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Hu Y, Chen JM, Zuo H, Pu N, Zhang G, Duan Y, Li G, Tong Z, Li W, Li B, Yang Q. Significant but partial lipoprotein lipase functional loss caused by a novel occurrence of rare LPL biallelic variants. Lipids Health Dis 2024; 23:92. [PMID: 38561841 PMCID: PMC10983719 DOI: 10.1186/s12944-024-02086-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Lipoprotein lipase (LPL) plays a crucial role in triglyceride hydrolysis. Rare biallelic variants in the LPL gene leading to complete or near-complete loss of function cause autosomal recessive familial chylomicronemia syndrome. However, rare biallelic LPL variants resulting in significant but partial loss of function are rarely documented. This study reports a novel occurrence of such rare biallelic LPL variants in a Chinese patient with hypertriglyceridemia-induced acute pancreatitis (HTG-AP) during pregnancy and provides an in-depth functional characterization. METHODS The complete coding sequences and adjacent intronic regions of the LPL, APOC2, APOA5, LMF1, and GPIHBP1 genes were analyzed by Sanger sequencing. The aim was to identify rare variants, including nonsense, frameshift, missense, small in-frame deletions or insertions, and canonical splice site mutations. The functional impact of identified LPL missense variants on protein expression, secretion, and activity was assessed in HEK293T cells through single and co-transfection experiments, with and without heparin treatment. RESULTS Two rare LPL missense variants were identified in the patient: the previously reported c.809G > A (p.Arg270His) and a novel c.331G > C (p.Val111Leu). Genetic testing confirmed these variants were inherited biallelically. Functional analysis showed that the p.Arg270His variant resulted in a near-complete loss of LPL function due to effects on protein synthesis/stability, secretion, and enzymatic activity. In contrast, the p.Val111Leu variant retained approximately 32.3% of wild-type activity, without impacting protein synthesis, stability, or secretion. Co-transfection experiments indicated a combined activity level of 20.7%, suggesting no dominant negative interaction between the variants. The patient's post-heparin plasma LPL activity was about 35% of control levels. CONCLUSIONS This study presents a novel case of partial but significant loss-of-function biallelic LPL variants in a patient with HTG-AP during pregnancy. Our findings enhance the understanding of the nuanced relationship between LPL genotypes and clinical phenotypes, highlighting the importance of residual LPL function in disease manifestation and severity. Additionally, our study underscores the challenges in classifying partial loss-of-function variants in classical Mendelian disease genes according to the American College of Medical Genetics and Genomics (ACMG)'s variant classification guidelines.
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Affiliation(s)
- Yuepeng Hu
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, F-29200, France
| | - Han Zuo
- Nanjing University of Chinese Medicine, Nanjing, China
| | - Na Pu
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Guofu Zhang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Yichen Duan
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Gang Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Zhihui Tong
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Weiqin Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Baiqiang Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
- The First School of Clinical Medicine, Southern Medical University, Nanjing, China.
| | - Qi Yang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
- School of Basic Medical Sciences, Southern Medical University, Nanjing, China.
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Paragh G, Németh Á, Harangi M, Banach M, Fülöp P. Causes, clinical findings and therapeutic options in chylomicronemia syndrome, a special form of hypertriglyceridemia. Lipids Health Dis 2022; 21:21. [PMID: 35144640 PMCID: PMC8832680 DOI: 10.1186/s12944-022-01631-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/30/2022] [Indexed: 02/07/2023] Open
Abstract
The prevalence of hypertriglyceridemia has been increasing worldwide. Attention is drawn to the fact that the frequency of a special hypertriglyceridemia entity, named chylomicronemia syndrome, is variable among its different forms. The monogenic form, termed familial chylomicronemia syndrome, is rare, occuring in 1 in every 1 million persons. On the other hand, the prevalence of the polygenic form of chylomicronemia syndrome is around 1:600. On the basis of the genetical alterations, other factors, such as obesity, alcohol consumption, uncontrolled diabetes mellitus and certain drugs may significantly contribute to the development of the multifactorial form. In this review, we aimed to highlight the recent findings about the clinical and laboratory features, differential diagnosis, as well as the epidemiology of the monogenic and polygenic forms of chylomicronemias. Regarding the therapy, differentiation between the two types of the chylomicronemia syndrome is essential, as well. Thus, proper treatment options of chylomicronemia and hypertriglyceridemia will be also summarized, emphasizing the newest therapeutic approaches, as novel agents may offer solution for the effective treatment of these conditions.
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Affiliation(s)
- György Paragh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary.
| | - Ákos Németh
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Mariann Harangi
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Maciej Banach
- Department of Hypertension, WAM University Hospital in Lodz, Medical University of Lodz, Lodz, Poland.,Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland
| | - Péter Fülöp
- Division of Metabolic Diseases, Department of Internal Medicine, University of Debrecen Faculty of Medicine, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
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Wang M, Zhou Y, He X, Deng C, Liu X, Li J, Zhou L, Li Y, Zhang Y, Liu H, Li L. Two novel mutations of the LPL gene in two Chinese family cases with familial chylomicronemia syndrome. Clin Chim Acta 2021; 521:264-271. [PMID: 34324844 DOI: 10.1016/j.cca.2021.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
The aim of this study was to investigate the clinical features and genetic causes of two family cases with familial chylomicronemia syndrome (FCS). Clinical manifestations of proband 1 and her families, and also proband 2 showed severe hypertriglyceridemia, especially the triglycerides levels of two probands were extremely high. Gene sequencing results showed that the LPL genes in each of the two probands had a new mutation site. For the proband 1, a compound heterozygous mutation at c.429 (c.429 + 1G > T) was detected in the LPL gene, which was splicing mutation and inherited from her mother. Homozygous mutation was detected in the LPL gene of proband 2, the nucleotide mutation at c.802 (c.802C > T) exhibited missense mutation, his parents and brother had a heterozygous mutation at the same site. It was confirmed that the conservative lipoprotein lipase superfamily domain changed an amino acid from histidine to tyrosine at p. 268 (p. His268Tyr). Flow cytometry confirmed the deficient expression of LPL protein in two families. These results indicated that the mutation in LPL gene might be the cause of familial chylomicronemia syndrome.
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Affiliation(s)
- Mingying Wang
- Department of Gastroenterology, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Yuantao Zhou
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children's Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Xiaoli He
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children's Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Chengjun Deng
- Department of Gastroenterology, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Xiaoning Liu
- Department of Pharmacy, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Juan Li
- Department of Gastroenterology, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Lin Zhou
- Department of Nutrition, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Ying Li
- Department of Gastroenterology, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Yu Zhang
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children's Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Haifeng Liu
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children's Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming 650228, Yunnan, China
| | - Li Li
- Kunming Key Laboratory of Children Infection and Immunity, Yunnan Key Laboratory of Children's Major Disease Research, Yunnan Medical Center for Pediatric Diseases, Yunnan Institute of Pediatrics, Kunming Children's Hospital, Kunming 650228, Yunnan, China.
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The Role of Genetics in Cardiovascular Risk Reduction: Findings From a Single Lipid Clinic and Review of the Literature. CARDIOVASCULAR REVASCULARIZATION MEDICINE 2019; 21:200-204. [PMID: 31153847 DOI: 10.1016/j.carrev.2019.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Genetic information is not routinely obtained in the management of most lipid disorders or in primary or secondary prevention of cardiovascular disease (CVD). We sought to determine the prevalence of pathogenic variants associated with lipoprotein metabolism or coronary artery disease (CAD) in a single lipid clinic and discuss the future use of genetic information in CVD prevention. METHODS Genetic testing was offered to patients with hypertriglyceridemia (defined as pre-treatment fasting triglycerides ≥150 mg/dL), elevated LDL-C (defined as pre-treatment ≥190 mg/dL), low HDL-C (defined as ≤40 mg/dL), elevated lipoprotein (a) (defined as ≥50 mg/dL or 100 nmol/L) or premature CAD (defined as an acute coronary syndrome or revascularization before age 40 years in men and 50 years in women) using next-generation DNA sequencing of 327 exons and selected variants in 129 genes known or suspected to be associated with lipoprotein metabolism or CAD. RESULTS 82 of 84 patients (97.6%) were found to have a variant associated with abnormal lipid metabolism or CAD. The most common pathogenic or likely pathogenic variants included those of the LDL receptor (15 patients) and lipoprotein lipase (9 patients). Other common variants included those of apolipoprotein A5 (14 patients) and variants associated with elevated lipoprotein (a) (25 patients). CONCLUSIONS The majority of patients presenting to a single lipid clinic were found to have at least one variant associated with abnormal lipoprotein metabolism or CAD. Incorporating genetic information, including the use of genetic risk scores, is anticipated in the future care of lipid disorders and CVD prevention.
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Characterizing familial chylomicronemia syndrome: Baseline data of the APPROACH study. J Clin Lipidol 2018; 12:1234-1243.e5. [PMID: 30318066 DOI: 10.1016/j.jacl.2018.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/16/2018] [Accepted: 05/22/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND Familial chylomicronemia syndrome (FCS) is a rare metabolic disorder caused by mutations in lipoprotein lipase (LPL) or genes required for LPL functionality and is characterized by hyperchylomicronemia that results in recurrent episodes of acute pancreatitis. Owing to the rarity of FCS, there are few case series describing the phenotypic variability in FCS patients in detail. OBJECTIVE To provide baseline characteristics in the largest study population to date of patients with FCS. METHODS We analyzed baseline demographic and clinical characteristics of adult FCS patients in the phase 3 APPROACH study of volanesorsen sodium (antisense inhibitor of apolipoprotein C-III). RESULTS Sixty-six patients were included in the analysis. Mean (SD) age was 46 (13) years; and mean body mass index was 24.9 (5.7) kg/m2. We identified causal mutations in 79% (52) of patients, with LPL mutations accounting for 62% (41) of cases. Median age at diagnosis was 24 years, 54% were females, and 81% were Caucasian. All patients followed a low-fat diet, 43% received fibrates, 27% fish oils, and 21% statins. Median fasting triglyceride levels (P25, P75) were 1985 (1179, 3047 mg/dL). Overall, 76% of patients reported ≥1 lifetime episode of acute pancreatitis; 23 patients reported a total of 53 pancreatitis events in the 5 years before enrollment. CONCLUSIONS Our data emphasize the severe hypertriglyceridemia characteristic of FCS patients despite restrictive low-fat diets and frequent use of existing hypolipemic therapies. Acute pancreatitis and recurrent acute pancreatitis are frequent complications of FCS. Diagnosis at an older age suggests likely underdiagnosis and underappreciation of this rare disorder.
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Lee J, Hegele RA. Investigated treatments for lipoprotein lipase deficiency and related metabolic disorders. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1311784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
This Review discusses new developments in understanding the basis of chylomicronaemia--a challenging metabolic disorder for which there is an unmet clinical need. Chylomicronaemia presents in two distinct primary forms. The first form is very rare monogenic early-onset chylomicronaemia, which presents in childhood or adolescence and is often caused by homozygous mutations in the gene encoding lipoprotein lipase (LPL), its cofactors apolipoprotein C-II or apolipoprotein A-V, the LPL chaperone lipase maturation factor 1 or glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1. The second form, polygenic late-onset chylomicronaemia, which is caused by an accumulation of several genetic variants, can be exacerbated by secondary factors, such as poor diet, obesity, alcohol intake and uncontrolled type 1 or type 2 diabetes mellitus, and is more common than early-onset chylomicronaemia. Both forms of chylomicronaemia are associated with an increased risk of life-threatening pancreatitis; the polygenic form might also be associated with an increased risk of cardiovascular disease. Treatment of chylomicronaemia focuses on restriction of dietary fat and control of secondary factors, as available pharmacological therapies are only minimally effective. Emerging therapies that might prove more effective than existing agents include LPL gene therapy, inhibition of microsomal triglyceride transfer protein and diacylglycerol O-acyltransferase 1, and interference with the production and secretion of apoC-III and angiopoietin-like protein 3.
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Affiliation(s)
- Amanda J Brahm
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
| | - Robert A Hegele
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
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Kastelein JJP, Ross CJD, Hayden MR. From mutation identification to therapy: discovery and origins of the first approved gene therapy in the Western world. Hum Gene Ther 2013; 24:472-8. [PMID: 23578007 DOI: 10.1089/hum.2013.063] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- John J P Kastelein
- Department of Vascular Medicine, Academic Medical Centre, University of Amsterdam, The Netherlands.
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Rip J, Nierman MC, Sierts JA, Petersen W, Van den Oever K, Van Raalte D, Ross CJD, Hayden MR, Bakker AC, Dijkhuizen P, Hermens WT, Twisk J, Stroes E, Kastelein JJP, Kuivenhoven JA, Meulenberg JM. Gene therapy for lipoprotein lipase deficiency: working toward clinical application. Hum Gene Ther 2006; 16:1276-86. [PMID: 16259561 DOI: 10.1089/hum.2005.16.1276] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lipoprotein lipase (LPL) deficiency causes hypertriglyceridemia and recurrent, potentially life-threatening pancreatitis. There currently is no adequate treatment for this disease. Previously, we showed that intramuscular administration of an adeno-associated virus serotype 1 (AAV1) vector encoding the human LPL(S447X) variant cDNA (AAV1-LPL(S447X)) normalized the dyslipidemia of LPL-/- mice for more than 1 year. In preparation for a clinical trial, we evaluated the safety and biodistribution of AAV1-LPL(S447X) in wild-type mice and fully characterized six LPL-deficient patients. Toxicological analysis in mice showed that intramuscular administration was well tolerated. Acute inflammatory response markers were transiently increased, and anti- AAV1 antibodies were generated. Histological analyses indicated a dose-dependent reversible spleen hyperplasia, and myositis at the injection sites. Biodistribution data showed short-term vector leakage from injection sites into the circulation, followed by liver-mediated clearance. Persistence of vector DNA was limited to the injected muscle and draining lymph nodes, and spread to reproductive organs was limited. Characterization of LPL-deficient patients showed that all patients presented with hypertriglyceridemia and recurrent pancreatitis. LPL catalytic activity was absent, but LPL protein levels were 20-100% of normal. Myoblasts derived from skeletal muscle biopsies of these patients were efficiently transduced by AAV1-LPL(S447X) and secreted active LPL. These data support the initiation of a clinical trial in LPL-deficient patients, for which regulatory approval has been granted.
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Affiliation(s)
- Jaap Rip
- Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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Rip J, Nierman MC, Sierts JA, Petersen W, Den Oever KV, Raalte DV, Ross CJ, Hayden MR, Bakker AC, Dijkhuizen P, Hermens WT, Twisk J, Stroes E, Kastelein JJP, Kuivenhoven JA, Meulenberg JM. Gene Therapy for Lipoprotein Lipase Deficiency: Working Toward Clinical Application. Hum Gene Ther 2005. [DOI: 10.1089/hum.2005.16.ft-138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Gilbert B, Rouis M, Griglio S, de Lumley L, Laplaud P. Lipoprotein lipase (LPL) deficiency: a new patient homozygote for the preponderant mutation Gly188Glu in the human LPL gene and review of reported mutations: 75 % are clustered in exons 5 and 6. ANNALES DE GENETIQUE 2001; 44:25-32. [PMID: 11334614 DOI: 10.1016/s0003-3995(01)01037-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We have investigated the lipoprotein lipase (LPL) gene of a 2-year-old patient presenting classical features of the familial LPL deficiency including undetectable LPL activity. DNA sequence analysis of exon 5 identified the patient as a homozygote for the Gly188Glu mutation, frequently involved in this disease. A review of cases of LPL deficiency with molecular study of the LPL gene showed a total number of 221 reported mutations involved in this disease. Gly188Glu was involved in 23.5 % of cases and 74.6 % of mutations were clustered in exons 5 and 6. Based on these observations, we propose a method of screening for mutations in this gene.
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Affiliation(s)
- B Gilbert
- Unité de génétique, hôpital Dupuytren, Limoges, France.
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