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Pintanel-Raymundo M, Menao-Guillén S, Perales-Afán JJ, García-Gutiérrez A, Moreno-Gázquez I, Julián-Ansón M, Ramos-Álvarez M, Olivera-González S, Gutiérrez-Cía I, Torralba-Cabeza MA. Analysis of the expression of the Serpina1 gene in SARS-CoV-2 infection: study of a new biomarker. Rev Clin Esp 2024; 224:253-258. [PMID: 38608729 DOI: 10.1016/j.rceng.2024.04.006] [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: 09/11/2023] [Accepted: 03/13/2024] [Indexed: 04/14/2024]
Abstract
INTRODUCTION The SERPINA1 gene encodes the protein Alpha-1 Antitrypsin (AAT1). Possible imbalances between the concentrations of proteases and antiproteases (AAT1) can lead to the development of serious pulmonary and extrapulmonary pathologies. In this work we study the importance of this possible imbalance in patients with COVID-19. OBJECTIVES To correlate the severity of the symptoms of SARS-COV-2 infection with the AAT1 concentrations at diagnosis of the disease. METHODS An observational, prospective, cross-sectional, non-interventional, analytical study was carried out where 181 cases with COVID-19 admitted to the "Lozano Blesa" University Clinical Hospital of Zaragoza were selected. The concentration of AAT1 was studied in all of them and this was correlated with the clinical aspects and biochemical parameters at hospital admission. RESULTS 141 cases corresponded to patients with severe COVID and 40 patients with mild COVID. AAT1 levels were positively correlated with the days of hospitalization, severity, C-Reactive Protein, ferritin, admission to Intensive Care, and death, and presented a negative correlation with the number of lymphocytes/mm3. AAT1 concentrations higher than 237.5 mg/dL allowed the patient to be classified as "severe" (S72%; E78%) and 311.5 mg/dL were associated with the risk of admission to Intensive Care or Exitus (S67%; E79%). CONCLUSIONS Levels of the SERPINA1 gene expression product, AAT1, correlate with the severity of COVID-19 patients at diagnosis of the disease, being useful as a prognostic biomarker.
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Affiliation(s)
| | - S Menao-Guillén
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain; Insitututo de Investigación Sanitaria de Aaragón, España
| | - J J Perales-Afán
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain; Insitututo de Investigación Sanitaria de Aaragón, España
| | - A García-Gutiérrez
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain
| | - I Moreno-Gázquez
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain
| | - M Julián-Ansón
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain
| | - M Ramos-Álvarez
- Servicio de Bioquímica, Hospital Universitario "Lozano Blesa", Zaragoza, Spain
| | - S Olivera-González
- Servicio de Medicina Interna, Hospital Marina Salud de Denia, Alicante, Spain
| | - I Gutiérrez-Cía
- Servicio de Cuidados Intensivos, Hospital Universitario "Lozano Blesa", Zaragoza, Spain
| | - M A Torralba-Cabeza
- Facultad de Medicina, Universidad de Zaragoza, Spain; Insitututo de Investigación Sanitaria de Aaragón, España; Unidad de Enfermedades Minoritarias, Servicio de Medicina Interna, Hospital Universitario "Lozano Blesa", Zaragoza, Spain; Grupo de Trabajo de Enfermedades Minoritarias de la Sociedad Española de Medicina Interna, España.
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Ferrarotti I, Wencker M, Chorostowska-Wynimko J. Rare variants in alpha 1 antitrypsin deficiency: a systematic literature review. Orphanet J Rare Dis 2024; 19:82. [PMID: 38388492 PMCID: PMC10885523 DOI: 10.1186/s13023-024-03069-1] [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: 10/10/2023] [Accepted: 02/03/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Alpha 1 Antitrypsin Deficiency (AATD) is a largely underrecognized genetic condition characterized by low Alpha 1 Antitrypsin (AAT) serum levels, resulting from variations in SERPINA1. Many individuals affected by AATD are thought to be undiagnosed, leading to poor patient outcomes. The Z (c.1096G > A; p.Glu366Lys) and S (c.863A > T; p.Glu288Val) deficiency variants are the most frequently found variants in AATD, with the Z variant present in most individuals diagnosed with AATD. However, there are many other less frequent variants known to contribute to lung and/or liver disease in AATD. To identify the most common rare variants associated with AATD, we conducted a systematic literature review with the aim of assessing AATD variation patterns across the world. METHODS A systematic literature search was performed to identify published studies reporting AATD/SERPINA1 variants. Study eligibility was assessed for the potential to contain relevant information, with quality assessment and data extraction performed on studies meeting all eligibility criteria. AATD variants were grouped by variant type and linked to the geographical region identified from the reporting article. RESULTS Of the 4945 articles identified by the search string, 864 contained useful information for this study. Most articles came from the United States, followed by the United Kingdom, Germany, Spain, and Italy. Collectively, the articles identified a total of 7631 rare variants and 216 types of rare variant across 80 counties. The F (c.739C > T; p.Arg247Cys) variant was identified 1,281 times and was the most reported known rare variant worldwide, followed by the I (c.187C > T; p.Arg63Cys) variant. Worldwide, there were 1492 Null/rare variants that were unidentified at the time of source article publication and 75 rare novel variants reported only once. CONCLUSION AATD goes far beyond the Z and S variants, suggesting there may be widespread underdiagnosis of patients with the condition. Each geographical region has its own distinctive variety of AATD variants and, therefore, comprehensive testing is needed to fully understand the true number and type of variants that exist. Comprehensive testing is also needed to ensure accurate diagnosis, optimize treatment strategies, and improve outcomes for patients with AATD.
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Affiliation(s)
- Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, Pneumology Unit, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
| | | | - Joanna Chorostowska-Wynimko
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
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Denardo A, Ben Khlifa E, Bignotti M, Giuliani R, D'Acunto E, Miranda E, Irving JA, Fra A. Probing of the reactive center loop region of alpha-1-antitrypsin by mutagenesis predicts new type-2 dysfunctional variants. Cell Mol Life Sci 2023; 81:6. [PMID: 38087060 PMCID: PMC11073084 DOI: 10.1007/s00018-023-05059-1] [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: 07/12/2023] [Revised: 10/25/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023]
Abstract
Lung disease in alpha-1-antitrypsin deficiency (AATD) mainly results from insufficient control of the serine proteases neutrophil elastase (NE) and proteinase-3 due to reduced plasma levels of alpha-1-antitrypsin (AAT) variants. Mutations in the specificity-determining reactive center loop (RCL) of AAT would be predicted to minimally affect protein folding and secretion by hepatocytes but can impair anti-protease activity or alter the target protease. These properly secreted but dysfunctional 'type-2' variants would not be identified by common diagnostic protocols that are predicated on a reduction in circulating AAT. This has potential clinical relevance: in addition to the dysfunctional Pittsburgh and Iners variants reported previously, several uncharacterized RCL variants are present in genome variation databases. To prospectively evaluate the impact of RCL variations on secretion and anti-protease activity, here we performed a systematic screening of amino acid substitutions occurring at the AAT-NE interface. Twenty-three AAT variants that can result from single nucleotide polymorphisms in this region, including 11 present in sequence variation databases, were expressed in a mammalian cell model. All demonstrated unaltered protein folding and secretion. However, when their ability to form stable complexes with NE was evaluated by western blot, enzymatic assays, and a novel ELISA developed to quantify AAT-NE complexes, substrate-like and NE-binding deficient dysfunctional variants were identified. This emphasizes the ability of the RCL to accommodate inactivating substitutions without impacting the integrity of the native molecule and demonstrates that this class of molecule violates a generally accepted paradigm that equates circulating levels with functional protection of lung tissue.
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Affiliation(s)
- Andrea Denardo
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Emna Ben Khlifa
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Mattia Bignotti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Roberta Giuliani
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Emanuela D'Acunto
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy
| | - Elena Miranda
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy
| | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, UK
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
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Schuler BA, Bastarache L, Wang J, He J, Van Driest SL, Denny JC. Population genetic testing and SERPINA1 sequencing identifies unidentified alpha-1 antitrypsin deficiency alleles and gene-environment interaction with hepatitis C infection. PLoS One 2023; 18:e0286469. [PMID: 37651384 PMCID: PMC10470904 DOI: 10.1371/journal.pone.0286469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/16/2023] [Indexed: 09/02/2023] Open
Abstract
Alpha-1 antitrypsin deficiency (AATD), a relatively common autosomal recessive genetic disorder, is underdiagnosed in symptomatic individuals. We sought to compare the risk of liver transplantation associated with hepatitis C infection with AATD heterozygotes and homozygotes and determine if SERPINA1 sequencing would identify undiagnosed AATD. We performed a retrospective cohort study in a deidentified Electronic Health Record (EHR)-linked DNA biobank with 72,027 individuals genotyped for the M, Z, and S alleles in SERPINA1. We investigated liver transplantation frequency by genotype group and compared with hepatitis C infection. We performed SERPINA1 sequencing in carriers of pathogenic AATD alleles who underwent liver transplantation. Liver transplantation was associated with the Z allele (ZZ: odds ratio [OR] = 1.31, p<2e-16; MZ: OR = 1.02, p = 1.2e-13) and with hepatitis C (OR = 1.20, p<2e-16). For liver transplantation, there was a significant interaction between genotype and hepatitis C (ZZ: interaction OR = 1.23, p = 4.7e-4; MZ: interaction OR = 1.11, p = 6.9e-13). Sequencing uncovered a second, rare, pathogenic SERPINA1 variant in six of 133 individuals with liver transplants and without hepatitis C. Liver transplantation was more common in individuals with AATD risk alleles (including heterozygotes), and AATD and hepatitis C demonstrated evidence of a gene-environment interaction in relation to liver transplantation. The current AATD screening strategy may miss diagnoses whereas SERPINA1 sequencing may increase diagnostic yield for AATD, stratify risk for liver disease, and inform clinical management for individuals with AATD risk alleles and liver disease risk factors.
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Affiliation(s)
- Bryce A. Schuler
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Lisa Bastarache
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Janey Wang
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Jing He
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Sara L. Van Driest
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Joshua C. Denny
- All of Us Research Program, National Institutes of Health, Bethesda, Maryland, United States of America
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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Lopez-Campos JL, Rapun N, Czischke K, Jardim JR, Acquier MF, Munive AA, Günen H, Drobnic E, Miravitlles M, Osaba L. Distribution of alpha1 antitrypsin rare alleles in six countries: Results from the Progenika diagnostic network. Hum Genomics 2023; 17:48. [PMID: 37277845 DOI: 10.1186/s40246-023-00497-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 05/30/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND Knowledge of the frequency of rare SERPINA1 mutations could help in the management of alpha1 antitrypsin deficiency (AATD). The present study aims to assess the frequencies of rare and null alleles and their respiratory and hepatic pathogenicity. METHODS This is a secondary analysis of a study that evaluated the viability of the Progenika diagnostic genotyping system in six different countries by analyzing 30,827 samples from cases of suspected AATD. Allele-specific genotyping was carried out with the Progenika A1AT Genotyping Test which analyses 14 mutations in buccal swabs or dried blood spots samples. SERPINA1 gene sequencing was performed for serum AAT-genotype discrepancies or by request of the clinician. Only cases with rare mutations were included in this analysis. RESULTS There were 818 cases (2.6%) carrying a rare allele, excluding newly identified mutations. All were heterozygous except for 20 that were homozygous. The most frequent alleles were the M-like alleles, PI*Mmalton and PI*Mheerlen. Of the 14 mutations included in the Progenika panel, there were no cases detected of PI*Siiyama, PI*Q0granite falls and PI*Q0west. Other alleles not included in the 14-mutation panel and identified by gene sequencing included PI*Mwürzburg, PI*Zbristol, and PI*Zwrexham, and the null alleles PI*Q0porto, PI*Q0madrid, PI*Q0brescia, and PI*Q0kayseri. CONCLUSIONS The Progenika diagnostic network has allowed the identification of several rare alleles, some unexpected and not included in the initial diagnostic panel. This establishes a new perspective on the distribution of these alleles in different countries. These findings may help prioritize allele selection for routine testing and highlights the need for further research into their pathogenetic role.
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Affiliation(s)
- José Luis Lopez-Campos
- Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/Universidad de Sevilla, Avda. Manuel Siurot, S/N, 41013, Seville, Spain.
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain.
| | - Noelia Rapun
- Progenika Biopharma, a Grifols Company. Derio, Vizcaya, Spain
| | - Karen Czischke
- Departamento de Neumología, Clínica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile
| | - José R Jardim
- Centro de Reabilitação Pulmonar da Escola Paulista de Medicina da Universidade Federal de São Paulo (EPM/Unifesp), São Paulo, Brazil
| | | | - Abraham Ali Munive
- Departamento Médico, Fundación Neumológica Colombiana, Bogotá, D.C., Colombia
| | - Hakan Günen
- University of Health Sciences, Süreyyapaşa Research and Training Center for Chest Diseases and Thoracic Surgery, Istanbul, Turkey
| | | | - Marc Miravitlles
- Servicio de Neumología, Hospital Universitari Vall d'Hebron/Vall d'Hebron Research Institute (VHIR), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain
| | - Lourdes Osaba
- Progenika Biopharma, a Grifols Company. Derio, Vizcaya, Spain
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Tiensuu H, Haapalainen AM, Tissarinen P, Pasanen A, Määttä TA, Huusko JM, Ohlmeier S, Bergmann U, Ojaniemi M, Muglia LJ, Hallman M, Rämet M. Human placental proteomics and exon variant studies link AAT/SERPINA1 with spontaneous preterm birth. BMC Med 2022; 20:141. [PMID: 35477570 PMCID: PMC9047282 DOI: 10.1186/s12916-022-02339-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/14/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Preterm birth is defined as live birth before 37 completed weeks of pregnancy, and it is a major problem worldwide. The molecular mechanisms that lead to onset of spontaneous preterm birth are incompletely understood. Prediction and evaluation of the risk of preterm birth is challenging as there is a lack of accurate biomarkers. In this study, our aim was to identify placental proteins that associate with spontaneous preterm birth. METHODS We analyzed the proteomes from placentas to identify proteins that associate with both gestational age and spontaneous labor. Next, rare and potentially damaging gene variants of the identified protein candidates were sought for from our whole exome sequencing data. Further experiments we performed on placental samples and placenta-associated cells to explore the location and function of the spontaneous preterm labor-associated proteins in placentas. RESULTS Exome sequencing data revealed rare damaging variants in SERPINA1 in families with recurrent spontaneous preterm deliveries. Protein and mRNA levels of alpha-1 antitrypsin/SERPINA1 from the maternal side of the placenta were downregulated in spontaneous preterm births. Alpha-1 antitrypsin was expressed by villous trophoblasts in the placenta, and immunoelectron microscopy showed localization in decidual fibrinoid deposits in association with specific extracellular proteins. siRNA knockdown in trophoblast-derived HTR8/SVneo cells revealed that SERPINA1 had a marked effect on regulation of the actin cytoskeleton pathway, Slit-Robo signaling, and extracellular matrix organization. CONCLUSIONS Alpha-1 antitrypsin is a protease inhibitor. We propose that loss of the protease inhibition effects of alpha-1 antitrypsin renders structures critical to maintaining pregnancy susceptible to proteases and inflammatory activation. This may lead to spontaneous premature birth.
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Affiliation(s)
- Heli Tiensuu
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Antti M Haapalainen
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Pinja Tissarinen
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Anu Pasanen
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Tomi A Määttä
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Johanna M Huusko
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland.,Division of Human Genetics, Center for Prevention of Preterm Birth, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, March of Dimes Prematurity Research Center Ohio Collaborative, Cincinnati, OH, 45267, USA
| | - Steffen Ohlmeier
- Proteomics and Mass Spectrometry Core Facilities, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014, Oulu, Finland
| | - Ulrich Bergmann
- Proteomics and Mass Spectrometry Core Facilities, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014, Oulu, Finland
| | - Marja Ojaniemi
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland.,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland
| | - Louis J Muglia
- Division of Human Genetics, Center for Prevention of Preterm Birth, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, March of Dimes Prematurity Research Center Ohio Collaborative, Cincinnati, OH, 45267, USA.,Burroughs Wellcome Fund, Research Triangle Park, North Carolina, 27709, USA
| | - Mikko Hallman
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland. .,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland.
| | - Mika Rämet
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, PO Box 5000, 90014, Oulu, Finland. .,Department of Children and Adolescents, Oulu University Hospital, 90014, Oulu, Finland. .,Faculty of Medicine and Health Technology, Tampere University, 33014, Tampere, Finland.
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Fromme M, Schneider CV, Trautwein C, Brunetti-Pierri N, Strnad P. Alpha-1 antitrypsin deficiency: A re-surfacing adult liver disorder. J Hepatol 2022; 76:946-958. [PMID: 34848258 DOI: 10.1016/j.jhep.2021.11.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 11/05/2021] [Accepted: 11/18/2021] [Indexed: 12/21/2022]
Abstract
Alpha-1 antitrypsin deficiency (AATD) arises from mutations in the SERPINA1 gene encoding alpha-1 antitrypsin (AAT) that lead to AAT retention in the endoplasmic reticulum of hepatocytes, causing proteotoxic liver injury and loss-of-function lung disease. The homozygous Pi∗Z mutation (Pi∗ZZ genotype) is responsible for the majority of severe AATD cases and can precipitate both paediatric and adult liver diseases, while the heterozygous Pi∗Z mutation (Pi∗MZ genotype) is an established genetic modifier of liver disease. We review genotype-related hepatic phenotypes/disease predispositions. We also describe the mechanisms and factors promoting the development of liver disease, as well as approaches to evaluate the extent of liver fibrosis. Finally, we discuss emerging diagnostic and therapeutic approaches for the clinical management of this often neglected disorder.
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Affiliation(s)
- Malin Fromme
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Health Care Provider of the European Reference Network on Rare Liver Disorders (ERN RARE LIVER), Aachen, Germany
| | - Carolin V Schneider
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Health Care Provider of the European Reference Network on Rare Liver Disorders (ERN RARE LIVER), Aachen, Germany
| | - Christian Trautwein
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Health Care Provider of the European Reference Network on Rare Liver Disorders (ERN RARE LIVER), Aachen, Germany
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Pozzuoli, 80078 Naples, Italy; Department of Translational Medicine, Federico II University of Naples, Naples, Italy
| | - Pavel Strnad
- Medical Clinic III, Gastroenterology, Metabolic Diseases and Intensive Care, University Hospital RWTH Aachen, Health Care Provider of the European Reference Network on Rare Liver Disorders (ERN RARE LIVER), Aachen, Germany.
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Ghosh AJ, Hobbs BD. Recent advancements in understanding the genetic involvement of alpha-1 antitrypsin deficiency associated lung disease: a look at future precision medicine approaches. Expert Rev Respir Med 2022; 16:173-182. [PMID: 35025710 PMCID: PMC8983484 DOI: 10.1080/17476348.2022.2027755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Alpha-1 antitrypsin deficiency occurs in individuals with deleterious genetic mutations on both chromosomes (maternal and paternal) in SERPINA1, the gene encoding the alpha-1 antitrypsin protein. There has been substantial progress in understanding the genetic variation that underlies the heterogeneous penetrance of lung disease in alpha-1 antitrypsin deficiency. AREAS COVERED This review will cover SERPINA1 gene structure and genetic variation, population genetics, genome-wide genetic modifiers of lung disease, alternative mechanisms of disease, and emerging therapeutics - including gene and cell therapy - related to alpha-1 antitrypsin deficiency-associated lung disease. EXPERT OPINION There remains ample opportunity to employ precision medicine in the diagnosis, prognosis, and therapy of alpha-1 antitrypsin deficiency-associated lung disease. In particular, a genome-wide association study and subsequent polygenic risk score is an important first step in identifying genome-wide genetic modifiers contributing to the variability of lung disease in severe alpha-1 antitrypsin deficiency.
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Affiliation(s)
- Auyon J. Ghosh
- Assistant Professor of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, SUNY Upstate Medical University, 750 E. Adams St, Syracuse, NY, 13210
| | - Brian D. Hobbs
- Assistant Professor of Medicine, Channing Division of Network Medicine, Brigham and Women’s Hospital, 181 Longwood Ave, Boston, MA, 02115,Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital,Harvard Medical School
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9
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Foil KE. Variants of SERPINA1 and the increasing complexity of testing for alpha-1 antitrypsin deficiency. Ther Adv Chronic Dis 2021; 12_suppl:20406223211015954. [PMID: 34408833 PMCID: PMC8367212 DOI: 10.1177/20406223211015954] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/20/2021] [Indexed: 02/06/2023] Open
Abstract
Alpha-1 antitrypsin deficiency (AATD) is caused by mutations in the SERPINA1 gene, which encodes the alpha-1 antitrypsin (AAT) protein. Currently, over 200 SERPINA1 variants have been identified, many of which cause the quantitative and/or qualitative changes in AAT responsible for AATD-associated lung and liver disease. The types of these pathogenic mutations are varied, often resulting in misfolding, or truncating of the AAT amino acid sequence, and improvements in sequencing technology are helping to identify known and novel genetic variants. However, due to the diversity and novelty of rare variants, the clinical significance of many is largely unknown. There is, therefore, a lack of guidance on how patients should be monitored and treated when the clinical significance of their variant combination is unclear or variable. Nevertheless, it is important that physicians understand the advantages and disadvantages of the different testing methodologies available to diagnose AATD. Owing to the autosomal inheritance of the genetic mutations responsible for AATD, genetic testing should be offered not only to patients at increased AATD risk (e.g. patients with chronic obstructive pulmonary disease), but also to relatives of those with an abnormal result. Genetic counseling may help patients and family members understand the possible outcomes of testing and the implications for the family. While stress/anxiety can arise from genetic diagnosis or confirmation of carrier status, there can be positive consequences to genetic testing, including improved lifestyle choices, directed medical care, and empowered family planning. As genetic testing technology grows and becomes more popular, testing without physician referral is becoming more prevalent, irrespective of the availability of genetic counseling. Therefore, the Alpha-1 Foundation offers genetic counseling, as well as other support and educational material, for patients with AATD, as well as their families and physicians, to help improve the understanding of potential benefits and consequences of genetic testing.
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Affiliation(s)
- Kimberly E Foil
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
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10
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Seixas S, Marques PI. Known Mutations at the Cause of Alpha-1 Antitrypsin Deficiency an Updated Overview of SERPINA1 Variation Spectrum. APPLICATION OF CLINICAL GENETICS 2021; 14:173-194. [PMID: 33790624 PMCID: PMC7997584 DOI: 10.2147/tacg.s257511] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/24/2021] [Indexed: 12/12/2022]
Abstract
Alpha-1-Antitrypsin deficiency (AATD), caused by SERPINA1 mutations, is one of the most prevalent Mendelian disorders among individuals of European descend. However, this condition, which is characterized by reduced serum levels of alpha-1-antitrypsin (AAT) and associated with increased risks of pulmonary emphysema and liver disease in both children and adults, remains frequently underdiagnosed. AATD clinical manifestations are often correlated with two pathogenic variants, the Z allele (p.Glu342Lys) and the S allele (p.Glu264Val), which can be combined in severe ZZ or moderate SZ risk genotypes. Yet, screenings of AATD cases and large sequencing efforts carried out in both control and disease populations are disclosing outstanding numbers of rare SERPINA1 variants (>500), including many pathogenic and other likely deleterious mutations. Generally speaking, pathogenic variants can be subdivided into either loss- or gain-of-function according to their pathophysiological effects. In AATD, the loss-of-function is correlated with an uncontrolled activity of elastase by its natural inhibitor, the AAT. This phenomenon can result from the absence of circulating AAT (null alleles), poor AAT secretion from hepatocytes (deficiency alleles) or even from a modified inhibitory activity (dysfunctional alleles). On the other hand, the gain-of-function is connected with the formation of AAT polymers and their switching on of cellular stress and inflammatory responses (deficiency alleles). Less frequently, the gain-of-function is related to a modified protease affinity (dysfunctional alleles). Here, we revisit SERPINA1 mutation spectrum, its origins and population history with a greater emphasis on variants fitting the aforementioned processes of AATD pathogenesis. Those were selected based on their clinical significance and wider geographic distribution. Moreover, we also provide some directions for future studies of AATD clinically heterogeneity and comprehensive diagnosis.
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Affiliation(s)
- Susana Seixas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
| | - Patricia Isabel Marques
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
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Murray JD, Willrich MA, Krowka MJ, Bobr A, Murray DL, Halling KC, Graham RP, Snyder MR. Liquid Chromatography-Tandem Mass Spectrometry-Based α1-Antitrypsin (AAT) Testing. Am J Clin Pathol 2021; 155:547-552. [PMID: 33083828 DOI: 10.1093/ajcp/aqaa149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Failure to produce sufficient quantities of functional α1-antitrypsin (AAT) can result in AAT deficiency (AATD) and significant comorbidities. Laboratory testing plays a vital role in AATD, with diagnosis requiring documentation of both a low AAT level and a mutated allele. This retrospective evaluation examines the efficacy of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) (proteotyping)-based algorithm for AATD detection. METHODS A 16-month retrospective data analysis was performed on two cohorts: 5,474 samples tested with the proteotype-based algorithm and 16,147 samples directly tested by isoelectric focusing (IEF) phenotyping. RESULTS LC-MS/MS reduced the rate of IEF testing by 97%. The 3% of cases reflexed to IEF resulted in 12 (0.2%) additional phenotype findings. Retrospectively applying the proteotype-based algorithm to the IEF cohort demonstrated a 99.9% sensitivity for the detection of deficiency-associated phenotypes. Most deficiency phenotypes missed by the proteotyping algorithm would come from heterozygous patients with an F, I, or P paired to an S or Z. In all of these cases, patient AAT levels were greater than 70 mg/dL, above the threshold for AAT augmentation therapy. CONCLUSIONS The proteotype algorithm is a sensitive and cost-effective approach for the diagnosis of clinical AAT deficiency.
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Affiliation(s)
| | | | - Michael J Krowka
- Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN
| | - Aleh Bobr
- Blood Bank and Tissue Services, University of Nebraska Medical Center, Omaha
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Franciosi AN, Ralph J, O'Farrell NJ, Buckley C, Gulmann C, O'Kane M, Carroll TP, McElvaney NG. Alpha-1 antitrypsin deficiency-associated panniculitis. J Am Acad Dermatol 2021; 87:825-832. [PMID: 33516773 DOI: 10.1016/j.jaad.2021.01.074] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Panniculitis represents a rare and potentially lethal manifestation of alpha-1 antitrypsin deficiency (AATD). Evidence regarding management is limited to case reports and small case series. We sought to clarify typical features and investigation of AATD-associated panniculitis and assess the evidence regarding therapeutic options. SEARCH METHODOLOGY Articles and abstracts published between 1970 and 2020 were identified by searches of MEDLINE, PubMed, and secondary searches of references from relevant articles using the search terms "panniculitis," "alpha-1," "antitrypsin," "deficiency," and "Weber-Christian." FINDINGS We identified 117 cases of AATD-associated panniculitis. In 1 series, AATD was present in 15% of all cases of biopsy-proven panniculitis. Failure to achieve clinical response was seen in all instances of systemic steroid use. Dapsone, although effective and accessible, is frequently associated with failure to achieve remission. In these instances, intravenous AAT augmentation therapy generally resulted in response. CONCLUSIONS AATD may be more prevalent among patients presenting with panniculitis than previously thought. Patients presenting with panniculitis and systemic illness show high mortality risk. Although most cases are associated with the severe ZZ-genotype, moderate genotypes may also predispose to panniculitis. Dapsone remains the most cost-effective therapeutic option, whereas intravenous AAT augmentation remains the most efficacious. Finally, glucocorticoids appear ineffective in this setting.
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Affiliation(s)
- Alessandro N Franciosi
- Department of Medicine, Beaumont Hospital, Dublin, Ireland; Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.
| | - James Ralph
- Department of Dermatology, Beaumont Hospital, Dublin, Ireland
| | | | - Colm Buckley
- Department of Histopathology, Beaumont Hospital, Dublin, Ireland
| | | | - Marina O'Kane
- Department of Dermatology, Beaumont Hospital, Dublin, Ireland
| | - Tomás P Carroll
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland; Alpha-1 Foundation Ireland, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Noel G McElvaney
- Department of Medicine, Beaumont Hospital, Dublin, Ireland; Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland
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Mattman A, Gilfix BM, Chen SX, DeMarco ML, Kyle BD, Parker ML, Agbor TA, Jung B, Selvarajah S, Barakauskas VE, Vaags AK, Estey MP, Nelson TN, Speevak MD. Alpha-1-antitrypsin molecular testing in Canada: A seven year, multi-centre comparison. Clin Biochem 2020; 81:27-33. [DOI: 10.1016/j.clinbiochem.2020.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 10/24/2022]
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Emphysema in a Middle-aged Former Smoker. Ann Am Thorac Soc 2020; 17:762-766. [DOI: 10.1513/annalsats.202001-057cc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Adipose Mesenchymal Extracellular Vesicles as Alpha-1-Antitrypsin Physiological Delivery Systems for Lung Regeneration. Cells 2019; 8:cells8090965. [PMID: 31450843 PMCID: PMC6770759 DOI: 10.3390/cells8090965] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/14/2019] [Accepted: 08/23/2019] [Indexed: 12/15/2022] Open
Abstract
Accumulating evidence shows that Mesenchymal Stem/Stromal Cells (MSCs) exert their therapeutic effects by the release of secretome, made of both soluble proteins and nano/microstructured extracellular vesicles (EVs). In this work, for the first time, we proved by a proteomic investigation that adipose-derived (AD)-MSC-secretome contains alpha-1-antitrypsin (AAT), the main elastase inhibitor in the lung, 72 other proteins involved in protease/antiprotease balance, and 46 proteins involved in the response to bacteria. By secretome fractionation, we proved that AAT is present both in the soluble fraction of secretome and aggregated and/or adsorbed on the surface of EVs, that can act as natural carriers promoting AAT in vivo stability and activity. To modulate secretome composition, AD-MSCs were cultured in different stimulating conditions, such as serum starvation or chemicals (IL-1β and/or dexamethasone) and the expression of the gene encoding for AAT was increased. By testing in vitro the anti-elastase activity of MSC-secretome, a dose-dependent effect was observed; chemical stimulation of AD-MSCs did not increase their secretome anti-elastase activity. Finally, MSC-secretome showed anti-bacterial activity on Gram-negative bacteria, especially for Klebsiella pneumoniae. These preliminary results, in addition to the already demonstrated immunomodulation, pave the way for the use of MSC-secretome in the treatment of AAT-deficiency lung diseases.
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Kueppers F, Andrake MD, Xu Q, Dunbrack RL, Kim J, Sanders CL. Protein modeling to assess the pathogenicity of rare variants of SERPINA1 in patients suspected of having Alpha 1 Antitrypsin Deficiency. BMC MEDICAL GENETICS 2019; 20:125. [PMID: 31307431 PMCID: PMC6631921 DOI: 10.1186/s12881-019-0852-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 06/24/2019] [Indexed: 12/22/2022]
Abstract
Background Alpha 1 Antitrypsin (AAT) is a key serum proteinase inhibitor encoded by SERPINA1. Sequence variants of the gene can cause Alpha 1 Antitrypsin Deficiency (AATD), a condition associated with lung and liver disease. The majority of AATD cases are caused by the ‘Z’ and ‘S’ variants – single-nucleotide variations (SNVs) that result in amino acid substitutions of E342K and E264V. However, SERPINA1 is highly polymorphic, with numerous potentially clinically relevant variants reported. Novel variants continue to be discovered, and without reports of pathogenicity, it can be difficult for clinicians to determine the best course of treatment. Methods We assessed the utility of next-generation sequencing (NGS) and predictive computational analysis to guide the diagnosis of patients suspected of having AATD. Blood samples on serum separator cards were submitted to the DNA1 Advanced Screening Program (Biocerna LLC, Fulton, Maryland, USA) by physicians whose patients were suspected of having AATD. Laboratory analyses included quantification of serum AAT levels, qualitative analysis by isoelectric focusing, and targeted genotyping and NGS of the SERPINA1 gene. Molecular modeling software UCSF Chimera (University College of San Francisco, CA) was used to visualize the positions of amino acid changes as a result of rare/novel SNVs. Predictive software was used to assess the potential pathogenicity of these variants; methods included a support vector machine (SVM) program, PolyPhen-2 (Harvard University, Cambridge, MA), and FoldX (Centre for Genomic Regulation, Barcelona, Spain). Results Samples from 23 patients were analyzed; 21 rare/novel sequence variants were identified by NGS, including splice variants (n = 2), base pair deletions (n = 1), stop codon insertions (n = 2), and SNVs (n = 16). Computational modeling of protein structures caused by the novel SNVs showed that 8 were probably deleterious, and two were possibly deleterious. For the majority of probably/possibly deleterious SNVs (I50N, P289S, M385T, M221T, D341V, V210E, P369H, V333M and A142D), the mechanism is probably via disruption of the packed hydrophobic core of AAT. Several deleterious variants occurred in combination with more common deficiency alleles, resulting in very low AAT levels. Conclusions NGS and computational modeling are useful tools that can facilitate earlier, more precise diagnosis, and consideration for AAT therapy in AATD. Electronic supplementary material The online version of this article (10.1186/s12881-019-0852-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Friedrich Kueppers
- Department of Thoracic Medicine and Surgery, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA.
| | - Mark D Andrake
- Molecular Therapeutics Program, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Qifang Xu
- Molecular Therapeutics Program, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Roland L Dunbrack
- Molecular Therapeutics Program, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
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Sequencing Alpha-1 MZ Individuals Shows Frequent Biallelic Mutations. Pulm Med 2018; 2018:2836389. [PMID: 30254761 PMCID: PMC6145046 DOI: 10.1155/2018/2836389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/03/2018] [Accepted: 08/12/2018] [Indexed: 11/17/2022] Open
Abstract
Rationale Individuals with a single Z mutation in the SERPINA1 gene that codes for alpha-1 antitrypsin (AAT) are at increased risk for COPD if they have ever-smoked. Whether additional variants alter the risk for COPD in this population remains unknown. Objectives To determine whether additional SERPINA1 variants impact COPD development in a previously identified MZ (carrier) cohort. Methods Individuals with prior MZ results and AAT serum level <16uM were recruited from the Alpha-1 Coded Testing study and Alpha-1 Foundation Research Registry. Participants completed smoking history, demographics, and COPD Severity Score (Range 0-33) using REDCap data capture. At-home finger-stick tests were performed for next generation sequencing (NGS) at the Biocerna LLC laboratory. A genetic counselor reviewed records and interviewed participants with additional variants by NGS. A Wilcoxon Rank Sum test was used to assess correlation between variants and the COPD severity score. Results A second SERPINA1 variant of known or possible significance was identified in 6 (5.8%) participants. One each of ZZ, SZ, FZ, ZSmunich, ZM2obernburg, and Z/c.922G>T genotypes were identified. ZZ, SZ, and FZ are known pathogenic genotypes. Smunich is a likely pathogenic variant. M2obernburg and c.922G>T are variants of uncertain significance. The ZZ individual was on augmentation therapy when determined MZ by protease inhibitor (Pi) phenotyping; the others had limited targeted genotyping with MZ results. These six participants with biallelic variants had positive COPD severity scores >1. Presence of additional variants was not significantly associated with COPD symptoms in this small sample size. Conclusions Some diagnosed MZ individuals instead have biallelic variants. Larger studies are needed to determine COPD-risk liability of variants. Accurate diagnosis impacts medical management and familial risk assessment. Pi phenotyping can be confounded by augmentation therapy and liver transplantation. Because a normal M allele may be reported in the absence of tested mutation(s) in AATD genotyping, clinicians should consider clinical circumstances and laboratory methods when selecting and interpreting AATD tests. Advanced testing, including NGS, may be beneficial for select individuals with prior MZ results. Clinical Trial Registration This study was registered with clinicaltrials.gov (NCT NCT02810327).
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Reilkoff R, Stephenson L. Fulminant hepatic failure in the setting of progressive ANCA-associated vasculitis associated with a rare alpha-1 antitrypsin phenotype, 'PiEE'. BMJ Case Rep 2018; 2018:bcr-2017-222036. [PMID: 29592975 PMCID: PMC5878378 DOI: 10.1136/bcr-2017-222036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Abnormalities in alpha-1 antitrypsin (AAT) proteins are risk factors for human disease. While the most common is AAT deficiency, a genetic disorder associated with chronic obstructive pulmonary disease, additional disorders associated with AAT abnormalities are increasingly recognised. We describe a middle-aged woman who presented with fulminant hepatic and multiorgan failure. Evaluation revealed the patient to have a rare AAT phenotype PiEE. Her clinical presentation was consistent with antineutrophilic cytoplasmic antibody-associated vasculitis, and her history suggested features of panniculitis. This is the first description of this rare homozygous AAT phenotype and possible disease associations with the ’E' protein. Given that abnormal AAT are under-recognised, and that new mutations and phenotypes continue to be identified, we will need to expand on our knowledge base and report clinical manifestations associated with these abnormal phenotypes.
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Affiliation(s)
- Ronald Reilkoff
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.,Critical Care, Fairview Southdale Hospital, Edina, Minnesota, USA
| | - Laurel Stephenson
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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Alpha-1-antitrypsin (SERPINA1) mutation spectrum: Three novel variants and haplotype characterization of rare deficiency alleles identified in Portugal. Respir Med 2016; 116:8-18. [DOI: 10.1016/j.rmed.2016.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/21/2016] [Accepted: 05/02/2016] [Indexed: 01/24/2023]
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Belmonte I, Barrecheguren M, López-Martínez RM, Esquinas C, Rodríguez E, Miravitlles M, Rodríguez-Frías F. Application of a diagnostic algorithm for the rare deficient variant Mmalton of alpha-1-antitrypsin deficiency: a new approach. Int J Chron Obstruct Pulmon Dis 2016; 11:2535-2541. [PMID: 27877030 PMCID: PMC5113155 DOI: 10.2147/copd.s115940] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Alpha-1-antitrypsin deficiency (AATD) is associated with a high risk for the development of early-onset emphysema and liver disease. A large majority of subjects with severe AATD carry the ZZ genotype, which can be easily detected. Another rare pathologic variant, the Mmalton allele, causes a deficiency similar to that of the Z variant, but it is not easily recognizable and its detection seems to be underestimated. Therefore, we have included a rapid allele-specific genotyping assay for the detection of the Mmalton variant in the diagnostic algorithm of AATD used in our laboratory. The objective of this study was to test the usefulness of this new algorithm for Mmalton detection. MATERIALS AND METHODS We performed a retrospective revision of all AATD determinations carried out in our laboratory over 2 years using the new diagnostic algorithm. Samples with a phenotype showing one or two M alleles and AAT levels discordant with that phenotype were analyzed using the Mmalton allele-specific genotyping assay. RESULTS We detected 49 samples with discordant AAT levels; 44 had the MM and five the MS phenotype. In nine of these samples, a single rare Mmalton variant was detected. During the study period, two family screenings were performed and four additional Mmalton variants were identified. CONCLUSION The incorporation of the Mmalton allele-specific genotyping assay in the diagnostic algorithm of AATD resulted in a faster and cheaper method to detect this allele and avoided a significant delay in diagnosis when a sequencing assay was required. This methodology can be adapted to other rare variants. Standardized algorithms are required to obtain conclusive data of the real incidence of rare AAT alleles in each region.
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Affiliation(s)
- Irene Belmonte
- Liver Pathology Unit, Department of Biochemistry and Microbiology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain; Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | | | | | - Cristina Esquinas
- Pneumology Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Esther Rodríguez
- Pneumology Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain; CIBER of Respiratory Diseases, Barcelona, Spain
| | - Marc Miravitlles
- Pneumology Department, Hospital Universitari Vall d'Hebron, Barcelona, Spain; CIBER of Respiratory Diseases, Barcelona, Spain
| | - Francisco Rodríguez-Frías
- Liver Pathology Unit, Department of Biochemistry and Microbiology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain; CIBER of Liver and Digestive Diseases, Instituto Nacional de Salud Carlos III, Madrid, Spain
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Sinden NJ, Baker MJ, Smith DJ, Kreft JU, Dafforn TR, Stockley RA. α-1-antitrypsin variants and the proteinase/antiproteinase imbalance in chronic obstructive pulmonary disease. Am J Physiol Lung Cell Mol Physiol 2015; 308:L179-90. [PMID: 25416382 DOI: 10.1152/ajplung.00179.2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The excessive activities of the serine proteinases neutrophil elastase and proteinase 3 are associated with tissue damage in chronic obstructive pulmonary disease. Reduced concentrations and/or inhibitory efficiency of the main circulating serine proteinase inhibitor α-1-antitrypsin result from point mutations in its gene. In addition, α-2-macroglobulin competes with α-1-antitrypsin for proteinases, and the α-2-macroglobulin-sequestered enzyme can retain its catalytic activity. We have studied how serine proteinases partition between these inhibitors and the effects of α-1-antitrypsin mutations on this partitioning. Subsequently, we have developed a three-dimensional reaction-diffusion model to describe events occurring in the lung interstitium when serine proteinases diffuse from the neutrophil azurophil granule following degranulation and subsequently bind to either α-1-antitrypsin or α-2-macroglobulin. We found that the proteinases remained uninhibited on the order of 0.1 s after release and diffused on the order of 10 μm into the tissue before becoming sequestered. We have shown that proteinases sequestered to α-2-macroglobulin retain their proteolytic activity and that neutrophil elastase complexes with α-2-macroglobulin are able to degrade elastin. Although neutrophil elastase is implicated in the pathophysiology of emphysema, our results highlight a potentially important role for proteinase 3 because of its greater concentration in azurophil granules, its reduced association rate constant with all α-1-antitrypsin variants studied here, its greater diffusion distance, time spent uninhibited following degranulation, and its greater propensity to partition to α-2-macroglobulin where it retains proteolytic activity.
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