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Dasouki M, Jabr A, AlDakheel G, Elbadaoui F, Alazami AM, Al-Saud B, Arnaout R, Aldhekri H, Alotaibi I, Al-Mousa H, Hawwari A. TREC and KREC profiling as a representative of thymus and bone marrow output in patients with various inborn errors of immunity. Clin Exp Immunol 2020; 202:60-71. [PMID: 32691468 DOI: 10.1111/cei.13484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 12/13/2022] Open
Abstract
Primary immune deficiency (PID) disorders are clinically and molecularly heterogeneous diseases. T cell receptor excision circles (TRECs) and κ (kappa)-deleting excision circles (KRECs) are markers of T and B cell development, respectively. They are useful tools to assess T and B cell function and immune reconstitution and have been used for newborn screening for severe combined immunodeficiency disease (SCID) and agammaglobulinemia, respectively. Their profiles in several genetically confirmed PIDs are still lacking. The objective of this study was to determine TREC and KREC genomic profiling among various molecularly confirmed PIDs. We used real-time-quantitative polymerase chain reaction (RT-qPCR)-based triplex analysis of TRECs, KRECs and β-actin (ACTB) in whole blood genomic DNA isolated from 108 patients with molecularly confirmed PIDs. All agammaglobulinemia patients had low KREC counts. All SCIDs and Omenn syndrome patients secondary to mutations in RAG1, RAG2, DCLRE1C and NHEJ1 had low TREC and KREC counts. JAK3-deficient patients had normal KREC and the TREC count was influenced by the type of mutation. Early-onset ADA patients had low TREC and KREC counts. Four patients with zeta-chain-associated protein kinase 70 (ZAP70) had low TREC. All purine nucleoside phosphorylase (PNP) patients had low TREC. Combined immunodeficiency (CID) patients secondary to AK2, PTPRC, CD247, DCLREC1 and STAT1 had normal TREC and KREC counts. Most patients with ataxia-telangiectasia (AT) patients had low TREC and KREC, while most DOCK8-deficient patients had low TRECs only. Two of five patients with Wiskott-Aldrich syndrome (WAS) had low TREC counts as well as one patient each with bare lymphocyte syndrome (BLS) and chronic granulomatous disease. All patients with Griscelli disease, Chediak-Higashi syndrome, hyper-immunoglobulin (Ig)M syndrome and IFNGR2 had normal TREC and KREC counts. These data suggest that, in addition to classical SCID and agammaglobulinemia, TREC/KREC assay may identify ZAP70 patients and secondary target PIDs, including dedicator of cytokinesis 8 (DOCK8) deficiency, AT and some individuals with WAS and BLS.
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Affiliation(s)
- M Dasouki
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - A Jabr
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - G AlDakheel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F Elbadaoui
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - A M Alazami
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - B Al-Saud
- Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - R Arnaout
- Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Aldhekri
- Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - I Alotaibi
- Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Al-Mousa
- Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - A Hawwari
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City Hospital, Ministry of National Guard Health Affairs, Al-Ahsa, Saudi Arabia
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2
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Zambaldo C, Vinogradova EV, Qi X, Iaconelli J, Suciu RM, Koh M, Senkane K, Chadwick SR, Sanchez BB, Chen JS, Chatterjee AK, Liu P, Schultz PG, Cravatt BF, Bollong MJ. 2-Sulfonylpyridines as Tunable, Cysteine-Reactive Electrophiles. J Am Chem Soc 2020; 142:8972-8979. [PMID: 32302104 DOI: 10.1021/jacs.0c02721] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The emerging use of covalent ligands as chemical probes and drugs would benefit from an expanded repertoire of cysteine-reactive electrophiles for efficient and diverse targeting of the proteome. Here we use the endogenous electrophile sensor of mammalian cells, the KEAP1-NRF2 pathway, to discover cysteine-reactive electrophilic fragments from a reporter-based screen for NRF2 activation. This strategy identified a series of 2-sulfonylpyridines that selectively react with biological thiols via nucleophilic aromatic substitution (SNAr). By tuning the electrophilicity and appended recognition elements, we demonstrate the potential of the 2-sulfonylpyridine reactive group with the discovery of a selective covalent modifier of adenosine deaminase (ADA). Targeting a cysteine distal to the active site, this molecule attenuates the enzymatic activity of ADA and inhibits proliferation of lymphocytic cells. This study introduces a modular and tunable SNAr-based reactive group for targeting reactive cysteines in the human proteome and illustrates the pharmacological utility of this electrophilic series.
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Affiliation(s)
- Claudio Zambaldo
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Ekaterina V Vinogradova
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Xiaotian Qi
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jonathan Iaconelli
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Radu M Suciu
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Minseob Koh
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Kristine Senkane
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Stormi R Chadwick
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Brittany B Sanchez
- Automated Synthesis Facility, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Jason S Chen
- Automated Synthesis Facility, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Arnab K Chatterjee
- California Institute for Biomedical Research (Calibr), La Jolla, California 92037, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peter G Schultz
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Benjamin F Cravatt
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Michael J Bollong
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
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3
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Computational Analysis of nsSNPs of ADA Gene in Severe Combined Immunodeficiency Using Molecular Modeling and Dynamics Simulation. J Immunol Res 2020; 2019:5902391. [PMID: 31781678 PMCID: PMC6875294 DOI: 10.1155/2019/5902391] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/19/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022] Open
Abstract
Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency (PID), characterized by fatal opportunistic infections. The ADA gene encodes adenosine deaminase, an enzyme that catalyzes the irreversible deamination of adenosine and deoxyadenosine in the catabolic pathway of purine. Mutations of the ADA gene have been identified in patients with severe combined immunodeficiency. In this study, we performed a bioinformatics analysis of the human ADA gene to identify potentially harmful nonsynonymous SNPs and their effect on protein structure and stability. Using eleven prediction tools, we identified 15 nsSNPs (H15D, H15P, H17Q, H17Y, D19N, T26I, G140E, C153F, A183D, G216R, H258Y, C262Y, S291L, S291W, and K34OE) as harmful. The results of ConSurf's analysis revealed that all these nsSNPs are localised in the highly conserved positions and affect the structure of the native proteins. In addition, our computational analysis showed that the H15D, G140E, G216R, and S291L mutations identified as being associated with severe combined immunodeficiency affect protein structure. Similarly, the results of the analyses of Rmsd, Rmsf, and Rg showed that all these factors influence protein stability, flexibility, and compaction with different levels of impact. This study is the first comprehensive computational analysis of nsSNPs of the ADA gene. However, functional analyses are needed to elucidate the biological mechanisms of these polymorphisms in severe combined immunodeficiency.
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Bradford KL, Moretti FA, Carbonaro-Sarracino DA, Gaspar HB, Kohn DB. Adenosine Deaminase (ADA)-Deficient Severe Combined Immune Deficiency (SCID): Molecular Pathogenesis and Clinical Manifestations. J Clin Immunol 2017; 37:626-637. [PMID: 28842866 DOI: 10.1007/s10875-017-0433-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 08/07/2017] [Indexed: 12/18/2022]
Abstract
Deficiency of adenosine deaminase (ADA, EC3.5.4.4), a housekeeping enzyme of purine metabolism encoded by the Ada gene, is a cause of human severe combined immune deficiency (SCID). Numerous deleterious mutations occurring in the ADA gene have been found in patients with profound lymphopenia (T- B- NK-), thus underscoring the importance of functional purine metabolism for the development of the immune defense. While untreated ADA SCID is a fatal disorder, there are multiple life-saving therapeutic modalities to restore ADA activity and reconstitute protective immunity, including enzyme replacement therapy (ERT), allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) with autologous gene-corrected hematopoietic stem cells (HSC). We review the pathogenic mechanisms and clinical manifestations of ADA SCID.
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Affiliation(s)
- Kathryn L Bradford
- Department of Pediatrics, University of California, Los Angeles (UCLA), 3163 Terasaki Life Science Bldg., 610 Charles E. Young Drive East, Los Angeles, CA, 90095, USA
| | - Federico A Moretti
- Centre for Immunodeficiency, Molecular Immunology Unit, University College London Institute of Child Health, London, UK
| | | | - Hubert B Gaspar
- Centre for Immunodeficiency, Molecular Immunology Unit, University College London Institute of Child Health, London, UK
| | - Donald B Kohn
- Department of Pediatrics, University of California, Los Angeles (UCLA), 3163 Terasaki Life Science Bldg., 610 Charles E. Young Drive East, Los Angeles, CA, 90095, USA.
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA University of California, Los Angeles, CA, USA.
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Blewett MM, Xie J, Zaro BW, Backus KM, Altman A, Teijaro JR, Cravatt BF. Chemical proteomic map of dimethyl fumarate-sensitive cysteines in primary human T cells. Sci Signal 2016; 9:rs10. [PMID: 27625306 DOI: 10.1126/scisignal.aaf7694] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dimethyl fumarate (DMF) is an electrophilic drug that is used to treat autoimmune conditions, including multiple sclerosis and psoriasis. The mechanism of action of DMF is unclear but may involve the covalent modification of proteins or DMF serving as a prodrug that is converted to monomethyl fumarate (MMF). We found that DMF, but not MMF, blocked the activation of primary human and mouse T cells. Using a quantitative, site-specific chemical proteomic platform, we determined the DMF sensitivity of >2400 cysteine residues in human T cells. Cysteines sensitive to DMF, but not MMF, were identified in several proteins with established biochemical or genetic links to T cell function, including protein kinase Cθ (PKCθ). DMF blocked the association of PKCθ with the costimulatory receptor CD28 by perturbing a CXXC motif in the C2 domain of this kinase. Mutation of these DMF-sensitive cysteines also impaired PKCθ-CD28 interactions and T cell activation, designating the C2 domain of PKCθ as a key functional, electrophile-sensing module important for T cell biology.
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Affiliation(s)
- Megan M Blewett
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jiji Xie
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - Balyn W Zaro
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Keriann M Backus
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Amnon Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - John R Teijaro
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Benjamin F Cravatt
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Baffelli R, Notarangelo LD, Imberti L, Hershfield MS, Serana F, Santisteban I, Bolda F, Porta F, Lanfranchi A. Diagnosis, Treatment and Long-Term Follow Up of Patients with ADA Deficiency: a Single-Center Experience. J Clin Immunol 2015; 35:624-37. [PMID: 26376800 DOI: 10.1007/s10875-015-0191-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 08/26/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE We carried out a retrospective analysis of 27 patients with Adenosine Deaminase (ADA) deficiency diagnosed in a single center from 1997 to the 2013, for evaluating whether data regarding types of disease-inducing mutations, biochemical and immunological features as well as clinical outcomes of patients treated with enzyme replacement or transplantation, were comparable to those obtained in multicenter studies. METHODS The ADA deficiency diagnosis was performed with biochemical, immunological and molecular techniques. Ten patients treated with hematopoietic stem cell transplantation and three in treatment with enzyme replacement were followed up in our center. RESULTS Twenty-four different mutations were identified and five were not previously reported. Identical mutations were found among patients from the same Romani ethnic group or from the same geographical region. A more rapid recovery was observed in enzyme replacement treated patients in comparison with those transplanted that, however, showed a continuous and long-lasting improvement both in terms of immune and metabolic recovery. CONCLUSION The data obtained in our single center are comparable with those that have been reported in multicenter surveys.
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Affiliation(s)
- Renata Baffelli
- Stem Cell Laboratory, Section of Hematology and Blood Coagulation, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy
| | - Lucia D Notarangelo
- Pediatric Onco-Haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy
| | - Luisa Imberti
- Centro Ricerca Emato-oncologica AIL (CREA), Diagnostics Department, Spedali Civili of Brescia, Brescia, Italy
| | | | - Federico Serana
- Centro Ricerca Emato-oncologica AIL (CREA), Diagnostics Department, Spedali Civili of Brescia, Brescia, Italy
| | - Ines Santisteban
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Federica Bolda
- Stem Cell Laboratory, Section of Hematology and Blood Coagulation, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy
| | - Fulvio Porta
- Pediatric Onco-Haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy
| | - Arnalda Lanfranchi
- Stem Cell Laboratory, Section of Hematology and Blood Coagulation, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy.
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7
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Adams SP, Wilson M, Harb E, Fairbanks L, Xu-Bayford J, Brown L, Kearney L, Madkaikar M, Bobby Gaspar H. Spectrum of mutations in a cohort of UK patients with ADA deficient SCID: Segregation of genotypes with specific ethnicities. Clin Immunol 2015; 161:174-9. [PMID: 26255240 DOI: 10.1016/j.clim.2015.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 05/21/2015] [Accepted: 08/01/2015] [Indexed: 10/23/2022]
Abstract
Severe combined immunodeficiency (SCID) arises from a number of different genetic defects, one of the most common being mutations in the gene encoding adenosine deaminase (ADA). In the UK, ADA deficient SCID compromises approximately 20% of all known cases of SCID. We carried out a retrospective analysis of the ADA gene in 46 known ADA deficient SCID patients on whom DNA had been stored. Here, we report a high frequency of two previously reported mutations and provide a link between the mutations and patient ethnicity within our patient cohort. We also report on 9 novel mutations that have been previously unreported.
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Affiliation(s)
- Stuart P Adams
- Haematology, Cellular and Molecular Diagnostic Service, Great Ormond Street Hospital for Children NHS Trust, London, UK; Molecular and Cellular Immunology, Institute of Child Health, University College London, UK.
| | - Melanie Wilson
- Haematology, Cellular and Molecular Diagnostic Service, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - Elissar Harb
- Haematology, Cellular and Molecular Diagnostic Service, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | | | - Jinhua Xu-Bayford
- Immunology and Bone Marrow Transplant Units, Great Ormond Street Hospital for Children, London NHS Trust, UK
| | - Lucie Brown
- Immunology and Bone Marrow Transplant Units, Great Ormond Street Hospital for Children, London NHS Trust, UK
| | - Laura Kearney
- Haematology, Cellular and Molecular Diagnostic Service, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - Manisha Madkaikar
- National Institute of Immunohaematology, ICMR, K E M Hospital, Parel, Mumbai, India
| | - H Bobby Gaspar
- Molecular and Cellular Immunology, Institute of Child Health, University College London, UK; Immunology and Bone Marrow Transplant Units, Great Ormond Street Hospital for Children, London NHS Trust, UK
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Abolhassani H, Rezaei N, Mohammadinejad P, Mirminachi B, Hammarstrom L, Aghamohammadi A. Important differences in the diagnostic spectrum of primary immunodeficiency in adults versus children. Expert Rev Clin Immunol 2015; 11:289-302. [DOI: 10.1586/1744666x.2015.990440] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kalman L, Lindegren ML, Kobrynski L, Vogt R, Hannon H, Howard JT, Buckley R. Mutations in genes required for T-cell development:IL7R, CD45, IL2RG, JAK3, RAG1, RAG2, ARTEMIS, and ADA and severe combined immunodeficiency: HuGE review. Genet Med 2004; 6:16-26. [PMID: 14726805 DOI: 10.1097/01.gim.0000105752.80592.a3] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Severe combined immunodeficiency (SCID) is an inherited immune disorder characterized by T-cell lymphopenia (TCLP), a profound lack of cellular (T-cell) and humoral (B-cell) immunity and, in some cases, decreased NK-cell number and function. Affected children develop severe bacterial and viral infections within the first 6 months of life and die before 1 year of age without treatment. Mutations in any of eight known genes: IL2RG, ARTEMIS, RAG1, RAG2, ADA, CD45, JAK3, and IL7R cause SCID. Mutations in unidentified genes may also cause SCID. Population-based genotype and allelic frequencies of these gene defects have not been measured. Some minimal estimates of SCID prevalence are presented. Currently, hematopoietic stem cell transplants are the standard treatment. In clinical trials, gene therapy has been used to reconstitute immune function in patients with IL2RG and ADA defects. The availability of effective therapies, plus the short asymptomatic period after birth, (when stem-cell transplantation is most effective), make SCID a potentially good candidate for newborn screening. Dried blood spots are currently collected from all infants at birth for newborn metabolic screening. Tests for TCLP on dried blood spots could be developed as a screen for SCID. Because SCID may be unrecognized, with infant deaths from infection attributed to other causes, newborn screening is the only way to ascertain true birth prevalence. Validated tests and pilot population studies are necessary to determine newborn screening's potential for identifying infants with SCID.
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Affiliation(s)
- Lisa Kalman
- Centers for Disease Control and Prevention, Newborn Screening Quality Assurance Program, Office of Genomics and Disease Prevention, Atlanta, Georgia, USA
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Cristalli G, Costanzi S, Lambertucci C, Lupidi G, Vittori S, Volpini R, Camaioni E. Adenosine deaminase: functional implications and different classes of inhibitors. Med Res Rev 2001; 21:105-28. [PMID: 11223861 DOI: 10.1002/1098-1128(200103)21:2<105::aid-med1002>3.0.co;2-u] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Adenosine deaminase (ADA) is an enzyme of the purine metabolism which catalyzes the irreversible deamination of adenosine and deoxyadenosine to inosine and deoxyinosine, respectively. This ubiquitous enzyme has been found in a wide variety of microorganisms, plants, and invertebrates. In addition, it is present in all mammalian cells that play a central role in the differentiation and maturation of the lymphoid system. However, despite a number of studies performed to date, the physiological role played by ADA in the different tissues is not clear. Inherited ADA deficiency causes severe combined immunodeficiency disease (ADA-SCID), in which both B-cell and T-cell development is impaired. ADA-SCID has been the first disorder to be treated by gene therapy, using polyethylene glycol-modified bovine ADA (PEG-ADA). Conversely, there are several diseases in which the level of ADA is above normal. A number of ADA inhibitors have been designed and synthesized, classified as ground-state and transition-state inhibitors. They may be used to mimic the genetic deficiency of the enzyme, in lymphoproliferative disorders or immunosuppressive therapy (i.e., in graft rejection), to potentiate the effect of antileukemic or antiviral nucleosides, and, together with adenosine kinase, to reduce breakdown of adenosine in inflammation, hypertension, and ischemic injury.
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Affiliation(s)
- G Cristalli
- Dipartimento di Scienze Chimiche, Università di Camerino, Via S. Agostino 1, 62032 Camerino, Italy.
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Arredondo-Vega FX, Santisteban I, Daniels S, Toutain S, Hershfield MS. Adenosine deaminase deficiency: genotype-phenotype correlations based on expressed activity of 29 mutant alleles. Am J Hum Genet 1998; 63:1049-59. [PMID: 9758612 PMCID: PMC1377486 DOI: 10.1086/302054] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Adenosine deaminase (ADA) deficiency causes lymphopenia and immunodeficiency due to toxic effects of its substrates. Most patients are infants with severe combined immunodeficiency disease (SCID), but others are diagnosed later in childhood (delayed onset) or as adults (late onset); healthy individuals with "partial" ADA deficiency have been identified. More than 50 ADA mutations are known; most patients are heteroallelic, and most alleles are rare. To analyze the relationship of genotype to phenotype, we quantitated the expression of 29 amino acid sequence-altering alleles in the ADA-deleted Escherichia coli strain SO3834. Expressed ADA activity of wild-type and mutant alleles ranged over five orders of magnitude. The 26 disease-associated alleles expressed 0.001%-0.6% of wild-type activity, versus 5%-28% for 3 alleles from "partials." We related these data to the clinical phenotypes and erythrocyte deoxyadenosine nucleotide (dAXP) levels of 52 patients (49 immunodeficient and 3 with partial deficiency) who had 43 genotypes derived from 42 different mutations, including 28 of the expressed alleles. We reduced this complexity to 13 "genotype categories," ranked according to the potential of their constituent alleles to provide ADA activity. Of 31 SCID patients, 28 fell into 3 genotype categories that could express <=0.05% of wild-type ADA activity. Only 2 of 21 patients with delayed, late-onset, or partial phenotypes had one of these "severe" genotypes. Among 37 patients for whom pretreatment metabolic data were available, we found a strong inverse correlation between red-cell dAXP level and total ADA activity expressed by each patient's alleles in SO3834. Our system provides a quantitative framework and ranking system for relating genotype to phenotype.
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