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Hernandez JD, Hsieh EW. A great disturbance in the force: IL-2 receptor defects disrupt immune homeostasis. Curr Opin Pediatr 2022; 34:580-588. [PMID: 36165614 PMCID: PMC9633542 DOI: 10.1097/mop.0000000000001181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE OF REVIEW The current review highlights how inborn errors of immunity (IEI) due to IL-2 receptor (IL-2R) subunit defects may result in children presenting with a wide variety of infectious and inflammatory presentations beyond typical X-linked severe combined immune deficiency (X-SCID) associated with IL-2Rγ. RECENT FINDINGS Newborn screening has made diagnosis of typical SCID presenting with severe infections less common. Instead, infants are typically diagnosed in the first days of life when they appear healthy. Although earlier diagnosis has improved clinical outcomes for X-SCID, atypical SCID or other IEI not detected on newborn screening may present with more limited infectious presentations and/or profound immune dysregulation. Early management to prevent/control infections and reduce inflammatory complications is important for optimal outcomes of definitive therapies. Hematopoietic stem cell transplant (HSCT) is curative for IL-2Rα, IL-2Rβ, and IL-2Rγ defects, but gene therapy may yield comparable results for X-SCID. SUMMARY Defects in IL-2R subunits present with infectious and inflammatory phenotypes that should raise clinician's concern for IEI. Immunophenotyping may support the suspicion for diagnosis, but ultimately genetic studies will confirm the diagnosis and enable family counseling. Management of infectious and inflammatory complications will determine the success of gene therapy or HSCT.
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Affiliation(s)
- Joseph D. Hernandez
- Department of Pediatrics, Division of Allergy, Immunology and Rheumatology, School of Medicine, Stanford University, Lucile Packard Children’s Hospital
| | - Elena W.Y. Hsieh
- Department of Pediatrics, Section of Allergy and Immunology, School of Medicine, University of Colorado, Children’s Hospital Colorado
- Department of Immunology and Microbiology, School of Medicine, University of Colorado
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Strubbe S, De Bruyne M, Pannicke U, Beyls E, Vandekerckhove B, Leclercq G, De Baere E, Bordon V, Vral A, Schwarz K, Haerynck F, Taghon T. A Novel Non-Coding Variant in DCLRE1C Results in Deregulated Splicing and Induces SCID Through the Generation of a Truncated ARTEMIS Protein That Fails to Support V(D)J Recombination and DNA Damage Repair. Front Immunol 2021; 12:674226. [PMID: 34220820 PMCID: PMC8248492 DOI: 10.3389/fimmu.2021.674226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/03/2021] [Indexed: 11/13/2022] Open
Abstract
Severe Combined Immune Deficiency (SCID) is a primary deficiency of the immune system in which opportunistic and recurring infections are often fatal during neonatal or infant life. SCID is caused by an increasing number of genetic defects that induce an abrogation of T lymphocyte development or function in which B and NK cells might be affected as well. Because of the increased availability and usage of next-generation sequencing (NGS), many novel variants in SCID genes are being identified and cause a heterogeneous disease spectrum. However, the molecular and functional implications of these new variants, of which some are non-coding, are often not characterized in detail. Using targeted NGS, we identified a novel homozygous c.465-1G>C splice acceptor site variant in the DCLRE1C gene in a T-B-NK+ SCID patient and fully characterized the molecular and functional impact. By performing a minigene splicing reporter assay, we revealed deregulated splicing of the DCLRE1C transcript since a cryptic splice acceptor in exon 7 was employed. This induced a frameshift and the generation of a p.Arg155Serfs*15 premature termination codon (PTC) within all DCLRE1C splice variants, resulting in the absence of full-length ARTEMIS protein. Consistently, a V(D)J recombination assay and a G0 micronucleus assay demonstrated the inability of the predicted mutant ARTEMIS protein to perform V(D)J recombination and DNA damage repair, respectively. Together, these experiments molecularly and functionally clarify how a newly identified c.465-1G>C variant in the DCLRE1C gene is responsible for inducing SCID. In a clinical context, this demonstrates how the experimental validation of new gene variants, that are identified by NGS, can facilitate the diagnosis of SCID which can be vital for implementing appropriate therapies.
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Affiliation(s)
- Steven Strubbe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | | | - Ulrich Pannicke
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Elien Beyls
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - Bart Vandekerckhove
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Georges Leclercq
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
| | - Elfride De Baere
- Center for Medical Genetics Ghent (CMGG), Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Victoria Bordon
- Department of Internal Medicine and Pediatrics, Division of Pediatric Hemato-Oncology and Stem Cell Transplantation, Ghent University Hospital, Ghent, Belgium
| | - Anne Vral
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium
| | - Klaus Schwarz
- The Institute for Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, Germa Red Cross Blood Service Baden-Württemberg - Hessen, Ulm, Germany
| | - Filomeen Haerynck
- Primary Immunodeficiency Research Lab, Jeffrey Modell Diagnosis and Research Center, Ghent University Hospital, Ghent, Belgium.,Department of Internal Medicine and Pediatrics, Division of Pediatric Immunology and Pulmonology, Ghent University Hospital, Ghent, Belgium
| | - Tom Taghon
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent, Belgium
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