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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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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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Wiesemann GS, Oshins RA, Flagg TO, Brantly ML. Novel SERPINA1 Alleles Identified through a Large Alpha-1 Antitrypsin Deficiency Screening Program and Review of Known Variants. CHRONIC OBSTRUCTIVE PULMONARY DISEASES (MIAMI, FLA.) 2023; 10:7-21. [PMID: 36367950 PMCID: PMC9995231 DOI: 10.15326/jcopdf.2022.0321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The SERPINA1 gene encodes the serine protease inhibitor alpha-1 antitrypsin (AAT) and is located on chromosome 14q31-32.3 in a cluster of homologous genes likely formed by exon duplication. AAT has a variety of anti-inflammatory properties. Its clinical relevance is best illustrated by the genetic disease alpha-1 antitrypsin deficiency (AATD) which is associated with an increased risk for chronic obstructive pulmonary disease (COPD) and cirrhosis. While 2 single nucleotide polymorphisms (SNPs) , S and Z, are responsible for more than 95% of all individuals with AATD, there are a number of rare variants associated with deficiency and dysfunction, as well as those associated with normal levels and function. Our laboratory has identified a number of novel AAT alleles that we report in this manuscript. We screened more than 500,000 individuals for AATD alleles through our testing program over the past 20 years. The characterization of these alleles was accomplished by DNA sequencing, measurement of AAT plasma levels and isoelectric focusing at pH 4-5. We report 22 novel AAT alleles discovered through our screening programs, such as Zlittle rock and QOchillicothe, and review the current literature of known AAT genetic variants.
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Affiliation(s)
- Gayle S Wiesemann
- University of Florida College of Medicine, Gainesville, Florida, United States
| | - Regina A Oshins
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
| | - Tammy O Flagg
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
| | - Mark L Brantly
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
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Presotto MA, Veith M, Trinkmann F, Schlamp K, Polke M, Eberhardt R, Herth F, Trudzinski FC. Clinical characterization of a novel alpha1-antitrypsin null variant: PiQ0 Heidelberg. Respir Med Case Rep 2022; 35:101570. [PMID: 35028284 PMCID: PMC8741486 DOI: 10.1016/j.rmcr.2021.101570] [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] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/02/2021] [Accepted: 12/30/2021] [Indexed: 10/24/2022] Open
Abstract
The clinical characterization of a null variant of SERPINA1 - PiQ0Heidelberg - resulting in alpha1-antitrypsin (AAT) deficiency is described. This rare mutation (c.-5+5 G > A) has been previously identified but not clinically described. The 77 year-old female patient had GOLD-3, Group B COPD, severe destructive panlobular emphysema and newly observed respiratory failure on exertion at the time the genetic analysis was performed. Serum AAT level was 0.1 g/L (reference 0.9-2.0 g/L). Isoelectric focusing showed only the Z-protein indicating that this was a null mutation. The patient has started AAT replacement. Early screening and identification of AAT deficiency would allow for earlier intervention.
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Affiliation(s)
- Maria A. Presotto
- Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Martina Veith
- University Medical Centre Giessen and Marburg, Philipps-University, Dept of Medicine, Pulmonary and Critical Care Medicine, Member of the German Centre for Lung Research (DZL), Marburg, Germany
| | - Frederik Trinkmann
- Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Kai Schlamp
- Department of Radiology, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Markus Polke
- Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Ralf Eberhardt
- Department of Pneumology and Critical Care Medicine, Asklepios Klinik Barmbek, Hamburg, Germany
| | - Felix Herth
- Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Franziska C. Trudzinski
- Department of Pneumology and Critical Care Medicine, Thoraxklinik University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC-H), German Center for Lung Research (DZL), Heidelberg, Germany
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Jardim JR, Casas-Maldonado F, Fernandes FLA, Castellano MVCDO, Torres-Durán M, Miravitlles M. Update on and future perspectives for the diagnosis of alpha-1 antitrypsin deficiency in Brazil. J Bras Pneumol 2021; 47:e20200380. [PMID: 34076174 PMCID: PMC8332724 DOI: 10.36416/1806-3756/e20200380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/25/2021] [Indexed: 12/05/2022] Open
Abstract
Alpha-1 antitrypsin deficiency (AATD) is a rare genetic disorder caused by a mutation in the SERPINA1 gene, which encodes the protease inhibitor alpha-1 antitrypsin (AAT). Severe AATD predisposes individuals to COPD and liver disease. Early diagnosis is essential for implementing preventive measures and limiting the disease burden. Although national and international guidelines for the diagnosis and management of AATD have been available for 20 years, more than 85% of cases go undiagnosed and therefore untreated. In Brazil, reasons for the underdiagnosis of AATD include a lack of awareness of the condition among physicians, a racially diverse population, serum AAT levels being assessed in a limited number of individuals, and lack of convenient diagnostic tools. The diagnosis of AATD is based on laboratory test results. The standard diagnostic approach involves the assessment of serum AAT levels, followed by phenotyping, genotyping, gene sequencing, or combinations of those, to detect the specific mutation. Over the past 10 years, new techniques have been developed, offering a rapid, minimally invasive, reliable alternative to traditional testing methods. One such test available in Brazil is the A1AT Genotyping Test, which simultaneously analyzes the 14 most prevalent AATD mutations, using DNA extracted from a buccal swab or dried blood spot. Such advances may contribute to overcoming the problem of underdiagnosis in Brazil and elsewhere, as well as being likely to increase the rate detection of AATD and therefore mitigate the harmful effects of delayed diagnosis.
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Affiliation(s)
- José R Jardim
- . Centro de Reabilitação Pulmonar, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo (SP) Brasil
| | | | - Frederico Leon Arrabal Fernandes
- . Divisão de Pneumologia, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo (SP) Brasil
| | | | - María Torres-Durán
- . Departamento de Neumología, Hospital Álvaro Cunqueiro, Vigo, España
- . Instituto de Investigación Sanitaria Galicia Sur - IISGS - Vigo, España
| | - Marc Miravitlles
- . Departamento de Neumología, Hospital Universitario Vall d'Hebron, Barcelona, España
- . Vall d'Hebron Institut de Recerca - VHIR - Hospital Universitario Vall d'Hebron Barcelona, Barcelona, España
- . CIBER de Enfermedades Respiratorias - CIBERES - Barcelona, España
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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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7
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Balderacchi AM, Barzon V, Ottaviani S, Corino A, Zorzetto M, Wencker M, Corsico AG, Ferrarotti I. Comparison of different algorithms in laboratory diagnosis of alpha1-antitrypsin deficiency. Clin Chem Lab Med 2021; 59:1384-1391. [PMID: 33675199 DOI: 10.1515/cclm-2020-1881] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/17/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Alpha1-antitrypsin deficiency (AATD) is an inherited condition that predisposes individuals to an increased risk of developing lung and liver disease. Even though AATD is one of the most widespread inherited diseases in Caucasian populations, only a minority of affected individuals has been detected. Whereas methods have been validated for AATD testing, there is no universally-established algorithm for the detection and diagnosis of the disorder. In order to compare different methods for diagnosing AATD, we carried out a systematic review of the literature on AATD diagnostic algorithms. METHODS Complete biochemical and molecular analyses of 5,352 samples processed in our laboratory were retrospectively studied using each of the selected algorithms. RESULTS When applying the diagnostic algorithms to the same samples, the frequency of False Negatives varied from 1.94 to 12.9%, the frequency of True Negatives was 62.91% for each algorithm and the frequency of True Positives ranged from 24.19 to 35.15%. We, therefore, highlighted some differences among Negative Predictive Values, ranging from 0.83 to 0.97. Accordingly, the sensitivity of each algorithm ranged between 0.61 and 0.95. We also postulated 1.108 g/L as optimal AAT cut-off value, in absence of inflammatory status, which points to the possible presence of genetic AATD. CONCLUSIONS The choice of the diagnostic algorithm has a significant impact on the correct diagnosis of AATD, which is essential for appropriate treatment and medical care. The fairly large number of possible false negative diagnoses revealed by the present paper should also warn clinicians of negative results in patients with clinically-suspected AATD.
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Affiliation(s)
- Alice M Balderacchi
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Valentina Barzon
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Stefania Ottaviani
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Alessandra Corino
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Michele Zorzetto
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | | | - Angelo G Corsico
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
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Sanoguera-Miralles L, Valenzuela-Palomo A, Bueno-Martínez E, Llovet P, Díez-Gómez B, Caloca MJ, Pérez-Segura P, Fraile-Bethencourt E, Colmena M, Carvalho S, Allen J, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. Comprehensive Functional Characterization and Clinical Interpretation of 20 Splice-Site Variants of the RAD51C Gene. Cancers (Basel) 2020; 12:E3771. [PMID: 33333735 PMCID: PMC7765170 DOI: 10.3390/cancers12123771] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary breast and/or ovarian cancer is a highly heterogeneous disease with more than 10 known disease-associated genes. In the framework of the BRIDGES project (Breast Cancer Risk after Diagnostic Gene Sequencing), the RAD51C gene has been sequenced in 60,466 breast cancer patients and 53,461 controls. We aimed at functionally characterizing all the identified genetic variants that are predicted to disrupt the splicing process. Forty RAD51C variants of the intron-exon boundaries were bioinformatically analyzed, 20 of which were selected for splicing functional assays. To test them, a splicing reporter minigene with exons 2 to 8 was designed and constructed. This minigene generated a full-length transcript of the expected size (1062 nucleotides), sequence, and structure (Vector exon V1- RAD51C exons_2-8- Vector exon V2). The 20 candidate variants were genetically engineered into the wild type minigene and functionally assayed in MCF-7 cells. Nineteen variants (95%) impaired splicing, while 18 of them produced severe splicing anomalies. At least 35 transcripts were generated by the mutant minigenes: 16 protein-truncating, 6 in-frame, and 13 minor uncharacterized isoforms. According to ACMG/AMP-based standards, 15 variants could be classified as pathogenic or likely pathogenic variants: c.404G > A, c.405-6T > A, c.571 + 4A > G, c.571 + 5G > A, c.572-1G > T, c.705G > T, c.706-2A > C, c.706-2A > G, c.837 + 2T > C, c.905-3C > G, c.905-2A > C, c.905-2_905-1del, c.965 + 5G > A, c.1026 + 5_1026 + 7del, and c.1026 + 5G > T.
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Affiliation(s)
- Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Patricia Llovet
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - María José Caloca
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain;
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
- Knight Cancer Research Building, 2720 S Moody Ave, Portland, OR 97201, USA
| | - Marta Colmena
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Douglas F. Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Peter Devilee
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Maaike P. G. Vreeswijk
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
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9
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Gailite L, Valenzuela-Palomo A, Sanoguera-Miralles L, Rots D, Kreile M, Velasco EA. UGT1A1 Variants c.864+5G>T and c.996+2_996+5del of a Crigler-Najjar Patient Induce Aberrant Splicing in Minigene Assays. Front Genet 2020; 11:169. [PMID: 32211025 PMCID: PMC7067894 DOI: 10.3389/fgene.2020.00169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
A large fraction of DNA variants impairs pre-mRNA splicing in human hereditary disorders. Crigler-Najjar syndrome (CNS) is characterized by a severe unconjugated hyperbilirubinemia caused by variants in the UGT1A1 gene. We previously reported one CNS-type II patient with two splice-site variants in trans (c.864+5G>T and c.996+2_996+5del). According to MaxEntScan, both disrupt their corresponding donor sites (c.864+5G>T: 6.99 → 2.28; c.996+2_996+5del: 5.96 → -11.02), so they were selected for subsequent functional tests. Given the unavailability of patient RNA, we constructed an UGT1A1 splicing-reporter minigene with exons 1-4 to characterize the underlying splicing anomaly. The variant c.996+2_996+5del generated two aberrant transcripts, Δ(E2) (exon 2 skipping/64%) and ▼(E2q135) (intron retention of 135-nt/36%), which lead to the loss of 18 conserved amino-acids and the gain of 45 new ones of a critical functional domain, respectively. The c.864+5G>T variant mainly produced the aberrant transcript Δ(E1q141) (141-nt deletion/70.4%) and the full-length isoform (29.6%). Δ(E1q141) would provoke the loss of 47 amino-acids of the N-terminal domain that encodes for substrate specificity. Thus, the three anomalous transcripts are likely to inactivate UGT1A1. Moreover, this patient is also homozygous for the promoter variant A(TA)7TAA that decreases UGT1A1 expression by 70%, so the full-length transcript produced by c.864+5G>T would be even more reduced (<9%), thus supporting the diagnosis of CNS-type II. Therefore, minigenes represent valuable tools for the functional and clinical classifications of genetic variants.
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Affiliation(s)
- Linda Gailite
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Dmitrijs Rots
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Madara Kreile
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
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10
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Chen S, DeMarco ML, Estey MP, Kyle B, Parker ML, Agbor TA, Kawada P, Speevak M, Nelson TN, Mattman A. Null Canada: A novel α 1-antitrypsin allele with in cis variants Glu366Lys and Ile100Asn. Clin Biochem 2020; 79:23-27. [PMID: 32087139 DOI: 10.1016/j.clinbiochem.2020.02.013] [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: 10/15/2019] [Revised: 01/23/2020] [Accepted: 02/18/2020] [Indexed: 11/17/2022]
Abstract
BACKGROUND α1-Antitrypsin (A1AT) deficiency predisposes patients to pulmonary disease due to inadequate protection against human neutrophil elastase released during inflammatory responses. A1AT deficiency is caused by homozygosity or compound heterozygosity for A1AT variants; individuals with A1AT deficiency most commonly have at least one Z variant allele (c.1096G > A (Glu366Lys)). Null variants that result in complete absence of A1AT in the plasma are much rarer. With one recent exception, all reported A1AT variants are characterized by a single pathogenic variant. CASE An 8 years old patient from Edmonton, Alberta, Canada, was investigated for A1AT deficiency. His A1AT phenotype was determined to be M (wild type)/Null by isoelectric focusing (IEF) but M/Z by targeted genotyping. Gene sequencing revealed two heterozygous variants: Z and Ile100Asn (c.299 T > A). The Ile100Asn substitution is predicted to disrupt the secondary structure of an α-helix in which it resides and the neighbouring tertiary structure, resulting in intracellular degradation of A1AT prior to hepatocyte secretion. METHODS Family testing was conducted to verify potential inheritance of an A1AT allele carrying the two mutations in cis, as this arrangement of the mutations would explain "Z" detection by genotyping but not by IEF. Molecular modeling was used to assess the effect of the variants on A1AT structure and stability. DISCUSSION Carrier status for a novel variant NullCanada with in cis mutations (c.[299 T > A;1096G > A], p.[(Ileu100Asn;Glu366Lys)]) was confirmed. A sibling was identified as having A1AT deficiency on the basis of compound heterozygosity for two alleles: NullCanada and the common Z allele. A separate pedigree from the Maritimes was subsequently recognized as carrying NullCanada. CONCLUSION In cis mutations such as NullCanada may be more common than previously described due to failure to detect such mutations using historical testing methods. Combined approaches that include gene sequencing and segregation studies allow recognition of rare A1AT variants, including in cis mutations.
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Affiliation(s)
- Sharon Chen
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, BC, Canada
| | - Mari L DeMarco
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, BC, Canada; Centre for Heart Lung Innovation, University of British Columbia, BC, Canada
| | - Mathew P Estey
- DynaLIFE Medical Labs, AB, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, AB, Canada
| | - Barry Kyle
- DynaLIFE Medical Labs, AB, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, AB, Canada
| | - Michelle L Parker
- DynaLIFE Medical Labs, AB, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, AB, Canada
| | - Terence A Agbor
- DynaLIFE Medical Labs, AB, Canada; Department of Laboratory Medicine and Pathology, University of Alberta, AB, Canada
| | - Patricia Kawada
- Division of Pediatric Gastroenterology & Nutrition, Department of Pediatrics, University of Alberta, AB, Canada
| | - Marsha Speevak
- Department of Laboratory Medicine and Genetics, Trillium Health Partners, ON, Canada
| | - Tanya N Nelson
- Department of Pathology and Laboratory Medicine, University of British Columbia, BC, Canada; Department of Pathology and Laboratory Medicine, BC Children's & BC Women's Hospitals, BC, Canada
| | - Andre Mattman
- Department of Pathology and Laboratory Medicine, St. Paul's Hospital, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, BC, Canada.
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11
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Bari E, Ferrarotti I, Di Silvestre D, Grisoli P, Barzon V, Balderacchi A, Torre ML, Rossi R, Mauri P, Corsico AG, Perteghella S. Adipose Mesenchymal Extracellular Vesicles as Alpha-1-Antitrypsin Physiological Delivery Systems for Lung Regeneration. Cells 2019; 8:E965. [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] [MESH Headings] [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 Klebsiellapneumoniae. 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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Affiliation(s)
- Elia Bari
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Ilaria Ferrarotti
- Center for Diagnosis of Inherited Alpha1-antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, Pneumology Unit, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy
| | - Dario Di Silvestre
- Institute for Biomedical Technologies, F.lli Cervi 93, 20090 Segrate, Milan, Italy
| | - Pietro Grisoli
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Valentina Barzon
- Center for Diagnosis of Inherited Alpha1-antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, Pneumology Unit, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy
| | - Alice Balderacchi
- Center for Diagnosis of Inherited Alpha1-antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, Pneumology Unit, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy
| | - Maria Luisa Torre
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy.
- PharmaExceed S.r.l., Piazza Castello, 19, 27100 Pavia, Italy.
| | - Rossana Rossi
- Institute for Biomedical Technologies, F.lli Cervi 93, 20090 Segrate, Milan, Italy
| | - Pierluigi Mauri
- Institute for Biomedical Technologies, F.lli Cervi 93, 20090 Segrate, Milan, Italy
| | - Angelo Guido Corsico
- Center for Diagnosis of Inherited Alpha1-antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, Pneumology Unit, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy
- PharmaExceed S.r.l., Piazza Castello, 19, 27100 Pavia, Italy
| | - Sara Perteghella
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
- PharmaExceed S.r.l., Piazza Castello, 19, 27100 Pavia, Italy
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12
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Fraile-Bethencourt E, Valenzuela-Palomo A, Díez-Gómez B, Caloca MJ, Gómez-Barrero S, Velasco EA. Minigene Splicing Assays Identify 12 Spliceogenic Variants of BRCA2 Exons 14 and 15. Front Genet 2019; 10:503. [PMID: 31191615 PMCID: PMC6546720 DOI: 10.3389/fgene.2019.00503] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/07/2019] [Indexed: 12/11/2022] Open
Abstract
A relevant fraction of BRCA2 variants is associated with splicing alterations and with an increased risk of hereditary breast and ovarian cancer (HBOC). In this work, we have carried out a thorough study of variants from BRCA2 exons 14 and 15 reported at mutation databases. A total of 294 variants from exons 14 and 15 and flanking intronic sequences were analyzed with the online splicing tools NNSplice and Human Splicing Finder. Fifty-three out of these 294 variants were selected as candidate splicing variants. All variants but one, were introduced into the minigene MGBR2_ex14-20 (with exons 14–20) by site-directed mutagenesis and assayed in MCF-7 cells. Twelve of the remaining 52 variants (23.1%) impaired splicing at different degrees, yielding from 5 to 100% of aberrant transcripts. Nine variants affected the natural acceptor or donor sites of both exons and three affected putative enhancers or silencers. Fluorescent capillary electrophoresis revealed at least 10 different anomalous transcripts: (E14q5), Δ (E14p10), Δ(E14p246), Δ(E14q256), Δ(E14), Δ(E15p12), Δ(E15p13), Δ(E15p83), Δ(E15) and a 942-nt fragment of unknown structure. All transcripts, except for Δ(E14q256) and Δ(E15p12), are expected to truncate the BRCA2 protein. Nine variants induced severe splicing aberrations with more than 90% of abnormal transcripts. Thus, according to the guidelines of the American College of Medical Genetics and Genomics, eight variants should be classified as pathogenic (c.7008-2A > T, c.7008-1G > A, c.7435+1G > C, c.7436-2A > T, c.7436-2A > G, c.7617+1G > A, c.7617+1G > T, and c.7617+2T > G), one as likely pathogenic (c.7008-3C > G) and three remain as variants of uncertain clinical significance or VUS (c.7177A > G, c.7447A > G and c.7501C > T). In conclusion, functional assays by minigenes constitute a valuable strategy to primarily check the splicing impact of DNA variants and their clinical interpretation. While bioinformatics predictions of splice site variants were accurate, those of enhancer or silencer variants were poor (only 3/23 spliceogenic variants) which showed weak impacts on splicing (∼5–16% of aberrant isoforms). So, the Exonic Splicing Enhancer and Silencer (ESE and ESS, respectively) prediction algorithms require further improvement.
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Affiliation(s)
- Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - María José Caloca
- Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | | | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
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13
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Fraile-Bethencourt E, Valenzuela-Palomo A, Díez-Gómez B, Goina E, Acedo A, Buratti E, Velasco EA. Mis-splicing in breast cancer: identification of pathogenic BRCA2 variants by systematic minigene assays. J Pathol 2019; 248:409-420. [PMID: 30883759 DOI: 10.1002/path.5268] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/21/2019] [Accepted: 03/11/2019] [Indexed: 12/21/2022]
Abstract
Splicing disruption is a common mechanism of gene inactivation associated with germline variants of susceptibility genes. To study the role of BRCA2 mis-splicing in hereditary breast/ovarian cancer (HBOC), we performed a comprehensive analysis of variants from BRCA2 exons 2-9, as well as the initial characterization of the regulatory mechanisms of such exons. A pSAD-based minigene with exons 2-9 was constructed and validated in MCF-7 cells, producing the expected transcript (1016-nt/V1-BRCA2_exons_2-9-V2). DNA variants from mutational databases were analyzed by NNSplice and Human Splicing Finder softwares. To refine ESE-variant prediction, we mapped the regulatory regions through a functional strategy whereby 26 exonic microdeletions were introduced into the minigene and tested in MCF-7 cells. Thus, we identified nine spliceogenic ESE-rich intervals where ESE-variants may be located. Combining bioinformatics and microdeletion assays, 83 variants were selected and genetically engineered in the minigene. Fifty-three changes impaired splicing: 28 variants disrupted the canonical sites, four created new ones, 10 abrogated enhancers, eight created silencers and three caused a double-effect. Notably, nine spliceogenic-ESE variants were located within ESE-containing intervals. Capillary electrophoresis and sequencing revealed more than 23 aberrant transcripts, where exon skipping was the most common event. Interestingly, variant c.67G>A triggered the usage of a noncanonical GC-donor 4-nt upstream. Thirty-six variants that induced severe anomalies (>60% aberrant transcripts) were analyzed according to the ACMG guidelines. Thus, 28 variants were classified as pathogenic, five as likely pathogenic and three as variants of uncertain significance. Interestingly, 13 VUS were reclassified as pathogenic or likely pathogenic variants. In conclusion, a large fraction of BRCA2 variants (∼64%) provoked splicing anomalies lending further support to the high prevalence of this disease-mechanism. The low accuracy of ESE-prediction algorithms may be circumvented by functional ESE-mapping that represents an optimal strategy to identify spliceogenic ESE-variants. Finally, systematic functional assays by minigenes depict a valuable tool for the initial characterization of splicing anomalies and the clinical interpretation of variants. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Elisa Goina
- Molecular Pathology Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Alberto Acedo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Emanuele Buratti
- Molecular Pathology Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
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14
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Matamala N, Lara B, Gomez-Mariano G, Martínez S, Retana D, Fernandez T, Silvestre RA, Belmonte I, Rodriguez-Frias F, Vilar M, Sáez R, Iturbe I, Castillo S, Molina-Molina M, Texido A, Tirado-Conde G, Lopez-Campos JL, Posada M, Blanco I, Janciauskiene S, Martinez-Delgado B. Characterization of Novel Missense Variants of SERPINA1 Gene Causing Alpha-1 Antitrypsin Deficiency. Am J Respir Cell Mol Biol 2018; 58:706-716. [PMID: 29232161 DOI: 10.1165/rcmb.2017-0179oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The SERPINA1 gene is highly polymorphic, with more than 100 variants described in databases. SERPINA1 encodes the alpha-1 antitrypsin (AAT) protein, and severe deficiency of AAT is a major contributor to pulmonary emphysema and liver diseases. In Spanish patients with AAT deficiency, we identified seven new variants of the SERPINA1 gene involving amino acid substitutions in different exons: PiSDonosti (S+Ser14Phe), PiTijarafe (Ile50Asn), PiSevilla (Ala58Asp), PiCadiz (Glu151Lys), PiTarragona (Phe227Cys), PiPuerto Real (Thr249Ala), and PiValencia (Lys328Glu). We examined the characteristics of these variants and the putative association with the disease. Mutant proteins were overexpressed in HEK293T cells, and AAT expression, polymerization, degradation, and secretion, as well as antielastase activity, were analyzed by periodic acid-Schiff staining, Western blotting, pulse-chase, and elastase inhibition assays. When overexpressed, S+S14F, I50N, A58D, F227C, and T249A variants formed intracellular polymers and did not secrete AAT protein. Both the E151K and K328E variants secreted AAT protein and did not form polymers, although K328E showed intracellular retention and reduced antielastase activity. We conclude that deficient variants may be more frequent than previously thought and that their discovery is possible only by the complete sequencing of the gene and subsequent functional characterization. Better knowledge of SERPINA1 variants would improve diagnosis and management of individuals with AAT deficiency.
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Affiliation(s)
- Nerea Matamala
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Beatriz Lara
- 2 Respiratory Medicine Department, Coventry University Hospital, Coventry, United Kingdom
| | - Gema Gomez-Mariano
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Selene Martínez
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Diana Retana
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Taiomara Fernandez
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | | | - Irene Belmonte
- 4 Biochemistry Department, Hospital Vall d'Hebron, Barcelona, Spain
| | | | - Marçal Vilar
- 5 Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Cientificas (CSIC), Valencia, Spain
| | - Raquel Sáez
- 6 Immunology and Genetics, Hospital Donosti, San Sebastián, Spain
| | - Igor Iturbe
- 7 Pneumology, Hospital de Zumárraga, Gipuzkoa, Spain
| | | | - María Molina-Molina
- 9 Pulmonary Medicine, Bellvitge University Hospital, Bellvitge Biomedical Research Institute (IDIBELL), Hospital de Llobregat, Barcelona, Spain
| | - Anna Texido
- 10 Pneumology, Hospital Universitari Sant Joan de Reus, Reus (Tarragona), Spain
| | - Gema Tirado-Conde
- 11 Complejo Hospitalario Universitario Granada, Parque Tecnológico de las Ciencias de la Salud, Granada, Spain
| | - Jose Luis Lopez-Campos
- 13 Consorcio Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), and
- 12 Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/Universidad de Sevilla, Sevilla, Spain
| | - Manuel Posada
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
- 14 Consorcio Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Ignacio Blanco
- 15 Spanish Registry of Patients with Alpha-1 Antitrypsin Deficiency (REDAAT), Spanish Society of Pneumology (SEPAR), Fundación Española de Pulmón (RESPIRA), Barcelona, Spain
| | - Sabina Janciauskiene
- 16 Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany; and
- 17 Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
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15
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Fraile-Bethencourt E, Valenzuela-Palomo A, Díez-Gómez B, Acedo A, Velasco EA. Identification of Eight Spliceogenic Variants in BRCA2 Exon 16 by Minigene Assays. Front Genet 2018; 9:188. [PMID: 29881398 PMCID: PMC5977032 DOI: 10.3389/fgene.2018.00188] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 11/17/2022] Open
Abstract
Genetic testing of BRCA1 and BRCA2 identifies a large number of variants of uncertain clinical significance whose functional and clinical interpretations pose a challenge for genetic counseling. Interestingly, a relevant fraction of DNA variants can disrupt the splicing process in cancer susceptibility genes. We have tested more than 200 variants throughout 19 BRCA2 exons mostly by minigene assays, 54% of which displayed aberrant splicing, thus confirming the utility of this assay to check genetic variants in the absence of patient RNA. Our goal was to investigate BRCA2 exon 16 with a view to characterizing spliceogenic variants recorded at the mutational databases. Seventy-two different BIC and UMD variants were analyzed with NNSplice and Human Splicing Finder, 12 of which were selected because they were predicted to disrupt essential splice motifs: canonical splice sites (ss; eight variants) and exonic/intronic splicing enhancers (four variants). These 12 candidate variants were introduced into the BRCA2 minigene with seven exons (14–20) by site-directed mutagenesis and then transfected into MCF-7 cells. Seven variants (six intronic and one missense) induced complete abnormal splicing patterns: c.7618-2A>T, c.7618-2A>G, c.7618-1G>C, c.7618-1G>A, c.7805G>C, c.7805+1G>A, and c.7805+3A>C, as well as a partial anomalous outcome by c.7802A>G. They generated at least 10 different transcripts: Δ16p44 (alternative 3’ss 44-nt downstream; acceptor variants), Δ16 (exon 16-skipping; donor variants), Δ16p55 (alternative 3’ss 55-nt downstream), Δ16q4 (alternative 5’ss 4-nt upstream), Δ16q100 (alternative 5’ss 4-nt upstream), ▾16q20 (alternative 5’ss 20-nt downstream), as well as minor (Δ16p93 and Δ16,17p69) and uncharacterized transcripts of 893 and 954 nucleotides. Isoforms Δ16p44, Δ16, Δ16p55, Δ16q4, Δ16q100, and ▾16q20 introduced premature termination codons which presumably inactivate BRCA2. According to the guidelines the American College of Medical Genetics and Genomics these eight variants could be classified as pathogenic or likely pathogenic whereas the Evidence-based Network for the Interpretation of Germline Mutant Alleles rules suggested seven class 4 and one class 3 variants. In conclusion, our study highlights the relevance of splicing functional assays by hybrid minigenes for the clinical classification of genetic variations. Hence, we provide new data about spliceogenic variants of BRCA2 exon 16 that are directly correlated with breast cancer susceptibility.
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Affiliation(s)
- Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
| | - Alberto Acedo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain.,Biome Makers Inc., San Francisco, CA, United States
| | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, Valladolid, Spain
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16
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Hadzik-Blaszczyk M, Zdral A, Zielonka TM, Rozy A, Krupa R, Falkowski A, Wardyn KA, Chorostowska-Wynimko J, Zycinska K. SERPINA1 Gene Variants in Granulomatosis with Polyangiitis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1070:9-18. [PMID: 29460271 DOI: 10.1007/5584_2018_156] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Alpha-1 antitrypsin (A1AT) deficiency is one of the most common genetic disorders in Caucasian population. There is a link between granulomatosis with polyangiitis (GPA) and most frequent variants of SERPINA1 gene encoding severe alpha-1 antitripsin deficiency. However, the potential effect of Pi*Z, Pi*S as well as other SERPINA1 variants on clinical course of vasculitis are not well understood. The aim of the study was to analyze the potential effect of A1AT protein phenotype representing the SERPINA1 gene variants on the clinical course of GPA. The study group consisted of 64 subjects with GPA, stratified according to the disease severity: patients in active phase (group I, n = 12), patients during remission on treatment (group II, n = 40) or untreated (group III, n = 12). Normal Pi*MM SERPINA1 genotype was detected by means of real-time polymerase chain reaction (PCR) or direct sequencing in 59 patients, Pi*MZ genotype in 2, and Pi*IM, Pi*MS or Pi*SZ in 1 patient respectively. The patients with abnormal Pi*Z, Pi*S, or Pi*I allele constituted 17% in group I, 5% in group II, and 8% in group III. The serum content of A1AT and high sensitivity C-reactive protein (hsCRP) assessed by nephelometry did not differ between the groups. Interestingly, the mean serum antiPR3-antibodies level detected by Elisa method was significantly greater in the GPA patients with Pi*Z, Pi*S, or Pi*I SERPINA1 variants than in the Pi*MM homozygotes. In summary, heterozygous Pi*MZ, Pi*MS, and Pi*SZ genotype was detected in 7.8% of total group of GPA patients, and in 10.5% of those with lung lesions. The abnormal alleles of Pi*S and Pi*Z may affect the clinical course of the disease.
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Affiliation(s)
| | - Aneta Zdral
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
| | - Tadeusz M Zielonka
- Department of Family Medicine, Internal and Metabolic Diseases, Warsaw Medical University, Warsaw, Poland.
| | - Ada Rozy
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
| | - Renata Krupa
- Department of Family Medicine, Internal and Metabolic Diseases, Warsaw Medical University, Warsaw, Poland
| | - Andrzej Falkowski
- Department of Family Medicine, Internal and Metabolic Diseases, Warsaw Medical University, Warsaw, Poland
| | - Kazimierz A Wardyn
- Department of Family Medicine, Internal and Metabolic Diseases, Warsaw Medical University, Warsaw, Poland
| | - Joanna Chorostowska-Wynimko
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
| | - Katarzyna Zycinska
- Department of Family Medicine, Internal and Metabolic Diseases, Warsaw Medical University, Warsaw, Poland
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Belmonte I, Barrecheguren M, Esquinas C, Rodríguez E, Miravitlles M, Rodríguez-Frías F. Genetic diagnosis of α1-antitrypsin deficiency using DNA from buccal swab and serum samples. Clin Chem Lab Med 2017; 55:1276-1283. [PMID: 28107169 DOI: 10.1515/cclm-2016-0842] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/16/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND α1-Antitrypsin deficiency (AATD) is associated with a high risk of developing lung and liver disease. Despite being one of the most common hereditary disorders worldwide, AATD remains under-diagnosed and prolonged delays in diagnosis are usual. The aim of this study was to validate the use of buccal swab samples and serum circulating DNA for the complete laboratory study of AATD. METHODS Sixteen buccal swab samples from previously characterized AATD patients were analyzed using an allele-specific genotyping assay and sequencing method. In addition, 19 patients were characterized by quantification, phenotyping and genotyping using only serum samples. RESULTS The 16 buccal swab samples were correctly characterized by genotyping. Definitive results were obtained in the 19 serum samples analyzed by quantification, phenotyping and genotyping, thereby performing the complete AATD diagnostic algorithm. CONCLUSIONS Buccal swab samples may be useful to expand AATD screening programs and family studies. Genotyping using DNA from serum samples permits the application of the complete diagnostic algorithm without delay. These two methods will be useful for obtaining more in depth knowledge of the real prevalence of patients with AATD.
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Figueira Gonçalves JM, Martínez Bugallo F, García-Talavera I, Rodríguez González J. Alpha-1-Antitrypsin Deficiency Associated With Null Alleles. Arch Bronconeumol 2017; 53:700-702. [PMID: 28705390 DOI: 10.1016/j.arbres.2017.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/08/2017] [Accepted: 05/05/2017] [Indexed: 11/25/2022]
Affiliation(s)
- Juan Marco Figueira Gonçalves
- Servicio de Neumología y Cirugía Torácica, Hospital Universitario Nuestra Señora de la Candelaria, Santa Cruz de Tenerife, España.
| | - Francisco Martínez Bugallo
- Unidad de Genética, Servicio de Análisis Clínicos, Hospital Universitario Nuestra Señora de la Candelaria, Santa Cruz de Tenerife, España
| | - Ignacio García-Talavera
- Servicio de Neumología y Cirugía Torácica, Hospital Universitario Nuestra Señora de la Candelaria, Santa Cruz de Tenerife, España
| | - Jesús Rodríguez González
- Servicio de Neumología y Cirugía Torácica, Hospital Universitario Nuestra Señora de la Candelaria, Santa Cruz de Tenerife, España
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Functional classification of DNA variants by hybrid minigenes: Identification of 30 spliceogenic variants of BRCA2 exons 17 and 18. PLoS Genet 2017; 13:e1006691. [PMID: 28339459 PMCID: PMC5384790 DOI: 10.1371/journal.pgen.1006691] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 04/07/2017] [Accepted: 03/14/2017] [Indexed: 11/30/2022] Open
Abstract
Mutation screening of the breast cancer genes BRCA1 and BRCA2 identifies a large fraction of variants of uncertain clinical significance (VUS) whose functional and clinical interpretations pose a challenge for genomic medicine. Likewise, an increasing amount of evidence indicates that genetic variants can have deleterious effects on pre-mRNA splicing. Our goal was to investigate the impact on splicing of a set of reported variants of BRCA2 exons 17 and 18 to assess their role in hereditary breast cancer and to identify critical regulatory elements that may constitute hotspots for spliceogenic variants. A splicing reporter minigene with BRCA2 exons 14 to-20 (MGBR2_ex14-20) was constructed in the pSAD vector. Fifty-two candidate variants were selected with splicing prediction programs, introduced in MGBR2_ex14-20 by site-directed mutagenesis and assayed in triplicate in MCF-7 cells. Wild type MGBR2_ex14-20 produced a stable transcript of the expected size (1,806 nucleotides) and structure (V1-[BRCA2_exons_14–20]–V2). Functional mapping by microdeletions revealed essential sequences for exon recognition on the 3’ end of exon 17 (c.7944-7973) and the 5’ end of exon 18 (c.7979-7988, c.7999-8013). Thirty out of the 52 selected variants induced anomalous splicing in minigene assays with >16 different aberrant transcripts, where exon skipping was the most common event. A wide range of splicing motifs were affected including the canonical splice sites (15 variants), novel alternative sites (3 variants), the polypyrimidine tract (3 variants) and enhancers/silencers (9 variants). According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), 20 variants could be classified as pathogenic (c.7806-2A>G, c.7806-1G>A, c.7806-1G>T, c.7806-1_7806-2dup, c.7976+1G>A, c.7977-3_7978del, c.7977-2A>T, c.7977-1G>T, c.7977-1G>C, c.8009C>A, c.8331+1G>T and c.8331+2T>C) or likely pathogenic (c.7806-9T>G, c.7976G>C, c.7976G>A, c.7977-7C>G, c.7985C>G, c.8023A>G, c.8035G>T and c.8331G>A), accounting for 30.8% of all pathogenic/likely pathogenic variants of exons 17–18 at the BRCA Share database. The remaining 8 variants (c.7975A>G, c.7977-6T>G, c.7988A>T, c.7992T>A, c.8007A>G, c.8009C>T, c.8009C>G, and c.8072C>T) induced partial splicing anomalies with important ratios of the full-length transcript (≥70%), so that they remained classified as VUS. Aberrant splicing is therefore especially prevalent in BRCA2 exons 17 and 18 due to the presence of active ESEs involved in exon recognition. Splicing functional assays with minigenes are a valuable strategy for the initial characterization of the splicing outcomes and the subsequent clinical interpretation of variants of any disease-gene, although these results should be checked, whenever possible, against patient RNA. A significant proportion of disease-causing mutations of inherited disorders impair splicing. Massive sequencing projects of genetic diseases generate thousands of sequence variations that require functional and clinical interpretations. We have shown that splicing reporter minigenes of the breast cancer genes BRCA1 and BRCA2 are useful tools to functionally test DNA variants. In this work, we have constructed a 7-exon BRCA2 minigene (exons 14 to 20) where we mapped critical splicing regulatory sequences and tested 52 selected variants of exons 17 and 18 detected in breast cancer patients. We finely located three DNA segments on both exons that presumably contain splicing enhancer sequences. We observed that a total of 30 variants of any type disrupted the splicing patterns and, given the severity of their outcomes, we classified 20 of them as pathogenic or likely pathogenic. We also showed that a wide range of splicing elements were affected including canonical and novel 5’ and 3’ splice sites, the polypyrimidine tract and enhancer and silencer sequences. We concluded that splicing aberrations are frequent in Hereditary Breast and Ovarian Cancer and that minigenes are valuable tools to functionally classify DNA variants of any human disease gene under the splicing viewpoint.
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Bashir A, Shah NN, Hazari YM, Habib M, Bashir S, Hilal N, Banday M, Asrafuzzaman S, Fazili KM. Novel variants of SERPIN1A gene: Interplay between alpha1-antitrypsin deficiency and chronic obstructive pulmonary disease. Respir Med 2016; 117:139-49. [DOI: 10.1016/j.rmed.2016.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/18/2016] [Accepted: 06/06/2016] [Indexed: 12/31/2022]
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21
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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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Greulich T, Vogelmeier CF. Alpha-1-antitrypsin deficiency: increasing awareness and improving diagnosis. Ther Adv Respir Dis 2016; 10:72-84. [PMID: 26341117 PMCID: PMC5933657 DOI: 10.1177/1753465815602162] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Alpha-1-antitrypsin deficiency (AATD) is a hereditary disorder that is characterized by a low serum level of alpha-1-antitrypsin (AAT). The loss of anti-inflammatory and antiproteolytic functions, together with pro-inflammatory effects of polymerized AAT contribute to protein degradation and increased inflammation resulting in an increased risk of developing chronic obstructive pulmonary disease (COPD) and emphysema, especially in smokers. AATD is a rare disease that is significantly underdiagnosed. According to recent data that are based on extrapolations, in many countries only 5-15% of homozygous individuals have been identified. Furthermore, the diagnostic delay typically exceeds 5 years, resulting in an average age at diagnosis of about 45 years. Although the American Thoracic Society/European Respiratory Society recommendations state that all symptomatic adults with persistent airway obstruction should be screened, these recommendations are not being followed. Potential reasons for that include missing knowledge about the disease and the appropriate tests, and the low awareness of physicians with regard to the disorder. Once the decision to initiate testing has been made, a screening test (AAT serum level or other) should be performed. Further diagnostic evaluation is based on the following techniques: polymerase chain reaction (PCR) for frequent and clinically important mutations, isoelectric focusing (IEF) with or without immunoblotting, and sequencing of the gene locus coding for AAT. Various diagnostic algorithms have been published for AATD detection (severe deficiency or carrier status). Modern laboratory approaches like the use of serum separator cards, a lateral flow assay to detect the Z-protein, and a broader availability of next-generation sequencing are recent advances, likely to alter existing algorithms.
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Affiliation(s)
- Timm Greulich
- Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Centre Giessen and Marburg, Philipps-University, Baldingerstrasse, 35043 Marburg, Germany
| | - Claus F Vogelmeier
- Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Centre Giessen and Marburg, Philipps-University, Member of the German Centre for Lung Research (DZL), Marburg, Germany
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23
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SERPINA1 Full-Gene Sequencing Identifies Rare Mutations Not Detected in Targeted Mutation Analysis. J Mol Diagn 2015; 17:689-94. [DOI: 10.1016/j.jmoldx.2015.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/19/2015] [Accepted: 07/01/2015] [Indexed: 01/18/2023] Open
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24
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Joly P, Guillaud O, Hervieu V, Francina A, Mornex JF, Chapuis-Cellier C. Clinical heterogeneity and potential high pathogenicity of the Mmalton Alpha 1 antitrypsin allele at the homozygous, compound heterozygous and heterozygous states. Orphanet J Rare Dis 2015; 10:130. [PMID: 26446624 PMCID: PMC4596512 DOI: 10.1186/s13023-015-0350-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/01/2015] [Indexed: 11/20/2022] Open
Abstract
Background Alpha 1 antitrypsin (A1AT) deficiency (A1ATD) is potentially associated with a high degree of liver and/or lung disease. Apart from the most frequent deficiency alleles, Pi S and Pi Z, some A1AT alleles of clinical significance may be easily misdiagnosed. This is typically the case of the Pi Mmalton variant which shares the same ‘gain-of-function’ liver toxicity than Pi Z and the same ‘loss of function’ lung disease as well. Methods The biological diagnosis of A1ATD typically relies on a low serum concentration associated with an abnormal isoelectric focusing (IEF) pattern of migration. However, Sanger direct DNA sequencing may be required for deficiency alleles without biochemical expression (Null alleles) or for A1AT variants whose IEF profiles resemble the wild-type and sub-types M allele but with a low concentration. Results We report four cases of A1ATD involving the deficient Pi Mmalton allele with very different clinical expressions: (i) one Mmalton/Mmalton with liver fibrosis and cirrhosis, (ii) two Mmalton/Z with chronic pulmonary obstructive disease in one case and (iii) one M/Mmalton without liver or lung disease. In both cases, the correct diagnosis has necessitated a genetic analysis. Conclusions Our study provides another example of Pi Mmalton homozygosity associated with a severe liver disease that emphasizes the necessity of a not delayed diagnosis. The great clinical heterogeneity of the other genotypes (which is in agreement with the literature data) questions about the role of environmental and other modifier genes in the pathogenicity of A1ATD.
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Affiliation(s)
- Philippe Joly
- Unité de Pathologie Moléculaire du Globule Rouge, Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France. .,Centre de Recherche et d'Innovation sur le Sport (CRIS)-EA 647, Université Claude-Bernard Lyon 1, Villeurbanne, France. .,Labex GR-Ex, Institut Universitaire de France, Paris, France.
| | - Olivier Guillaud
- Service d'hépato-gastroentérologie, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Valérie Hervieu
- Service d'anatomie pathologique, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Alain Francina
- Unité de Pathologie Moléculaire du Globule Rouge, Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Jean-François Mornex
- Service de pneumologie, Groupement Hospitalier Est, Hospices Civils & Université Claude Bernard-Lyon 1, Bron, France.
| | - Colette Chapuis-Cellier
- Laboratoire d'Immunologie, Centre de Biologie Sud, Centre hospitalier Lyon-Sud, Hospices Civils & Université Claude Bernard-Lyon 1, Lyon, France.
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25
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Hernández Pérez JM, Blanco I. First Argentine study on alpha-1 antitrypsin deficiency in dried blood spot samples from COPD patients. Arch Bronconeumol 2015; 51:535-6. [PMID: 26143134 DOI: 10.1016/j.arbres.2015.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 05/06/2015] [Indexed: 11/30/2022]
Affiliation(s)
| | - Ignacio Blanco
- Neumólogo retirado, Hospital Valle del Nalón, Langreo, Asturias, España
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26
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Matamala N, Martínez MT, Lara B, Pérez L, Vázquez I, Jimenez A, Barquín M, Ferrarotti I, Blanco I, Janciauskiene S, Martinez-Delgado B. Alternative transcripts of the SERPINA1 gene in alpha-1 antitrypsin deficiency. J Transl Med 2015; 13:211. [PMID: 26141700 PMCID: PMC4490674 DOI: 10.1186/s12967-015-0585-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/25/2015] [Indexed: 12/14/2022] Open
Abstract
Background SERPINA1 is the gene for alpha-1 antitrypsin (AAT), an acute phase protein with anti-protease and immunoregulatory activities. Mutations in SERPINA1 gene cause AAT deficiency and predispose individuals to early-onset emphysema and liver diseases. Expression of the SERPINA1 gene is regulated by different promoters and alternative splicing events among non-coding exons 1A, 1B and 1C. Methods We have developed three quantitative PCR (QT-PCR) assays (1A, 1B and 1C). These assays were applied for the analysis of SERPINA1 alternative transcripts in: (1) 16 human tissues and (2) peripheral blood leukocytes from 33 subjects with AAT mutations and 7 controls. Results Tissue-specific expression was found for the SERPINA1 transcripts. The 1A transcripts were mainly expressed in leukocytes and lung tissue while those detected with the 1B assay were highly restricted to leukocytes. Only 1B transcripts significantly correlated with serum AAT levels. The 1C transcripts were specifically found in lung, liver, kidney and pancreas. Furthermore, the expression of transcripts was related to AAT genotypes. While deficient variants of AAT had no pronounced effect on the transcript expression, null alleles were associated with significant reduction of different transcripts. Conclusions The possibility to discriminate between SERPINA1 alternative splicing products will help us to understand better the regulation of SERPINA1 gene and its association with SERPINA1 mutations-related diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0585-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nerea Matamala
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
| | | | - Beatriz Lara
- Respiratory Medicine Department, Royal Exeter and Devon Hospital, Exeter, Devon, UK.
| | - Laura Pérez
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
| | - Irene Vázquez
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
| | - Azucena Jimenez
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
| | - Miguel Barquín
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
| | - Ilaria Ferrarotti
- Section of Pneumology, Department of Molecular Medicine, Center for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, IRCCS San Matteo Hospital Foundation, University of Pavia, Pavia, Italy.
| | - Ignacio Blanco
- Alpha1-Antitrypsin Deficiency Spanish Registry, Lung Foundation RESPIRA, Spanish Society of Pneumology (SEPAR), Barcelona, Spain.
| | - Sabina Janciauskiene
- Department of Respiratory Medicine, Hannover Medical School, Hanover, Germany. .,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), 30626, Hanover, Germany.
| | - Beatriz Martinez-Delgado
- Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III (ISCIII), Carretera Majadahonda-Pozuelo Km 2,200, 28220, Majadahonda, Madrid, Spain.
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27
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Milger K, Holdt LM, Teupser D, Huber RM, Behr J, Kneidinger N. Identification of a novel SERPINA-1 mutation causing alpha-1 antitrypsin deficiency in a patient with severe bronchiectasis and pulmonary embolism. Int J Chron Obstruct Pulmon Dis 2015; 10:891-7. [PMID: 26005342 PMCID: PMC4428364 DOI: 10.2147/copd.s80173] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Deficiency in the serine protease inhibitor, alpha-1 antitrypsin (AAT), is known to cause emphysema and liver disease. Other manifestations, including airway disease or skin disorders, have also been described. A 44-year-old woman presented to our emergency department with dyspnea and respiratory insufficiency. She had never smoked, and had been diagnosed with COPD 9 years earlier. Three months previously, she had suffered a pulmonary embolism. Chest computed tomography scan revealed severe cystic bronchiectasis with destruction of the lung parenchyma. The sweat test was normal and there was no evidence of the cystic fibrosis transmembrane conductance regulator (CFTR) mutation. Capillary zone electrophoresis showed a decrease of alpha-1 globin band and AAT levels were below the quantification limit (<25 mg/dL). No S or Z mutation was identified, but sequencing analysis found a homozygous cytosine and adenine (CA) insertion in exon 2 of the SERPINA-1 gene, probably leading to a dysfunctional protein (PI Null/Null). This mutation has not been previously identified. The atypical presentation of the patient, with severe cystic bronchiectasis, highlights AAT deficiency as a differential diagnosis in bronchiectasis. Further, awareness should be raised regarding a possible increased risk of thromboembolism associated with AAT deficiency.
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Affiliation(s)
- Katrin Milger
- Department of Internal Medicine V, University of Munich, Comprehensive Pneumology Center, Member of the German Center for Lung Research, Munich, Germany
| | | | - Daniel Teupser
- Institute of Laboratory Medicine, University of Munich, Munich, Germany
| | - Rudolf Maria Huber
- Department of Internal Medicine V, University of Munich, Comprehensive Pneumology Center, Member of the German Center for Lung Research, Munich, Germany
| | - Jürgen Behr
- Department of Internal Medicine V, University of Munich, Comprehensive Pneumology Center, Member of the German Center for Lung Research, Munich, Germany
| | - Nikolaus Kneidinger
- Department of Internal Medicine V, University of Munich, Comprehensive Pneumology Center, Member of the German Center for Lung Research, Munich, Germany
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Ferrarotti I, Carroll TP, Ottaviani S, Fra AM, O'Brien G, Molloy K, Corda L, Medicina D, Curran DR, McElvaney NG, Luisetti M. Identification and characterisation of eight novel SERPINA1 Null mutations. Orphanet J Rare Dis 2014; 9:172. [PMID: 25425243 PMCID: PMC4255440 DOI: 10.1186/s13023-014-0172-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022] Open
Abstract
Background Alpha-1 antitrypsin (AAT) is the most abundant circulating antiprotease and is a member of the serine protease inhibitor (SERPIN) superfamily. The gene encoding AAT is the highly polymorphic SERPINA1 gene, found at 14q32.1. Mutations in the SERPINA1 gene can lead to AAT deficiency (AATD) which is associated with a substantially increased risk of lung and liver disease. The most common pathogenic AAT variant is Z (Glu342Lys) which causes AAT to misfold and polymerise within hepatocytes and other AAT-producing cells. A group of rare mutations causing AATD, termed Null or Q0, are characterised by a complete absence of AAT in the plasma. While ultra rare, these mutations confer a particularly high risk of emphysema. Methods We performed the determination of AAT serum levels by a rate immune nephelometric method or by immune turbidimetry. The phenotype was determined by isoelectric focusing analysis on agarose gel with specific immunological detection. DNA was isolated from whole peripheral blood or dried blood spot (DBS) samples using a commercial extraction kit. The new mutations were identified by sequencing all coding exons (II-V) of the SERPINA1 gene. Results We have found eight previously unidentified SERPINA1 Null mutations, named: Q0cork, Q0perugia, Q0brescia, Q0torino, Q0cosenza, Q0pordenone, Q0lampedusa, and Q0dublin . Analysis of clinical characteristics revealed evidence of the recurrence of lung symptoms (dyspnoea, cough) and lung diseases (emphysema, asthma, chronic bronchitis) in M/Null subjects, over 45 years-old, irrespective of smoking. Conclusions We have added eight more mutations to the list of SERPINA1 Null alleles. This study underlines that the laboratory diagnosis of AATD is not just a matter of degree, because the precise determination of the deficiency and Null alleles carried by an AATD individual may help to evaluate the risk for the lung disease. Electronic supplementary material The online version of this article (doi:10.1186/s13023-014-0172-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. .,Department of Molecular Medicine, University of Pavia, Pavia, Italy.
| | - Tomás P Carroll
- Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland.
| | - Stefania Ottaviani
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
| | - Anna M Fra
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
| | - Geraldine O'Brien
- Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland.
| | - Kevin Molloy
- Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland.
| | - Luciano Corda
- Department of Internal Medicine, Respiratory Disease Unit, Spedali Civili, Brescia, Italy.
| | - Daniela Medicina
- Department of Pathology, Spedali Civili of Brescia, Brescia, Italy.
| | - David R Curran
- Respiratory Department, Mercy University Hospital, Cork, Ireland.
| | - Noel G McElvaney
- Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland.
| | - Maurizio Luisetti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. .,Department of Molecular Medicine, University of Pavia, Pavia, Italy.
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