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Lipoprotein lipase gene mutations D9N and N291S in familial combined hyperlipidemia
Oral session abstracts /Atherosclerosis 115 (SuppL) (1995) $ 3 - $ 4 2 013 L P L Gene Mutations
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O13 LPL GENE MUTATIONS 073
075
THE REGRESSION GROWTH EVALUTION STATIN STUDY (REGRESS): TWO FREQUENTLY OCCURING MUTATIONS IN THE LPLGENE AGGRAVATES THE DYSLIPIDEMIA IN CAD-PATIENTS P.W.A. Reymef, B.E. Groenemeyer, E. Gagn& E.E.G. Appelman, K. v/d never, T. Bruin, D. Kromhout, J.C. Seidel, H. Jansen, K.I. Lie, M.R. Hayden, J.J.P. Kastelein ~Department of Vasculair Medicine, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
L I P O P R O T E I N LIPASE G E N E M U T A T I O N S D9N and N291S in FAMILIAL COMBINED HYPERLIPIDEM1A T . W . A . de Bruin, P.Talmud I. H.H.J.J. van Barlingen, F. M a i l l f , R. Fisher ~, M. Castro Cabezas, G. Dallinga-Thie, S. Humphries ~ Dept of Medicine, Utrecht, the Netherlands, and ~Division of Cardiovascular Genetics. London. U.K.
Objective: To elucidate the possible role of mutations in the lipoprotein lipase (LPL) gene on the development of CAD. Methods: Patients with angiographically documented coronary artery disease were screened for mutations in the LPL-gene using the DGGE-technique. The D9N and the N291S mutation were frequently identified. Using mismatch-PCR, 802 CAD-patients (REGRESS-study) and 201 normolipidemic controls were screened for both mutations. In vitro mutagenesis and expression studies were used to determine LPL-activity of both mutants and wildtype LPL. Results: The frequency of the D9N and the N291S substitution was more than two and half times higher in CAD-patients compared to normolipidemic controls (D9N: 38/769= 4.9% vs 3/190= 1.6% p=0.09, N291S: 42/802= 5.2% vs 3/158= 1.9% p=0,09). Lipid values of carriers and non-carriers for both mutations: "= significant different. D9N+ D9N_..~ 1] N29S+ N291St~ Tot.C 6.18-~0.81 6.015:0.87 0.243 6.074-0.86 6.11:t:0.91 0880 LDL 4.43+0.78 4.28::[:0.79 0.298 4365:0.84 437±0 80 0,966 HDL 0.85±0.17 0.93±0.22 0.015' 0.85±0.11 1.00±026 0.001" Tri. 1.96+0.86 1.76±0.76 0.176 1.90±0.43 1.63±072 0.201 In vitro mutagenesis and expression data: The LPL-activity and LPL-mass of the D9N construct were both decreased but the specific activity was normal. The LPL-N291S construct shows a 35-50% reduction of the specific LPL-activity. Conclusion: Our data suggest that both the D9N and the N291S mutation are more frequent in CAD-patients than in controls and aggrevate dyslipidemia in these patients, thereby increasing the risk for premature CAD.
The role of the lipoprotein lipase (LPL) gene in familial combined hyperlipidemia (FCH) is unclear at present. We screened a group of 28 well-defined probands with FCH and 91 population controls on two L P L gene mutations, D9N and N291S. D9N was found in two probands and one normolipidemic control. N291S was found in 4 probands and 4 controls. These L P L gene mutations were therefore not confined to FCH probands but also found in the population. Four F C H families with 24 individuals including two D9N and two N291S probands were studied. In the relatives, D 9 N and N291S were not concordant with (combined) hyperlipidemia or hyperapobetalipoproteinemia. These findings argued against a causal role of these mutations in FCH. Nevertheless. relatives with D 9 N ( n = 7 ) or N 2 9 l S ( n = 6 ) mutations showed increased T G concentrations (2.765:2.50 (SD) mmol/L and 3 . 0 3 + 1.11 mmol/L, respectively) compared to 11 noncarriers (TG 1.90_+0.98 retool/L; P=0.04 and P=0.005, respectively). In N 2 9 l S carriers, a reduction in H D L cholesterol was observed ( 1.03 + 0 . 2 3 nmaol/L) compared to non-carriers (1,20_+0.20 retool/L: P = 0 . 0 2 ) . The effect of N291S on reduction of H D L cholesterol depended on a high body mass index ( > 25.0 k g . m :), but was independent of postheparin plasma L P L activity, that was normal. Thus, when these LPL gene variants occur in (obese) F C H subjects, the interaction results in an atherogenic lipoprotein phenotype.
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INTERACTION OF THE LIPOPROTEIN LIPASE ASN291 -> SER MUTATION WITH BODY MASS INDEX IN DETERMINING ELEVATED PLASMA LIPID CONCENTRATIONS IN HYPERLIPIDAEMIC SUBJECTS. MYOCARDIAL INFARCTION SURVIVORS AND HEALTHY CONTROLS R.M. Fisher*, F. Mailly+, R.E. Peacock*, G. Miller, A. Hamsten, M. Seed, U. Beisiegel, G. Feussner, S.E. Humphries+~ P.J. Talmud* Division of Cardiovascular Genetics, *UCLMS, Rayne Institute, London WCIE6JJ, UK
THE LIPOPROTEIN LIPASE (ASN291~SER) MUTATION IS ASSOCIATED WITH ELEVATED LIPID LEVELS IN FAMILIAL COMBINED HYPERLIPIDEMIA M.J.V. Hoffer ~ S.J.H. Bredie:, D.I. Boomsma 3, P.W.A. Reymer4, J.J,P. Kastelein4, L.A. Sandkuyl 1, A.F.H. Stalenhoef2, L.M, Havekes~, R.R. Frants J I: MGC-Dept. of Human Genetics, Leiden University; 2: Dept. of Medicine, University Hospital Nijmegen; 3: Dept. of Psychophysiology, Free University; 4: Dept. of Vascular Medicine, Academic Medical Centre, Amsterdam; 5: PG-TNO, Ganbius Laboratory, Leiden, The Netherlands
A mutation in the lipoprotein lipase (LPL) gene, resulting in the substitution of an asparagine for a serine at residue 291, was found to occur in young survivors of a myocardial infarction from Sweden, combined hyperlipidaemic subjects from the UK, and type III hyperlipidaemic subjects from Germany at allelic carrier frequencies no different m those found in companion healthy control subjects (2.00 vs 1.56; 3.53 vs 3.37; and 1.85 vs 1.60% respectively). In a group of 620 of the healthy controls from the UK with baseline and 3 subsequent annual lipid measurements, mean plasma triacylglycerol (TG), but not plasma cholesterol concentrations, in carriers of the mutation were significantly elevated over non-carriers (TG: 1.95 vs 1.61mmol/I, P=0.05). When these healthy control subjects were divided according to tertiles of body mass index (BMI), carriers of N291S in the upper two tertiles had elevated concentrations of plasma TG as compared to the non-carriers, an effect similar to that reported previously for another mutation in the LPL gene, D9N. In these healthy men, when carriers of either mutation were combined (i.e. N291S+D9N), plasma TG concentrations of carriers with BMIs in the upper 2 tertiles were significantly higher than non-carriers (P=0.006). In post prandial studies, Swedish carriers of Ser291 had higher plasma TG concentrations (adjusted for fasting TG concentrations) than non-carriers, the difference becoming more pronounced in the late post prandial period. In vitro mutagenesis and expression in COS cells demonstrated that the Asn291 -> Ser mutation resulted in an LPL protein with activity reduced by 30-50% compared to that of the wild type protein, and a decreased stability. Thus the LPL-291S may predispose individuals to elevated plasma TG concentrations under conditions such as increased BM[.
Familial combined hyperlipidemia (FCH) is one of the major genetic causes of coronary heart disease cbaracterised by elevated levels of plasma cholesterol and/or triglycerides in individuals within one family. Since heterozygosity for mutations in the lipopmtein lipase (LPL) gene has been proposed as one of the genetic factors contributing to FCH, we investigated this candidate gene for mutations by DGGE. We found that the LPL(Asn291~Ser) mutation occurs with a high frequency among Dutch combined hyperlipidemic patients. Screening of 17 FCH pmbands revealed three carriers of this mutation. Extensive family studies were subsequently performed using a pedigree-based maximum likelihood estimate to study the effect of this mutation on various quantitative lipid parameters. We could demonstrate that the LPL(Asn291~ser) mutation significantly affects the levels of plasma and very low density lipoprotein (VLDL) triglyeerides, VLDL- and high density lipoprotein (HDL) cholesterol but not those of plasma and low density lipopmtein (LDL) cholesterol. These findings suggest that the LPL(Asp291+Ser) mutation is associated with elevated lipid levels within FCH families indicating that it is one of the genetic factors contributing to FCH.
S21
O13 LPL GENE MUTATIONS 073
075
THE REGRESSION GROWTH EVALUTION STATIN STUDY (REGRESS): TWO FREQUENTLY OCCURING MUTATIONS IN THE LPLGENE AGGRAVATES THE DYSLIPIDEMIA IN CAD-PATIENTS P.W.A. Reymef, B.E. Groenemeyer, E. Gagn& E.E.G. Appelman, K. v/d never, T. Bruin, D. Kromhout, J.C. Seidel, H. Jansen, K.I. Lie, M.R. Hayden, J.J.P. Kastelein ~Department of Vasculair Medicine, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
L I P O P R O T E I N LIPASE G E N E M U T A T I O N S D9N and N291S in FAMILIAL COMBINED HYPERLIPIDEM1A T . W . A . de Bruin, P.Talmud I. H.H.J.J. van Barlingen, F. M a i l l f , R. Fisher ~, M. Castro Cabezas, G. Dallinga-Thie, S. Humphries ~ Dept of Medicine, Utrecht, the Netherlands, and ~Division of Cardiovascular Genetics. London. U.K.
Objective: To elucidate the possible role of mutations in the lipoprotein lipase (LPL) gene on the development of CAD. Methods: Patients with angiographically documented coronary artery disease were screened for mutations in the LPL-gene using the DGGE-technique. The D9N and the N291S mutation were frequently identified. Using mismatch-PCR, 802 CAD-patients (REGRESS-study) and 201 normolipidemic controls were screened for both mutations. In vitro mutagenesis and expression studies were used to determine LPL-activity of both mutants and wildtype LPL. Results: The frequency of the D9N and the N291S substitution was more than two and half times higher in CAD-patients compared to normolipidemic controls (D9N: 38/769= 4.9% vs 3/190= 1.6% p=0.09, N291S: 42/802= 5.2% vs 3/158= 1.9% p=0,09). Lipid values of carriers and non-carriers for both mutations: "= significant different. D9N+ D9N_..~ 1] N29S+ N291St~ Tot.C 6.18-~0.81 6.015:0.87 0.243 6.074-0.86 6.11:t:0.91 0880 LDL 4.43+0.78 4.28::[:0.79 0.298 4365:0.84 437±0 80 0,966 HDL 0.85±0.17 0.93±0.22 0.015' 0.85±0.11 1.00±026 0.001" Tri. 1.96+0.86 1.76±0.76 0.176 1.90±0.43 1.63±072 0.201 In vitro mutagenesis and expression data: The LPL-activity and LPL-mass of the D9N construct were both decreased but the specific activity was normal. The LPL-N291S construct shows a 35-50% reduction of the specific LPL-activity. Conclusion: Our data suggest that both the D9N and the N291S mutation are more frequent in CAD-patients than in controls and aggrevate dyslipidemia in these patients, thereby increasing the risk for premature CAD.
The role of the lipoprotein lipase (LPL) gene in familial combined hyperlipidemia (FCH) is unclear at present. We screened a group of 28 well-defined probands with FCH and 91 population controls on two L P L gene mutations, D9N and N291S. D9N was found in two probands and one normolipidemic control. N291S was found in 4 probands and 4 controls. These L P L gene mutations were therefore not confined to FCH probands but also found in the population. Four F C H families with 24 individuals including two D9N and two N291S probands were studied. In the relatives, D 9 N and N291S were not concordant with (combined) hyperlipidemia or hyperapobetalipoproteinemia. These findings argued against a causal role of these mutations in FCH. Nevertheless. relatives with D 9 N ( n = 7 ) or N 2 9 l S ( n = 6 ) mutations showed increased T G concentrations (2.765:2.50 (SD) mmol/L and 3 . 0 3 + 1.11 mmol/L, respectively) compared to 11 noncarriers (TG 1.90_+0.98 retool/L; P=0.04 and P=0.005, respectively). In N 2 9 l S carriers, a reduction in H D L cholesterol was observed ( 1.03 + 0 . 2 3 nmaol/L) compared to non-carriers (1,20_+0.20 retool/L: P = 0 . 0 2 ) . The effect of N291S on reduction of H D L cholesterol depended on a high body mass index ( > 25.0 k g . m :), but was independent of postheparin plasma L P L activity, that was normal. Thus, when these LPL gene variants occur in (obese) F C H subjects, the interaction results in an atherogenic lipoprotein phenotype.
O74
076
INTERACTION OF THE LIPOPROTEIN LIPASE ASN291 -> SER MUTATION WITH BODY MASS INDEX IN DETERMINING ELEVATED PLASMA LIPID CONCENTRATIONS IN HYPERLIPIDAEMIC SUBJECTS. MYOCARDIAL INFARCTION SURVIVORS AND HEALTHY CONTROLS R.M. Fisher*, F. Mailly+, R.E. Peacock*, G. Miller, A. Hamsten, M. Seed, U. Beisiegel, G. Feussner, S.E. Humphries+~ P.J. Talmud* Division of Cardiovascular Genetics, *UCLMS, Rayne Institute, London WCIE6JJ, UK
THE LIPOPROTEIN LIPASE (ASN291~SER) MUTATION IS ASSOCIATED WITH ELEVATED LIPID LEVELS IN FAMILIAL COMBINED HYPERLIPIDEMIA M.J.V. Hoffer ~ S.J.H. Bredie:, D.I. Boomsma 3, P.W.A. Reymer4, J.J,P. Kastelein4, L.A. Sandkuyl 1, A.F.H. Stalenhoef2, L.M, Havekes~, R.R. Frants J I: MGC-Dept. of Human Genetics, Leiden University; 2: Dept. of Medicine, University Hospital Nijmegen; 3: Dept. of Psychophysiology, Free University; 4: Dept. of Vascular Medicine, Academic Medical Centre, Amsterdam; 5: PG-TNO, Ganbius Laboratory, Leiden, The Netherlands
A mutation in the lipoprotein lipase (LPL) gene, resulting in the substitution of an asparagine for a serine at residue 291, was found to occur in young survivors of a myocardial infarction from Sweden, combined hyperlipidaemic subjects from the UK, and type III hyperlipidaemic subjects from Germany at allelic carrier frequencies no different m those found in companion healthy control subjects (2.00 vs 1.56; 3.53 vs 3.37; and 1.85 vs 1.60% respectively). In a group of 620 of the healthy controls from the UK with baseline and 3 subsequent annual lipid measurements, mean plasma triacylglycerol (TG), but not plasma cholesterol concentrations, in carriers of the mutation were significantly elevated over non-carriers (TG: 1.95 vs 1.61mmol/I, P=0.05). When these healthy control subjects were divided according to tertiles of body mass index (BMI), carriers of N291S in the upper two tertiles had elevated concentrations of plasma TG as compared to the non-carriers, an effect similar to that reported previously for another mutation in the LPL gene, D9N. In these healthy men, when carriers of either mutation were combined (i.e. N291S+D9N), plasma TG concentrations of carriers with BMIs in the upper 2 tertiles were significantly higher than non-carriers (P=0.006). In post prandial studies, Swedish carriers of Ser291 had higher plasma TG concentrations (adjusted for fasting TG concentrations) than non-carriers, the difference becoming more pronounced in the late post prandial period. In vitro mutagenesis and expression in COS cells demonstrated that the Asn291 -> Ser mutation resulted in an LPL protein with activity reduced by 30-50% compared to that of the wild type protein, and a decreased stability. Thus the LPL-291S may predispose individuals to elevated plasma TG concentrations under conditions such as increased BM[.
Familial combined hyperlipidemia (FCH) is one of the major genetic causes of coronary heart disease cbaracterised by elevated levels of plasma cholesterol and/or triglycerides in individuals within one family. Since heterozygosity for mutations in the lipopmtein lipase (LPL) gene has been proposed as one of the genetic factors contributing to FCH, we investigated this candidate gene for mutations by DGGE. We found that the LPL(Asn291~Ser) mutation occurs with a high frequency among Dutch combined hyperlipidemic patients. Screening of 17 FCH pmbands revealed three carriers of this mutation. Extensive family studies were subsequently performed using a pedigree-based maximum likelihood estimate to study the effect of this mutation on various quantitative lipid parameters. We could demonstrate that the LPL(Asn291~ser) mutation significantly affects the levels of plasma and very low density lipoprotein (VLDL) triglyeerides, VLDL- and high density lipoprotein (HDL) cholesterol but not those of plasma and low density lipopmtein (LDL) cholesterol. These findings suggest that the LPL(Asp291+Ser) mutation is associated with elevated lipid levels within FCH families indicating that it is one of the genetic factors contributing to FCH.