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Tada H, Kojima N, Nomura A, Takamura M. A Family with Familial Hypobetalipoproteinemia Caused by a c.1468C>T in APOB. Intern Med 2024; 63:2637-2640. [PMID: 38369355 DOI: 10.2169/internalmedicine.3033-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/20/2024] Open
Abstract
We herein report the first family of Japanese individuals with familial hypobetalipoproteinemia caused by the c.1468C>T mutation in apolipoprotein B (APOB). A 13-year-old boy with extremely low levels of low-density lipoprotein (LDL) cholesterol (24 mg/dL) was referred to our hospital. The patient had no secondary causes of hypobetalipoproteinemia. His father and grandmother also exhibited low LDL cholesterol levels. A genetic analysis confirmed that they all had this variant in APOB (c.1468C>T). None of the patients exhibited atherosclerotic cardiovascular diseases or any other complications associated with low LDL cholesterol levels, including fatty liver, neurocognitive disorders, and cerebral hemorrhaging.
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Affiliation(s)
- Hayato Tada
- Department of Cardiology, Kanazawa University Graduate School of Medicine, Japan
| | - Nobuko Kojima
- Department of Cardiology, Kanazawa University Graduate School of Medicine, Japan
| | - Akihiro Nomura
- Department of Cardiology, Kanazawa University Graduate School of Medicine, Japan
| | - Masayuki Takamura
- Department of Cardiology, Kanazawa University Graduate School of Medicine, Japan
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2
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Henry Z, Janin A, Nony S, Marmontel O, Cariou B, Marrec M, Caussy C, Charrière S, Moulin P, Rieusset J, Perros F, Di Filippo M. Interest of minigene splicing reporter assay in familial hypobetalipoproteinemia genetic diagnosis: the example of the missense mutation APOB c.1468C>T. Clin Chem Lab Med 2023; 61:e259-e262. [PMID: 37309596 DOI: 10.1515/cclm-2023-0330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/02/2023] [Indexed: 06/14/2023]
Affiliation(s)
- Zoé Henry
- Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, Bron, France
- Fédération d'endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Alexandre Janin
- Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, Bron, France
- CNRS UMR5261, INSERM U1315, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Séverine Nony
- Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, Bron, France
| | - Oriane Marmontel
- Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, Bron, France
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Bertrand Cariou
- Nantes Université, CHU Nantes, CNRS, INSERM, L'institut du Thorax, Nantes, France
| | - Marie Marrec
- Nantes Université, CHU Nantes, CNRS, INSERM, L'institut du Thorax, Nantes, France
| | - Cyrielle Caussy
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
- Hôpital Lyon Sud, Département Endocrinologie, Diabète et Nutrition, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Sybil Charrière
- Fédération d'endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Philippe Moulin
- Fédération d'endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Jennifer Rieusset
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Frédéric Perros
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Mathilde Di Filippo
- Service de Biochimie et Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, Bron, France
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Claude Bernard Lyon 1, Pierre-Bénite, France
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3
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Strøm TB, Asprusten E, Laerdahl JK, Øygard I, Hussain MM, Bogsrud MP, Leren TP. Missense mutation Q384K in the APOB gene affecting the large lipid transfer module of apoB reduces the secretion of apoB-100 in the liver without reducing the secretion of apoB-48 in the intestine. J Clin Lipidol 2023; 17:800-807. [PMID: 37718180 DOI: 10.1016/j.jacl.2023.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/10/2023] [Accepted: 08/26/2023] [Indexed: 09/19/2023]
Abstract
BACKGROUND Molecular genetic testing of patients with hypobetalipoproteinemia may identify a genetic cause that can form the basis for starting proper therapy. Identifying a genetic cause may also provide novel data on the structure-function relationship of the mutant protein. OBJECTIVE To identify a genetic cause of hypobetalipoproteinemia in a patient with levels of low density lipoprotein cholesterol at the detection limit of 0.1 mmol/l. METHODS DNA sequencing of the translated exons with flanking intron sequences of the genes adenosine triphosphate-binding cassette transporter 1, angiopoietin-like protein 3, apolipoprotein B, apolipoprotein A1, lecithin-cholesterol acyltransferase, microsomal triglyceride transfer protein and proprotein convertase subtilisin/kexin type 9. RESULTS The patient was homozygous for mutation Q384K (c.1150C>A) in the apolipoprotein B gene, and this mutation segregated with hypobetalipoproteinemia in the family. Residue Gln384 is located in the large lipid transfer module of apoB that has been suggested to be important for lipidation of apolipoprotein B through interaction with microsomal triglyceride transfer protein. Based on measurements of serum levels of triglycerides and apolipoprotein B-48 after an oral fat load, we conclude that the patient was able to synthesize apolipoprotein B-48 in the intestine in a seemingly normal fashion. CONCLUSION Our data indicate that mutation Q384K severely reduces the secretion of apolipoprotein B-100 in the liver without reducing the secretion of apolipoprotein B-48 in the intestine. Possible mechanisms for the different effects of this and other missense mutations affecting the large lipid transfer module on the two forms of apoB are discussed.
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Affiliation(s)
- Thea Bismo Strøm
- Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital, Oslo, Norway (Drs Strøm, Bogsrud and Leren).
| | - Emil Asprusten
- Lipid Clinic, Oslo University Hospital, Oslo, Norway (Dr Asprusten)
| | - Jon K Laerdahl
- Department of Microbiology, Oslo University Hospital, Oslo, Norway (Dr Laerdahl); ELIXIR Norway, Department of Informatics, University of Oslo, Oslo, Norway (Dr Laerdahl)
| | - Irene Øygard
- Fagernes Medical Center, Fagernes, Norway (Dr Øygard)
| | - M Mahmood Hussain
- Department of Foundations of Medicine, NYU Long Island School of Medicine, Mineola, NY 11501, USA (Dr. Hussain)
| | - Martin Prøven Bogsrud
- Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital, Oslo, Norway (Drs Strøm, Bogsrud and Leren)
| | - Trond P Leren
- Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital, Oslo, Norway (Drs Strøm, Bogsrud and Leren)
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4
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Guidance for the diagnosis and treatment of hypolipidemia disorders. J Clin Lipidol 2022; 16:797-812. [DOI: 10.1016/j.jacl.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 08/31/2022] [Indexed: 11/15/2022]
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5
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Vanhoye X, Janin A, Caillaud A, Rimbert A, Venet F, Gossez M, Dijk W, Marmontel O, Nony S, Chatelain C, Durand C, Lindenbaum P, Rieusset J, Cariou B, Moulin P, Di Filippo M. APOB CRISPR-Cas9 Engineering in Hypobetalipoproteinemia: A Promising Tool for Functional Studies of Novel Variants. Int J Mol Sci 2022; 23:4281. [PMID: 35457099 PMCID: PMC9030618 DOI: 10.3390/ijms23084281] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 02/01/2023] Open
Abstract
Hypobetalipoproteinemia is characterized by LDL-cholesterol and apolipoprotein B (apoB) plasma levels below the fifth percentile for age and sex. Familial hypobetalipoproteinemia (FHBL) is mostly caused by premature termination codons in the APOB gene, a condition associated with fatty liver and steatohepatitis. Nevertheless, many families with a FHBL phenotype carry APOB missense variants of uncertain significance (VUS). We here aimed to develop a proof-of-principle experiment to assess the pathogenicity of VUS using the genome editing of human liver cells. We identified a novel heterozygous APOB-VUS (p.Leu351Arg), in a FHBL family. We generated APOB knock-out (KO) and APOB-p.Leu351Arg knock-in Huh7 cells using CRISPR-Cas9 technology and studied the APOB expression, synthesis and secretion by digital droplet PCR and ELISA quantification. The APOB expression was decreased by 70% in the heterozygous APOB-KO cells and almost abolished in the homozygous-KO cells, with a consistent decrease in apoB production and secretion. The APOB-p.Leu351Arg homozygous cells presented with a 40% decreased APOB expression and undetectable apoB levels in cellular extracts and supernatant. Thus, the p.Leu351Arg affected the apoB secretion, which led us to classify this new variant as likely pathogenic and to set up a hepatic follow-up in this family. Therefore, the functional assessment of APOB-missense variants, using gene-editing technologies, will lead to improvements in the molecular diagnosis of FHBL and the personalized follow-up of these patients.
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Affiliation(s)
- Xavier Vanhoye
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
| | - Alexandre Janin
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Université Claude Bernard Lyon 1, Université de Lyon, F-69008 Lyon, France
| | - Amandine Caillaud
- Institut du Thorax, Nantes Université, CHU Nantes, CNRS, INSERM, F-44000 Nantes, France; (A.C.); (B.C.)
| | - Antoine Rimbert
- Institut du Thorax, Nantes Université, CNRS, INSERM, F-44000 Nantes, France; (A.R.); (W.D.); (P.L.)
| | - Fabienne Venet
- Laboratoire d’Immunologie, Edouard Herriot Hospital, Hospices Civils de Lyon, F-69437 Lyon, France; (F.V.); (M.G.)
- Centre International de Recherche en Infectiologie (CIRI), INSERM U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard-Lyon 1, F-69364 Lyon, France
| | - Morgane Gossez
- Laboratoire d’Immunologie, Edouard Herriot Hospital, Hospices Civils de Lyon, F-69437 Lyon, France; (F.V.); (M.G.)
- Centre International de Recherche en Infectiologie (CIRI), INSERM U1111, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard-Lyon 1, F-69364 Lyon, France
| | - Wieneke Dijk
- Institut du Thorax, Nantes Université, CNRS, INSERM, F-44000 Nantes, France; (A.R.); (W.D.); (P.L.)
| | - Oriane Marmontel
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, F-69364 Lyon, France; (C.D.); (J.R.); (P.M.)
| | - Séverine Nony
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
| | - Charlotte Chatelain
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
| | - Christine Durand
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, F-69364 Lyon, France; (C.D.); (J.R.); (P.M.)
| | - Pierre Lindenbaum
- Institut du Thorax, Nantes Université, CNRS, INSERM, F-44000 Nantes, France; (A.R.); (W.D.); (P.L.)
| | - Jennifer Rieusset
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, F-69364 Lyon, France; (C.D.); (J.R.); (P.M.)
| | - Bertrand Cariou
- Institut du Thorax, Nantes Université, CHU Nantes, CNRS, INSERM, F-44000 Nantes, France; (A.C.); (B.C.)
| | - Philippe Moulin
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, F-69364 Lyon, France; (C.D.); (J.R.); (P.M.)
- Fédération d’Endocrinologie, Maladies Métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, F-69677 Bron, France
| | - Mathilde Di Filippo
- Service de Biochimie et de Biologie Moléculaire, Laboratoire de Biologie Médicale MultiSites, Hospices Civils de Lyon, F-69677 Bron, France; (X.V.); (A.J.); (O.M.); (S.N.); (C.C.)
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, F-69364 Lyon, France; (C.D.); (J.R.); (P.M.)
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Domenech M, Llano-Rivas I, Arroyo V, Ortega E. Novel APOB mutation in familial hypobetalipoproteinemia. J Clin Lipidol 2021; 16:28-32. [PMID: 34852964 DOI: 10.1016/j.jacl.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Affiliation(s)
- M Domenech
- Lipid and Vascular Risk Unit, Endocrinology and Nutrition Department, Hospital Clinic of Barcelona, Spain; Faculty of Medicine and Health Sciences. University of Barcelona. Spain; Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN). Institute of Health Carlos III, ISCIII. Spain
| | - Isabel Llano-Rivas
- Clinical Genetics, Genetic Service. Hospital Universitario Cruces, Basque Country, Spain
| | - Vicente Arroyo
- EF Clif, EASL-CLIF Consortium and Grifols Chair, Barcelona, Spain
| | - Emilio Ortega
- Lipid and Vascular Risk Unit, Endocrinology and Nutrition Department, Hospital Clinic of Barcelona, Spain; Faculty of Medicine and Health Sciences. University of Barcelona. Spain; Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBEROBN). Institute of Health Carlos III, ISCIII. Spain.
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7
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Ayoub C, Azar Y, Abou-Khalil Y, Ghaleb Y, Elbitar S, Halaby G, Jambart S, Gannagé-Yared MH, Yaghi C, Saade Riachy C, El Khoury R, Rabès JP, Varret M, Boileau C, El Khoury P, Abifadel M. Identification of a Variant in APOB Gene as a Major Cause of Hypobetalipoproteinemia in Lebanese Families. Metabolites 2021; 11:564. [PMID: 34564380 PMCID: PMC8469161 DOI: 10.3390/metabo11090564] [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] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 08/13/2021] [Accepted: 08/14/2021] [Indexed: 12/03/2022] Open
Abstract
Familial hypobetalipoproteinemia (FHBL) is a codominant genetic disorder characterized by reduced plasma levels of low-density lipoprotein cholesterol and apolipoprotein B. To our knowledge, no study on FHBL in Lebanon and the Middle East region has been reported. Therefore, we conducted genetic studies in unrelated families and probands of Lebanese origin presenting with FHBL, in order to identify the causes of this disease. We found that 71% of the recruited probands and their affected relatives were heterozygous for the p.(Arg490Trp) variant in the APOB gene. Haplotype analysis showed that these patients presented the same mutant haplotype. Moreover, there was a decrease in plasma levels of PCSK9 in affected individuals compared to the non-affected and a significant positive correlation between circulating PCSK9 and ApoB levels in all studied probands and their family members. Some of the p.(Arg490Trp) carriers suffered from diabetes, hepatic steatosis or neurological problems. In conclusion, the p.(Arg490Trp) pathogenic variant seems a cause of FHBL in patients from Lebanese origin, accounting for approximately 70% of the probands with FHBL presumably as a result of a founder mutation in Lebanon. This study is crucial to guide the early diagnosis, management and prevention of the associated complications of this disease.
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Affiliation(s)
- Carine Ayoub
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
| | - Yara Azar
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
- Centre Hospitalo-Universitaire Xavier Bichat, Université de Paris, F-75018 Paris, France
| | - Yara Abou-Khalil
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
- Centre Hospitalo-Universitaire Xavier Bichat, Université de Paris, F-75018 Paris, France
| | - Youmna Ghaleb
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
| | - Sandy Elbitar
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
| | - Georges Halaby
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
| | - Selim Jambart
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
| | - Marie-Hélène Gannagé-Yared
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Hotel Dieu de France of Beirut University Hospital, Beirut 166830, Lebanon
| | - Cesar Yaghi
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Hotel Dieu de France of Beirut University Hospital, Beirut 166830, Lebanon
| | - Carole Saade Riachy
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
| | - Ralph El Khoury
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
| | - Jean-Pierre Rabès
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
- Biochemistry and Molecular Genetics Laboratory, AP-HP, Université Paris-Saclay, Ambroise Paré Hospital, Boulogne Billancourt, UVSQ, UFR Simone Veil-Santé, F-78180 Montigny-Le-Bretonneux, France
| | - Mathilde Varret
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
- Centre Hospitalo-Universitaire Xavier Bichat, Université de Paris, F-75018 Paris, France
| | - Catherine Boileau
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
- Centre Hospitalo-Universitaire Xavier Bichat, Université de Paris, F-75018 Paris, France
- Genetics Department, AP-HP, Bichat Hospital, F-75018 Paris, France
| | - Petra El Khoury
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
| | - Marianne Abifadel
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie-Santé, Saint Joseph University of Beirut, Beirut 17-5208, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM U1148, Bichat Hospital, F-75018 Paris, France
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8
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Rimbert A, Vanhoye X, Coulibaly D, Marrec M, Pichelin M, Charrière S, Peretti N, Valéro R, Wargny M, Carrié A, Lindenbaum P, Deleuze JF, Genin E, Redon R, Rollat-Farnier PA, Goxe D, Degraef G, Marmontel O, Divry E, Bigot-Corbel E, Moulin P, Cariou B, Di Filippo M. Phenotypic Differences Between Polygenic and Monogenic Hypobetalipoproteinemia. Arterioscler Thromb Vasc Biol 2020; 41:e63-e71. [PMID: 33207932 DOI: 10.1161/atvbaha.120.315491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Primary hypobetalipoproteinemia is characterized by LDL-C (low-density lipoprotein cholesterol) concentrations below the fifth percentile. Primary hypobetalipoproteinemia mostly results from heterozygous mutations in the APOB (apolipoprotein B) and PCSK9 genes, and a polygenic origin is hypothesized in the remaining cases. Hypobetalipoproteinemia patients present an increased risk of nonalcoholic fatty liver disease and steatohepatitis. Here, we compared hepatic alterations between monogenic, polygenic, and primary hypobetalipoproteinemia of unknown cause. Approach and Results: Targeted next-generation sequencing was performed in a cohort of 111 patients with hypobetalipoproteinemia to assess monogenic and polygenic origins using an LDL-C-dedicated polygenic risk score. Forty patients (36%) had monogenic hypobetalipoproteinemia, 38 (34%) had polygenic hypobetalipoproteinemia, and 33 subjects (30%) had hypobetalipoproteinemia from an unknown cause. Patients with monogenic hypobetalipoproteinemia had lower LDL-C and apolipoprotein B plasma levels compared with those with polygenic hypobetalipoproteinemia. Liver function was assessed by hepatic ultrasonography and liver enzymes levels. Fifty-nine percent of patients with primary hypobetalipoproteinemia presented with liver steatosis, whereas 21% had increased alanine aminotransferase suggestive of liver injury. Monogenic hypobetalipoproteinemia was also associated with an increased prevalence of liver steatosis (81% versus 29%, P<0.001) and liver injury (47% versus 0%) compared with polygenic hypobetalipoproteinemia. CONCLUSIONS This study highlights the importance of genetic diagnosis in the clinical care of primary hypobetalipoproteinemia patients. It shows for the first time that a polygenic origin of hypobetalipoproteinemia is associated with a lower risk of liver steatosis and liver injury versus monogenic hypobetalipoproteinemia. Thus, polygenic risk score is a useful tool to establish a more personalized follow-up of primary hypobetalipoproteinemia patients.
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Affiliation(s)
- Antoine Rimbert
- Université de Nantes, CNRS, INSERM, l'institut du thorax, France (A.R., M.P., M.W., P.L., R.R., B.C.)
| | - Xavier Vanhoye
- Hospices Civils de Lyon, UF Dyslipidémies Service de Biochimie et de Biologie Moléculaire Grand Est, Bron, France (X.V., D.C., O.M., E.D., M.D.F.)
| | - Dramane Coulibaly
- Hospices Civils de Lyon, UF Dyslipidémies Service de Biochimie et de Biologie Moléculaire Grand Est, Bron, France (X.V., D.C., O.M., E.D., M.D.F.)
| | - Marie Marrec
- L'institut du thorax, CHU NANTES, CIC INSERM 1413, France (M.M., M.P., M.W., B.C.)
| | - Matthieu Pichelin
- L'institut du thorax, CHU NANTES, CIC INSERM 1413, France (M.M., M.P., M.W., B.C.)
| | - Sybil Charrière
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France (S.C., N.P., O.M., P.M., M.D.F.).,Hospices Civils de Lyon, Fédération d'endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Bron, France (S.C., P.M.)
| | - Noël Peretti
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France (S.C., N.P., O.M., P.M., M.D.F.).,Hospices Civils de Lyon, Service de Gastroentérologie Hépatologie et Nutrition Pédiatrique, HFME, Bron, France (N.P.)
| | - René Valéro
- Aix Marseille Univ, APHM, INSERM, INRAE, C2VN, University Hospital La Conception, Department of Nutrition, Metabolic Diseases and Endocrinology, Marseille, France (R.V.)
| | - Matthieu Wargny
- Université de Nantes, CNRS, INSERM, l'institut du thorax, France (A.R., M.P., M.W., P.L., R.R., B.C.).,L'institut du thorax, CHU NANTES, CIC INSERM 1413, France (M.M., M.P., M.W., B.C.)
| | - Alain Carrié
- Sorbonne Universite, Inserm UMR_S116, Institute of Cardiometabolism and Nutrition (ICAN), Hopital Pitie-Salpetriere 75651 Paris, France (A.C.).,UF de génétique de l'Obésité et des Dyslipidémies, Laboratoire de Biochimie Endocrinienne et Oncologique, APHP, Sorbonne Université, Hôpital de la Pitié-salpêtrière, Paris, France (A.C.)
| | - Pierre Lindenbaum
- Université de Nantes, CNRS, INSERM, l'institut du thorax, France (A.R., M.P., M.W., P.L., R.R., B.C.)
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine, Institut de Génomique, CEA, Evry, France (J.-F.D.)
| | - Emmanuelle Genin
- Inserm, Univ Brest, EFS, CHU Brest, UMR 1078, GGB, France (E.G.)
| | - Richard Redon
- Université de Nantes, CNRS, INSERM, l'institut du thorax, France (A.R., M.P., M.W., P.L., R.R., B.C.)
| | | | - Didier Goxe
- CPAM, Centre d'examens de santé de la CPAM de la Vendée, La Roche-sur-Yon, France (D.G.)
| | | | - Oriane Marmontel
- Hospices Civils de Lyon, UF Dyslipidémies Service de Biochimie et de Biologie Moléculaire Grand Est, Bron, France (X.V., D.C., O.M., E.D., M.D.F.).,CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France (S.C., N.P., O.M., P.M., M.D.F.)
| | - Eléonore Divry
- Hospices Civils de Lyon, UF Dyslipidémies Service de Biochimie et de Biologie Moléculaire Grand Est, Bron, France (X.V., D.C., O.M., E.D., M.D.F.)
| | - Edith Bigot-Corbel
- Laboratoire de Biochimie, CHU de Nantes, Hôpital G et R Laënnec, Bd Jacques Monod, Saint-Herblain (E.B.-C.)
| | - Philippe Moulin
- CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France (S.C., N.P., O.M., P.M., M.D.F.).,Hospices Civils de Lyon, Fédération d'endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Bron, France (S.C., P.M.)
| | - Bertrand Cariou
- Université de Nantes, CNRS, INSERM, l'institut du thorax, France (A.R., M.P., M.W., P.L., R.R., B.C.).,L'institut du thorax, CHU NANTES, CIC INSERM 1413, France (M.M., M.P., M.W., B.C.)
| | - Mathilde Di Filippo
- Hospices Civils de Lyon, UF Dyslipidémies Service de Biochimie et de Biologie Moléculaire Grand Est, Bron, France (X.V., D.C., O.M., E.D., M.D.F.).,CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France (S.C., N.P., O.M., P.M., M.D.F.)
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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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10
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Koerner CM, Roberts BS, Neher SB. Endoplasmic reticulum quality control in lipoprotein metabolism. Mol Cell Endocrinol 2019; 498:110547. [PMID: 31442546 PMCID: PMC6814580 DOI: 10.1016/j.mce.2019.110547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 12/26/2022]
Abstract
Lipids play a critical role in energy metabolism, and a suite of proteins is required to deliver lipids to tissues. Several of these proteins require an intricate endoplasmic reticulum (ER) quality control (QC) system and unique secondary chaperones for folding. Key examples include apolipoprotein B (apoB), which is the primary scaffold for many lipoproteins, dimeric lipases, which hydrolyze triglycerides from circulating lipoproteins, and the low-density lipoprotein receptor (LDLR), which clears cholesterol-rich lipoproteins from the circulation. ApoB requires specialized proteins for lipidation, dimeric lipases lipoprotein lipase (LPL) and hepatic lipase (HL) require a transmembrane maturation factor for secretion, and the LDLR requires several specialized, domain-specific chaperones. Deleterious mutations in these proteins or their chaperones may result in dyslipidemias, which are detrimental to human health. Here, we review the ER quality control systems that ensure secretion of apoB, LPL, HL, and LDLR with a focus on the specialized chaperones required by each protein.
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Affiliation(s)
- Cari M Koerner
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, USA
| | - Benjamin S Roberts
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, USA
| | - Saskia B Neher
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, USA.
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11
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In vitro functional characterization of splicing variants of the APOB gene found in familial hypobetalipoproteinemia. J Clin Lipidol 2019; 13:960-969. [PMID: 31629702 DOI: 10.1016/j.jacl.2019.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. OBJECTIVE The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. METHODS ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. RESULTS Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. CONCLUSIONS These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1.
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12
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Buonuomo PS, Rabacchi C, Macchiaiolo M, Trenti C, Fasano T, Tarugi P, Bartuli A, Bertolini S, Calandra S. Incidental finding of severe hypertriglyceridemia in children. Role of multiple rare variants in genes affecting plasma triglyceride. J Clin Lipidol 2017; 11:1329-1337.e3. [PMID: 28951076 DOI: 10.1016/j.jacl.2017.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/18/2017] [Accepted: 08/25/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND The incidental finding of severe hypertriglyceridemia (HyperTG) in a child may suggest the diagnosis of familial chylomicronemia syndrome (FCS), a recessive disorder of the intravascular hydrolysis of triglyceride (TG)-rich lipoproteins. FCS may be due to pathogenic variants in lipoprotein lipase (LPL), as well as in other proteins, such as apolipoprotein C-II and apolipoprotein A-V (activators of LPL), GPIHBP1 (the molecular platform required for LPL activity on endothelial surface) and LMF1 (a factor required for intracellular formation of active LPL). OBJECTIVE Molecular characterization of 5 subjects in whom HyperTG was an incidental finding during infancy/childhood. METHODS We performed the parallel sequencing of 20 plasma TG-related genes. RESULTS Three children with severe HyperTG were found to be compound heterozygous for rare pathogenic LPL variants (2 nonsense, 3 missense, and 1 splicing variant). Another child was found to be homozygous for a nonsense variant of APOA5, which was also found in homozygous state in his father with longstanding HyperTG. The fifth patient with a less severe HyperTG was found to be heterozygous for a frameshift variant in LIPC resulting in a truncated Hepatic Lipase. In addition, 1 of the patients with LPL deficiency and the patient with APOA-V deficiency were also heterozygous carriers of a pathogenic variant in LIPC and LPL gene, respectively, whereas the patient with LIPC variant was also a carrier of a rare APOB missense variant. CONCLUSIONS Targeted parallel sequencing of TG-related genes is recommended to define the molecular defect in children presenting with an incidental finding of HyperTG.
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Affiliation(s)
| | - Claudio Rabacchi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - Marina Macchiaiolo
- Rare Diseases and Medical Genetics, Bambino Gesù Children Hospital, Rome, Italy
| | - Chiara Trenti
- Department of Internal Medicine, Lipid Clinic, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy
| | - Tommaso Fasano
- Clinical Chemistry and Endocrinology Laboratory, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy
| | - Patrizia Tarugi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - Andrea Bartuli
- Rare Diseases and Medical Genetics, Bambino Gesù Children Hospital, Rome, Italy
| | - Stefano Bertolini
- Department of Internal Medicine, University of Genova, Genova, Italy.
| | - Sebastiano Calandra
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia, Modena, Italy.
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13
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Endoplasmic Reticulum Stress Caused by Lipoprotein Accumulation Suppresses Immunity against Bacterial Pathogens and Contributes to Immunosenescence. mBio 2017; 8:mBio.00778-17. [PMID: 28559483 PMCID: PMC5449662 DOI: 10.1128/mbio.00778-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The unfolded protein response (UPR) is a stress response pathway that is activated upon increased unfolded and/or misfolded proteins in the endoplasmic reticulum (ER), and enhanced ER stress response prolongs life span and improves immunity. However, the mechanism by which ER stress affects immunity remains poorly understood. Using the nematode Caenorhabditis elegans, we show that mutations in the lipoproteins vitellogenins, which are homologs of human apolipoprotein B-100, resulted in upregulation of the UPR. Lipoprotein accumulation in the intestine adversely affects the immune response and the life span of the organism, suggesting that it could be a contributing factor to immunosenescence. We show that lipoprotein accumulation inhibited the expression of several immune genes encoding proteins secreted by the intestinal cells in an IRE-1-independent manner. Our studies provide a mechanistic explanation for adverse effects caused by protein aggregation and ER stress on immunity and highlight the role of an IRE-1-independent pathway in the suppression of the expression of genes encoding secreted proteins. Increased accumulation of unfolded and/or misfolded proteins in the endoplasmic reticulum (ER) leads to enhanced ER stress. However, the mechanism(s) by which ER stress affects immunity remain understudied. Using the nematode C. elegans, we showed that mutations in lipoproteins lead to their accumulation in the intestine, causing ER stress and adversely affecting the life span of the organisms and their resistance to pathogen infection. Our results indicate that the ER stress caused by lipoprotein accumulation significantly reduced the levels of expression of genes encoding secreted immune effectors, contributing to immunosenescence. It is known that ER stress may suppress gene expression via IRE-1, which is a sensor of ER stress. The novel mechanism uncovered in our study is IRE-1 independent, which highlights the role of a novel process by which ER stress suppresses innate immunity.
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14
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Rabacchi C, Bigazzi F, Puntoni M, Sbrana F, Sampietro T, Tarugi P, Bertolini S, Calandra S. Phenotypic variability in 4 homozygous familial hypercholesterolemia siblings compound heterozygous for LDLR mutations. J Clin Lipidol 2016; 10:944-952.e1. [DOI: 10.1016/j.jacl.2016.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 12/31/2022]
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15
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Rimbert A, Pichelin M, Lecointe S, Marrec M, Le Scouarnec S, Barrak E, Croyal M, Krempf M, Le Marec H, Redon R, Schott JJ, Magré J, Cariou B. Identification of novel APOB mutations by targeted next-generation sequencing for the molecular diagnosis of familial hypobetalipoproteinemia. Atherosclerosis 2016; 250:52-6. [PMID: 27179706 DOI: 10.1016/j.atherosclerosis.2016.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/08/2016] [Accepted: 04/08/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND AIMS Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by decreased plasma levels of LDL-cholesterol and apolipoprotein B (ApoB). Currently, genetic diagnosis in FHBL relies largely on Sanger sequencing to identify APOB and PCSK9 gene mutations and on western blotting to detect truncated ApoB species. METHODS Here, we applied targeted enrichment and next-generation sequencing (NGS) on a panel of three FHBL genes and two abetalipoproteinemia genes (APOB, PCSK9, ANGPTL3, MTTP and SAR1B). RESULTS In this study, we identified five likely pathogenic heterozygous rare variants. These include four novel nonsense mutations in APOB (p.Gln845*, p.Gln2571*, p.Cys2933* and p.Ser3718*) and a rare variant in PCSK9 (Minor Allele Frequency <0.1%). The affected family members tested were shown to be carriers, suggesting co-segregation with low LDL-C. CONCLUSIONS Our study further demonstrates that NGS is a reliable and practical approach for the molecular screening of FHBL-causative genes that may provide a mean for deciphering the genetic basis in FHBL.
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Affiliation(s)
- Antoine Rimbert
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France
| | - Matthieu Pichelin
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France; CIC Thorax, CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Simon Lecointe
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Marie Marrec
- CHU Nantes, l'institut du Thorax, Nantes, F-44000, France; CIC Thorax, CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Solena Le Scouarnec
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France
| | - Elias Barrak
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Mikael Croyal
- Centre de Recherche en Nutrition Humaine de l'Ouest (CRNHO, INRA UMR1280), Nantes, F-44093, France
| | - Michel Krempf
- Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France; Centre de Recherche en Nutrition Humaine de l'Ouest (CRNHO, INRA UMR1280), Nantes, F-44093, France
| | - Hervé Le Marec
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Richard Redon
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France
| | - Jean-Jacques Schott
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France.
| | - Jocelyne Magré
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France
| | - Bertrand Cariou
- INSERM, UMR1087, l'institut du thorax, Nantes, F-44000, France; CNRS, UMR 6291, Nantes, F-44000, France; Université de Nantes, Nantes, F-44000, France; CHU Nantes, l'institut du Thorax, Nantes, F-44000, France; CIC Thorax, CHU Nantes, l'institut du Thorax, Nantes, F-44000, France.
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16
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Magnolo L, Noto D, Cefalù AB, Averna M, Calandra S, Yao Z, Tarugi P. Characterization of a mutant form of human apolipoprotein B (Thr26_Tyr27del) associated with familial hypobetalipoproteinemia. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:371-9. [DOI: 10.1016/j.bbalip.2016.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/14/2015] [Accepted: 01/24/2016] [Indexed: 10/22/2022]
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17
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Miller SA, Hooper AJ, Mantiri GA, Marais D, Tanyanyiwa DM, McKnight J, Burnett JR. Novel APOB missense variants, A224T and V925L, in a black South African woman with marked hypocholesterolemia. J Clin Lipidol 2016; 10:604-9. [PMID: 27206948 DOI: 10.1016/j.jacl.2016.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/06/2016] [Accepted: 01/25/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND One genetic cause of markedly low plasma concentrations of apolipoprotein (apo) B and low density lipoprotein (LDL)-cholesterol is familial hypobetalipoproteinemia. OBJECTIVE We aimed to determine the molecular basis for the marked hypocholesterolemia consistent with heterozygous familial hypobetalipoproteinemia in a black female subject of Xhosa lineage. METHODS Coding regions of APOB, MTTP, PCSK9,ANGPTL3, SAR1B and APOC3 were sequenced, and APOE was genotyped. COS-7 cells were transfected with plasmids containing apoB variants. Western blotting was used to detect cellular and secreted apoB, and co-immunoprecipitation performed to assess binding with the microsomal triglyceride transfer protein (MTP). RESULTS Sequence analysis of the APOB gene revealed her to be heterozygous for two novel variants, c.751G>A (A224T) and c.2854G>C (V925L). She was also homozygous for the APOEε2 allele, and did not carry a PCSK9 loss-of-function mutation. Although Ala(224) is within the postulated MTP binding region in apoB, it is not conserved among mammalian species. Subsequent genotyping showed that Ala224Thr is found in a southern African population (n=654) with an allele frequency of 1.15% and is not associated with plasma lipid levels. Val(925), like Ala(224), is within the N-terminal 1000 amino acids required for lipoprotein assembly, but was not found in the population screen. However, in vitro studies showed that apoB V925L did not affect apoB48 production or secretion nor have a deleterious effect on MTP interaction with apoB. CONCLUSION Taken together, this suggests that the hypocholesterolemia in our case may be a result of being homozygous for APOEε2 with a low baseline cholesterol.
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Affiliation(s)
- Sharon A Miller
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia
| | - Amanda J Hooper
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia; School of Medicine and Pharmacology, University of Western Australia, Perth, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine WA, Royal Perth Hospital and Fiona Stanley Hospital, Perth, Western Australia, Australia
| | - George A Mantiri
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia
| | - David Marais
- Division of Chemical Pathology, University of Cape Town, National Health Laboratory Service and MRC Cape Heart Group, Cape Town, South Africa
| | - Donald M Tanyanyiwa
- University of Witwatersrand and National Health Laboratory Service and Division of Human Genetics, University of Cape Town, Cape Town, South Africa
| | - James McKnight
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - John R Burnett
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine WA, Royal Perth Hospital and Fiona Stanley Hospital, Perth, Western Australia, Australia.
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18
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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19
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Yilmaz BS, Mungan NO, Di Leo E, Magnolo L, Artuso L, Bernardis I, Tumgor G, Kor D, Tarugi P. Homozygous familial hypobetalipoproteinemia: A Turkish case carrying a missense mutation in apolipoprotein B. Clin Chim Acta 2016; 452:185-90. [DOI: 10.1016/j.cca.2015.11.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/15/2022]
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20
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Hooper AJ, Heeks L, Robertson K, Champain D, Hua J, Song S, Parhofer KG, Barrett PHR, van Bockxmeer FM, Burnett JR. Lipoprotein Metabolism in APOB L343V Familial Hypobetalipoproteinemia. J Clin Endocrinol Metab 2015; 100:E1484-90. [PMID: 26323024 DOI: 10.1210/jc.2015-2731] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
CONTEXT Familial hypobetalipoproteinemia (FHBL) is a codominant disorder of lipoprotein metabolism characterized by decreased plasma concentrations of low-density lipoprotein (LDL)-cholesterol and apolipoprotein B (apoB). OBJECTIVE The objective was to examine the effect of heterozygous APOB L343V FHBL on postprandial triglyceride-rich lipoprotein (TRL) and fasting lipoprotein metabolism. METHODS Plasma incremental area under the curve apoB-48 and apoB-48 kinetics were determined after ingestion of a standardized oral fat load using compartmental modeling. Very low-density lipoprotein (VLDL)-, intermediate-density lipoprotein (IDL)-, and LDL-apoB kinetics were determined in the fasting state using stable isotope methods and compartmental modeling. RESULTS The postprandial incremental area under the curve (0-10 h) in FHBL subjects (n = 3) was lower for large TRL-triglyceride (-77%; P < .0001), small TRL-cholesterol (-83%; P < .001), small TRL-triglyceride (-88%; P < .001), and for plasma triglyceride (-70%; P < .01) and apoB (-63%; P < .0001) compared with controls. Compartmental analysis showed that apoB-48 production was lower (-91%; P < .05) compared with controls. VLDL-apoB concentrations in FHBL subjects (n = 2) were lower by more than 75% compared with healthy, normolipidemic control subjects (P < .01). The VLDL-apoB fractional catabolic rate (FCR) was more than 5-fold higher in the FHBL subjects (P = .07). ApoB production rates and IDL- and LDL-apoB FCRs were not different between FHBL subjects and controls. CONCLUSIONS We conclude that when compared to controls, APOB L343V FHBL heterozygotes show lower TRL production with normal postprandial TRL particle clearance. In contrast, VLDL-apoB production was normal, whereas the FCR was higher in heterozygotes compared with lean control subjects. These mechanisms account for the marked hypolipidemic state observed in these FHBL subjects.
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MESH Headings
- Adult
- Amino Acid Substitution
- Apolipoprotein B-48/blood
- Apolipoprotein B-48/metabolism
- Apolipoproteins B/blood
- Apolipoproteins B/genetics
- Apolipoproteins B/metabolism
- Diet, High-Fat/adverse effects
- Down-Regulation
- Female
- Heterozygote
- Humans
- Hypobetalipoproteinemia, Familial, Apolipoprotein B/blood
- Hypobetalipoproteinemia, Familial, Apolipoprotein B/genetics
- Hypobetalipoproteinemia, Familial, Apolipoprotein B/metabolism
- Lipoproteins/blood
- Lipoproteins/metabolism
- Lipoproteins, IDL/blood
- Lipoproteins, IDL/metabolism
- Lipoproteins, VLDL/blood
- Lipoproteins, VLDL/metabolism
- Male
- Meals
- Middle Aged
- Models, Biological
- Mutation
- Postprandial Period
- Triglycerides/blood
- Triglycerides/metabolism
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Affiliation(s)
- Amanda J Hooper
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Liesl Heeks
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Ken Robertson
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Danie Champain
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Jianmin Hua
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Swithin Song
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Klaus G Parhofer
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - P Hugh R Barrett
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - Frank M van Bockxmeer
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
| | - John R Burnett
- Department of Clinical Biochemistry (A.J.H., L.H., K.R., F.M.v.B., J.R.B.), PathWest Laboratory Medicine WA, Royal Perth Hospital, Perth WA 6000, Australia; School of Medicine and Pharmacology (A.J.H., D.C., P.H.R.B., J.R.B.), and School of Pathology and Laboratory Medicine (A.J.H., K.R.), University of Western Australia, Crawley WA 6009, Australia; Department of Radiology (J.H., S.S.), Royal Perth Hospital, Perth WA 6000, Australia; Medical Department II (K.G.P.), Grosshadern, University of Munich, 81377 Munich, Germany; and School of Surgery (F.M.v.B.), University of Western Australia, Crawley WA 6009, Australia
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Burnett JR, Hooper AJ. Vitamin E and oxidative stress in abetalipoproteinemia and familial hypobetalipoproteinemia. Free Radic Biol Med 2015; 88:59-62. [PMID: 26086616 DOI: 10.1016/j.freeradbiomed.2015.05.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/07/2015] [Accepted: 05/26/2015] [Indexed: 01/13/2023]
Abstract
Abetalipoproteinemia (ABL) and familial hypobetalipoproteinemia (FHBL) are genetic diseases characterized by low density lipoprotein deficiency. ABL presents early in life with the gastroenterological manifestations of fat malabsorption, steatorrhea, and failure to thrive, and later in life, with progressive ophthalmopathy and neuropathy as a result of deficiency of the fat-soluble vitamins A and E. Heterozygous FHBL subjects are usually asymptomatic, but may develop fatty liver disease. In homozygous (compound heterozygous) FHBL, the clinical and biochemical features are indistinguishable from those of ABL and treatment recommendations are the same: dietary fat restriction to prevent steatorrhea, and long-term high-dose vitamin E and A supplementation to prevent or at least slow the progression of neuromuscular and retinal degenerative disease. Despite their low plasma vitamin E levels, individuals with heterozygous FHBL do not require vitamin E supplementation. There are conflicting reports on whether increased oxidative stress is seen in ABL; these differences may relate to the small size of patient groups as well as differences in patient age and dose of vitamin E supplementation, or the contribution from dietary sources of vitamin E. High density lipoproteins in ABL appear to be severely oxidized yet able to inhibit platelet aggregation by binding to scavenger receptor B1. We review the role of vitamin E and oxidative stress in ABL and FHBL.
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Affiliation(s)
- John R Burnett
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Australia.
| | - Amanda J Hooper
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Australia; School of Pathology & Laboratory Medicine, University of Western Australia, Perth, Australia
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22
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Identification of Novel Mutations in Spatacsin and Apolipoprotein B Genes in a Patient with Spastic Paraplegia and Hypobetalipoproteinemia. Case Rep Genet 2015; 2015:219691. [PMID: 26064709 PMCID: PMC4439468 DOI: 10.1155/2015/219691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/14/2015] [Indexed: 11/30/2022] Open
Abstract
Complicated hereditary spastic paraplegia (HSP) presents with complex neurological and nonneurological manifestations. We report a patient with autosomal recessive (AR) HSP in whom laboratory investigations revealed hypobetalipoproteinemia raising the possibility of a shared pathophysiology of these clinical features. A lipid profile of his parents disclosed a normal maternal lipid profile. However, the paternal lipid profile was similar to that of the patient suggesting autosomal dominant transmission of this trait. Whole exome sequence analysis was performed and novel mutations were detected in both the SPG11 and the APOB genes. Genetic testing of the parents showed that both APOB variants were inherited from the father while the SPG11 variants were inherited one from each parent. Our results indicate that, in this patient, the hypobetalipoproteinemia and spastic paraplegia are unrelated resulting from mutations in two independent genes. This clinical study provides support for the use of whole exome sequencing as a diagnostic tool for identification of mutations in conditions with complex presentations.
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23
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The Janus-faced manifestations of homozygous familial hypobetalipoproteinemia due to apolipoprotein B truncations. J Clin Lipidol 2015; 9:400-5. [PMID: 26073401 DOI: 10.1016/j.jacl.2015.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/05/2014] [Accepted: 01/18/2015] [Indexed: 11/23/2022]
Abstract
Familial hypobetalipoproteinemia is a codominant disorder characterized by low plasma levels of low-density lipoprotein cholesterol and apolipoprotein B (apoB), which in ∼50% of the cases is due to mutations in APOB gene. In most cases, these mutations cause the formation of truncated apoBs of various sizes, which have a reduced capacity to bind lipids and form lipoprotein particles. Here, we describe 2 children with severe hypobetalipoproteinemia found to be homozygous for novel APOB gene mutations. The first case (HBL-201) was an asymptomatic 13-year-old boy incidentally found to have slightly elevated serum transaminases associated with hepatic steatosis. He was homozygous for a truncated apoB (2211 amino acids, apoB-48.74) whose size is similar to that of wild-type apoB-48 (2152 amino acids) produced by the intestine. ApoB-48.74 is expected to be incorporated into chylomicrons in the intestine but might have a reduced capacity to form secretion-competent very low-density lipoprotein in the liver. The second patient (HBL-96) was a 6-month-old girl suspected to have abetalipoproteinemia, for the presence of chronic diarrhea, failure to thrive, extremely severe hypobetalipoproteinemia, and low plasma levels of vitamin E and vitamin A. She was homozygous for a nonsense mutation (Gln513*) resulting in a short truncated apoB (apoB-11.30), which is not secreted into the plasma. In this patient, the impaired chylomicron formation is responsible for the severe clinical manifestations and growth retardation. In homozygous familial hypobetalipoproteinemia, the capacity of truncated apoBs to form chylomicrons is the major factor, which affects the severity of the clinical manifestations.
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24
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Cefalù AB, Norata GD, Ghiglioni DG, Noto D, Uboldi P, Garlaschelli K, Baragetti A, Spina R, Valenti V, Pederiva C, Riva E, Terracciano L, Zoja A, Grigore L, Averna MR, Catapano AL. Homozygous familial hypobetalipoproteinemia: two novel mutations in the splicing sites of apolipoprotein B gene and review of the literature. Atherosclerosis 2015; 239:209-17. [PMID: 25618028 DOI: 10.1016/j.atherosclerosis.2015.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/21/2014] [Accepted: 01/13/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Familial hypobetalipoproteinemia (FHBL) is autosomal codominant disorder of lipoprotein metabolism characterized by low plasma levels of total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) below the 5(th) percentile of the distribution in the population. Patients with the clinical diagnosis of homozygous FHBL (Ho-FHBL) are extremely rare and few patients have been characterized at the molecular level. Here we report the medical history and the molecular characterization of one paediatric patient with clinical features of Ho-FHBL. METHODS A one month old infant with failure to thrive, severe hypocholesterolemia and acanthocytosis was clinically and genetically characterized. Molecular characterization of the proband and her parents was performed by direct sequencing of the APOB gene and functional role of the identified mutations was assessed by the minigene methodology. RESULTS The proband was found carrying two novel splicing mutations of the APOB gene (c.3696+1G > C and c.3697-1G > A). CHOK1H8 cells expressing minigenes harbouring the mutations showed that these two mutations were associated with the retention of intron 23 and skipping of exon 24, resulting in two truncated apoB fragments of approximate size of 26-28 % of ApoB-100 and the total absence of apoB. CONCLUSION We describe the first case of Ho-FHBL due to two splicing mutations affecting both the donor and the acceptor splice sites of the same intron of the APOB gene occurring in the same patient. The clinical management of the proband is discussed and a review of the clinical and genetic features of the published Ho-FHBL cases is reported.
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Affiliation(s)
- Angelo B Cefalù
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), Università degli Studi di Palermo, Italy
| | - Giuseppe D Norata
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | | | - Davide Noto
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), Università degli Studi di Palermo, Italy
| | - Patrizia Uboldi
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Katia Garlaschelli
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Andrea Baragetti
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Rossella Spina
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), Università degli Studi di Palermo, Italy
| | - Vincenza Valenti
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), Università degli Studi di Palermo, Italy
| | - Cristina Pederiva
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Italy
| | - Enrica Riva
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Italy
| | | | - Alexa Zoja
- Department of Paediatrics, Melloni Hospital, Milano, Italy
| | - Liliana Grigore
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy; IRCCS Multimedica, Milano, Italy
| | - Maurizio R Averna
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), Università degli Studi di Palermo, Italy.
| | - Alberico L Catapano
- Department of Pharmacology and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy; IRCCS Multimedica, Milano, Italy.
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Abstract
"Primary hypobetalipoproteinemia" refers to an eclectic group of inherited lipoprotein disorders characterized by low concentrations of or absence of low-density lipoprotein cholesterol and apolipoprotein B in plasma. Abetalipoproteinemia and homozygous familial hypobetalipoproteinemia, although caused by mutations in different genes, are clinically indistinguishable. A framework for the clinical follow-up and management of these two disorders has been proposed recently, focusing on monitoring of growth in children and preventing complications by providing specialized dietary advice and fat-soluble vitamin therapeutic regimens. Other recent publications on familial combined hypolipidemia suggest that although a reduction of angiopoietin-like 3 activity may improve insulin sensitivity, complete deficiency also reduces serum cholesterol efflux capacity and increases the risk of early vascular atherosclerotic changes, despite low low-density lipoprotein cholesterol levels. Specialist laboratories offer exon-by-exon sequence analysis for the molecular diagnosis of primary hypobetalipoproteinemia. In the future, massively parallel sequencing of panels of genes involved in dyslipidemia may play a greater role in the diagnosis of these conditions.
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PCSK9 inhibition in LDL cholesterol reduction: Genetics and therapeutic implications of very low plasma lipoprotein levels. Pharmacol Ther 2015; 145:58-66. [DOI: 10.1016/j.pharmthera.2014.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 07/11/2014] [Indexed: 01/15/2023]
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27
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Di Filippo M, Moulin P, Roy P, Samson-Bouma ME, Collardeau-Frachon S, Chebel-Dumont S, Peretti N, Dumortier J, Zoulim F, Fontanges T, Parini R, Rigoldi M, Furlan F, Mancini G, Bonnefont-Rousselot D, Bruckert E, Schmitz J, Scoazec JY, Charrière S, Villar-Fimbel S, Gottrand F, Dubern B, Doummar D, Joly F, Liard-Meillon ME, Lachaux A, Sassolas A. Homozygous MTTP and APOB mutations may lead to hepatic steatosis and fibrosis despite metabolic differences in congenital hypocholesterolemia. J Hepatol 2014; 61:891-902. [PMID: 24842304 DOI: 10.1016/j.jhep.2014.05.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 04/16/2014] [Accepted: 05/06/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic steatohepatitis leading to fibrosis occurs in patients with abetalipoproteinemia (ABL) and homozygous or compound heterozygous familial hypobetalipoproteinemia (Ho-FHBL). We wanted to establish if liver alterations were more frequent in one of both diseases and were influenced by comorbidities. METHODS We report genetic, clinical, histological and biological characteristics of new cases of ABL (n =7) and Ho-FHBL (n = 7), and compare them with all published ABL (51) and Ho-FHBL (22) probands. RESULTS ABL patients, diagnosed during infancy, presented mainly with diarrhea, neurological and ophthalmological impairments and remained lean, whereas Ho-FHBL were diagnosed later, with milder symptoms often becoming overweight in adulthood. Despite subtle differences in lipid phenotype, liver steatosis was observed in both groups with a high prevalence of severe fibrosis (5/27 for Ho-FHBL vs. 4/58 for ABL (n.s.)). Serum triglycerides concentration was higher in Ho-FHBL whereas total and HDL-cholesterol were similar in both groups. In Ho-FHBL liver alterations were found to be independent from the apoB truncation size and apoB concentrations. CONCLUSIONS Our findings provide evidence for major liver abnormalities in both diseases. While ABL and Ho-FHBL patients have subtle differences in lipid phenotype, carriers of APOB mutations are more frequently obese. These results raise the question of a complex causal link between apoB metabolism and obesity. They suggest that the genetic defect in VLDL assembly is critical for the occurrence of liver steatosis leading to fibrosis and shows that obesity and insulin resistance might contribute by increasing lipogenesis.
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Affiliation(s)
- Mathilde Di Filippo
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France; INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France.
| | - Philippe Moulin
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France; Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Pascal Roy
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France; Centre National de la Recherche Scientifique UMR5558, Univ Lyon-1, Villeurbanne, France
| | | | | | - Sabrina Chebel-Dumont
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France
| | - Noël Peretti
- Service de Gastroentérologie Hépatologie et Nutrition Pédiatrique, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
| | - Jérôme Dumortier
- Fédération des Spécialités Digestives, Hôpital Edouard Herriot, Hospices Civils, Lyon, France
| | - Fabien Zoulim
- Service d'Hépato-Gastro-Entérologie, Hôpital de la Croix Rousse, Hospices Civils, Lyon, France
| | - Thierry Fontanges
- Service d'Hépato-Gastro-Entérologie, Centre Hospitalier Pierre Oudot, Bourgoin Jallieu, France
| | - Rossella Parini
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Miriam Rigoldi
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Francesca Furlan
- Rare Metabolic Disease Unit, Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Grazia Mancini
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Dominique Bonnefont-Rousselot
- Unité pédagogique de Biochimie, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; UPMC University Paris 6, UMR_S1166 Inserm ICAN, Paris, France; Service de Biochimie métabolique, Groupe hospitalier Pitié-Salpêtrière-Charles Foix, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Eric Bruckert
- Service d'Endocrinologie, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | - Jacques Schmitz
- Service de Gastroentérologie Pédiatrique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Jean Yves Scoazec
- Service d'anatomie pathologique, Hôpital Edouard Herriot, Hospices Civils, Lyon, France
| | - Sybil Charrière
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France; Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Sylvie Villar-Fimbel
- Fédération d'Endocrinologie, Maladies métaboliques, Diabète et Nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Frederic Gottrand
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Jeanne de Flandre university hospital, Lille, France
| | - Béatrice Dubern
- Nutrition et Gastroentérologie Pédiatriques, Hôpital Trousseau, AP-HP, Paris, France; Institut de Cardiométabolisme et Nutrition (ICAN), INSERM UMRS U872 (Eq7) Nutriomique, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Diane Doummar
- Service de Neuropédiatrie, Hôpital Trousseau, Paris, France
| | - Francesca Joly
- Service de Gastroentérologie et d'Assistance Nutritive, Hôpital Beaujon, Clichy, France
| | | | - Alain Lachaux
- Service de Gastroentérologie Hépatologie et Nutrition Pédiatrique, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France; INSERM U 1111, Faculté de médecine Lyon Est, Université Lyon 1, Lyon, France
| | - Agnès Sassolas
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et de Biologie Moléculaire du GHE, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Lyon, France; INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
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Lambert G, Petrides F, Chatelais M, Blom DJ, Choque B, Tabet F, Wong G, Rye KA, Hooper AJ, Burnett JR, Barter PJ, Marais AD. Elevated plasma PCSK9 level is equally detrimental for patients with nonfamilial hypercholesterolemia and heterozygous familial hypercholesterolemia, irrespective of low-density lipoprotein receptor defects. J Am Coll Cardiol 2014; 63:2365-73. [PMID: 24632287 DOI: 10.1016/j.jacc.2014.02.538] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/09/2014] [Accepted: 02/11/2014] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Do elevated proprotein convertase subtilisin/kexin type 9 (PCSK9) levels constitute an even greater risk for patients who already have reduced low-density lipoprotein receptor (LDLR) levels, such as those with heterozygous familial hypercholesterolemia (HeFH)? BACKGROUND As a circulating inhibitor of LDLR, PCSK9 is an attractive target for lowering LDL-cholesterol (LDL-C) levels. METHODS Circulating PCSK9 levels were measured by enzyme-linked immunosorbent assay in nontreated patients with HeFH carrying a D206E (n = 237), V408M (n = 117), or D154N (n = 38) LDLR missense mutation and in normolipidemic controls (n = 152). Skin fibroblasts and lymphocytes were isolated from a subset of patients and grown in 0.5% serum and mevastatin with increasing amounts of recombinant PCSK9. LDLR abundance at the cell surface was determined by flow cytometry. RESULTS PCSK9 reduced LDLR expression in a dose-dependent manner in control and FH fibroblasts to similar extents, by up to 77 ± 8% and 82 ± 7%, respectively. Likewise, PCSK9 reduced LDLR abundance by 39 ± 8% in nonfamilial hypercholesterolemia (non-FH) and by 45 ± 10% in HeFH lymphocytes, irrespective of their LDLR mutation status. We found positive correlations of the same magnitude between PCSK9 and LDL-C levels in controls (beta = 0.22; p = 0.0003), D206E (beta = 0.20; p = 0.0002), V408M (beta = 0.24; p = 0.0002), and D154N (beta = 0.25; p = 0.048) patients with HeFH. The strengths of these associations were all similar. CONCLUSIONS Elevated PCSK9 levels are equally detrimental for patients with HeFH or non-FH: a 100-ng/ml increase in PCSK9 will lead to an increase in LDL-C of 0.20 to 0.25 mmol/l in controls and HeFH alike, irrespective of their LDLR mutation. This explains why patients with non-FH or HeFH respond equally well to monoclonal antibodies targeting PCSK9.
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Affiliation(s)
- Gilles Lambert
- Faculté de Médecine, Université de Nantes, UMR PhAN 1280, Nantes, France; Lipid Research Group, Heart Research Institute, Sydney, Australia.
| | - Francine Petrides
- Lipid Research Group, Heart Research Institute, Sydney, Australia; Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Mathias Chatelais
- Faculté de Médecine, Université de Nantes, UMR PhAN 1280, Nantes, France
| | - Dirk J Blom
- Lipidology Division of Internal Medicine, MRC Cape Heart Group, University of Cape Town Health Science Faculty, Cape Town, South Africa
| | - Benjamin Choque
- Lipid Research Group, Heart Research Institute, Sydney, Australia
| | - Fatiha Tabet
- Lipid Research Group, Heart Research Institute, Sydney, Australia; Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Gida Wong
- Lipid Research Group, Heart Research Institute, Sydney, Australia
| | - Kerry-Anne Rye
- Lipid Research Group, Heart Research Institute, Sydney, Australia; Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Amanda J Hooper
- Royal Perth Hospital, Department of Clinical Biochemistry, PathWest Laboratory of Medicine WA, Perth, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia; School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - John R Burnett
- Royal Perth Hospital, Department of Clinical Biochemistry, PathWest Laboratory of Medicine WA, Perth, Australia; School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Philip J Barter
- Lipid Research Group, Heart Research Institute, Sydney, Australia; Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - A David Marais
- Chemical Pathology Division of Clinical Laboratory Sciences, MRC Cape Heart Group, University of Cape Town Health Science Faculty, Cape Town, South Africa
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Jiang ZG, Mukamal K, Tapper E, Robson SC, Tsugawa Y. Low LDL-C and high HDL-C levels are associated with elevated serum transaminases amongst adults in the United States: a cross-sectional study. PLoS One 2014; 9:e85366. [PMID: 24454851 PMCID: PMC3893181 DOI: 10.1371/journal.pone.0085366] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 11/25/2013] [Indexed: 01/14/2023] Open
Abstract
Background Dyslipidemia, typically recognized as high serum triglyceride, high low-density lipoprotein cholesterol (LDL-C) or low high-density lipoprotein cholesterol (HDL-C) levels, are associated with nonalcoholic fatty liver disease (NAFLD). However, low LDL-C levels could result from defects in lipoprotein metabolism or impaired liver synthetic function, and may serve as ab initio markers for unrecognized liver diseases. Whether such relationships exist in the general population has not been investigated. We hypothesized that despite common conception that low LDL-C is desirable, it might be associated with elevated liver enzymes due to metabolic liver diseases. Methods and Findings We examined the associations between alanine aminotransferase (ALT), aspartate aminotransferase (AST) and major components of serum lipid profiles in a nationally representative sample of 23,073 individuals, who had no chronic viral hepatitis and were not taking lipid-lowering medications, from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010. ALT and AST exhibited non-linear U-shaped associations with LDL-C and HDL-C, but not with triglyceride. After adjusting for potential confounders, individuals with LDL-C less than 40 and 41–70 mg/dL were associated with 4.2 (95% CI 1.5–11.7, p = 0.007) and 1.6 (95% CI 1.1–2.5, p = 0.03) times higher odds of abnormal liver enzymes respectively, when compared with those with LDL-C values 71–100 mg/dL (reference group). Surprisingly, those with HDL-C levels above 100 mg/dL was associated with 3.2 (95% CI 2.1–5.0, p<0.001) times higher odds of abnormal liver enzymes, compared with HDL-C values of 61–80 mg/dL. Conclusions Both low LDL-C and high HDL-C, often viewed as desirable, were associated with significantly higher odds of elevated transaminases in the general U.S. adult population. Our findings underscore an underestimated biological link between lipoprotein metabolism and liver diseases, and raise a potential need for liver evaluation among over 10 million people with particularly low LDL-C or high HDL-C in the United States.
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Affiliation(s)
- Zhenghui Gordon Jiang
- Division of Gastroenterology and Hepatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kenneth Mukamal
- Division of General Medicine and Primary Care, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Elliot Tapper
- Division of Gastroenterology and Hepatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Simon C Robson
- Division of Gastroenterology and Hepatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yusuke Tsugawa
- Division of General Medicine and Primary Care, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America ; Harvard University Interfaculty Initiative in Health Policy, Harvard University, Cambridge, Massachusetts, United States of America
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Non-alcoholic steatohepatitis-related cirrhosis in a patient with APOB L343V familial hypobetalipoproteinaemia. Clin Chim Acta 2013; 421:121-5. [DOI: 10.1016/j.cca.2013.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/01/2013] [Accepted: 03/01/2013] [Indexed: 01/01/2023]
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Cefalù AB, Pirruccello JP, Noto D, Gabriel S, Valenti V, Gupta N, Spina R, Tarugi P, Kathiresan S, Averna MR. A novel APOB mutation identified by exome sequencing cosegregates with steatosis, liver cancer, and hypocholesterolemia. Arterioscler Thromb Vasc Biol 2013; 33:2021-5. [PMID: 23723369 DOI: 10.1161/atvbaha.112.301101] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE In familial hypobetalipoproteinemia, fatty liver is a characteristic feature, and there are several reports of associated cirrhosis and hepatocarcinoma. We investigated a large kindred in which low-density lipoprotein cholesterol, fatty liver, and hepatocarcinoma displayed an autosomal dominant pattern of inheritance. APPROACH AND RESULTS The proband was a 25-year-old female with low plasma cholesterol and hepatic steatosis. Low plasma levels of total cholesterol and fatty liver were observed in 10 more family members; 1 member was affected by liver cirrhosis, and 4 more subjects died of either hepatocarcinoma or carcinoma on cirrhosis. To identify the causal mutation in this family, we performed exome sequencing in 2 participants with hypocholesterolemia and fatty liver. Approximately 22 400 single nucleotide variants were identified in each sample. After variant filtering, 300 novel shared variants remained. A nonsense variant, p.K2240X, attributable to an A>T mutation in exon 26 of APOB (c.6718A>T) was identified, and this variant was confirmed by Sanger sequencing. The gentotypic analysis of 16 family members in total showed that this mutation segregated with the low cholesterol trait. In addition, genotyping of the PNPLA3 p.I148M did not show significant frequency differences between carriers and noncarriers of the c.6718A>T APOB gene mutation. CONCLUSIONS We used exome sequencing to discover a novel nonsense mutation in exon 26 of APOB (p.K2240X) responsible for low cholesterol and fatty liver in a large kindred. This mutation may also be responsible for cirrhosis and liver cancer in this family.
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Affiliation(s)
- Angelo B Cefalù
- Dipartimento Biomedico di Medicina Interna e Specialistica, Università degli Studi di Palermo, Palermo, Italy
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Magnolo L, Najah M, Fancello T, Di Leo E, Pinotti E, Brini I, Gueddiche NM, Calandra S, Slimene NM, Tarugi P. Novel mutations in SAR1B and MTTP genes in Tunisian children with chylomicron retention disease and abetalipoproteinemia. Gene 2013; 512:28-34. [DOI: 10.1016/j.gene.2012.09.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 09/29/2012] [Indexed: 10/27/2022]
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Jiang ZG, Robson SC, Yao Z. Lipoprotein metabolism in nonalcoholic fatty liver disease. J Biomed Res 2012; 27:1-13. [PMID: 23554788 PMCID: PMC3596749 DOI: 10.7555/jbr.27.20120077] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/23/2012] [Accepted: 08/29/2012] [Indexed: 12/18/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), an escalating health problem worldwide, covers a spectrum of pathologies characterized by fatty accumulation in hepatocytes in early stages, with potential progression to liver inflammation, fibrosis, and failure. A close, yet poorly understood link exists between NAFLD and dyslipidemia, a constellation of abnormalities in plasma lipoproteins including triglyceride-rich very low density lipoproteins. Apolipoproteins are a group of primarily liver-derived proteins found in serum lipoproteins; they not only play an extracellular role in lipid transport between vital organs through circulation, but also play an important intracellular role in hepatic lipoprotein assembly and secretion. The liver functions as the central hub for lipoprotein metabolism, as it dictates lipoprotein production and to a significant extent modulates lipoprotein clearance. Lipoprotein metabolism is an integral component of hepatocellular lipid homeostasis and is implicated in the pathogenesis, potential diagnosis, and treatment of NAFLD.
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Affiliation(s)
- Zhenghui Gordon Jiang
- Department of Medicine, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
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Lam MCW, Singham J, Hegele RA, Riazy M, Hiob MA, Francis G, Steinbrecher UP. Familial hypobetalipoproteinemia-induced nonalcoholic steatohepatitis. Case Rep Gastroenterol 2012; 6:429-37. [PMID: 22855658 PMCID: PMC3398101 DOI: 10.1159/000339761] [Citation(s) in RCA: 8] [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] [Indexed: 01/30/2023] Open
Abstract
Familial hypobetalipoproteinemia (FHBL) is a rare genetic disorder of lipid metabolism that is associated with abnormally low serum levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B. It is an autosomal co-dominant disorder, and depending on zygosity, the clinical manifestations may vary from none to neurological, endocrine, hematological or liver dysfunction. Nonalcoholic fatty liver disease is common in persons with FHBL, however progression to nonalcoholic steatohepatitis is unusual. We describe here a patient with a novel APOB mutation, V703I, which appears to contribute to the severity of the FHBL phenotype. He had liver enzyme abnormalities, increased echogenicity of the liver consistent with steatosis, very low LDL cholesterol at 0.24 mmol/l (normal 1.8–3.5 mmol/l) and an extremely low apolipoprotein B level of 0.16 g/l (normal 0.6–1.2 g/l). APOB gene sequencing revealed him to be a compound heterozygote with two mutations (R463W and V703I). APOB R463W has previously been reported to cause FHBL. Genetic sequencing of his first-degree relatives identified the APOB V703I mutation in his normolipidemic brother and father and the APOB R463W mutation in his mother and sister, both of whom have very low LDL cholesterol levels. These results suggest that the APOB V703I mutation alone does not cause the FHBL phenotype. However, it is possible that it has a contributory role to a more aggressive phenotype in the presence of APOB R463W.
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Affiliation(s)
- Mindy C W Lam
- Divisions of Gastroenterology, University of British Columbia, Vancouver, B.C
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Pisciotta L, Favari E, Magnolo L, Simonelli S, Adorni MP, Sallo R, Fancello T, Zavaroni I, Ardigò D, Bernini F, Calabresi L, Franceschini G, Tarugi P, Calandra S, Bertolini S. Characterization of Three Kindreds With Familial Combined Hypolipidemia Caused by Loss-of-Function Mutations of ANGPTL3. ACTA ACUST UNITED AC 2012; 5:42-50. [DOI: 10.1161/circgenetics.111.960674] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Angiopoietin-like protein 3 (ANGPTL3) affects lipid metabolism by inhibiting the activity of lipoprotein and endothelial lipases.
Angptl3
knockout mice have marked hypolipidemia, and heterozygous carriers of
ANGPLT3
, loss-of-function mutations were found among individuals in the lowest quartile of plasma triglycerides in population studies. Recently, 4 related individuals with primary hypolipidemia were found to be compound heterozygotes for
ANGPTL3
loss-of-function mutations.
Methods and Results—
We resequenced
ANGPTL3
in 4 members of 3 kindreds originally identified for very low levels of low-density lipoprotein cholesterol and high-density lipoprotein cholesterol (0.97±0.16 and 0.56±0.20 mmol/L, respectively) in whom no mutations of known candidate genes for monogenic hypobetalipoproteinemia and hypoalphalipoproteinemia had been detected. These subjects were found to be homozygous or compound heterozygous for
ANGPTL3
loss-of-function mutations (p.G400VfsX5, p.I19LfsX22/p.N147X) associated with the absence of ANGPTL3 in plasma. They had reduced plasma levels of triglyceride-containing lipoproteins and of HDL particles that contained only apolipoprotein A-I and pre-β–high-density lipoprotein. In addition, their apolipoprotein B–depleted sera had a reduced capacity to promote cell cholesterol efflux through the various pathways (ABCA1-, SR-BI–, and ABCG1-mediated efflux); however, these subjects had no clinical evidence of accelerated atherosclerosis. Heterozygous carriers of the
ANGPTL3
mutations had low plasma ANGPTL3 and moderately reduced low-density lipoprotein cholesterol (2.52±0.38 mmol/L) but normal plasma high-density lipoprotein cholesterol.
Conclusions—
Complete ANGPTL3 deficiency caused by loss-of-function mutations of
ANGPTL3
is associated with a recessive hypolipidemia characterized by a reduction of apolipoprotein B and apolipoprotein A-I–containing lipoproteins, changes in subclasses of high-density lipoprotein, and reduced cholesterol efflux potential of serum. Partial ANGPTL3 deficiency is associated only with a moderate reduction of low-density lipoprotein.
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Affiliation(s)
- Livia Pisciotta
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Elda Favari
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Lucia Magnolo
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Sara Simonelli
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Maria Pia Adorni
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Raffaella Sallo
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Tatiana Fancello
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Ivana Zavaroni
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Diego Ardigò
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Franco Bernini
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Laura Calabresi
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Guido Franceschini
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Patrizia Tarugi
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Sebastiano Calandra
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
| | - Stefano Bertolini
- From the Department of Internal Medicine (L.P., R.S., S.B.), University of Genoa, Genoa, Italy; Department of Pharmacological and Biological Sciences and Applied Chemistries (E.F., M.P.A., F.B.) and Department of Internal Medicine and Biomedical Sciences (I.Z., D.A.), University of Parma, Parma, Italy; Department of Biomedical Sciences (L.M., T.F., P.T., S.C.), University of Modena and Reggio Emilia, Modena, Italy; and Center E. Grossi Paoletti (S.S., L.C., G.F.), Department of Pharmacological
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Calandra S, Tarugi P, Speedy HE, Dean AF, Bertolini S, Shoulders CC. Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk. J Lipid Res 2011; 52:1885-926. [PMID: 21862702 DOI: 10.1194/jlr.r017855] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.
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Affiliation(s)
- Sebastiano Calandra
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy.
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Hooper AJ, Adams LA, Burnett JR. Genetic determinants of hepatic steatosis in man. J Lipid Res 2011; 52:593-617. [PMID: 21245030 DOI: 10.1194/jlr.r008896] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatic steatosis is one of the most common liver disorders in the general population. The main cause of hepatic steatosis is nonalcoholic fatty liver disease (NAFLD), representing the hepatic component of the metabolic syndrome, which is characterized by type 2 diabetes, obesity, and dyslipidemia. Insulin resistance and excess adiposity are considered to play key roles in the pathogenesis of NAFLD. Although the risk factors for NAFLD are well established, the genetic basis of hepatic steatosis is largely unknown. Here we review recent progress on genomic variants and their association with hepatic steatosis and discuss the potential impact of these genetic studies on clinical practice. Identifying the genetic determinants of hepatic steatosis will lead to a better understanding of the pathogenesis and progression of NAFLD.
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Affiliation(s)
- Amanda J Hooper
- Department of Core Clinical Pathology and Biochemistry, Royal Perth Hospital, Perth, Australia
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New mutations in APOB100 involved in familial hypobetalipoproteinemia. J Clin Lipidol 2010; 4:181-4. [DOI: 10.1016/j.jacl.2010.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 02/16/2010] [Accepted: 02/16/2010] [Indexed: 11/15/2022]
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Sundaram M, Yao Z. Recent progress in understanding protein and lipid factors affecting hepatic VLDL assembly and secretion. Nutr Metab (Lond) 2010; 7:35. [PMID: 20423497 PMCID: PMC2873297 DOI: 10.1186/1743-7075-7-35] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 04/27/2010] [Indexed: 02/06/2023] Open
Abstract
Excess lipid induced metabolic disorders are one of the major existing challenges for the society. Among many different causes of lipid disorders, overproduction and compromised catabolism of triacylglycerol-rich very low density lipoproteins (VLDL) have become increasingly prevalent leading to hyperlipidemia worldwide. This review provides the latest understanding in different aspects of VLDL assembly process, including structure-function relationships within apoB, mutations in APOB causing hypobetalipoproteinemia, significance of modulating microsomal triglyceride-transfer protein activity in VLDL assembly, alterations of VLDL assembly by different fatty acid species, and hepatic proteins involved in vesicular trafficking, and cytosolic lipid droplet metabolism that contribute to VLDL assembly. The role of lipoprotein receptors and exchangeable apolipoproteins that promote or diminish VLDL assembly and secretion is discussed. New understanding on dysregulated insulin signaling as a consequence of excessive triacylglycerol-rich VLDL in the plasma is also presented. It is hoped that a comprehensive view of protein and lipid factors that contribute to molecular and cellular events associated with VLDL assembly and secretion will assist in the identification of pharmaceutical targets to reduce disease complications related to hyperlipidemia.
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Affiliation(s)
- Meenakshi Sundaram
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
| | - Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
- Department of Pathology and Laboratory Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
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Hu G, Wang SZ, Zhang S, Chen WX, Liu S, Tian JW, Li H. [Genetic analysis of epistatic effects between ApoB and UCP on abdominal fat trait in chicken]. YI CHUAN = HEREDITAS 2010; 32:59-66. [PMID: 20085887 DOI: 10.3724/sp.j.1005.2010.00059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
It has been found that epistasis for selective response plays an indispensible role in animal genetics and breeding. In this study, the polymorphisms of T123G in apoliprotein B (ApoB) and C1197A in uncoupling protein (UCP) among individuals from the 8th to the 10th generation populations of the Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHFL) were detected, and genetic analysis of the epistatic effects between the two SNPs on abdominal fat percentage (AFP) was performed using Natural and Orthogonal InterActions (NOIA) model. According to these assays, we concluded that at least one out of four epistatic components between these two SNPs was significantly associated with AFP (Plt;0.05) in fat lines from the 8th to the 10th generations of NEAUHFL; on the contrary, none was significantly associated with AFP (P>0.05) in lean lines. Our results suggested that epistatic interactions among QTLs and functional SNPs in candidate genes affecting fat traits might lead to differences in growth patterns of fat traits between lean and fat chicken lines.
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Affiliation(s)
- Guo Hu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
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Zhong S, Magnolo AL, Sundaram M, Zhou H, Yao EF, Di Leo E, Loria P, Wang S, Bamji-Mirza M, Wang L, McKnight CJ, Figeys D, Wang Y, Tarugi P, Yao Z. Nonsynonymous mutations within APOB in human familial hypobetalipoproteinemia: evidence for feedback inhibition of lipogenesis and postendoplasmic reticulum degradation of apolipoprotein B. J Biol Chem 2009; 285:6453-64. [PMID: 20032471 DOI: 10.1074/jbc.m109.060467] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Five nontruncating missense APOB mutations, namely A31P, G275S, L324M, G912D, and G945S, were identified in heterozygous carriers of familial hypobetalipoproteinemia (FHBL) in the Italian population. To test that the FHBL phenotype was a result of impaired hepatic secretion of mutant apoB proteins, we performed transfection studies using McA-RH7777 cells stably expressing wild type or mutant forms of human apolipoprotein B-48 (apoB-48). All mutant proteins displayed varied impairment in secretion, with G912D the least affected and A31P barely secreted. Although some A31P was degraded by proteasomes, a significant proportion of it (although inappropriately glycosylated) escaped endoplasmic reticulum (ER) quality control and presented in the Golgi compartment. Degradation of the post-ER A31P was achieved by autophagy. Expression of A31P also decreased secretion of endogenous apoB and triglycerides, yet the impaired lipoprotein secretion did not lead to lipid accumulation in the cells or ER stress. Rather, expression of genes involved in lipogenesis was down-regulated, including liver X receptor alpha, sterol regulator element-binding protein 1c, fatty acid synthase, acetyl-CoA carboxylase 1, stearoyl-CoA desaturase 1, and lipin-1. These results suggest that feedback inhibition of hepatic lipogenesis in conjunction with post-ER degradation of misfolded apoB proteins can contribute to reduce fat accumulation in the FHBL liver.
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Affiliation(s)
- Shumei Zhong
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Najah M, Di Leo E, Awatef J, Magnolo L, Imene J, Pinotti E, Bahri M, Barsaoui S, Brini I, Fekih M, Slimane MN, Tarugi P. Identification of patients with abetalipoproteinemia and homozygous familial hypobetalipoproteinemia in Tunisia. Clin Chim Acta 2009; 401:51-6. [DOI: 10.1016/j.cca.2008.11.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 11/06/2008] [Indexed: 11/30/2022]
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Noto D, Cefalù AB, Cannizzaro A, Minà M, Fayer F, Valenti V, Barbagallo CM, Tuttolomondo A, Pinto A, Sciumè C, Licata G, Averna M. Familial hypobetalipoproteinemia due to apolipoprotein B R463W mutation causes intestinal fat accumulation and low postprandial lipemia. Atherosclerosis 2009; 206:193-8. [PMID: 19344897 DOI: 10.1016/j.atherosclerosis.2009.01.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 01/22/2009] [Accepted: 01/23/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Familial hypobetalipoproteinemia (FHBL) is characterized by inherited low plasma levels of apolipoprotein B (apoB)-containing lipoproteins. In this paper we investigated whether the already described APOB R463W missense mutation, a FHBL mutation able to impair the activity of microsomal triglyceride transfer protein (MTP), may cause intestinal fat accumulation and reduced postprandial lipemia. METHODS Four out of five probands harboring APOB R463W mutation were compared with six healthy controls and six patients with celiac disease (CD). An oral fat load supplemented with retinyl palmitate (RP) was administered and a gastro-duodenal endoscopy with biopsy was performed. RESULTS Plasma triglyceride area under curves was significantly reduced in FHBL probands compared to controls and CD patients; the proportion of absorbed RP was similar to that of CD patients. Only the intestinal biopsies of FHBL patients showed lipids accumulating within the duodenal mucosa. CONCLUSIONS FHBL due to R463W apoB mutation is a cause of intestinal fat accumulation and postprandial lipid absorption impairment.
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Affiliation(s)
- Davide Noto
- Department of Clinical Medicine and Emerging Diseases, University of Palermo, Italy
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Di Leo E, Magnolo L, Pinotti E, Martini S, Cortella I, Vitturi N, Rabacchi C, Wunsch A, Pucci F, Bertolini S, Calandra S, Tarugi P. Functional analysis of two novel splice site mutations of APOB gene in familial hypobetalipoproteinemia. Mol Genet Metab 2009; 96:66-72. [PMID: 19084451 DOI: 10.1016/j.ymgme.2008.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 10/25/2008] [Accepted: 10/26/2008] [Indexed: 11/24/2022]
Abstract
Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by reduced plasma levels of low density lipoprotein cholesterol (LDL-C) and its protein constituent apolipoprotein B (apoB), which may be due to mutations in APOB gene, mostly located in the coding region of this gene. We report two novel APOB gene mutations involving the acceptor splice site of intron 11 (c.1471-1G>A) and of intron 23 (c.3697-1G>C), respectively, which were identified in two patients with heterozygous FHBL associated with severe fatty liver disease. The effects of these mutations on APOB pre-mRNA splicing were assessed in COS-1 cells expressing the mutant APOB minigenes. The c.1471-1G>A APOB minigene generated two abnormal mRNAs. In one mRNA the entire intron 11 was retained; in the other mRNA exon 11 joined to exon 12, in which the first nucleotide was deleted due to the activation of a novel acceptor splice site. The predicted products of these mRNAs are truncated proteins of 546 and 474 amino acids, designated apoB-12.03 and apoB-10.45, respectively. The c.3697-1G>C APOB minigene generated a single abnormal mRNA in which exon 23 joined to exon 25, with the complete skipping of exon 24. This abnormal mRNA is predicted to encode a truncated protein of 1220 amino acids, designated apoB-26.89. These splice site mutations cause the formation of short truncated apoBs, which are not secreted into the plasma as lipoprotein constituents. This secretion defect is the major cause of severe fatty liver observed in carriers of these mutations.
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Affiliation(s)
- Enza Di Leo
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Via Campi 287, I-41100 Modena, Italy
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Katsuda S, Kawashiri MA, Inazu A, Tada H, Tsuchida M, Kaneko Y, Nozue T, Nohara A, Okada T, Kobayashi J, Michishita I, Mabuchi H, Yamagishi M. Apolipoprotein B gene mutations and fatty liver in Japanese hypobetalipoproteinemia. Clin Chim Acta 2009; 399:64-8. [DOI: 10.1016/j.cca.2008.09.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 08/27/2008] [Accepted: 09/12/2008] [Indexed: 11/26/2022]
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Hooper AJ, van Bockxmeer FM, Burnett JR. Monogenic Hypocholesterolaemic Lipid Disorders and Apolipoprotein B Metabolism. Crit Rev Clin Lab Sci 2008; 42:515-45. [PMID: 16390683 DOI: 10.1080/10408360500295113] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The study of apolipoprotein (apo) B metabolism is central to our understanding of human lipoprotein metabolism. Moreover, the assembly and secretion of apoB-containing lipoproteins is a complex process. Increased plasma concentrations of apoB-containing lipoproteins are an important risk factor for the development of atherosclerotic coronary heart disease. In contrast, decreased levels of, but not the absence of, these apoB-containing lipoproteins is associated with resistance to atherosclerosis and potential long life. The study of inherited monogenic dyslipidaemias has been an effective means to elucidate key metabolic steps and biologically relevant mechanisms. Naturally occurring gene mutations in affected families have been useful in identifying important domains of apoB and microsomal triglyceride transfer protein (MTP) governing the metabolism of apoB-containing lipoproteins. Truncation-causing mutations in the APOB gene cause familial hypobetalipoproteinaemia, whereas mutations in MTP result in abetalipoproteinaemia; both rare conditions are characterised by marked hypocholesterolaemia. The purpose of this review is to examine the role of apoB in lipoprotein metabolism and to explore the key biochemical, clinical, metabolic and genetic features of the monogenic hypocholesterolaemic lipid disorders affecting apoB metabolism.
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Affiliation(s)
- Amanda J Hooper
- School of Surgery and Pathology, University of Western Australia, Crawley, Australia
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Familial hypobetalipoproteinemia due to a novel early stop mutation. J Clin Lipidol 2008; 2:384-90. [DOI: 10.1016/j.jacl.2008.08.446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 08/14/2008] [Accepted: 08/16/2008] [Indexed: 11/19/2022]
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Jiang ZG, Liu Y, Hussain MM, Atkinson D, McKnight CJ. Reconstituting initial events during the assembly of apolipoprotein B-containing lipoproteins in a cell-free system. J Mol Biol 2008; 383:1181-94. [PMID: 18804479 DOI: 10.1016/j.jmb.2008.09.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 09/02/2008] [Accepted: 09/04/2008] [Indexed: 12/12/2022]
Abstract
The synthesis of apolipoprotein B (apoB) dictates the formation of chylomicrons and very low-density lipoproteins, two major lipoprotein precursors in the human plasma. Despite its biological significance, the mechanism of the assembly of these apoB-containing lipoproteins remains elusive. An essential obstacle is the lack of systems that allow fine dissection of key components during assembly, including nascent apoB peptide, lipids in defined forms, chaperones, and microsomal triglyceride transfer protein (MTP). In this study, we used a prokaryotic cell-free expression system to reconstitute early events in the assembly of apoB-containing lipoprotein that involve the N-terminal domains of apoB. Our study shows that N-terminal domains larger than 20.5% of apoB (B20.5) have an intrinsic ability to remodel vesicular phospholipid bilayers into discrete protein-lipid complexes. The presence of appropriate lipid substrates during apoB translation plays a pivotal role for successful lipid recruitment, and similar lipid recruitment fails to occur if the lipids are added posttranslationally. Cotranslational presence of MTP can dramatically promote the folding of B6.4-20.5 and B6.4-22. Furthermore, apoB translated in the presence of MTP retains its phospholipid recruitment capability posttranslationally. Our data suggest that during the synthesis of apoB, the N-terminal domain has a short window for intrinsic phospholipid recruitment, the time frame of which is predetermined by the environment where apoB synthesis occurs. The presence of MTP prolongs this window of time by acting as a chaperone. The absence of either proper lipid substrate or MTP may result in the improper folding of apoB and, consequently, its degradation.
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Affiliation(s)
- Z Gordon Jiang
- Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA
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Leren TP, Berge KE. Identification of mutations in the apolipoprotein B-100 gene and in the PCSK9 gene as the cause of hypocholesterolemia. Clin Chim Acta 2008; 397:92-5. [PMID: 18710658 DOI: 10.1016/j.cca.2008.07.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/09/2008] [Accepted: 07/24/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND Characterization of the normally occurring mutations as the cause of hypocholesterolemia may increase our understanding of the normal lipid metabolism. METHODS DNA from 93 unrelated hypocholesterolemic subjects with a mean (+/-SD) value for total serum cholesterol of 3.3 (+/-0.5) mmol/l) were subjected to DNA sequencing of the individual exons of the apolipoprotein B-100 (apoB-100) gene and of the proprotein convertase subtilisin/kexin 9 (PCSK9) gene. The same analyses were also performed in 23 unrelated subjects with autosomal dominant hypercholesterolemia who had unusually low levels of total serum cholesterol. RESULTS Of the 93 hypocholesterolemic subjects, 9 subjects (9.7%) were heterozygous for a truncating mutation in the apoB-100 gene and six subjects (6.5%) were heterozygous for a loss-of-function mutation in the PCSK9 gene. Of the 23 subjects with autosomal dominant hypercholesterolemia, four subjects (17.4%) were heterozygous for mutations in the apoB-100 gene. CONCLUSION Truncating mutations in the apoB-100 gene are slightly more common as the cause of hypocholesterolemia compared to loss-of-function mutations in the PCSK9 gene. It appears that mutations in the apoB-100 gene may completely normalize the lipid profile in subjects with autosomal dominant hypercholesterolemia, whereas loss-of-function mutations in the PCSK9 gene do not have a sufficient cholesterol-lowering capacity.
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Affiliation(s)
- Trond P Leren
- Medical Genetics Laboratory, Department of Medical Genetics, Rikshospitalet University Hospital, NO 0027 Oslo, Norway.
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