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Mendes C, Loureiro T, Villela D, Bittencourt MI, Sobreira J, Bermeo D, Gomes M, Alencar D, de Castro LSS, Fock RA, Tinoco ML, Galvão H, Scapulatempo-Neto C, Schiavetti K, Senerchia AA, Gurgel MHC. Germline variant analysis from a cohort of patients with severe hypertriglyceridemia in Brazil. Mol Genet Metab Rep 2024; 40:101100. [PMID: 38933898 PMCID: PMC11201343 DOI: 10.1016/j.ymgmr.2024.101100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
Hypertriglyceridemia (HTG) is a common dyslipidemia associated with an increased risk of cardiovascular disease and pancreatitis. It is well stablished that the severe cases of disease often present with an underlying genetic cause. In this study, we determined the frequency and variation spectrum of genes involved in the triglyceride metabolism in a series of Brazilian patients with severe HTG. A total of 212 patients with very high HTG, defined with fasting triglycerides (TG) ≥ 880 mg/ dL, that underwent a multi-gene panel testing were included in this research. Germline deleterious variants (i.e. Pathogenic/Likely Pathogenic (P/LP) variants) were identified in 28 out of 212 patients, reflecting an overall diagnostic yield of 13% in our cohort. Variants of unknown significance (VUS) were identified in 87 patients, and represent 80% of detected variants in this dataset. We confirm the LPL as the most frequently mutated gene in patients with severe HTG, and we had only one suspected case of familial chylomicronemia syndrome, caused by a homozygous variant in LMF1, in our cohort. Notably, we report 16 distinct and novel variants (P/LP and VUS), each of them representing a single case, not previously reported in any public databases or other studies. Our data expand our knowledge of genetic variation spectrum in patients with severe HTG in the Brazilian population, often underrepresented in public genomic databases, being also a valuable clinical resource for genetic counseling and healthcare programs in the country.
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Affiliation(s)
- Camila Mendes
- Diagnósticos da América S.A., DASA, São Paulo, SP, Brazil
| | | | - Darine Villela
- Diagnósticos da América S.A., DASA, São Paulo, SP, Brazil
| | | | | | - Diana Bermeo
- Diagnósticos da América S.A., DASA, São Paulo, SP, Brazil
| | - Mireille Gomes
- Diagnósticos da América S.A., DASA, São Paulo, SP, Brazil
| | - Dayse Alencar
- Diagnósticos da América S.A., DASA, São Paulo, SP, Brazil
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Bardey F, Rieck L, Spira D, März W, Binner P, Schwab S, Kleber ME, Danyel M, Barkowski R, Bobbert T, Spranger J, Steinhagen-Thiessen E, Demuth I, Kassner U. Clinical characterization and mutation spectrum of patients with hypertriglyceridemia in a German outpatient clinic. J Lipid Res 2024:100589. [PMID: 38969064 DOI: 10.1016/j.jlr.2024.100589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/13/2024] [Accepted: 06/21/2024] [Indexed: 07/07/2024] Open
Abstract
BACKGROUND Severe hypertriglyceridemia (HTG) has predominantly multifactorial causes (MCS). Yet a small subset of patients have the monogenetic form (FCS). It remains a challenge to distinguish patients clinically, since decompensated MCS might mimic FCS´s severity. Aim of the current study was to determine clinical criteria that could sufficiently distinguish both forms as well as to apply the FCS score proposed by Moulin and colleagues. METHODS We retrospectively studied 72 patients who presented with severe HTG in our clinic during a time span of seven years and received genetic testing. We classified genetic variants (ACMG-criteria), followed by genetic categorization into MCS or FCS. Clinical data were gathered from the medical records and the FCS score was calculated for each patient. RESULTS Molecular genetic screening revealed eight FCS patients and 64 MCS patients. Altogether, we found 13 pathogenic variants of which four have not been described before. The FCS patients showed a significantly higher median triglyceride level compared to the MCS. The FCS score yielded a sensitivity of 75% and a specificity of 93.7% in our cohort, and significantly differentiated between the FCS and MCS group (p<0.001). CONCLUSIONS In our cohort we identified several variables that significantly differentiated FCS from MCS. The FCS score performed similar to the original study by Moulin, thereby further validating the discriminatory power of the FCS score in an independent cohort.
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Affiliation(s)
- Frieda Bardey
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Lorenz Rieck
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Dominik Spira
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Winfried März
- Synlab Academy, P5, 7, 68167 Mannheim, Germany; Vth Department of Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbrugger Platz 15, 8036 Graz
| | - Priska Binner
- Synlab Center of Human Genetics, Harrlachweg 1, 68163 Mannheim, Germany
| | - Stefanie Schwab
- Synlab Center of Human Genetics, Harrlachweg 1, 68163 Mannheim, Germany
| | - Marcus E Kleber
- Vth Department of Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; Synlab Center of Human Genetics, Harrlachweg 1, 68163 Mannheim, Germany
| | - Magdalena Danyel
- Berlin Institute of Health (BIH), Berlin, Germany; Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, Berlin, 13353, Germany
| | - Rasmus Barkowski
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Thomas Bobbert
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Joachim Spranger
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Elisabeth Steinhagen-Thiessen
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
| | - Ilja Demuth
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, BCRT - Berlin Institute of Health Center for Regenerative Therapies, Berlin, Germany.
| | - Ursula Kassner
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Endocrinology and Metabolic Diseases (including Division of Lipid Metabolism), Augustenburger Platz 1, 13353 Berlin, Germany
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Xu Y, Shen H, Shi Y, Zhao Y, Zhen X, Sun J, Li X, Zhou D, Yang C, Wang J, Huang X, Wei J, Huang J, Meng H, Yu W, Tong H, Jin J, Xie W. Dyslipidemia in diffuse large B-cell lymphoma based on the genetic subtypes: a single-center study of 259 Chinese patients. Front Oncol 2023; 13:1172623. [PMID: 37384286 PMCID: PMC10299728 DOI: 10.3389/fonc.2023.1172623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/23/2023] [Indexed: 06/30/2023] Open
Abstract
Background Diffuse large B-cell lymphoma (DLBCL) is a kind of highly heterogeneous non-Hodgkin lymphoma, both in clinical and genetic terms. DLBCL is admittedly categorized into six subtypes by genetics, which contain MCD, BN2, EZB, N1, ST2, and A53. Dyslipidemia is relevant to a multitude of solid tumors and has recently been reported to be associated with hematologic malignancies. We aim to present a retrospective study investigating dyslipidemia in DLBCL based on the molecular subtypes. Results This study concluded that 259 patients with newly diagnosed DLBCL and their biopsy specimens were available for molecular typing. Results show that the incidence of dyslipidemia (87.0%, p <0.001) is higher in the EZB subtype than in others, especially hypertriglyceridemia (78.3%, p = 0.001) in the EZB subtype. Based on the pathological gene-sequencing, patients with BCL2 gene fusion mutation are significantly correlative with hyperlipidemia (76.5%, p = 0.006) and hypertriglyceridemia (88.2%, p = 0.002). Nevertheless, the occurrence of dyslipidemia has no remarkable influence on prognosis. Conclusion In summary, dyslipidemia correlates with genetic heterogeneity in DLBCL without having a significant influence on survival. This research first connects lipids and genetic subtypes in DLBCL.
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Abstract
Lipid disorders involving derangements in serum cholesterol, triglycerides, or both are commonly encountered in clinical practice and often have implications for cardiovascular risk and overall health. Recent advances in knowledge, recommendations, and treatment options have necessitated an updated approach to these disorders. Older classification schemes have outlived their usefulness, yielding to an approach based on the primary lipid disturbance identified on a routine lipid panel as a practical starting point. Although monogenic dyslipidemias exist and are important to identify, most individuals with lipid disorders have polygenic predisposition, often in the context of secondary factors such as obesity and type 2 diabetes. With regard to cardiovascular disease, elevated low-density lipoprotein cholesterol is essentially causal, and clinical practice guidelines worldwide have recommended treatment thresholds and targets for this variable. Furthermore, recent studies have established elevated triglycerides as a cardiovascular risk factor, whereas depressed high-density lipoprotein cholesterol now appears less contributory than was previously believed. An updated approach to diagnosis and risk assessment may include measurement of secondary lipid variables such as apolipoprotein B and lipoprotein(a), together with selective use of genetic testing to diagnose rare monogenic dyslipidemias such as familial hypercholesterolemia or familial chylomicronemia syndrome. The ongoing development of new agents-especially antisense RNA and monoclonal antibodies-targeting dyslipidemias will provide additional management options, which in turn motivates discussion on how best to incorporate them into current treatment algorithms.
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Affiliation(s)
- Amanda J Berberich
- Department of Medicine; Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, N6A 5C1.,Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, N6A 5B7
| | - Robert A Hegele
- Department of Medicine; Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, N6A 5C1.,Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada, N6A 5B7
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Abstract
INTRODUCTION Primary chylomicronemia is characterized by pathological accumulation of chylomicrons in the plasma causing severe hypertriglyceridemia, typically >10 mmol/L (>875 mg/dL). Patients with the ultra-rare familial chylomicronemia syndrome (FCS) subtype completely lack lipolytic capacity and respond minimally to traditional triglyceride-lowering therapies. The mainstay of treatment is a low-fat diet, which is difficult to follow and compromises quality of life. New therapies are being developed primarily to prevent episodes of life-threatening acute pancreatitis. AREAS COVERED Antagonists of apolipoprotein (apo) C-III, such as the antisense oligonucleotide (ASO) volanesorsen, significantly reduce triglyceride levels in chylomicronemia. However, approval of and access to volanesorsen are restricted since a substantial proportion of treated FCS patients developed thrombocytopenia. Newer apo C-III antagonists, namely, the ASO olezarsen (formerly AKCEA-APOCIII-LRx) and short interfering RNA (siRNA) ARO-APOC3, appear to show efficacy with less risk of thrombocytopenia. Potential utility of antagonists of angiopoietin-like protein 3 (ANGPTL3) such as evinacumab and the siRNA ARO-ANG3 in subtypes of chylomicronemia remains to be defined. EXPERT OPINION Emerging pharmacologic therapies for chylomicronemia show promise, particularly apo C-III antagonists. However, these treatments are still investigational. Further study of their efficacy and safety in patients with both rare FCS and more common multifactorial chylomicronemia is needed.
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Affiliation(s)
- Isabel Shamsudeen
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert A Hegele
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
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Paragh G, Németh Á, Harangi M, Banach M, Fülöp P. Causes, clinical findings and therapeutic options in chylomicronemia syndrome, a special form of hypertriglyceridemia. Lipids Health Dis 2022; 21:21. [PMID: 35144640 PMCID: PMC8832680 DOI: 10.1186/s12944-022-01631-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/30/2022] [Indexed: 02/07/2023] Open
Abstract
The prevalence of hypertriglyceridemia has been increasing worldwide. Attention is drawn to the fact that the frequency of a special hypertriglyceridemia entity, named chylomicronemia syndrome, is variable among its different forms. The monogenic form, termed familial chylomicronemia syndrome, is rare, occuring in 1 in every 1 million persons. On the other hand, the prevalence of the polygenic form of chylomicronemia syndrome is around 1:600. On the basis of the genetical alterations, other factors, such as obesity, alcohol consumption, uncontrolled diabetes mellitus and certain drugs may significantly contribute to the development of the multifactorial form. In this review, we aimed to highlight the recent findings about the clinical and laboratory features, differential diagnosis, as well as the epidemiology of the monogenic and polygenic forms of chylomicronemias. Regarding the therapy, differentiation between the two types of the chylomicronemia syndrome is essential, as well. Thus, proper treatment options of chylomicronemia and hypertriglyceridemia will be also summarized, emphasizing the newest therapeutic approaches, as novel agents may offer solution for the effective treatment of these conditions.
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Affiliation(s)
- György Paragh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary.
| | - Ákos Németh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Mariann Harangi
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Maciej Banach
- Department of Hypertension, WAM University Hospital in Lodz, Medical University of Lodz, Lodz, Poland.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
| | - Péter Fülöp
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
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Lee DD, Li CL. Periungual xanthomas in a case of hepatocellular carcinoma and dyslipidemia. DERMATOL SIN 2022. [DOI: 10.4103/1027-8117.359340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Rare novel LPL mutations are associated with neonatal onset lipoprotein lipase (LPL) deficiency in two cases. BMC Pediatr 2021; 21:414. [PMID: 34544385 PMCID: PMC8451144 DOI: 10.1186/s12887-021-02875-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 08/25/2021] [Indexed: 12/18/2022] Open
Abstract
Background Lipoprotein lipase (LPL) deficiency is a monogenic lipid metabolism disorder biochemically characterized by hypertriglyceridemia (HTG) inherited in an autosomal recessive manner. Neonatal onset LPL deficiency is rare. The purpose of this study was to clarify the clinical features of neonatal LPL deficiency and to analyze the genetic characteristics of LPL gene. Methods In order to reach a definite molecular diagnose, metabolic diseases-related genes were sequenced through gene capture and next generation sequencing. Meanwhile, the clinical characteristics and follow-up results of the two newborns were collected and analyzed. Results Three different mutations in the LPL gene were identified in the two newborns including a novel compound heterozygous mutation (c.347G > C and c.472 T > G) and a reported homozygous mutation (c.836 T > G) was identified. Interestingly, both the two neonatal onset LPL deficiency patients presented with suffered recurrent infection in the hyperlipidemia stage, which was not usually found in childhood or adulthood onset LPL deficiency patients. Conclusion The two novel mutaitons, c.347G > C and c.472 T > G, identified in this study were novel, which expanded the LPL gene mutation spectrum. In addition, suffered recurrent infection in the hyperlipidemia stage implied a certain correlation between immune deficiency and lipid metabolism abnormality. This observation further supplemented and expanded the clinical manifestations of LPL deficiency. Supplementary Information The online version contains supplementary material available at 10.1186/s12887-021-02875-x.
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Tripathi M, Wong A, Solomon V, Yassine HN. THE PREVALENCE OF PROBABLE FAMILIAL CHYLOMICRONEMIA SYNDROME IN A SOUTHERN CALIFORNIA POPULATION. Endocr Pract 2020; 27:71-76. [PMID: 33475504 DOI: 10.4158/ep-2020-0135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To estimate the prevalence of probable familial chylomicronemia syndrome (FCS) in a major Southern California Academic Center as well as to provide a systematic review of past FCS studies and management recommendations. METHODS Electronic medical records were queried based on single fasting plasma triglyceride (TG) levels of ≥880 mg/dL and at least 1 episode of acute pancreatitis. After the exclusion of secondary causes (diabetes, alcohol misuse, gallbladder disease, chronic kidney disease, uncontrolled hypothyroidism, estrogen, and drug use) and responses to lipid-lowering treatment, probable patients with FCS were identified. A systematic review of all published literature on the prevalence and management guidelines for FCS was then presented and discussed. RESULTS Out of 7 699 288 charts queried, 138 patients with TG levels of ≥880 mg/dL and documented evidence of at least 1 episode of acute pancreatitis were identified. Nine patients did not have any documented secondary causes of chylomicronemia. Four of the 9 patients had >20% decrease in TG levels after lipid-lowering treatment, 2 patients were not responsive to lipid-lowering medication, and data on lipid-lowering medications were missing in 3 patients. CONCLUSION Our study estimates the prevalence of probable FCS at a range of 0.26 to 0.66 per million. Using the recommended criteria, probable FCS cases can be identified to allow early diagnosis and management.
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Affiliation(s)
- Mrinali Tripathi
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - April Wong
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Victoria Solomon
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Hussein N Yassine
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California.
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Hegele RA, Dron JS. 2019 George Lyman Duff Memorial Lecture: Three Decades of Examining DNA in Patients With Dyslipidemia. Arterioscler Thromb Vasc Biol 2020; 40:1970-1981. [PMID: 32762461 DOI: 10.1161/atvbaha.120.313065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dyslipidemias include both rare single gene disorders and common conditions that have a complex underlying basis. In London, ON, there is fortuitous close physical proximity between the Lipid Genetics Clinic and the London Regional Genomics Centre. For >30 years, we have applied DNA sequencing of clinical samples to help answer scientific questions. More than 2000 patients referred with dyslipidemias have participated in an ongoing translational research program. In 2013, we transitioned to next-generation sequencing; our targeted panel is designed to concurrently assess both monogenic and polygenic contributions to dyslipidemias. Patient DNA is screened for rare variants underlying 25 mendelian dyslipidemias, including familial hypercholesterolemia, hepatic lipase deficiency, abetalipoproteinemia, and familial chylomicronemia syndrome. Furthermore, polygenic scores for LDL (low-density lipoprotein) and HDL (high-density lipoprotein) cholesterol, and triglycerides are calculated for each patient. We thus simultaneously document both rare and common genetic variants, allowing for a broad view of genetic predisposition for both individual patients and cohorts. For instance, among patients referred with severe hypertriglyceridemia, defined as ≥10 mmol/L (≥885 mg/dL), <1% have a mendelian disorder (ie, autosomal recessive familial chylomicronemia syndrome), ≈15% have heterozygous rare variants (a >3-fold increase over normolipidemic individuals), and ≈35% have an extreme polygenic score (a >3-fold increase over normolipidemic individuals). Other dyslipidemias show a different mix of genetic determinants. Genetic results are discussed with patients and can support clinical decision-making. Integrating DNA testing into clinical care allows for a bidirectional flow of information, which facilitates scientific discoveries and clinical translation.
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Affiliation(s)
- Robert A Hegele
- From the Department of Medicine (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Biochemistry (R.A.H., J.S.D.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Robarts Research Institute (R.A.H., J.S.D.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Jacqueline S Dron
- Department of Biochemistry (R.A.H., J.S.D.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Robarts Research Institute (R.A.H., J.S.D.), Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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11
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Sun X, Zhou X, Xiao X, Chi J, Dong B, Wang Y. Generation of the induced pluripotent stem cell(iPSC) line (AHQUi001-A) from a patient with familial hypertriglyceridemia (FHTG) carrying a heterozygous p.C310R (c.928 T > C) mutation in LPL gene. Stem Cell Res 2020; 45:101802. [PMID: 32353702 DOI: 10.1016/j.scr.2020.101802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 03/02/2020] [Accepted: 03/25/2020] [Indexed: 12/01/2022] Open
Abstract
Familial hypertriglyceridemia (FHTG) is an autosomal dominant disorder of lipoprotein metabolism, partly caused by mutations in the LPL gene, which encodes for the lipoprotein lipase. LPL deficiency can impair triglyceride hydrolysis which causes elevated plasma triglyceride levels. An induced pluripotent stem cell (iPSC) line was generated from peripheral blood mononuclear cells (PBMCs) of a 53 years-old male patient with FHTG who had a heterozygous p.C310R (c.928 T > C) mutation in the LPL gene based on the sendai virus delivery system. The cellular model will offer a powerful tool to investigate pathogenic mechanisms in FHTG and to develop a treatment for FHTG.
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Affiliation(s)
- Xiaofang Sun
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Xiang Zhou
- Key Laboratory of Endocrinology, Translational Medicine Centre, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xinhua Xiao
- Key Laboratory of Endocrinology, Translational Medicine Centre, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
| | - Jingwei Chi
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Bingzi Dong
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Yangang Wang
- Department of Endocrinology and Metabolic Diseases, The Affiliated Hospital of Qingdao University, Qingdao 266003, China.
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Pinilla-Monsalve GD, Lores J, Pachajoa H, López-Ponce de León JD, López A, Rodríguez-Rojas LX, Nastasi-Catanese JA. A Novel APOC2 Mutation in a Colombian Patient with Recurrent Hypertriglyceridemic Pancreatitis. Appl Clin Genet 2020; 13:63-69. [PMID: 32280258 PMCID: PMC7125404 DOI: 10.2147/tacg.s243148] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/20/2020] [Indexed: 11/26/2022] Open
Abstract
Hypertriglyceridemia is a common disease with only 2% of cases exhibiting monogenic mutations. Familial chylomicronemia syndrome (FCS) is a rare genetic condition associated with recurrent and severe episodes of pancreatitis and is mainly caused by mutations in the LPL gene, with few cases related to abnormal function of apolipoprotein C-II. This is a 50-year-old female with a past medical history of arterial hypertension, miscarriage and recurrent pancreatitis. In the last four years, her triglycerides and lipase concentration reached >3000 mg/dL and >700 U/L, respectively. The patient was not responsive to statins, fibrates, or tetrahydrolipstatin. A novel homozygous frameshift mutation on exon 3 of the APOC2 gene was detected, c.133_134delTC. Subsequent Sanger sequencing confirmed that three first-degree relatives were carriers of the same mutation. To the best of our knowledge, we are reporting the first Colombian patient with FCS due to an APOC2 mutation. We propose that this mutation caused recurrent hypertriglyceridemic pancreatitis.
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Affiliation(s)
| | - Juliana Lores
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Genetics, Fundación Valle del Lili, Cali 760032, Colombia
| | - Harry Pachajoa
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Genetics, Fundación Valle del Lili, Cali 760032, Colombia
| | - Juan D López-Ponce de León
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Cardiology, Fundación Valle del Lili, Cali 760032, Colombia
| | - Alejandro López
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Endocrinology, Fundación Valle del Lili, Cali 760032, Colombia
| | - Lisa X Rodríguez-Rojas
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Genetics, Fundación Valle del Lili, Cali 760032, Colombia
| | - José A Nastasi-Catanese
- Faculty of Health Sciences, Universidad Icesi, Cali 760032, Colombia.,Department of Genetics, Fundación Valle del Lili, Cali 760032, Colombia
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Dapas M, Dunaif A. The contribution of rare genetic variants to the pathogenesis of polycystic ovary syndrome. ACTA ACUST UNITED AC 2020; 12:26-32. [PMID: 32440573 DOI: 10.1016/j.coemr.2020.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a highly heritable disorder, but only a small proportion of the heritability can be accounted for by common genetic risk variants identified to date. It is possible that variants with lower allele frequencies that cannot be detected using genome-wide association study arrays contribute to PCOS. Here, we discuss the challenges inherent to studying rare genetic variants in complex disease and review several recent studies that have used DNA sequencing techniques to investigate whether rare variants play a role in PCOS pathogenesis. We evaluate these findings in the context of the latest literature in PCOS and complex disease genetics.
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Baass A, Paquette M, Bernard S, Hegele RA. Familial chylomicronemia syndrome: an under-recognized cause of severe hypertriglyceridaemia. J Intern Med 2020; 287:340-348. [PMID: 31840878 DOI: 10.1111/joim.13016] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder of chylomicron metabolism causing severe elevation of triglyceride (TG) levels (>10 mmol L-1 ). This condition is associated with a significant risk of recurrent acute pancreatitis (AP). AP caused by hypertriglyceridaemia (HTG) has been associated with a worse prognosis and higher mortality rates compared to pancreatitis of other aetiology. Despite its association with poor quality of life and increased lifelong risk of HTG-AP, few healthcare providers are familiar with FCS. Because this condition is under-recognized, the majority of FCS patients are diagnosed after age 20 often after consulting several physicians. Although other forms of severe HTG such as multifactorial chylomicronemia have been associated with high atherosclerotic cardiovascular disease (ASCVD) risk and metabolic abnormalities, ASCVD and metabolic syndrome are not usually observed in FCS patients. Because FCS is a genetic condition, the optimal diagnosis strategy remains genetic testing. The presence of bi-allelic pathogenic mutations in LPL, APOC2, GPIHBP1, APOA5 or LMF1 genes confirms the diagnosis. However, some cases of FCS caused by autoantibodies against LPL or GPIHBP1 proteins have also been reported. Furthermore, a clinical score for the diagnosis of FCS has been proposed but needs further validation. Available treatment options to lower triglycerides such as fibrates or omega-3 fatty acids are not efficacious in FCS patients. Currently, the cornerstone of treatment remains a lifelong very low-fat diet, which prevents the formation of chylomicrons. Finally, inhibitors of apo C-III and ANGPTL3 are in development and may eventually constitute additional treatment options for FCS patients.
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Affiliation(s)
- A Baass
- From the, Lipids, Nutrition and Cardiovascular Prevention Clinic, Montreal Clinical Research Institute, Québec, Canada.,Divisions of Experimental Medicine and Medical Biochemistry, Department of Medicine, McGill University, Québec, Canada
| | - M Paquette
- From the, Lipids, Nutrition and Cardiovascular Prevention Clinic, Montreal Clinical Research Institute, Québec, Canada
| | - S Bernard
- From the, Lipids, Nutrition and Cardiovascular Prevention Clinic, Montreal Clinical Research Institute, Québec, Canada.,Division of Endocrinology, Department of Medicine, Université de Montreal, Montreal, Canada
| | - R A Hegele
- Department of Medicine, University of Western Ontario and Robarts Research Institute, Ontario, Canada
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Abstract
Hypertriglyceridemia, a commonly encountered phenotype in cardiovascular and metabolic clinics, is surprisingly complex. A range of genetic variants, from single-nucleotide variants to large-scale copy number variants, can lead to either the severe or mild-to-moderate forms of the disease. At the genetic level, severely elevated triglyceride levels resulting from familial chylomicronemia syndrome (FCS) are caused by homozygous or biallelic loss-of-function variants in LPL, APOC2, APOA5, LMF1, and GPIHBP1 genes. In contrast, susceptibility to multifactorial chylomicronemia (MCM), which has an estimated prevalence of ~1 in 600 and is at least 50-100-times more common than FCS, results from two different types of genetic variants: (1) rare heterozygous variants (minor allele frequency <1%) with variable penetrance in the five causal genes for FCS; and (2) common variants (minor allele frequency >5%) whose individually small phenotypic effects are quantified using a polygenic score. There is indirect evidence of similar complex genetic predisposition in other clinical phenotypes that have a component of hypertriglyceridemia, such as combined hyperlipidemia and dysbetalipoproteinemia. Future considerations include: (1) evaluation of whether the specific type of genetic predisposition to hypertriglyceridemia affects medical decisions or long-term outcomes; and (2) searching for other genetic contributors, including the role of genome-wide polygenic scores, novel genes, non-linear gene-gene or gene-environment interactions, and non-genomic mechanisms including epigenetics and mitochondrial DNA.
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Musambil M, Al-Rubeaan K, Al-Qasim S, Al Naqeb D, Al-Soghayer A. Primary Hypertriglyceridemia: A Look Back on the Clinical Classification and Genetics of the Disease. Curr Diabetes Rev 2020; 16:521-531. [PMID: 31057121 DOI: 10.2174/1573399815666190502164131] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/21/2019] [Accepted: 04/17/2019] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Hypertriglyceridemia (HTG) is one of the most common metabolic disorders leading to pancreatitis and cardiovascular disease. HTG develops mostly due to impaired metabolism of triglyceride-rich lipoproteins. Although monogenic types of HTG exist, most reported cases are polygenic in nature. AIM This review article is focused on the classification of Primary HTG and the genetic factors behind its development with the aim of providing clinicians a useful tool for early detection of the disease in order to administer proper and effective treatment. DISCUSSION HTG is often characterized by a complex phenotype resulting from interactions between genetic and environmental factors. In many instances, the complexity, perplexing causes, and classification of HTG make it difficult for clinicians to properly diagnose and manage the disorder. Better availability of information on its pathophysiology, genetic factors involved, environmental causes, and their interactions could help in understanding such complex disorders and could support its effective diagnosis and treatment. CONCLUSION The current review has summarized the case definition, epidemiology, pathophysiology, clinical presentation, classification, associated genetic factors, and scope of genetic screening in the diagnosis of primary HTG.
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Affiliation(s)
- Mohthash Musambil
- Department of Genetics, Strategic Center for Diabetes Research, King Saud University, Riyadh, Saudi Arabia
| | - Khalid Al-Rubeaan
- Strategic Center for Diabetes Research, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- University Diabetes Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Sara Al-Qasim
- Department of Genetics, Strategic Center for Diabetes Research, King Saud University, Riyadh, Saudi Arabia
| | - Dhekra Al Naqeb
- University Diabetes Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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Benes LB, Brandt DJ, Brandt EJ, Davidson MH. How Genomics Is Personalizing the Management of Dyslipidemia and Cardiovascular Disease Prevention. Curr Cardiol Rep 2018; 20:138. [DOI: 10.1007/s11886-018-1079-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Roberts BS, Babilonia-Rosa MA, Broadwell LJ, Wu MJ, Neher SB. Lipase maturation factor 1 affects redox homeostasis in the endoplasmic reticulum. EMBO J 2018; 37:embj.201797379. [PMID: 30068531 DOI: 10.15252/embj.201797379] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/18/2018] [Accepted: 06/20/2018] [Indexed: 11/09/2022] Open
Abstract
Lipoprotein lipase (LPL) is a secreted lipase that clears triglycerides from the blood. Proper LPL folding and exit from the endoplasmic reticulum (ER) require lipase maturation factor 1 (LMF1), an ER-resident transmembrane protein, but the mechanism involved is unknown. We used proteomics to identify LMF1-binding partners necessary for LPL secretion in HEK293 cells and found these to include oxidoreductases and lectin chaperones, suggesting that LMF1 facilitates the formation of LPL's five disulfide bonds. In accordance with this role, we found that LPL aggregates in LMF1-deficient cells due to the formation of incorrect intermolecular disulfide bonds. Cells lacking LMF1 were hypersensitive to depletion of glutathione, but not DTT treatment, suggesting that LMF1 helps reduce the ER Accordingly, we found that loss of LMF1 results in a more oxidized ER Our data show that LMF1 has a broader role than simply folding lipases, and we identified fibronectin and the low-density lipoprotein receptor (LDLR) as novel LMF1 clients that contain multiple, non-sequential disulfide bonds. We conclude that LMF1 is needed for secretion of some ER client proteins that require reduction of non-native disulfides during their folding.
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Affiliation(s)
- Benjamin S Roberts
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Melissa A Babilonia-Rosa
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lindsey J Broadwell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ming Jing Wu
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Saskia B Neher
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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19
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Qin YY, Wei AQ, Shan QW, Xian XY, Wu YY, Liao L, Yan J, Lai ZF, Lin FQ. Rare LPL gene missense mutation in an infant with hypertriglyceridemia. J Clin Lab Anal 2018; 32:e22414. [PMID: 29479812 DOI: 10.1002/jcla.22414] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/27/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Severe hypertriglyceridemia usually results from a combination of genetic and environmental factors and is most often attributable to mutations in the lipoprotein lipase (LPL) gene. OBJECTIVES The aim of this study was to identify rare mutations in the LPL gene causing severe hypertriglyceridemia. METHODS A Chinese infant who presented classical features of severe hypertriglyceridemia recruited for DNA sequencing of the LPL gene. The pathogenicity grade of the variants was defined based on the prediction of pathogenicity using in silico prediction tools. Review some studies to understand the molecular mechanisms underlying the severe hypertriglyceridemia. RESULTS We identified a rare mutation in the LPL gene causing severe hypertriglyceridemia: a nucleotide substitution (c.836T>G) resulting in a leucine to arginine substitution at position 279 of the protein (p.Leu279Arg).The pathogenicity of the variant was predicted by in silico analysis using PolyPhen2 and SIFT prediction programs, which indicated that mutation p.Leu279Arg is probably harmful. We have also reviewed published studies concerning the molecular mechanisms underlying severe hypertriglyceridemia. A missense mutation in the 6 exon of the LPL gene is reportedly associated with LPL deficiency. CONCLUSIONS We have here identified a rare pathogenic mutation in the LPL gene in a Chinese infant with severe hypertriglyceridemia.
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Affiliation(s)
- Yuan-Yuan Qin
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Ai-Qiu Wei
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Qing-Wen Shan
- Department of pediatric, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xiao-Ying Xian
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yang-Yang Wu
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Lin Liao
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jie Yan
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zhan-Feng Lai
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Fa-Quan Lin
- Department of Clinical Laboratory, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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Benes LB, Brandt EJ, Davidson MH. Advances in diagnosis and potential therapeutic options for familial chylomicronemia syndrome. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1419863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lane B. Benes
- Section of Cardiology, The University of Chicago Medicine, Chicago, IL, USA
| | - Eric J. Brandt
- Section of Cardiology, Yale University School of Medicine, New Haven, CT, USA
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21
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Wolska A, Dunbar RL, Freeman LA, Ueda M, Amar MJ, Sviridov DO, Remaley AT. Apolipoprotein C-II: New findings related to genetics, biochemistry, and role in triglyceride metabolism. Atherosclerosis 2017; 267:49-60. [PMID: 29100061 DOI: 10.1016/j.atherosclerosis.2017.10.025] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/03/2017] [Accepted: 10/19/2017] [Indexed: 02/08/2023]
Abstract
Apolipoprotein C-II (apoC-II) is a small exchangeable apolipoprotein found on triglyceride-rich lipoproteins (TRL), such as chylomicrons (CM) and very low-density lipoproteins (VLDL), and on high-density lipoproteins (HDL), particularly during fasting. ApoC-II plays a critical role in TRL metabolism by acting as a cofactor of lipoprotein lipase (LPL), the main enzyme that hydrolyses plasma triglycerides (TG) on TRL. Here, we present an overview of the role of apoC-II in TG metabolism, emphasizing recent novel findings regarding its transcriptional regulation and biochemistry. We also review the 24 genetic mutations in the APOC2 gene reported to date that cause hypertriglyceridemia (HTG). Finally, we describe the clinical presentation of apoC-II deficiency and assess the current therapeutic approaches, as well as potential novel emerging therapies.
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Affiliation(s)
- Anna Wolska
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Richard L Dunbar
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; ICON plc, North Wales, PA, USA; Cardiometabolic and Lipid Clinic, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Lita A Freeman
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Masako Ueda
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Marcelo J Amar
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Denis O Sviridov
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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22
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Lee J, Hegele RA. Investigated treatments for lipoprotein lipase deficiency and related metabolic disorders. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1311784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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23
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Zhang YP, Zhang YY, Duan DD. From Genome-Wide Association Study to Phenome-Wide Association Study: New Paradigms in Obesity Research. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:185-231. [PMID: 27288830 DOI: 10.1016/bs.pmbts.2016.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Obesity is a condition in which excess body fat has accumulated over an extent that increases the risk of many chronic diseases. The current clinical classification of obesity is based on measurement of body mass index (BMI), waist-hip ratio, and body fat percentage. However, these measurements do not account for the wide individual variations in fat distribution, degree of fatness or health risks, and genetic variants identified in the genome-wide association studies (GWAS). In this review, we will address this important issue with the introduction of phenome, phenomics, and phenome-wide association study (PheWAS). We will discuss the new paradigm shift from GWAS to PheWAS in obesity research. In the era of precision medicine, phenomics and PheWAS provide the required approaches to better definition and classification of obesity according to the association of obese phenome with their unique molecular makeup, lifestyle, and environmental impact.
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Affiliation(s)
- Y-P Zhang
- Pediatric Heart Center, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Y-Y Zhang
- Department of Cardiology, Changzhou Second People's Hospital, Changzhou, Jiangsu, China
| | - D D Duan
- Laboratory of Cardiovascular Phenomics, Center for Cardiovascular Research, Department of Pharmacology, and Center for Molecular Medicine, University of Nevada School of Medicine, Reno, NV, United States.
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24
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Lamiquiz-Moneo I, Blanco-Torrecilla C, Bea AM, Mateo-Gallego R, Pérez-Calahorra S, Baila-Rueda L, Cenarro A, Civeira F, de Castro-Orós I. Frequency of rare mutations and common genetic variations in severe hypertriglyceridemia in the general population of Spain. Lipids Health Dis 2016; 15:82. [PMID: 27108409 PMCID: PMC4842266 DOI: 10.1186/s12944-016-0251-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/18/2016] [Indexed: 11/10/2022] Open
Abstract
Background Hypertriglyceridemia (HTG) is a common complex metabolic trait that results of the accumulation of relatively common genetic variants in combination with other modifier genes and environmental factors resulting in increased plasma triglyceride (TG) levels. The majority of severe primary hypertriglyceridemias is diagnosed in adulthood and their molecular bases have not been fully defined yet. The prevalence of HTG is highly variable among populations, possibly caused by differences in environmental factors and genetic background. However, the prevalence of very high TG and the frequency of rare mutations causing HTG in a whole non-selected population have not been previously studied. Methods The total of 23,310 subjects over 18 years from a primary care-district in a middle-class area of Zaragoza (Spain) with TG >500 mg/dL were selected to establish HTG prevalence. Those affected of primary HTG were considered for further genetic analisys. The promoters, coding regions and exon-intron boundaries of LPL, LMF1, APOC2, APOA5, APOE and GPIHBP1 genes were sequenced. The frequency of rare variants identified was studied in 90 controls. Results One hundred ninety-four subjects (1.04 %) had HTG and 90 subjects (46.4 %) met the inclusion criteria for primary HTG. In this subgroup, nine patients (12.3 %) were carriers of 7 rare variants in LPL, LMF1, APOA5, GPIHBP1 or APOE genes. Three of these mutations are described for the first time in this work. The presence of a rare pathogenic mutation did not confer a differential phenotype or a higher family history of HTG. Conclusion The prevalence of rare mutations in candidate genes in subjects with primary HTG is low. The low frequency of rare mutations, the absence of a more severe phenotype or the dominant transmission of the HTG would not suggest the use of genetic analysis in the clinical practice in this population. Electronic supplementary material The online version of this article (doi:10.1186/s12944-016-0251-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Itziar Lamiquiz-Moneo
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain.
| | - Cristian Blanco-Torrecilla
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Ana M Bea
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Rocío Mateo-Gallego
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Sofía Pérez-Calahorra
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Lucía Baila-Rueda
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Ana Cenarro
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Fernando Civeira
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Isabel de Castro-Orós
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain.,Universidad de Zaragoza, Departamento de Bioquímica, Biología Molecular y Celular, 50009, Zaragoza, Spain
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25
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Lamiquiz-Moneo I, Bea AM, Mateo-Gallego R, Baila-Rueda L, Cenarro A, Pocoví M, Civeira F, de Castro-Orós I. [Identification of variants in LMF1 gene associated with primary hypertriglyceridemia]. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ARTERIOSCLEROSIS 2015; 27:246-252. [PMID: 25817768 DOI: 10.1016/j.arteri.2015.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 06/04/2023]
Abstract
The majority of severe primary hypertriglyceridemia (HTG) are diagnosed in adults, and their molecular bases have not yet been fully defined. The promoter, coding regions and intron-exon boundaries of LMF1 were sequenced in 112 patients with severe primary hipertrigliceridemia (defined as TG above 500mg/dl). Five patients (4.46%) were carriers of four rare variants in the LMF1 gene associated with HTG, which participate in lipoprotein lipase (LpL) function. Also, we have identified two common variants, c.194-28 T>G and c.729+18C>G that were associated with HTG, with a different allelic frequency to that observed in the general population. A bioinformatic analysis of all found variants was conducted, defining the following as potentially harmful: p.Arg364Gln, p.Arg451Trp, p.Pro562Arg and p.Leu85Leu. Our results suggest that LMF1 mutations are involved in a substantial proportion of cases with severe HTG, putting together the moderate-aggressive effect of rare mutations with polymorphisms classically associated with this disease.
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Affiliation(s)
- Itziar Lamiquiz-Moneo
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España.
| | - Ana M Bea
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Rocío Mateo-Gallego
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Lucía Baila-Rueda
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Ana Cenarro
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Miguel Pocoví
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Fernando Civeira
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Isabel de Castro-Orós
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
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Abstract
This Review discusses new developments in understanding the basis of chylomicronaemia--a challenging metabolic disorder for which there is an unmet clinical need. Chylomicronaemia presents in two distinct primary forms. The first form is very rare monogenic early-onset chylomicronaemia, which presents in childhood or adolescence and is often caused by homozygous mutations in the gene encoding lipoprotein lipase (LPL), its cofactors apolipoprotein C-II or apolipoprotein A-V, the LPL chaperone lipase maturation factor 1 or glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1. The second form, polygenic late-onset chylomicronaemia, which is caused by an accumulation of several genetic variants, can be exacerbated by secondary factors, such as poor diet, obesity, alcohol intake and uncontrolled type 1 or type 2 diabetes mellitus, and is more common than early-onset chylomicronaemia. Both forms of chylomicronaemia are associated with an increased risk of life-threatening pancreatitis; the polygenic form might also be associated with an increased risk of cardiovascular disease. Treatment of chylomicronaemia focuses on restriction of dietary fat and control of secondary factors, as available pharmacological therapies are only minimally effective. Emerging therapies that might prove more effective than existing agents include LPL gene therapy, inhibition of microsomal triglyceride transfer protein and diacylglycerol O-acyltransferase 1, and interference with the production and secretion of apoC-III and angiopoietin-like protein 3.
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Affiliation(s)
- Amanda J Brahm
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
| | - Robert A Hegele
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
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27
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Role of 3 lipoprotein lipase variants in triglycerides in children receiving highly active antiretroviral therapy. Pediatr Infect Dis J 2015; 34:155-61. [PMID: 24988117 DOI: 10.1097/inf.0000000000000474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Lipoprotein lipase is a key enzyme in lipid metabolism, especially for plasma triglycerides (TGs). Genetic variants have been associated with lipid levels in healthy individuals, cardiovascular disease, obesity and diabetes. Our aim was to evaluate the influence of 3 polymorphisms: Hind III, Pvu II and S447X in plasma TG levels in human immunodeficiency virus-1-infected children under highly active antiretroviral therapy (HAART). METHODS Fifty-two children diagnosed with human immunodeficiency virus-1 between 2005 and 2009 were retrospectively selected with at least 1 plasma TG level assessment. TG levels were examined before and after 1 year of HAART. Hypertriglyceridemia was defined as TG > 150 mg/dL. Hind III (H+/H-), Pvu II (P+/P-) and S447X (S/X) were determined by polymerase chain reaction and restricted fragment length polymorphism. The Wilcoxon sum-rank test was used to compare median plasma TG among groups. Also, allelic frequencies were estimated for these variants in an Argentinean population. RESULTS Allelic frequencies for human immunodeficiency virus-1-infected children were: H-, 0.21; P-, 0.53; and X, 0.05 with no significant differences to controls. After 1 year of HAART, median TG levels were significantly lower in P-/P- (98.5 mg/dL) when compared with P+/P+ (180 mg/dL) (P = 0.039). The presence of the P- allele was associated with an 11-fold lower risk of hypertriglyceridemia. Hind III and S447X were not associated with TG at the selected time points. CONCLUSIONS Our findings suggest a protective effect of lipoprotein lipase polymorphisms against hypertriglyceridemia in children after 1 year of HAART. These results could endorse a prompt nutritional or pharmacological intervention in patients lacking the P- allele.
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van de Woestijne AP, van der Graaf Y, de Bakker PIW, Asselbergs FW, Spiering W, Visseren FLJ. Rs964184 (APOA5-A4-C3-A1) is related to elevated plasma triglyceride levels, but not to an increased risk for vascular events in patients with clinically manifest vascular disease. PLoS One 2014; 9:e101082. [PMID: 24979386 PMCID: PMC4076225 DOI: 10.1371/journal.pone.0101082] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/03/2014] [Indexed: 01/08/2023] Open
Abstract
Background Single nucleotide polymorphisms in the APOA5-A4-C3-A1 gene complex are associated with elevated plasma triglycerides and elevated vascular risk in healthy populations. In patients with clinically manifest vascular disease, hypertriglyceridemia and metabolic syndrome are frequently present, but the contribution of these single nucleotide polymorphisms to plasma triglycerides, effect modification by obesity and risk of recurrent vascular events is unknown in these patients. Methods Prospective cohort study of 5547 patients with vascular disease. Rs964184 (APOA5-A4-C3-A1 gene complex) was genotyped, and we evaluated the relation with plasma lipid levels, presence of metabolic syndrome and the risk for new vascular events. Results The minor allele of rs964184 was strongly associated with log plasma triglycerides (β 0.12; 95%CI 0.10-0.15, p = 1.1*10−19), and was also associated with 0.03 mmol/L lower high-density lipoprotein-cholesterol (95%CI 0.01–0.04), and 0.14 mmol/L higher non-high-density lipoprotein-cholesterol (95%CI 0.09–0.20). The minor allele frequency increased from 10.9% in patients with plasma triglycerides <1 mmol/L to 24.6% in patients with plasma triglycerides between 4 and 10 mmol/L. The relation between rs964184 and plasma triglycerides was modified by body mass index in patients with one minor allele (β 0.02; (95%CI −0.04–0.09) if body mass index <24 kg/m2, β 0.17 (95%CI 0.12–0.22) if body mass index >27 kg/m2, p for interaction = 0.02). The prevalence of the metabolic syndrome increased from 52% for patients with two copies of the major allele to 62% for patients with two copies of the minor allele (p = 0.01). Rs964184 was not related with recurrent vascular events (HR 0.99; 95%CI 0.86–1.13). Conclusion The single nucleotide polymorphism rs964184 (APOA5-A4-C3-A1) is associated with elevated plasma triglycerides concentrations in patients with clinically manifest vascular disease. In carriers of one minor allele, the effect on plasma triglycerides was modified by body mass index. There is no relation between rs964184 and recurrent vascular events in these patients.
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Affiliation(s)
| | - Yolanda van der Graaf
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul I. W. de Bakker
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Folkert W. Asselbergs
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
- Durrer Center for Cardiogenetic Research, ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Frank L. J. Visseren
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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Babilonia-Rosa MA, Neher SB. Purification, cellular levels, and functional domains of lipase maturation factor 1. Biochem Biophys Res Commun 2014; 450:423-8. [PMID: 24909692 DOI: 10.1016/j.bbrc.2014.05.136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 05/28/2014] [Indexed: 01/17/2023]
Abstract
Over a third of the US adult population has hypertriglyceridemia, resulting in an increased risk of atherosclerosis, pancreatitis, and metabolic syndrome. Lipoprotein lipase (LPL), a dimeric enzyme, is the main lipase responsible for TG clearance from the blood after food intake. LPL requires an endoplasmic reticulum (ER)-resident, transmembrane protein known as lipase maturation factor 1 (LMF1) for secretion and enzymatic activity. LMF1 is believed to act as a client specific chaperone for dimeric lipases, but the precise mechanism by which LMF1 functions is not understood. Here, we examine which domains of LMF1 contribute to dimeric lipase maturation by assessing the function of truncation variants. N-terminal truncations of LMF1 show that all the domains are necessary for LPL maturation. Fluorescence microscopy and protease protection assays confirmed that these variants were properly oriented in the ER. We measured cellular levels of LMF1 and found that it is expressed at low levels and each molecule of LMF1 promotes the maturation of 50 or more molecules of LPL. Thus we provide evidence for the critical role of the N-terminus of LMF1 for the maturation of LPL and relevant ratio of chaperone to substrate.
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Affiliation(s)
- Melissa A Babilonia-Rosa
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Saskia B Neher
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
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Lee BH, Carr TP, Weller CL, Cuppett S, Dweikat IM, Schlegel V. Grain sorghum whole kernel oil lowers plasma and liver cholesterol in male hamsters with minimal wax involvement. J Funct Foods 2014. [DOI: 10.1016/j.jff.2013.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Kwan HY, Hu YM, Chan CL, Cao HH, Cheng CY, Pan SY, Tse KW, Wu YC, Yu ZL, Fong WF. Lipidomics identification of metabolic biomarkers in chemically induced hypertriglyceridemic mice. J Proteome Res 2013; 12:1387-98. [PMID: 23336740 DOI: 10.1021/pr3010327] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, we aim to identify the potential biomarkers in hTG pathogenesis in schisandrin B-induced hTG mouse model. To investigate whether these identified biomarkers are only specific to schisandrin B-induced hTG mouse model, we also measured these biomarkers in a high fat diet (HFD)-induced hTG mouse model. We employed a LC/MS/MS-based lipidomic approach for the study. Mouse liver and serum metabolites were separated by reversed phase liquid chromatography. Metabolite candidates were identified by matching with marker retention times, isotope distribution patterns, and high-resolution MS/MS fragmentation patterns. Subsequently, target candidates were quantified by quantitative MS. In the schisandrin B-induced hTG mice, we found that the plasma fatty acids, diglyceroids, and phospholipids were significantly increased. Palmitic acid and stearic acid were increased in the plasma; oleic acid, linoleic acid, linolenic acid, arachidonic acid, and docosahexaenoic acid were increased in both the plasma and the liver. Acetyl-CoA, malonyl-CoA, and succinyl-CoA were increased only in the liver. The changes in levels of these identified markers were also observed in HFD-induced hTG mouse model. The consistent results obtained from both hTG models not only suggest novel biomarkers in hTG pathogenesis, but they also provide insight into the underlying mechanism of the schisandrin B-induced hTG.
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Affiliation(s)
- Hiu Yee Kwan
- Centre for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
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Dussaillant C, Serrano V, Maiz A, Eyheramendy S, Cataldo LR, Chavez M, Smalley SV, Fuentes M, Rigotti A, Rubio L, Lagos CF, Martinez JA, Santos JL. APOA5 Q97X mutation identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family. BMC MEDICAL GENETICS 2012; 13:106. [PMID: 23151256 PMCID: PMC3523038 DOI: 10.1186/1471-2350-13-106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 10/23/2012] [Indexed: 12/31/2022]
Abstract
Background Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. Methods We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. Results A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. Conclusion The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.
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Affiliation(s)
- Catalina Dussaillant
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Alameda, Santiago, Chile
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Johansen CT, Hegele RA. Allelic and phenotypic spectrum of plasma triglycerides. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:833-42. [PMID: 22033228 DOI: 10.1016/j.bbalip.2011.10.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 10/04/2011] [Indexed: 01/10/2023]
Abstract
The genetic underpinnings of both normal and pathological variation in plasma triglyceride (TG) concentration are relatively well understood compared to many other complex metabolic traits. For instance, genome-wide association studies (GWAS) have revealed 32 common variants that are associated with plasma TG concentrations in healthy epidemiologic populations. Furthermore, GWAS in clinically ascertained hypertriglyceridemia (HTG) patients have shown that almost all of the same TG-raising alleles from epidemiologic samples are also associated with HTG disease status, and that greater accumulation of these alleles reflects the severity of the HTG phenotype. Finally, comprehensive resequencing studies show a burden of rare variants in some of these same genes - namely in LPL, GCKR, APOB and APOA5 - in HTG patients compared to normolipidemic controls. A more complete understanding of the genes and genetic variants associated with plasma TG concentration will enrich our understanding of the molecular pathways that modulate plasma TG metabolism, which may translate into clinical benefit. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.
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Johansen CT, Wang J, Lanktree MB, McIntyre AD, Ban MR, Martins RA, Kennedy BA, Hassell RG, Visser ME, Schwartz SM, Voight BF, Elosua R, Salomaa V, O'Donnell CJ, Dallinga-Thie GM, Anand SS, Yusuf S, Huff MW, Kathiresan S, Cao H, Hegele RA. An increased burden of common and rare lipid-associated risk alleles contributes to the phenotypic spectrum of hypertriglyceridemia. Arterioscler Thromb Vasc Biol 2011; 31:1916-26. [PMID: 21597005 DOI: 10.1161/atvbaha.111.226365] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Earlier studies have suggested that a common genetic architecture underlies the clinically heterogeneous polygenic Fredrickson hyperlipoproteinemia (HLP) phenotypes defined by hypertriglyceridemia (HTG). Here, we comprehensively analyzed 504 HLP-HTG patients and 1213 normotriglyceridemic controls and confirmed that a spectrum of common and rare lipid-associated variants underlies this heterogeneity. METHODS AND RESULTS First, we demonstrated that genetic determinants of plasma lipids and lipoproteins, including common variants associated with plasma triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) from the Global Lipids Genetics Consortium were associated with multiple HLP-HTG phenotypes. Second, we demonstrated that weighted risk scores composed of common TG-associated variants were distinctly increased across all HLP-HTG phenotypes compared with controls; weighted HDL-C and LDL-C risk scores were also increased, although to a less pronounced degree with some HLP-HTG phenotypes. Interestingly, decomposition of HDL-C and LDL-C risk scores revealed that pleiotropic variants (those jointly associated with TG) accounted for the greatest difference in HDL-C and LDL-C risk scores. The APOE E2/E2 genotype was significantly overrepresented in HLP type 3 versus other phenotypes. Finally, rare variants in 4 genes accumulated equally across HLP-HTG phenotypes. CONCLUSIONS HTG susceptibility and phenotypic heterogeneity are both influenced by accumulation of common and rare TG-associated variants.
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Affiliation(s)
- Christopher T Johansen
- Department of Biochemistry, Robarts Research Institute, University of Western Ontario, London, Canada
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Baig U, Belsare P, Watve M, Jog M. Can Thrifty Gene(s) or Predictive Fetal Programming for Thriftiness Lead to Obesity? J Obes 2011; 2011:861049. [PMID: 21773010 PMCID: PMC3136239 DOI: 10.1155/2011/861049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Accepted: 02/18/2011] [Indexed: 01/01/2023] Open
Abstract
Obesity and related disorders are thought to have their roots in metabolic "thriftiness" that evolved to combat periodic starvation. The association of low birth weight with obesity in later life caused a shift in the concept from thrifty gene to thrifty phenotype or anticipatory fetal programming. The assumption of thriftiness is implicit in obesity research. We examine here, with the help of a mathematical model, the conditions for evolution of thrifty genes or fetal programming for thriftiness. The model suggests that a thrifty gene cannot exist in a stable polymorphic state in a population. The conditions for evolution of thrifty fetal programming are restricted if the correlation between intrauterine and lifetime conditions is poor. Such a correlation is not observed in natural courses of famine. If there is fetal programming for thriftiness, it could have evolved in anticipation of social factors affecting nutrition that can result in a positive correlation.
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Affiliation(s)
- Ulfat Baig
- Indian Institute of Science Education and Research, Pune 411021, India
| | - Prajakta Belsare
- Indian Institute of Science Education and Research, Pune 411021, India
| | - Milind Watve
- Indian Institute of Science Education and Research, Pune 411021, India
- Anujeeva Biosciences Pvt. Ltd., Pune 411030, India
| | - Maithili Jog
- Department of Biotechnology, Abasaheb Garware College, Pune 411004, India
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Tremblay K, Méthot J, Brisson D, Gaudet D. Etiology and risk of lactescent plasma and severe hypertriglyceridemia. J Clin Lipidol 2011; 5:37-44. [DOI: 10.1016/j.jacl.2010.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 10/28/2010] [Accepted: 11/09/2010] [Indexed: 01/12/2023]
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Johansen CT, Kathiresan S, Hegele RA. Genetic determinants of plasma triglycerides. J Lipid Res 2010; 52:189-206. [PMID: 21041806 DOI: 10.1194/jlr.r009720] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Plasma triglyceride (TG) concentration is reemerging as an important cardiovascular disease risk factor. More complete understanding of the genes and variants that modulate plasma TG should enable development of markers for risk prediction, diagnosis, prognosis, and response to therapies and might help specify new directions for therapeutic interventions. Recent genome-wide association studies (GWAS) have identified both known and novel loci associated with plasma TG concentration. However, genetic variation at these loci explains only ∼10% of overall TG variation within the population. As the GWAS approach may be reaching its limit for discovering genetic determinants of TG, alternative genetic strategies, such as rare variant sequencing studies and evaluation of animal models, may provide complementary information to flesh out knowledge of clinically and biologically important pathways in TG metabolism. Herein, we review genes recently implicated in TG metabolism and describe how some of these genes likely modulate plasma TG concentration. We also discuss lessons regarding plasma TG metabolism learned from various genomic and genetic experimental approaches. Treatment of patients with moderate to severe hypertriglyceridemia with existing therapies is often challenging; thus, gene products and pathways found in recent genetic research studies provide hope for development of more effective clinical strategies.
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Affiliation(s)
- Christopher T Johansen
- Department of Biochemistry, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8, Canada
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Wilke RA, Berg RL, Linneman JG, Peissig P, Starren J, Ritchie MD, McCarty CA. Quantification of the clinical modifiers impacting high-density lipoprotein cholesterol in the community: Personalized Medicine Research Project. ACTA ACUST UNITED AC 2010; 13:63-8. [PMID: 20377807 DOI: 10.1111/j.1751-7141.2009.00055.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
High-density lipoprotein (HDL) cholesterol levels are inversely correlated with the development of cardiovascular disease. To date, genetic association studies have explained only a small proportion of the overall variance in HDL cholesterol. Further studies are needed, within practice-based cohorts, to place genetic findings into context alongside important clinical variables (eg, age, sex, body mass index, medication use, and clinical comorbidity). The Marshfield Clinic Personalized Medicine Research Project database was designed for large-scale studies of genetic epidemiology in a clinical practice-based setting. Because of its size and its unique practice-based design, this resource will provide adequate statistical power for the assessment of genetic findings related to HDL cholesterol level within the context of covariates known to modify lipid homeostasis. The authors report construction and validation of novel electronic phenotyping algorithms that can be used to model individual baseline HDL cholesterol levels within this practice-based resource. Because these algorithms were developed in a setting that reflects routine clinical care, future genetic studies using these algorithms within practice-based DNA biobanks should facilitate the identification of markers with optimal effect size after adjustment for known clinical factors contributing to the overall variance in HDL cholesterol level within the community.
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Affiliation(s)
- Russell A Wilke
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA.
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Johansen CT, Gallinger ZR, Wang J, Ban MR, Young TK, Bjerregaard P, Hegele RA. Rare ATGL haplotypes are associated with increased plasma triglyceride concentrations in the Greenland Inuit. Int J Circumpolar Health 2010; 69:3-12. [PMID: 20167152 DOI: 10.3402/ijch.v69i1.17427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES To genotype common genetic variants found in the adipose triglyceride lipase (ATGL) gene and test them for association with cardiovascular disease risk factors in the Greenland Inuit. STUDY DESIGN Candidate gene association study of discrete and quantitative traits related to cardiovascular health. METHODS ATGL was sequenced in 10 European subjects to identify DNA sequence variants. The identified polymorphisms were subsequently genotyped in a population-based cohort of 1,218 unrelated Greenland Inuit subjects, ascertained from the Greenland Population Study. Genotypes and reconstructed haplotypes were tested for association with cardiovascular disease risk factors using additive, dominant or recessive models, corrected for age, sex and body mass index. RESULTS Five single nucleotide polymorphisms and one 4-base pair deletion were identified in the European sample and were similarly polymorphic in the Greenland Inuit. Independently, variants were not associated with any cardiovascular traits. However, reconstructed rare ATGL haplotypes were associated with increased plasma triglyceride (TG) concentrations compared to the major haplotype under a dominant model (1.21+/-0.7 mmol/L and 1.11+/-0.6 mmol/L, respectively, p=0.006). CONCLUSIONS Rare ATGL haplotypes are associated with increased plasma TG concentrations in the Greenland Inuit.
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Current world literature. Curr Opin Lipidol 2010; 21:148-52. [PMID: 20616627 DOI: 10.1097/mol.0b013e3283390e49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Mateo-Gallego R, Calmarza P, Jarauta E, Burillo E, Cenarro A, Civeira F. Serum ferritin is a major determinant of lipid phenotype in familial combined hyperlipidemia and familial hypertriglyceridemia. Metabolism 2010; 59:154-8. [PMID: 19913843 DOI: 10.1016/j.metabol.2009.06.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 06/22/2009] [Accepted: 06/29/2009] [Indexed: 11/18/2022]
Abstract
Familial combined hyperlipidemia (FCH) and familial hypertriglyceridemia (FHTG) share pathogenic mechanisms and a high interaction with components of the metabolic syndrome. The metabolic syndrome associates increased serum ferritin concentration and high cardiovascular risk. The objective was to describe the frequency of iron overload and the relationship between serum ferritin and the phenotype in patients with FCH and FHTG. The study was composed of 211 consecutive unrelated patients aged at least 18 years with primary hypertriglyceridemia, 149 with FCH, and 62 with FHTG. The prevalence of the metabolic syndrome and hyperferritinemia was very high in both hypertriglyceridemic groups (51.7% and 20.1% in FCH and 62.9% and 16.1% in FHTG, respectively), without significant statistical differences between them. Serum ferritin concentration did not show any significant association with the number of metabolic syndrome criteria. Subjects in the highest tertile of ferritin concentration (ferritin >200 mug/L) presented higher concentrations of triglycerides and liver enzymes than subjects in the first tertile of ferritin concentration (ferritin <90 mug/L). The highest positive correlation coefficient for triglycerides was found with ferritin in FCH and in FHTG subjects (R = 0.317 [P < .001] when combined). Ferritin was also the covariate that showed the highest independent association with triglycerides in FCH and FHTG. In contrast, ferritin was not associated with carotid intima-media thickness. In summary, serum ferritin is commonly increased in FCH and in FHTG, it is not related with the presence of metabolic syndrome, and it is highly correlated with liver enzymes.
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Affiliation(s)
- Rocio Mateo-Gallego
- Unidad de Lípidos and Laboratorio de Investigación Molecular, Hospital Universitario Miguel Servet, Instituto Aragonés de Ciencias de la Salud, 50009 Zaragoza, Spain.
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Solanas-Barca M, Mateo-Gallego R, Calmarza P, Jarauta E, Bea AM, Cenarro A, Civeira F. Mutations in HFE causing hemochromatosis are associated with primary hypertriglyceridemia. J Clin Endocrinol Metab 2009; 94:4391-7. [PMID: 19820015 DOI: 10.1210/jc.2009-0814] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Most cases of primary hypertriglyceridemia (HTG) are caused by the interaction of unknown polygenes and environmental factors. Elevated iron storage is associated with metabolic syndrome, diabetes, and obesity, and all of them are associated with HTG. OBJECTIVE The aim of the study was to analyze whether HFE mutations causing hereditary hemochromatosis (HH) are associated with primary HTG. DESIGN Genetic predisposition to HH was analyzed in a case-control study. SETTING The study was conducted at University Hospital Lipid Clinic. PARTICIPANTS We studied two groups: 1) the HTG group, composed of 208 patients; and 2) the control group, composed of 215 normolipemic subjects and 161 familial hypercholesterolemia patients. INTERVENTION Two HFE mutations (C282Y and H63D) were analyzed. MAIN OUTCOME MEASURE We measured HH genetic predisposition difference between groups. RESULTS HH genetic predisposition was 5.9 and 4.4 times higher in the HTG group than in the normolipemic (P = 0.02) and FH (P = 0.05) subjects, respectively. There were 35 cases (16.8%) of iron overload in the primary HTG group, 14 (6.5%) and nine (5.6%) in the normolipidemic and FH groups, respectively. A higher HH genetic predisposition and a different prevalence of iron overload in subjects with HH genetic predisposition among groups contributed to this higher prevalence. None of the four cases with the HFE genotype associated with high risk of HH in the control groups presented iron overload; however, in eight of 11 subjects (72.7%) with primary HTG and HH genetic predisposition, the iron overload was present. CONCLUSION Mutations in HFE gene, favoring iron overload and causing HH, could play an important role in the development of several phenotypes of primary HTG.
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Affiliation(s)
- María Solanas-Barca
- Unidad de Lípidos and Laboratorio de Investigación Molecular, Hospital Universitario Miguel Servet, Instituto Aragonés de Ciencias de la Salud (I+CS), 50009 Zaragoza, Spain
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Hegele RA, Ban MR, Hsueh N, Kennedy BA, Cao H, Zou GY, Anand S, Yusuf S, Huff MW, Wang J. A polygenic basis for four classical Fredrickson hyperlipoproteinemia phenotypes that are characterized by hypertriglyceridemia. Hum Mol Genet 2009; 18:4189-94. [PMID: 19656773 PMCID: PMC2758142 DOI: 10.1093/hmg/ddp361] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Revised: 07/19/2009] [Accepted: 07/27/2009] [Indexed: 11/13/2022] Open
Abstract
Numerous single nucleotide polymorphisms (SNPs) have been found in recent genome wide association studies (GWAS) to be associated with subtle plasma triglyceride (TG) variation in normolipidemic subjects. However, since these GWAS did not specifically evaluate patients with rare disorders of lipoprotein metabolism--'hyperlipoproteinemia' (HLP)--it remains largely unresolved whether any of these SNP determinants of modest physiological changes in TG are necessarily also determinants of most HLP phenotypes. To address this question, we evaluated 28 TG-associated SNPs from GWAS in 386 unrelated adult patients with one of five Fredrickson phenotypes (HLP types 2A, 2B, 3, 4 and 5) and 242 matched normolipidemic controls. We found that several SNPs associated with TG in normolipidemic samples, including APOA5 p.S19W and -1131T>C, TRIB1 rs17321515, TBL2 rs17145738, GCKR rs780094, GALNT2 rs4846914 and ANGPTL3 rs12130333, were significantly associated with HLP types 2B, 3, 4 and 5. The findings indicate that: (i) the TG-associated Fredrickson HLP types 2B, 3, 4 and 5 are polygenic traits; (ii) these Fredrickson HLP types share numerous genetic determinants among themselves; and (iii) genetic determinants of modest TG variation in normolipidemic population samples also underlie--to an apparently even greater degree--susceptibility to these rare HLP phenotypes. Thus, the TG-associated Fredrickson HLP types 2B, 3, 4 and 5, although historically considered to be distinct are actually complex traits sharing among them several common genetic determinants seen in GWAS of normolipidemic population samples.
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Affiliation(s)
- Robert A Hegele
- Vascular Biology Research Group, Robarts Research Institute and Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
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