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Balderacchi AM, Bignotti M, Ottaviani S, Denardo A, Barzon V, Ben Khlifa E, Vailati G, Piloni D, Benini F, Corda L, Corsico AG, Ferrarotti I, Fra A. Quantification of circulating alpha-1-antitrypsin polymers associated with different SERPINA1 genotypes. Clin Chem Lab Med 2024; 62:1980-1990. [PMID: 38407261 DOI: 10.1515/cclm-2023-1348] [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: 11/24/2023] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
OBJECTIVES Alpha-1-antitrypsin deficiency is a genetic disorder caused by mutations in the SERPINA1 gene encoding alpha-1-antitrypsin (AAT), the major serine protease inhibitor in plasma. Reduced AAT levels are associated with elevated risk of developing emphysema mainly due to uncontrolled activity of neutrophil elastase in the lungs. The prevalent Z-AAT mutant and many rare pathogenic AAT variants also predispose to liver disease due to their accumulation as polymeric chains in hepatocytes. Part of these polymers are secreted into the bloodstream and could represent biomarkers of intra-hepatic accumulation. Moreover, being inactive, they further lower lung protection against proteases. Aim of our study is to accurately quantify the percentage of circulating polymers (CP) in a cohort of subjects with different SERPINA1 genotypes. METHODS CP concentration was measured in plasma or Dried Blood Spot (DBS) by a sensitive sandwich ELISA based on capture by the polymer-specific 2C1 monoclonal antibody. RESULTS CP were significantly elevated in patients with the prevalent PI*SZ and PI*ZZ genotypes, with considerable intra-genotype variability. Notably, higher percentage of polymers was observed in association with elevated C-reactive protein. CP levels were also increased in carriers of the Mmalton variant, and of Mprocida, I, Plowell and Mherleen in heterozygosity with Z-AAT. CONCLUSIONS These findings highlight the importance of implementing CP quantification in a clinical laboratory. Indeed, the variable amount of CP in patients with the same genotype may correlate with the variable severity of the associated lung and liver diseases. Moreover, CP can reveal the polymerogenic potential of newly discovered ultrarare AAT variants.
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Affiliation(s)
- Alice M Balderacchi
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Mattia Bignotti
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Stefania Ottaviani
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Andrea Denardo
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Valentina Barzon
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Emna Ben Khlifa
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Guido Vailati
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Davide Piloni
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Federica Benini
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Luciano Corda
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Angelo G Corsico
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Annamaria Fra
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
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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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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: 10] [Impact Index Per Article: 3.3] [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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Implications of a Change of Paradigm in Alpha1 Antitrypsin Deficiency Augmentation Therapy: From Biochemical to Clinical Efficacy. J Clin Med 2020; 9:jcm9082526. [PMID: 32764414 PMCID: PMC7465600 DOI: 10.3390/jcm9082526] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/31/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022] Open
Abstract
Ever since the first studies, restoring proteinase imbalance in the lung has traditionally been considered as the main goal of alpha1 antitrypsin (AAT) replacement therapy. This strategy was therefore based on ensuring biochemical efficacy, identifying a protection threshold, and evaluating different dosage regimens. Subsequently, the publication of the results of the main clinical trials showing a decrease in the progression of pulmonary emphysema has led to a debate over a possible change in the main objective of treatment, from biochemical efficacy to clinical efficacy in terms of lung densitometry deterioration prevention. This new paradigm has produced a series controversies and unanswered questions which face clinicians managing AAT deficiency. In this review, the concepts that led to the approval of AAT replacement therapy are reviewed and discussed under a new prism of achieving clinical efficacy, with the reduction of lung deterioration as the main objective. Here, we propose the use of current knowledge and clinical experience to face existing challenges in different clinical scenarios, in order to help clinicians in decision-making, increase interest in the disease, and stimulate research in this field.
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Corda L, Medicina D, La Piana GE, Bertella E, Moretti G, Bianchi L, Pinelli V, Savoldi G, Baiardi P, Facchetti F, Gatta N, Annesi-Maesano I, Balbi B. Population genetic screening for alpha1-antitrypsin deficiency in a high-prevalence area. ACTA ACUST UNITED AC 2011; 82:418-25. [PMID: 21474916 DOI: 10.1159/000325067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 02/07/2011] [Indexed: 12/20/2022]
Abstract
BACKGROUND Current guidelines for α1-antitrypsin deficiency (AATD) state that adult population screening should only be done in high-risk areas. Up-to-date genetic methods are always recommended. OBJECTIVES To determine the prevalence of AATD in a suspected high-risk area by population screening, applying new genetic analyses and comparing the prevalence of liver and lung abnormalities in subjects with or without AATD. METHODS Adult residents of Pezzaze, a village in an Italian alpine valley, voluntarily participated in the screening, and were examined for: nephelometric α1-antitrypsin (AAT) serum level, DNA analysis (mutagenic polymerase chain reaction and restriction fragment length polymorphism tests for Z and S AATD causative mutations, and denaturing high-performance liquid chromatography and/or direct gene sequencing if needed), serum aspartate and alanine transaminases, a respiratory questionnaire and the Medical Research Council dyspnea index scale. The prevalence of AATD was compared with that expected in Italy (Hardy-Weinberg equilibrium), and transaminases and the prevalence of respiratory symptoms were compared between study groups. RESULTS Of 1,353 residents, 817 (60.4%) participated; 67 (8.2%) had low AAT serum levels (<90 mg/dl); 118 were carriers of AATD-associated alleles, 4 (0.5%) homozygotes or compound heterozygotes (1 Z, 1 S, 2 ZP(brescia)), 114 (14%) heterozygotes (46 Z, 52 S, 9 P(brescia), 4 M(wurzburg), 2 I, 1 P(lowell)). The prevalence and frequency of all AATD-related alleles was higher than expected for Italy (p < 0.001). There were no differences in symptoms of respiratory disease and transaminases between individuals with normal and low serum AAT. CONCLUSION The screening design is one of the main strengths of this study. The large number of mostly asymptomatic individuals with AATD identified suggests that in high-risk areas adult population screening programs employing the latest genetic methods are feasible. Early recognition of individuals at risk means primary or secondary prevention measures can be taken.
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Affiliation(s)
- Luciano Corda
- Centro di Riferimento Regionale per il Deficit di Alfa1-Antitripsina, Prima Divisione di Medicina Interna, Spedali Civili, Cattedra di Malattie dell'Apparato Respiratorio, Università di Brescia, Brescia, Italy.
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Ljujic M, Topic A, Nikolic A, Divac A, Grujic M, Mitic-Milikic M, Radojkovic D. Identification of a rare p.G320R alpha-1-antitrypsin variant in emphysema and lung cancer patients. Genet Mol Biol 2010; 33:5-8. [PMID: 21637596 PMCID: PMC3036068 DOI: 10.1590/s1415-47572009005000100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 07/07/2009] [Indexed: 12/05/2022] Open
Abstract
The alpha-1-antitrypsin (A1AT) gene is highly polymorphic, with more than 100 genetic variants identified of which some can affect A1AT protein concentration and/or function and lead to pulmonary and/or liver disease. This study reports on the characterization of a p.G320R variant found in two patients, one with emphysema and the other with lung cancer. This variant results from a single base-pair substitution in exon 4 of the A1AT gene, and has been characterized as P by isoelectric focusing. Functional evaluation of the A1AT p.G320R variant was through comparing specific trypsin inhibitory activity in two patients with pulmonary disorders, carriers of the p.G320R variant, and 19 healthy individuals, carriers of normal A1AT M variants. Results showed that specific trypsin inhibitory activity was lower in both emphysema (2.45 mU/g) and lung cancer (2.07 mU/g) patients than in carriers of the normal variants (range 2.51-3.71 mU/g). This rare A1AT variant is associated with reduced functional activity of A1AT protein. Considering that it was found in patients with severe pulmonary disorders, this variant could be of clinical significance.
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Affiliation(s)
- Mila Ljujic
- Institute of Molecular Genetics and Genetic Engineering, Belgrade Serbia
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Bornhorst JA, Calderon FRO, Procter M, Tang W, Ashwood ER, Mao R. Genotypes and serum concentrations of human alpha-1-antitrypsin "P" protein variants in a clinical population. J Clin Pathol 2008; 60:1124-8. [PMID: 17906067 PMCID: PMC2014826 DOI: 10.1136/jcp.2006.042762] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Alpha-1-antitrypsin (AAT) deficiency is a relatively common genetic disorder that can lead to the development of pulmonary disorders. Diagnosis of AAT deficiency is typically performed by isoelectric focusing (IEF) protein phenotyping in concert with determination of AAT serum concentration levels. The "P" phenotypic variant is associated with several known genetic variants that are found at unknown relative frequencies. AIMS To investigate the genetic variation of "P" alleles in patient samples. METHODS A DNA sequencing protocol for the full AAT coding region from serum was developed. Additionally, a retrospective evaluation of AAT concentrations in serum samples containing "P" allele IEF phenotype variants was undertaken. RESULTS "P" phenotypic variants are observed in approximately 1 of every 900 samples received in the reference laboratory. Heterozygous "MP" allele samples exhibited a wide range of serum protein concentrations. Genotyping revealed the presence of the deleterious P lowell variant in six heterozygous MP samples, two heterozygous PZ samples, and one homozygous PP sample. A non-deleterious P st albans variant was observed in a single MP sample. A novel heterozygous AAT M"P" variant, P salt lake was identified, that did not exhibit a reduced AAT serum concentration. CONCLUSIONS Genetic heterogeneity is present in clinical "P" phenotype variants identified by IEF, and the deleterious P lowell variant appears to be relatively common. Sequencing of "P" phenotype variants can provide useful clinical information, especially when the "P" phenotype variant is paired with a deficiency phenotype allele.
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Affiliation(s)
- Joshua A Bornhorst
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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