AND PROGNOSIS IN ACUTE ISCHEMIC STROKE L.M. Smedbakken1 , J.K. Jensen2 , J. Hallen ´ 3 , D. Atar3 , J.L. Januzzi4 , B. Halvorsen1 , P. Aukrust1,5,6 , T. Ueland1,7 . 1 Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway, 2 Department of Cardiology, Odense University Hospital, Odense, Denmark, 3 Division of Cardiology, Oslo University Hospital, Aker, Oslo, Norway, 4 Cardiology Division, Massachusetts General Hospital, Boston, MA, USA, 5 Section for Clinical Immunology and Infectious Diseases, Oslo University Hospital, Rikshospitalet, 6 Faculty of Medicine, University of Oslo, 7 Section for Specialized Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway Background and Purpose: Biomarkers predicting mortality and functional outcome in stroke would be clinically helpful in identification of patients likely to benefit from intervention. Activated leukocyte cell adhesion molecule (ALCAM) is up-regulated during neuroinflammation and we investigated whether ALCAM
Atherosclerosis Supplements 12, no. 1 (2011) 13–184
606 ABC TRANSPORTER GENES AND RISK OF TYPE 2 DIABETES J. Schou1 , A. Tybjærg-Hansen1,2,3 , B.G. Nordestgaard2,3,4 , R. FrikkeSchmidt1,3 . 1 Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, 2 The Copenhagen City Heart Study, Bispebjerg Hospital, Copenhagen University Hospital, 3 The Copenhagen General Population Study, 4 Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Copenhagen, Denmark Background: ATP-Binding Cassette transporters A1 and G1 (ABCA1 and ABCG1) facilitate efflux of cholesterol from peripheral cells to apolipoprotein A1 and HDL particles, respectively. Decreased efflux of cholesterol in pancreatic beta cells is suggested to impair glucose tolerance in humans and mice, whereas the association with type 2 diabetes is unknown. We tested whether genetic variation in the promoter and coding regions of ABCA1 and ABCG1 predicted risk of type 2 diabetes in the general population. Methods: We resequenced the core promoter and coding region of ABCA1 and ABCG1 in 380 individuals from the Copenhagen City Heart Study (CCHS) with extreme levels of HDL-cholesterol. Twenty eight promoter or coding variants were identified and subsequently genotyped in the CCHS (n = 10,243), and two loss-of-function mutations (N1800H in ABCA1 and −376C>T in ABCG1) were further genotyped in the Copenhagen General Population Study (CGPS, n = 31,072). Results: None of the variants genotyped affected measures of glucose metabolism (blood glucose, hemoglobinA1C), except for two ABCG1 variants that associated with slight increases in hemoglobinA1C (−686G>A, P = 0.02; G327, P = 0.0002). None of the 28 genetic variants predicted increased risk of type 2 diabetes in the CCHS. The two loss-of-function mutations also did not associate with type 2 diabetes in the CGPS (N1800H, P = 0.51; −376C>T, P = 0.72). Conclusion: Genetic variation in ABCA1 and ABCG1 is not associated with increased risk of type 2 diabetes in the general population. These data were obtained in general population samples harboring the largest number (n = 325) of heterozygous carriers of loss-of-function mutations in ABCA1 and ABCG1. 607 APOLIPOPROTEIN E GENE MUTATIONS IN SUBJECTS WITH MIXED HYPERLIPOPROTEINEMIA AND A CLINICAL DIAGNOSIS OF FAMILIAL COMBINED HYPERLIPIDEMIA ´ 2 , A.M. Bea1 , M. Cofan ´ 3 , N. Plana4 , M. Solanas-Barca1 , I. de Castro-Oros ´ E. Ros3 , L. Masana4 , M. Pocov´ı2 , F. Civeira1 , A. Cenarro1 . 1 Instituto Aragones de Ciencias de la Salud, Zaragoza, 2 Universidad de Zaragoza, Zararagoza, 3 4 Hospital Cl´ınic de Barcelona, Barcelona, Hospital Universitari de Sant Joan, Reus, Spain Introduction: Familial combined hyperlipidemia (FCH) is characterized by elevated levels of total cholesterol and triglycerides, vertical transmission of a variable hyperlipidemic phenotype, and high risk of premature cardiovascular disease. FCH is the most common cause of primary mixed hyperlipoproteinemia. An APOE e2/e2 genotype in the presence of mixed hyperlipoproteinemia is diagnostic of familial dysbetalipoproteinemia. However, rare dominant mutations in APOE, which go undetected with the usual genotyping procedure, may also cause dysbetalipoproteinemia. Uncovering such rare APOE variants may change the diagnosis from FCH to dysbetalipoproteinemia. Objectives: To identify APOE mutations associated with dominant mixed hyperlipoproteinemia and to establish their frequency in subjects with a clinical diagnosis of FCH. Methods: We examined 445 unrelated subjects with dominant mixed hyperlipoproteinemia and a clinical diagnosis of FCH and 287 unrelated normolipidemic subjects (control group). Clinical and analytical determinations were done in all of them. DNA was obtained from each subject, and the APOE gene (4 exons and intron-flanking sequences) was sequenced. Results: In addition to common APOE genotypes, two rare functional APOE variants, R136S and DL149, were identified. In the mixed hyperlipoproteinemia group, 9 subjects (2.0%) were carriers of the R136S mutation and 5 subjects (1.1%) were carriers of the DL149 mutation. In the control group, no rare APOE mutations were identified. Conclusion: Rare mutations in the APOE gene, R136S and DL149, were identified in subjects with mixed hyperlipoproteinemia and a clinical diagnosis of FCH, indicating that the APOE gene contributes to this phenotype. 608 HYPOALPHA-HYPOBETALIPOPROTEINEMIA (FAMILIAL COMBINED HYPOLIPIDEMIA) CAUSED BY LOSS OF FUNCTION MUTATIONS OF ANGPTL3 GENE L. Pisciotta1 , E. Di Leo2 , P. Tarugi2 , R. Fresa1 , I. Zavaroni3 , D. Ardigo` 3 , S. Bertolini1 , S. Calandra2 . 1 Department of Internal Medicine, University of Genoa, Genoa, 2 Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, 3 Department of Internal Medicine, University of Parma, Parma, Italy Angiopoietin-like protein 3 (ANGPTL3) is a protein secreted by the liver affecting lipoprotein metabolism. Inactivation of Angptl3 in mice is
Poster presentations
associated with hypotriglyceridemia, while overproduction of Angptl3 causes hypertriglyceridemia. Recently, nonsense mutations in ANGPTL3 gene were found in four siblings with low plasma LDL-C and HDL-C. These lipoprotein changes are due ANGPTL3-mediated inhibition of lipoprotein lipase (LPL) and endothelial lipase (EL). Aim of our study was the analysis of ANGPTL3 gene in a series of subjects with low HDL-C (<5th percentile) associated with hypocholesterolemia and hypotriglyceridemia. In this survey we identified two kindred with loss of function (LOF) ANGTPL3 mutations. Proband D.V. was a 65 year-old female with the following plasma lipid profile: TC 1.87, LDL-C 1.09, HDL-C 0.61, TG 0.37 mmol/L, Apo A-I 58, Apo B 50 mg/dl. She had no clinical features of atherosclerosis. She was homozygous for an intronic mutation (c.1198 +1 g>t), which abolishes the donor splice site of intron 6. Proband’s offspring, heterozygous for the mutation, had a normal lipid profile. Probands M.R. and M.M. were two 59 and 53 year-old brothers, free of cardiovascular diseases, with the following lipid profile: TC 1.88 and 1.91, LDL-C 1.06 and 1.14, HDL-C 0.67 and 0.62, TG 0.35 and 0.33 mmol/L, respectively. They were compound heterozygous for two ANGPTL3 frame-shift mutations: c.55 del A (p.I19L>fs>X40) and c.439–442 del AACT (p.N147X). These observations suggest that individuals with primary hypoalphalipoproteinemia associated with low levels of LDL-C may be homozygous or compound heterozygous for LOF mutations of ANGPTL3. 609 ASSOCIATION OF DIABETES-MELLITUS-RELATED GENETIC VARIANTS WITH CORONARY ARTERY CALCIFICATION 2 3 S. Pechlivanis1 , A. Scherag1 , T.W. Muhleisen ¨ , S. Mohlenkamp ¨ , R. Erbel3 , 1 2 K.-H. Jockel ¨ , M.M. Nothen ¨ , S. Moebus1 , Heinz Nixdorf Recall Study Group. 1 Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, Essen, 2 Department of Genomics, Life & Brain Center, University of Bonn, Bonn, 3 West German Heart Center Essen, University Hospital of Essen, Essen, Germany Objective: To examine the association between diabetes-mellitus (DM)-related single nucleotide polymorphisms (SNPs) and coronary artery calcification (CAC), a valid risk factor for coronary heart disease, in a large population-based cohort. Methods: A custom iSELECT array containing >195,000 SNPs, the CardioMetabochip, has been designed to support large-scale follow-up of putative genetic associations for DM, cardiovascular and other metabolic traits. We selected 59 DM-related SNPs identified through recent large-scale genomewide association analyses for DM (p < 10-4 ) and analysed these 59 SNP in 4,459 participants (992 cases with DM) of the Heinz Nixdorf Recall Study. We applied generalized linear regression models to explore the impact of the diabetes SNPs on CAC. Results: As shown previously (1), the strongest association was observed for the cyclin-dependent kinase inhibitor 2A/2B (CDKN2A/2B) variant rs564398 and quantitative CAC (pnominal =2.26x10-6 ). Fine mapping of this region showed that several other SNPs are strongly associated with CAC (pnominal <10-7 ). We also observed association signals for SNPs located near the Kruppel-like factor 14 (KLF14) on chromosome 7q32.3 and the HLA region on chromosome 6p21.3 with CAC (both pnominal < 0.02). Conclusion: Our study shows that some of the well known diabetes-related genetic variants are associated with CAC even after correcting for diabetes status given that diabetes is associated with CAC. Reference(s) [1] Pechlivanis, S, Scherag, A, Muhleisen, TW, Mohlenkamp, S, Horsthemke, B, Boes, T, Brocker-Preuss, M, Mann, K, Erbel, R, Jockel, KH, Nothen, MM, Moebus, S: Coronary artery calcification and its relationship to validated genetic variants for diabetes mellitus assessed in the Heinz Nixdorf recall cohort. Arterioscler Thromb Vasc Biol 30: 1867–1872, 2010. 610 ACTIVATED LEUKOCYTE CELL ADHESION MOLECULE (ALCAM) AND PROGNOSIS IN ACUTE ISCHEMIC STROKE L.M. Smedbakken1 , J.K. Jensen2 , J. Hallen ´ 3 , D. Atar3 , J.L. Januzzi4 , B. Halvorsen1 , P. Aukrust1,5,6 , T. Ueland1,7 . 1 Research Institute for Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway, 2 Department of Cardiology, Odense University Hospital, Odense, Denmark, 3 Division of Cardiology, Oslo University Hospital, Aker, Oslo, Norway, 4 Cardiology Division, Massachusetts General Hospital, Boston, MA, USA, 5 Section for Clinical Immunology and Infectious Diseases, Oslo University Hospital, Rikshospitalet, 6 Faculty of Medicine, University of Oslo, 7 Section for Specialized Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway Background and Purpose: Biomarkers predicting mortality and functional outcome in stroke would be clinically helpful in identification of patients likely to benefit from intervention. Activated leukocyte cell adhesion molecule (ALCAM) is up-regulated during neuroinflammation and we investigated whether ALCAM