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A case of severe chylomicronaemia syndrome, in a patient with normal lipoprotein lipase activity, due to a previously unidentified mutation in the GPIHBP1 gene
e72
Abstracts / Atherosclerosis 252 (2016) e1ee196
adverse cardiovascular events, with the prevalence in a population of hypertensive adults. Methods: We studied 179 patients: 69 hospitalized very elderly (mean age: 88.5±5.5 years) admitted to our Internal Medicine and Geriatrics Department, and 110 hypertensive adults (mean age: 53.3±7.3 years) referred to our Hypertension Centre, affected by essential hypertension with or without other CV risk factors (gender, smoking, diabetes, dyslipidemia). Results: There was no significant difference in the prevalence of carotid plaque between the two populations (51.8% in the hypertensive adults vs. 58.0% in the very elderly). In the hypertensive adults, smoking was the main CV risk factor associated with the prevalence of carotid plaque (OR 2.41; p¼0.024), whereas in the very elderly the presence of hypertension had the strongest association (OR ¼ 10.5; p<0.001). Indeed, excluding the hypertensives among the very elderly, the prevalence of carotid plaque resulted significantly higher in the younger (51.8% vs. 27.6%; p¼0.020). Conclusions: Our results show that CV risk factors, especially hypertension, play a key role in atherosclerosis, not only in the adult population, but also in the very elderly. Ageing is not necessarily synonymous of atherosclerosis but the real determinants of arterial ‘‘bad aging’’ are the superimposed CV risk factors. Prevention and treatment of CV risk factors is probably the only way to obtain a healthy longevity.
EAS16-0445, GENETICS, NUTRITION, BIOMARKERS: BIOMARKERS. BIOMARKER DISCOVERY BY PLASMA PROTEOMICS IN FAMILIAL LMNA DILATED CARDIOMYOPATHY I. Izquierdo 1, D. De Gonzalo-Calvo 2, V. Llorente-Cortes 2, I. Rosa 1, R. Brugada 3, C. Oscar 3, A. Perez-Serra 3, J. Broncano 4, A. Luna 4, J. VazquezAlfageme 5, J.R. Gonzalez-Juanatey 6, A. Mangas 7, A. Garcia 1, R. Toro 7. 1 Center for Research in Molecular Medicine and Chronic Diseases CIMUS- Universidad de de Santiago de Compostela- Instituto de n Sanitaria de Santiago de Compostela IDIS, Molecular Investigacio Medicine and Chronic Diseases, Santiago de Compostela, Spain; 2 Cardiovascular Research Center- CSIC-ICCC-IIB-Sant Pau, Lipid and Cardiovascular Pathology Department, Barcelona, Spain; 3 Centro de Gen etica Cardiovascular- IDIBGI- Universidad de Girona, Genetic Department, Girona, Spain; 4 Clinica Las Nieves- SERCOSA. Health Time rdoba, Spain; 5 Clinica DADISA. Group, Cardiovascular Department, Co diz, Spain; 6 Hospital Health Time Group, Cardiovascular Department, Ca Clinico Universitario, Cardiology Department, Santiago de Compostela, Spain; 7 School of Medicine. Cadiz University, Medicine Department, CADIZ, Spain Objectives: Dilated cardiomyopathy (DCM) is a cardiac pathology characterized by left ventricular or biventricular dilatation. The familial form of DCM occurs in about 20%e50% of all cases. One of the genes involved is Lamin A / C (LMNA). This LMNA cardiomyopathy progress to intractable heart failure, leading to death or heart transplant in one-third of cases, whereas in as many as two-thirds, the fatal event is a life-threatening arrythmia. The aim of this study was to improve the tools for early diagnosis and risk assessment of this DCM. Methods: We have analyzed proteome changes from LMNA mutation symptomatic carriers with sudden death familial background and healthy donors. We described p.E291K_LMNA is a novel pathogenic mutation. The four most symptomatic carriers and four healthy controls matched by age and sex were selected for plasma proteomic study. Proteomic analysis was based on 2D-DIGE and mass spectrometry. Results: From the total of 111 proteins detected, 83 were identified by mass spectrometry, corresponding to 41 ORFs (Open Reading Frames) or unique proteins. High presence of actin -present in extracellular vesiclesand proteins that negatively regulate the coagulation process were observed in the patient group.Some of the most interesting proteins were validated by Western blotting (Actin, Alpha-1-antitrypsin, Clusterin and Vitamin D-binding protein) and turbidimetric techniques (antithrombinIII), confirming the proteomic results Conclusions: These proteins are potential biomarkers predictive of an episode of sudden death associated with a LMNA gene mutation and are
currently being validated in samples from all members of the affected family.
EAS16-0110, GENETICS, NUTRITION, BIOMARKERS: BIOMARKERS. BLOOD PRESSURE FLUCTUATIONS AS A LEADING LINK IN THE DEVELOPMENT OF COMPLICATIONS OF ATHEROSCLEROSIS A. Kebryakov, P. Bondarenko, M. Ermina, M. Ivanov, N. Koplyarova, A. Yadernaya, A. Mishchenko. North-Western State Medical University named after I.I. Mechnikov, general surgery, St. Petersburg-, Russia Objectives: Changes in hemodynamic parameters traditionally considered as the cause of endothelial disorders. The purpose of this study was to evaluate the relationship between fluctuations in blood pressure and the effects of reconstructive surgery on the main arteries in patients with advanced atherosclerosis. Methods: Study is based on an observation of the 58 patients who underwent reconstructive operations on major arteries. Among them, 30 people were required to perform drug correction of hemodynamic parameters (study group) and 28 patients who did not require this (control group). In examined patients were analyzed lipid spectrum of the blood, characteristics of carbohydrate metabolism, body weight and waist circumference, blood pressure variability index (arithmetic mean between the maximum and minimum values for 10 hours of observation), and the results of surgical interventions (adverse cardiovascular events). Results: The combination of diabetes with the experience of illness more than 3 years and the atherosclerotic process has negatively affected the development of hypertension with a tendency to thrombotic complications (p <0,05). The analysis of gender peculiarities showed a more variable hemodynamics in females in 1 day of post-operative period with a tendency to arterial hypertension (p <0,05). Among the predictors of significant variability in blood pressure must be identified myocardial infarction (p ¼ 0,05). Conclusions: Hemodynamic instability, suggesting the occurrence of arterial and venous thrombosis, has negative impact on the features of the postoperative period in patients with multifocal atherosclerosis.
EAS16-0346, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. A CASE OF SEVERE CHYLOMICRONAEMIA SYNDROME, IN A PATIENT WITH NORMAL LIPOPROTEIN LIPASE ACTIVITY, DUE TO A PREVIOUSLY UNIDENTIFIED MUTATION IN THE GPIHBP1 GENE P. Downie, G. Bayly. University Hospitals of Bristol NHS Foundation Trust, Department of Clinical BIochemistry, Bristol, United Kingdom Objectives: We present the case of a 28yr old female diagnosed with chylomicronaemia syndrome in infancy presumed secondary to lipoprotein lipase (LPL) deficiency. Methods: Since the age of 18, the patient had five admissions with confirmed acute pancreatitis. Despite maximally tolerated dietary and lipid lowering management, triglyceride concentrations ranged from 6 e49mmol/L (530-4300mg/dL). Formal measurement of LPL activity was performed. Results: Results: Lipoprotein lipase activity, 3.0umol FA/ml/h (2.0 e 12.0); Apolipoprotein C2 ¼ 28.9 mg/dL (1.0-12.0). Typical values for LPL activity in LPL deficiency are <0.2umol FA/ml/h, i.e. our patient demonstrated normal LPL activity. The increased ApoC2 concentration is consistent with previously published data. Once daily subcutaneous insulin was added in the hope this would augment LPL activity. Subsequent mutational analysis for alterations in genes regulating the metabolism of triglyceride rich lipoproteins (TRLs), identified our patient as homozygous for a previously unidentified mutation in the GPIHBP1 gene, c.132C>T (Q132X). This mutation causes truncation of the protein with bio-informatic analysis strongly supporting the pathogenicity of this alteration.
Abstracts / Atherosclerosis 252 (2016) e1ee196
Conclusions: LPL, synthesised primarily by adipocytes, skeletal muscle and cardiomyocytes, cleaves circulating triglycerides on capillary endothelial surfaces with resultant release of fatty acids. GPIHBP1 functions as a platform for lipolysis of triglycerides by binding LPL in the capillary subendothelial spaces as well as translocating the enzyme to the luminal surface of endothelial cells. In patients with chylomicronaemia syndrome, formal assessment of LPL activity should be performed. Where LPL activity is normal, this should prompt a search for rare variants that disrupt the lipolytic processing of TRLs in other ways.
EAS16-0567, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. MOLECULAR ANALYSIS OF GENES INVOLVED IN LIPOPROTEIN LIPASE DEFICIENCY IN SLOVAK PATIENTS WITH FAMILIAL CHYLOMICRONEMIA D. Gabcova 1, D. Stanikova 1,2, M. Huckova 1, V. Bzduch 2, J. Stanik 1, 2, I. Klimes 1, K. Raslova 3, D. Gasperikova 1. 1 Biomedical Center- Institute of Experimental Endocrinology - Slovak Academy of Sciences, Diabgene and Laboratory of Diabetes and Metabolic Disorders, Bratislava, Slovakia; 2 School of Medicine- Comenius University, First Department of Pediatrics, Bratislava, Slovakia; 3 Slovak Medical University, National Reference Center for Familial Hyperlipoproteinemias, Bratislava, Slovakia Objectives: Familial chylomicronemia is rare autosomal recessive disease with prevalence of 1:1 000 000 caused by homozygous or compound heterozygous mutations in genes LPL, APOC2, APOA5, LMF1 and GPIHBP1. Impaired function of lipoprotein lipase (LPL) leads to a defect in triglyceride hydrolysis, resulting in severe hypertriglyceridemia, hepatosplenomegaly and acute pancreatitis. Based on the Slovak population of 5.4 million inhabitants, we assume the existence of five patients with the disease. The aim of the study was to analyze the LPL gene in 9 patients with high levels of triglycerides (>16 mmol/l) and thereby confirm the diagnosis of LPL deficiency. Methods: DNA analysis consisted of direct sequencing of promoter and 10 coding exons of LPL gene including exon-intron boundaries. Results: We have identified mutations or unknown variants in LPL gene in five out of nine patients. Two patients were homozygous for known mutations (p.Trp113Arg and p.Gly215Glu). In three patients a known mutation in combination with new variant was identified in compound heterozygous form (p.Gly215Glu/p.Asn281*, p.Gly215Glu/p.Tyr233Ser and p.Arg197His/p.Gly215Ala). At least two of three in silico programs (SIFT, Polyphen2 and MutationTaster) predicted potential pathogenicity of all novel variants. In one patient only one heterozygous variant p.Glu283* was identified. Conclusions: The diagnosis of LPL deficiency was herewith confirmed in 5 patients. In one patient the DNA analysis revealed only one heterozygous mutation in LPL gene, therefore the other genes involved in the disorder need to be analysed. By analysing these genes, we expect a higher number of patients with familial chylomicronemia. Supported by: VEGA2/0166/14, Transendogen 26240220051
EAS16-0593, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. DISSECTION OF CLINICAL AND GENE EXPRESSION SIGNATURES OF FAMILIAL VS MULTIFACTORIAL CHYLOMICRONEMIA D. Gaudet, D. Brisson, K. Tremblay. Universit e de Montr eal et ECOGENE-21, Community Genomic Medicine Center- Lipidology Unit- Department of Medicine, Chicoutimi, Canada Objectives: LPL deficiency (LPLD) is a rare recessive disorder associated with chylomicronemia (CM) and increased risk of pancreatitis. The majority of individuals with CM do not have mendelian LPLD but exhibit multifactorial CM (MCM). The aim of this study was to investigate clinical and gene expression profiles of patients with LPLD and MCM. Methods: The study included 62 patients with genetically and functionally proven LPLD and 159 with MCM. Anthropometrics, clinical, biochemical,
e73
oxidation and inflammation markers were analyzed. Gene expression analyses included a subset of 62 subjects divided into three groups: 19 LPLD, 28 MCM and 15 normolipemic controls. Results: Analyses of area under the ROC curve for the diagnosis of LPLD was 0,72 for the BMI, 0.79 for free glycerol and 0.83 for apoB on delipidated fractions. Sensitivity, specificity, positive likelihood (PLR), and negative likelihood (NLR) of LPLD using the trio cutoffs of fasting plasma free glycerol <0.05 mmol/l, apoB <0,7g/l and BMI <25 showed a specificity of 93.4 (92.2-96.4), a sensitivity of 76.7 (64.5-90.8), a PLR 12.7 (8.6-18.8) and a NLR 0.3 (0.2-0.6). Age at CM diagnosis, lipid-lowering drug response and oxidation markers were also discriminant. A total of 142 probes were differentially expressed in LPLD and 32 in MCM compare to controls. Among them, 13 are shared between LPLD and MCM; 61 are specific to LPLD and 2 to MCM. Most of the LPLD annotated genes are involved in inflammatory, immune, circadian, postprandial metabolism, signalling, docking systems or receptor-mediated clearance mechanisms. Conclusions: These results reveal differential signatures of LPLD and MCM.
EAS16-0284, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. A NOVEL HOMOZYGOUS MUTATION IN GPD1 LEADING TO SEVERE HYPERTRIGLYCERIDEMIA ~ a-Aguilar 2, J. Peter 1, G.M. Dallinga-Thie 1. 1 Academic J. Levels 1, R. Pin Medical Center, Experimental Vascular Medicine, Amsterdam, Netherlands; 2 Centro M edico Nacional, Medical Genetics Division, San Lorenzo, Mexico Objectives: Severe hypertriglyceridemia (HTG) is a rare recessive disorder which in 50 % of the HTG patients is caused by loss-of-function mutations in LPL, APOC2, and GPIHBP1 and severely affects patient’s live-quality and live-expectancy. GWAS analysis for plasma triglycerides reveals associations with common variants genes which may explain part of the underlying pathobiology. Glycerol-3-phosphate dehydrogenase 1 (GPD1) is involved in hepatic glycerol metabolism and may potentially lead to the HTG phenotype. Here we describe a novel mutation in GPD1 in two siblings from a small Mexican family diagnosed with HTG. Methods: Standard plasma lipid biochemistry, liver ultrasound and liver biopsies were carried out in both mutation carrier siblings. From the parents only the plasma lipid biochemistry was performed. Genomic DNA was isolated from blood leucocytes and all 8 exons of GPD1 were subsequently sequenced. Results: Both siblings were diagnosed with elevated liver enzymes and hepatomegaly. Liver biopsies revealed in Sibling 1 the diagnosis NASH but not in Sibling 2. Plasma TG in the sibs were 971 and 663 mg/dl resp. Sequencing analysis of GPD1 revealed a homozygous spice site variant c.220-1G>A in both siblings, whereas both parents showed heterozygosity, which is consistent with the recessive mode of inheritance. This variant was also found in the Latino population with a frequency of 1/11544 in the ExaAC database and 1/76 in the Mexican exomes of Sigma subset study. Conclusions: Our data reveal GPD1 as a novel gene involved in hepatic triglyceride homeostasis.
EAS16-0712, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. IDENTIFICATION AND CHARACTERIZATION OF TWO NOVEL MUTATIONS IN THE LPL GENE CAUSING TYPE I HYPERLIPOPROTEINEMIA P. Pingitore 1, S.M. Lepore 2, C. Pirazzi 1, R.M. Mancina 1, B.M. Motta 1, L. Valenti 3, K.E. Berge 4, K. Retterstøl 5, T.P. Leren 4, O. Wiklund 1, S. Romeo 1. 1 University of Gothenburg, Department of Molecular and Clinical €teborg, Sweden; 2 Clinical Nutrition Unit- Magna Graecia Medicine, Go University- Catanzaro- Italy, Department of Medical and Surgical Sciences, Catanzaro, Italy; 3 Fondazione IRCCS Ca’ Granda Ospedale Policlinico Milano- Milan- Italy, Internal Medicine, Milan, Italy; 4 Unit for Cardiac and Cardiovascular Genetics- Oslo University Hospital Ullevaal- Oslo- Norway, Department of Medical Genetics-, Oslo, Norway; 5 Institute for Basic
Abstracts / Atherosclerosis 252 (2016) e1ee196
adverse cardiovascular events, with the prevalence in a population of hypertensive adults. Methods: We studied 179 patients: 69 hospitalized very elderly (mean age: 88.5±5.5 years) admitted to our Internal Medicine and Geriatrics Department, and 110 hypertensive adults (mean age: 53.3±7.3 years) referred to our Hypertension Centre, affected by essential hypertension with or without other CV risk factors (gender, smoking, diabetes, dyslipidemia). Results: There was no significant difference in the prevalence of carotid plaque between the two populations (51.8% in the hypertensive adults vs. 58.0% in the very elderly). In the hypertensive adults, smoking was the main CV risk factor associated with the prevalence of carotid plaque (OR 2.41; p¼0.024), whereas in the very elderly the presence of hypertension had the strongest association (OR ¼ 10.5; p<0.001). Indeed, excluding the hypertensives among the very elderly, the prevalence of carotid plaque resulted significantly higher in the younger (51.8% vs. 27.6%; p¼0.020). Conclusions: Our results show that CV risk factors, especially hypertension, play a key role in atherosclerosis, not only in the adult population, but also in the very elderly. Ageing is not necessarily synonymous of atherosclerosis but the real determinants of arterial ‘‘bad aging’’ are the superimposed CV risk factors. Prevention and treatment of CV risk factors is probably the only way to obtain a healthy longevity.
EAS16-0445, GENETICS, NUTRITION, BIOMARKERS: BIOMARKERS. BIOMARKER DISCOVERY BY PLASMA PROTEOMICS IN FAMILIAL LMNA DILATED CARDIOMYOPATHY I. Izquierdo 1, D. De Gonzalo-Calvo 2, V. Llorente-Cortes 2, I. Rosa 1, R. Brugada 3, C. Oscar 3, A. Perez-Serra 3, J. Broncano 4, A. Luna 4, J. VazquezAlfageme 5, J.R. Gonzalez-Juanatey 6, A. Mangas 7, A. Garcia 1, R. Toro 7. 1 Center for Research in Molecular Medicine and Chronic Diseases CIMUS- Universidad de de Santiago de Compostela- Instituto de n Sanitaria de Santiago de Compostela IDIS, Molecular Investigacio Medicine and Chronic Diseases, Santiago de Compostela, Spain; 2 Cardiovascular Research Center- CSIC-ICCC-IIB-Sant Pau, Lipid and Cardiovascular Pathology Department, Barcelona, Spain; 3 Centro de Gen etica Cardiovascular- IDIBGI- Universidad de Girona, Genetic Department, Girona, Spain; 4 Clinica Las Nieves- SERCOSA. Health Time rdoba, Spain; 5 Clinica DADISA. Group, Cardiovascular Department, Co diz, Spain; 6 Hospital Health Time Group, Cardiovascular Department, Ca Clinico Universitario, Cardiology Department, Santiago de Compostela, Spain; 7 School of Medicine. Cadiz University, Medicine Department, CADIZ, Spain Objectives: Dilated cardiomyopathy (DCM) is a cardiac pathology characterized by left ventricular or biventricular dilatation. The familial form of DCM occurs in about 20%e50% of all cases. One of the genes involved is Lamin A / C (LMNA). This LMNA cardiomyopathy progress to intractable heart failure, leading to death or heart transplant in one-third of cases, whereas in as many as two-thirds, the fatal event is a life-threatening arrythmia. The aim of this study was to improve the tools for early diagnosis and risk assessment of this DCM. Methods: We have analyzed proteome changes from LMNA mutation symptomatic carriers with sudden death familial background and healthy donors. We described p.E291K_LMNA is a novel pathogenic mutation. The four most symptomatic carriers and four healthy controls matched by age and sex were selected for plasma proteomic study. Proteomic analysis was based on 2D-DIGE and mass spectrometry. Results: From the total of 111 proteins detected, 83 were identified by mass spectrometry, corresponding to 41 ORFs (Open Reading Frames) or unique proteins. High presence of actin -present in extracellular vesiclesand proteins that negatively regulate the coagulation process were observed in the patient group.Some of the most interesting proteins were validated by Western blotting (Actin, Alpha-1-antitrypsin, Clusterin and Vitamin D-binding protein) and turbidimetric techniques (antithrombinIII), confirming the proteomic results Conclusions: These proteins are potential biomarkers predictive of an episode of sudden death associated with a LMNA gene mutation and are
currently being validated in samples from all members of the affected family.
EAS16-0110, GENETICS, NUTRITION, BIOMARKERS: BIOMARKERS. BLOOD PRESSURE FLUCTUATIONS AS A LEADING LINK IN THE DEVELOPMENT OF COMPLICATIONS OF ATHEROSCLEROSIS A. Kebryakov, P. Bondarenko, M. Ermina, M. Ivanov, N. Koplyarova, A. Yadernaya, A. Mishchenko. North-Western State Medical University named after I.I. Mechnikov, general surgery, St. Petersburg-, Russia Objectives: Changes in hemodynamic parameters traditionally considered as the cause of endothelial disorders. The purpose of this study was to evaluate the relationship between fluctuations in blood pressure and the effects of reconstructive surgery on the main arteries in patients with advanced atherosclerosis. Methods: Study is based on an observation of the 58 patients who underwent reconstructive operations on major arteries. Among them, 30 people were required to perform drug correction of hemodynamic parameters (study group) and 28 patients who did not require this (control group). In examined patients were analyzed lipid spectrum of the blood, characteristics of carbohydrate metabolism, body weight and waist circumference, blood pressure variability index (arithmetic mean between the maximum and minimum values for 10 hours of observation), and the results of surgical interventions (adverse cardiovascular events). Results: The combination of diabetes with the experience of illness more than 3 years and the atherosclerotic process has negatively affected the development of hypertension with a tendency to thrombotic complications (p <0,05). The analysis of gender peculiarities showed a more variable hemodynamics in females in 1 day of post-operative period with a tendency to arterial hypertension (p <0,05). Among the predictors of significant variability in blood pressure must be identified myocardial infarction (p ¼ 0,05). Conclusions: Hemodynamic instability, suggesting the occurrence of arterial and venous thrombosis, has negative impact on the features of the postoperative period in patients with multifocal atherosclerosis.
EAS16-0346, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. A CASE OF SEVERE CHYLOMICRONAEMIA SYNDROME, IN A PATIENT WITH NORMAL LIPOPROTEIN LIPASE ACTIVITY, DUE TO A PREVIOUSLY UNIDENTIFIED MUTATION IN THE GPIHBP1 GENE P. Downie, G. Bayly. University Hospitals of Bristol NHS Foundation Trust, Department of Clinical BIochemistry, Bristol, United Kingdom Objectives: We present the case of a 28yr old female diagnosed with chylomicronaemia syndrome in infancy presumed secondary to lipoprotein lipase (LPL) deficiency. Methods: Since the age of 18, the patient had five admissions with confirmed acute pancreatitis. Despite maximally tolerated dietary and lipid lowering management, triglyceride concentrations ranged from 6 e49mmol/L (530-4300mg/dL). Formal measurement of LPL activity was performed. Results: Results: Lipoprotein lipase activity, 3.0umol FA/ml/h (2.0 e 12.0); Apolipoprotein C2 ¼ 28.9 mg/dL (1.0-12.0). Typical values for LPL activity in LPL deficiency are <0.2umol FA/ml/h, i.e. our patient demonstrated normal LPL activity. The increased ApoC2 concentration is consistent with previously published data. Once daily subcutaneous insulin was added in the hope this would augment LPL activity. Subsequent mutational analysis for alterations in genes regulating the metabolism of triglyceride rich lipoproteins (TRLs), identified our patient as homozygous for a previously unidentified mutation in the GPIHBP1 gene, c.132C>T (Q132X). This mutation causes truncation of the protein with bio-informatic analysis strongly supporting the pathogenicity of this alteration.
Abstracts / Atherosclerosis 252 (2016) e1ee196
Conclusions: LPL, synthesised primarily by adipocytes, skeletal muscle and cardiomyocytes, cleaves circulating triglycerides on capillary endothelial surfaces with resultant release of fatty acids. GPIHBP1 functions as a platform for lipolysis of triglycerides by binding LPL in the capillary subendothelial spaces as well as translocating the enzyme to the luminal surface of endothelial cells. In patients with chylomicronaemia syndrome, formal assessment of LPL activity should be performed. Where LPL activity is normal, this should prompt a search for rare variants that disrupt the lipolytic processing of TRLs in other ways.
EAS16-0567, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. MOLECULAR ANALYSIS OF GENES INVOLVED IN LIPOPROTEIN LIPASE DEFICIENCY IN SLOVAK PATIENTS WITH FAMILIAL CHYLOMICRONEMIA D. Gabcova 1, D. Stanikova 1,2, M. Huckova 1, V. Bzduch 2, J. Stanik 1, 2, I. Klimes 1, K. Raslova 3, D. Gasperikova 1. 1 Biomedical Center- Institute of Experimental Endocrinology - Slovak Academy of Sciences, Diabgene and Laboratory of Diabetes and Metabolic Disorders, Bratislava, Slovakia; 2 School of Medicine- Comenius University, First Department of Pediatrics, Bratislava, Slovakia; 3 Slovak Medical University, National Reference Center for Familial Hyperlipoproteinemias, Bratislava, Slovakia Objectives: Familial chylomicronemia is rare autosomal recessive disease with prevalence of 1:1 000 000 caused by homozygous or compound heterozygous mutations in genes LPL, APOC2, APOA5, LMF1 and GPIHBP1. Impaired function of lipoprotein lipase (LPL) leads to a defect in triglyceride hydrolysis, resulting in severe hypertriglyceridemia, hepatosplenomegaly and acute pancreatitis. Based on the Slovak population of 5.4 million inhabitants, we assume the existence of five patients with the disease. The aim of the study was to analyze the LPL gene in 9 patients with high levels of triglycerides (>16 mmol/l) and thereby confirm the diagnosis of LPL deficiency. Methods: DNA analysis consisted of direct sequencing of promoter and 10 coding exons of LPL gene including exon-intron boundaries. Results: We have identified mutations or unknown variants in LPL gene in five out of nine patients. Two patients were homozygous for known mutations (p.Trp113Arg and p.Gly215Glu). In three patients a known mutation in combination with new variant was identified in compound heterozygous form (p.Gly215Glu/p.Asn281*, p.Gly215Glu/p.Tyr233Ser and p.Arg197His/p.Gly215Ala). At least two of three in silico programs (SIFT, Polyphen2 and MutationTaster) predicted potential pathogenicity of all novel variants. In one patient only one heterozygous variant p.Glu283* was identified. Conclusions: The diagnosis of LPL deficiency was herewith confirmed in 5 patients. In one patient the DNA analysis revealed only one heterozygous mutation in LPL gene, therefore the other genes involved in the disorder need to be analysed. By analysing these genes, we expect a higher number of patients with familial chylomicronemia. Supported by: VEGA2/0166/14, Transendogen 26240220051
EAS16-0593, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. DISSECTION OF CLINICAL AND GENE EXPRESSION SIGNATURES OF FAMILIAL VS MULTIFACTORIAL CHYLOMICRONEMIA D. Gaudet, D. Brisson, K. Tremblay. Universit e de Montr eal et ECOGENE-21, Community Genomic Medicine Center- Lipidology Unit- Department of Medicine, Chicoutimi, Canada Objectives: LPL deficiency (LPLD) is a rare recessive disorder associated with chylomicronemia (CM) and increased risk of pancreatitis. The majority of individuals with CM do not have mendelian LPLD but exhibit multifactorial CM (MCM). The aim of this study was to investigate clinical and gene expression profiles of patients with LPLD and MCM. Methods: The study included 62 patients with genetically and functionally proven LPLD and 159 with MCM. Anthropometrics, clinical, biochemical,
e73
oxidation and inflammation markers were analyzed. Gene expression analyses included a subset of 62 subjects divided into three groups: 19 LPLD, 28 MCM and 15 normolipemic controls. Results: Analyses of area under the ROC curve for the diagnosis of LPLD was 0,72 for the BMI, 0.79 for free glycerol and 0.83 for apoB on delipidated fractions. Sensitivity, specificity, positive likelihood (PLR), and negative likelihood (NLR) of LPLD using the trio cutoffs of fasting plasma free glycerol <0.05 mmol/l, apoB <0,7g/l and BMI <25 showed a specificity of 93.4 (92.2-96.4), a sensitivity of 76.7 (64.5-90.8), a PLR 12.7 (8.6-18.8) and a NLR 0.3 (0.2-0.6). Age at CM diagnosis, lipid-lowering drug response and oxidation markers were also discriminant. A total of 142 probes were differentially expressed in LPLD and 32 in MCM compare to controls. Among them, 13 are shared between LPLD and MCM; 61 are specific to LPLD and 2 to MCM. Most of the LPLD annotated genes are involved in inflammatory, immune, circadian, postprandial metabolism, signalling, docking systems or receptor-mediated clearance mechanisms. Conclusions: These results reveal differential signatures of LPLD and MCM.
EAS16-0284, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. A NOVEL HOMOZYGOUS MUTATION IN GPD1 LEADING TO SEVERE HYPERTRIGLYCERIDEMIA ~ a-Aguilar 2, J. Peter 1, G.M. Dallinga-Thie 1. 1 Academic J. Levels 1, R. Pin Medical Center, Experimental Vascular Medicine, Amsterdam, Netherlands; 2 Centro M edico Nacional, Medical Genetics Division, San Lorenzo, Mexico Objectives: Severe hypertriglyceridemia (HTG) is a rare recessive disorder which in 50 % of the HTG patients is caused by loss-of-function mutations in LPL, APOC2, and GPIHBP1 and severely affects patient’s live-quality and live-expectancy. GWAS analysis for plasma triglycerides reveals associations with common variants genes which may explain part of the underlying pathobiology. Glycerol-3-phosphate dehydrogenase 1 (GPD1) is involved in hepatic glycerol metabolism and may potentially lead to the HTG phenotype. Here we describe a novel mutation in GPD1 in two siblings from a small Mexican family diagnosed with HTG. Methods: Standard plasma lipid biochemistry, liver ultrasound and liver biopsies were carried out in both mutation carrier siblings. From the parents only the plasma lipid biochemistry was performed. Genomic DNA was isolated from blood leucocytes and all 8 exons of GPD1 were subsequently sequenced. Results: Both siblings were diagnosed with elevated liver enzymes and hepatomegaly. Liver biopsies revealed in Sibling 1 the diagnosis NASH but not in Sibling 2. Plasma TG in the sibs were 971 and 663 mg/dl resp. Sequencing analysis of GPD1 revealed a homozygous spice site variant c.220-1G>A in both siblings, whereas both parents showed heterozygosity, which is consistent with the recessive mode of inheritance. This variant was also found in the Latino population with a frequency of 1/11544 in the ExaAC database and 1/76 in the Mexican exomes of Sigma subset study. Conclusions: Our data reveal GPD1 as a novel gene involved in hepatic triglyceride homeostasis.
EAS16-0712, GENETICS, NUTRITION, BIOMARKERS: GENETICS, GENE REGULATION. IDENTIFICATION AND CHARACTERIZATION OF TWO NOVEL MUTATIONS IN THE LPL GENE CAUSING TYPE I HYPERLIPOPROTEINEMIA P. Pingitore 1, S.M. Lepore 2, C. Pirazzi 1, R.M. Mancina 1, B.M. Motta 1, L. Valenti 3, K.E. Berge 4, K. Retterstøl 5, T.P. Leren 4, O. Wiklund 1, S. Romeo 1. 1 University of Gothenburg, Department of Molecular and Clinical €teborg, Sweden; 2 Clinical Nutrition Unit- Magna Graecia Medicine, Go University- Catanzaro- Italy, Department of Medical and Surgical Sciences, Catanzaro, Italy; 3 Fondazione IRCCS Ca’ Granda Ospedale Policlinico Milano- Milan- Italy, Internal Medicine, Milan, Italy; 4 Unit for Cardiac and Cardiovascular Genetics- Oslo University Hospital Ullevaal- Oslo- Norway, Department of Medical Genetics-, Oslo, Norway; 5 Institute for Basic