1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Rodrigues R, Artieda M, Tejedor D, Martínez A, Konstantinova P, Petry H, Meyer C, Corzo D, Sundgreen C, Klor HU, Gouni-Berthold I, Westphal S, Steinhagen-Thiessen E, Julius U, Winkler K, Stroes E, Vogt A, Hardt P, Prophet H, Otte B, Nordestgaard BG, Deeb SS, Brunzell JD. Pathogenic classification of LPL gene variants reported to be associated with LPL deficiency. J Clin Lipidol 2015; 10:394-409. [PMID: 27055971 DOI: 10.1016/j.jacl.2015.12.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/21/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND Lipoprotein lipase (LPL) deficiency is a serious lipid disorder of severe hypertriglyceridemia (SHTG) with chylomicronemia. A large number of variants in the LPL gene have been reported but their influence on LPL activity and SHTG has not been completely analyzed. Gaining insight into the deleterious effect of the mutations is clinically essential. METHODS We used gene sequencing followed by in-vivo/in-vitro and in-silico tools for classification. We classified 125 rare LPL mutations in 33 subjects thought to have LPL deficiency and in 314 subjects selected for very SHTG. RESULTS Of the 33 patients thought to have LPL deficiency, only 13 were homozygous or compound heterozygous for deleterious mutations in the LPL gene. Among the 314 very SHTG patients, 3 were compound heterozygous for pathogenic mutants. In a third group of 51,467 subjects, from a general population, carriers of common variants, Asp9Asn and Asn291Ser, were associated with mild increase in triglyceride levels (11%-35%). CONCLUSION In total, 39% of patients clinically diagnosed as LPL deficient had 2 deleterious variants. Three patients selected for very SHTG had LPL deficiency. The deleterious mutations associated with LPL deficiency will assist in the diagnosis and selection of patients as candidates for the presently approved LPL gene therapy.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Hans U Klor
- Director of the German HITRIG, Third Medical Department and Policlinic, Giessen University Hospital, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Ioanna Gouni-Berthold
- Center for Endocrinology, Diabetes and Preventive Medicine, University of Cologne, Cologne, Germany
| | - Sabine Westphal
- Institute of Clinical Chemistry, Lipid Clinic, Magdeburg, Germany
| | | | - Ulrich Julius
- Universitätsklinikum Carl Gustav Carus an der Technischen Universität, Medizinische Klinik III, Dresden, Germany
| | - Karl Winkler
- Institute of Clinical Chemistry and Laboratory Medicine and Lipid Outpatient Clinic, University Hospital Freiburg, Freiburg, Germany
| | - Erik Stroes
- Department of Vascular Medicine, Amsterdam Medical Center/University of Amsterdam, Amsterdam, The Netherlands
| | - Anja Vogt
- LMU Klinikum der Universität München, Medizinische Klinik und Poliklinik 4, München, Germany
| | - Phillip Hardt
- Gießen and Marburg University Hospital, Giessen, Germany
| | | | - Britta Otte
- Universitätsklinikum Münster, Medizinische Klinik D, Med. Clinic, Münster, Münster, Germany
| | - Borge G Nordestgaard
- Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Copenhagen General Population Study, Herlev Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Samir S Deeb
- Department of Medicine (Division of Medical Genetics), University of Washington, Seattle, WA, USA; Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - John D Brunzell
- Department of Medicine (Division of Metabolism, Endocrinology and Nutrition), University of Washington, Seattle, WA, USA
| |
Collapse
|
3
|
Surendran RP, Visser ME, Heemelaar S, Wang J, Peter J, Defesche JC, Kuivenhoven JA, Hosseini M, Péterfy M, Kastelein JJP, Johansen CT, Hegele RA, Stroes ESG, Dallinga-Thie GM. Mutations in LPL, APOC2, APOA5, GPIHBP1 and LMF1 in patients with severe hypertriglyceridaemia. J Intern Med 2012; 272:185-96. [PMID: 22239554 PMCID: PMC3940136 DOI: 10.1111/j.1365-2796.2012.02516.x] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES The severe forms of hypertriglyceridaemia (HTG) are caused by mutations in genes that lead to the loss of function of lipoprotein lipase (LPL). In most patients with severe HTG (TG > 10 mmol L(-1) ), it is a challenge to define the underlying cause. We investigated the molecular basis of severe HTG in patients referred to the Lipid Clinic at the Academic Medical Center Amsterdam. METHODS The coding regions of LPL, APOC2, APOA5 and two novel genes, lipase maturation factor 1 (LMF1) and GPI-anchored high-density lipoprotein (HDL)-binding protein 1 (GPIHBP1), were sequenced in 86 patients with type 1 and type 5 HTG and 327 controls. RESULTS In 46 patients (54%), rare DNA sequence variants were identified, comprising variants in LPL (n = 19), APOC2 (n = 1), APOA5 (n = 2), GPIHBP1 (n = 3) and LMF1 (n = 8). In 22 patients (26%), only common variants in LPL (p.Asp36Asn, p.Asn318Ser and p.Ser474Ter) and APOA5 (p.Ser19Trp) could be identified, whereas no mutations were found in 18 patients (21%). In vitro validation revealed that the mutations in LMF1 were not associated with compromised LPL function. Consistent with this, five of the eight LMF1 variants were also found in controls and therefore cannot account for the observed phenotype. CONCLUSIONS The prevalence of mutations in LPL was 34% and mostly restricted to patients with type 1 HTG. Mutations in GPIHBP1 (n = 3), APOC2 (n = 1) and APOA5 (n = 2) were rare but the associated clinical phenotype was severe. Routine sequencing of candidate genes in severe HTG has improved our understanding of the molecular basis of this phenotype associated with acute pancreatitis and may help to guide future individualized therapeutic strategies.
Collapse
Affiliation(s)
- R P Surendran
- Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Lu J, Li J, Ji C, Yu W, Xu Z, Huang S. Expression of lipoprotein lipase associated with lung adenocarcinoma tissues. Mol Biol Rep 2007; 35:59-63. [PMID: 17347923 DOI: 10.1007/s11033-006-9053-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 12/22/2006] [Indexed: 01/19/2023]
Abstract
Lipoprotein lipase (LPL) plays a key role in the lipid metabolism and transporting. It can catalyze the hydrolysis of chylomicron and very low-density lipoprotein triglyceride. Moreover, the abnormality of LPL associates with many pathophysiological conditions. Herein cDNA microarray and Northern blots analysis were used to study the expression of lipoprotein lipase in lung adenocarcinoma tissues. There were 113 genes of all tested blots in cDNA microarray expressed lowly. LPL gene is expressed lowly at the average ratio 0.26 (Cy5/Cy3) in lung adenocarcinoma tissues over controls. Northern blots confirmed those changes detected from the cDNA microarray and suggested that low expression of LPL may play an important role in the lung adenocarcinoma development.
Collapse
Affiliation(s)
- Jizhong Lu
- Department of Cardiac-thoracic surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | | | | | | | | | | |
Collapse
|