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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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Zhang G, Hu Y, Yang Q, Pu N, Li G, Zhang J, Tong Z, Masson E, Cooper DN, Chen JM, Li W. Frameshift coding sequence variants in the LPL gene: identification of two novel events and exploration of the genotype-phenotype relationship for variants reported to date. Lipids Health Dis 2023; 22:128. [PMID: 37568214 PMCID: PMC10422730 DOI: 10.1186/s12944-023-01898-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Lipoprotein lipase (LPL) is the rate-limiting enzyme for triglyceride hydrolysis. Homozygous or compound heterozygous LPL variants cause autosomal recessive familial chylomicronemia syndrome (FCS), whereas simple heterozygous LPL variants are associated with hypertriglyceridemia (HTG) and HTG-related disorders. LPL frameshift coding sequence variants usually cause complete functional loss of the affected allele, thereby allowing exploration of the impact of different levels of LPL function in human disease. METHODS All exons and flanking intronic regions of LPL were Sanger sequenced in patients with HTG-related acute pancreatitis (HTG-AP) or HTG-AP in pregnancy. Previously reported LPL frameshift coding sequence variants were collated from the Human Gene Mutation Database and through PubMed keyword searching. Original reports were manually evaluated for the following information: zygosity status of the variant, plasma LPL activity of the variant carrier, disease referred for genetic analysis, patient's age at genetic analysis, and patient's disease history. SpliceAI was employed to predict the potential impact of collated variants on splicing. RESULTS Two novel rare variants were identified, and 53 known LPL frameshift coding sequence variants were collated. Of the 51 variants informative for zygosity, 30 were simple heterozygotes, 12 were homozygotes, and 9 were compound heterozygotes. Careful evaluation of the 55 variants with respect to their clinical and genetic data generated several interesting findings. First, we conclude that 6-7% residual LPL function could significantly delay the age of onset of FCS and reduce the prevalence of FCS-associated syndromes. Second, whereas a large majority of LPL frameshift coding sequence variants completely disrupt gene function through their "frameshift" nature, a small fraction of these variants may act wholly or partly as "in-frame" variants, leading to the generation of protein products with some residual LPL function. Third, we identified two candidate LPL frameshift coding sequence variants that may retain residual function based on genotype-phenotype correlation or SpliceAI-predicted data. CONCLUSIONS This study reported two novel LPL variants and yielded new insights into the genotype-phenotype relationship as it pertains to LPL frameshift coding sequence variants.
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Affiliation(s)
- Guofu Zhang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Yuepeng Hu
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Qi Yang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Na Pu
- 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
| | - Jingzhu Zhang
- 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
| | - Emmanuelle Masson
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 29200, Brest, France
- Service de Génétique Médicale Et de Biologie de La Reproduction, CHRU Brest, 29200, Brest, France
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 29200, Brest, France.
| | - Weiqin Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
- Institute of Critical Care Medicine, Nanjing University, Nanjing, China.
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Hu Y, Zhang G, Yang Q, Pu N, Li K, Li B, Cooper DN, Tong Z, Li W, Chen JM. The East Asian-specific LPL p.Ala288Thr (c.862G > A) missense variant exerts a mild effect on protein function. Lipids Health Dis 2023; 22:119. [PMID: 37550668 PMCID: PMC10405562 DOI: 10.1186/s12944-023-01875-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/17/2023] [Indexed: 08/09/2023] Open
Abstract
BACKGROUND Lipoprotein lipase (LPL) is the key enzyme responsible for the hydrolysis of triglycerides. Loss-of-function variants in the LPL gene are associated with hypertriglyceridemia (HTG) and HTG-related diseases. Unlike nonsense, frameshift and canonical GT-AG splice site variants, a pathogenic role for clinically identified LPL missense variants should generally be confirmed by functional analysis. Herein, we describe the clinical and functional analysis of a rare LPL missense variant. METHODS Chinese patients with HTG-associated acute pancreatitis (HTG-AP) were screened for rare nonsense, frameshift, missense or canonical GT-AG splice site variants in LPL and four other lipid metabolism-related genes (APOC2, APOA5, GPIHBP1 and LMF1) by Sanger sequencing. The functional consequences of the LPL missense variant of interest were characterized by in vitro expression in HEK-293T and COS-7 cells followed by Western blot and LPL activity assays. RESULTS Five unrelated HTG-AP patients were found to be heterozygous for a rare East Asian-specific LPL missense variant, c.862G > A (p.Ala288Thr). All five patients were adult males, and all were overweight and had a long history of alcohol consumption. Transfection of LPL wild-type and c.862G > A expression vectors into two cell lines followed by Western blot analysis served to exclude the possibility that the p.Ala288Thr missense variant either impaired protein synthesis or increased protein degradation. Contrary to a previous functional study that claimed that p.Ala288Thr had a severe impact on LPL function (reportedly having 36% normal activity), our experiments consistently demonstrated that the variant had a comparatively mild effect on LPL functional activity, which was mediated through its impact upon LPL protein secretion (~ 20% reduced secretion compared to wild-type). CONCLUSIONS In this study, we identified the East Asian-specific LPL c.862G > A (p.Ala288Thr) missense variant in five unrelated HTG-AP patients. We demonstrated that this variant exerted only a relatively mild effect on LPL function in two cell lines. Heterozygosity for this LPL variant may have combined with alcohol consumption to trigger HTG-AP in these patients.
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Affiliation(s)
- Yuepeng Hu
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Guofu Zhang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Qi Yang
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Na Pu
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Kaiwei Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Baiqiang Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Zhihui Tong
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China
| | - Weiqin Li
- Department of Critical Care Medicine, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, No.305 East Zhongshan Road, Xuanwu District, Nanjing, 210002, Jiangsu, China.
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, Brest, F-29200, France
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Guan L, Ding L, Wan J, Xia L, He W, Xiong H, Luo L, Lu N, Zhu Y. Serum triglyceride levels are associated with recurrence in patients with acute hypertriglyceridemic pancreatitis. Front Med (Lausanne) 2023; 10:1079637. [PMID: 37007797 PMCID: PMC10050706 DOI: 10.3389/fmed.2023.1079637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/21/2023] [Indexed: 03/17/2023] Open
Abstract
AimTo analyze the clinical profile of patients with acute hypertriglyceridemic pancreatitis (HTGP) and explore risk factors for recurrence.MethodsA retrospective observational study was conducted in patients who experienced an attack of HTGP for the first time. Patients were followed until the recurrence of acute pancreatitis (AP) or 1 year. The detailed clinical profile was compared between patients with or without recurrence. Multivariate logistic regression analysis was conducted to explore independent risk factors for recurrence.ResultsA total of 108 HTGP patients were included in this study with 73.1% being male, and the median age being 37 (interquartile range, IQR, 30.3–44.8) years. Recurrence occurred in 70 patients (64.8%). Compared with the nonrecurrent group, serum triglyceride (TG) levels before discharge [4.1 (2.8,6.3) mmol/L vs. 2.9 (2.2,4.2) mmol/L; p = 0.002], at 1 month [3.7 (2.3,9.7) mmol/L vs. 2.0 (1.4,2.7) mmol/L; p = 0.001], at 6 months [6.1 (3.1,13.1) mmol/L vs. 2.5 (1.1,3.5) mmol/L; p = 0.003] and 12 months [9.6 (3.5,20.0) mmol/L vs. 2.7 (1.6,5.5) mmol/L; p = 0.001] after discharge were higher in the recurrent group. Poor control of TG levels (TG > 3.1 mmol/l) at the 1-month follow-up after discharge and a high Charlson’s Comorbidity Index score (≥ 2 points) increased the risk of recurrence of HTGP.ConclusionHigh TG levels during follow-up and Charlson’s Comorbidity Index score were independently associated with recurrence in patients with HTGP.
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Stankov S, Vitali C, Park J, Nguyen D, Mayne L, Englander SW, Levin MG, Vujkovic M, Hand NJ, Phillips MC, Rader DJ. Comparison of the structure-function properties of wild-type human apoA-V and a C-terminal truncation associated with elevated plasma triglycerides. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.21.23286268. [PMID: 36865344 PMCID: PMC9980232 DOI: 10.1101/2023.02.21.23286268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Background Plasma triglycerides (TGs) are causally associated with coronary artery disease and acute pancreatitis. Apolipoprotein A-V (apoA-V, gene APOA5) is a liver-secreted protein that is carried on triglyceride-rich lipoproteins and promotes the enzymatic activity of lipoprotein lipase (LPL), thereby reducing TG levels. Little is known about apoA-V structure-function; naturally occurring human APOA5 variants can provide novel insights. Methods We used hydrogen-deuterium exchange mass spectrometry to determine the secondary structure of human apoA-V in lipid-free and lipid-associated conditions and identified a C-terminal hydrophobic face. Then, we used genomic data in the Penn Medicine Biobank to identify a rare variant, Q252X, predicted to specifically eliminate this region. We interrogated the function of apoA-V Q252X using recombinant protein in vitro and in vivo in apoa5 knockout mice. Results Human apoA-V Q252X carriers exhibited elevated plasma TG levels consistent with loss of function. Apoa5 knockout mice injected with AAV vectors expressing wildtype and variant APOA5-AAV recapitulated this phenotype. Part of the loss of function is due to reduced mRNA expression. Functionally, recombinant apoA-V Q252X was more readily soluble in aqueous solutions and more exchangeable with lipoproteins than WT apoA-V. Despite lacking the C-terminal hydrophobic region (a putative lipid binding domain) this protein also decreased plasma TG in vivo. Conclusions Deletion of apoA-V's C-terminus leads to reduced apoA-V bioavailability in vivo and higher TG levels. However, the C-terminus is not required for lipoprotein binding or enhancement of intravascular lipolytic activity. WT apoA-V is highly prone to aggregation, and this property is markedly reduced in recombinant apoA-V lacking the C-terminus.
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Affiliation(s)
- Sylvia Stankov
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cecilia Vitali
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph Park
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David Nguyen
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leland Mayne
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - S. Walter Englander
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Michael G. Levin
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Marijana Vujkovic
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Nicholas J. Hand
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael C. Phillips
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel J. Rader
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Biochemical, Clinical, and Genetic Characteristics of Mexican Patients with Primary Hypertriglyceridemia, Including the First Case of Hyperchylomicronemia Syndrome Due to GPIHBP1 Deficiency. Int J Mol Sci 2022; 24:ijms24010465. [PMID: 36613909 PMCID: PMC9820378 DOI: 10.3390/ijms24010465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/06/2022] [Accepted: 12/14/2022] [Indexed: 12/29/2022] Open
Abstract
Primary hypertriglyceridemia (PHTG) is characterized by a high concentration of triglycerides (TG); it is divided between familial hyperchylomicronemia syndrome and multifactorial chylomicronemia syndrome. In Mexico, hypertriglyceridemia constitutes a health problem in which the genetic bases have been scarcely explored; therefore, our objective was to describe biochemical-clinical characteristics and variants in the APOA5, GPIHBP1, LMF1, and LPL genes in patients with primary hypertriglyceridemia. Thirty DNA fragments were analyzed using PCR and Sanger sequencing in 58 unrelated patients. The patients' main clinical-biochemical features were hypoalphalipoproteinemia (77.6%), pancreatitis (18.1%), and a TG median value of 773.9 mg/dL. A total of 74 variants were found (10 in APOA5, 16 in GPIHBP1, 34 in LMF1, and 14 in LPL), of which 15 could be involved in the development of PHTG: 3 common variants with significative odds and 12 heterozygous rare pathogenic variants distributed in 12 patients. We report on the first Mexican patient with hyperchylomicronemia syndrome due to GPIHBP1 deficiency caused by three variants: p.R145*, p.A154_G155insK, and p.A154Rfs*152. Moreover, eleven patients were heterozygous for the rare variants described as causing PHTG and also presented common variants of risk, which could partially explain their phenotype. In terms of findings, two novel genetic variants, c.-40_-22del LMF1 and p.G242Dfs*10 LPL, were identified.
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Zhang GF, Yu XQ, Hu YP, Yang Q, Li WQ. Progress in research of acute pancreatitis in pregnancy. Shijie Huaren Xiaohua Zazhi 2022; 30:541-546. [DOI: 10.11569/wcjd.v30.i12.541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Acute pancreatitis in pregnancy (APIP) is a rare and severe complication of pregnancy, which is characterized by rapid onset, rapid progression, many complications, and high mortality. According to previous studies, the incidence of APIP is about 1/10000-1/1000 and increases with gestational age. Due to the differences in genetic background and dietary habits between Asian and European populations, the incidence of APIP in China is as high as 1.14‰-2.27‰, significantly higher than that in Western countries. The lack of specific clinical symptoms of APIP often leads to misdiagnosis or missed diagnosis, which greatly increases the difficulty of diagnosis and treatment. Despite the deepening of the research on APIP, its pathogenesis is still unclear. This paper will give a systematical review of APIP.
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Affiliation(s)
- Guo-Fu Zhang
- Department of Critical Care Medicine, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu Province, China
| | - Xian-Qiang Yu
- Medical College of Southeast University, Nanjing 210009, Jiangsu Province, China
| | - Yue-Peng Hu
- Department of Critical Care Medicine, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu Province, China
| | - Qi Yang
- Department of Critical Care Medicine, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu Province, China
| | - Wei-Qin Li
- Department of Critical Care Medicine, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu Province, China,Medical College of Southeast University, Nanjing 210009, Jiangsu Province, China,Department of Critical Care Medicine, General Hospital of Eastern Theater Command, Nanjing 210002, Jiangsu Province, China
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Liu S, Wang Z, Zheng X, Zhang Y, Wei S, OuYang H, Liang J, Chen N, Zeng W, Jiang J. Case Report: Successful Management of a 29-Day-Old Infant With Severe Hyperlipidemia From a Novel Homozygous Variant of GPIHBP1 Gene. Front Pediatr 2022; 10:792574. [PMID: 35359903 PMCID: PMC8960264 DOI: 10.3389/fped.2022.792574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/03/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Severe hyperlipidemia is characterized by markedly elevated blood triglyceride levels and severe early-onset cardiovascular diseases, pancreatitis, pancreatic necrosis or persistent multiple organ failure if left untreated. It is a rare autosomal recessive metabolic disorder originated from the variants of lipoprotein lipase gene, and previous studies have demonstrated that most cases with severe hyperlipidemia are closely related to the variants of some key genes for lipolysis, such as LPL, APOC2, APOA5, LMF1, and GPIHBP1. Meanwhile, other unidentified causes also exist and are equally worthy of attention. METHODS The 29-day-old infant was diagnosed with severe hyperlipidemia, registering a plasma triglyceride level as high as 25.46 mmol/L. Whole exome sequencing was conducted to explore the possible pathogenic gene variants for this patient. RESULTS The infant was put on a low-fat diet combined with pharmacological therapy, which was successful in restraining the level of serum triglyceride and total cholesterol to a low to medium range during the follow-ups. The patient was found to be a rare novel homozygous duplication variant-c.45_48dupGCGG (Pro17Alafs*22) in GPIHBP1 gene-leading to a frameshift which failed to form the canonical termination codon TGA. The mutant messenger RNA should presumably produce a peptide consisting of 16 amino acids at the N-terminus, with 21 novel amino acids on the heels of the wild-type protein. CONCLUSIONS Our study expands on the spectrum of GPIHBP1 variants and contributes to a more comprehensive understanding of the genetic diagnosis, genetic counseling, and multimodality therapy of families with severe hyperlipidemia. Our experience gained in this study is also contributory to a deeper insight into severe hyperlipidemia and highlights the importance of molecular genetic tests.
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Affiliation(s)
- Shu Liu
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Zhiqing Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xianhua Zheng
- Department of Clinical Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Ye Zhang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Sisi Wei
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Haimei OuYang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jinqun Liang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Nuan Chen
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Weihong Zeng
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jianhui Jiang
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
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