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Seleman M, Hoyos-Bachiloglu R, Geha RS, Chou J. Uses of Next-Generation Sequencing Technologies for the Diagnosis of Primary Immunodeficiencies. Front Immunol 2017; 8:847. [PMID: 28791010 PMCID: PMC5522848 DOI: 10.3389/fimmu.2017.00847] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 07/05/2017] [Indexed: 12/11/2022] Open
Abstract
Primary immunodeficiencies (PIDs) are genetic disorders impairing host immunity, leading to life-threatening infections, autoimmunity, and/or malignancies. Genomic technologies have been critical for expediting the discovery of novel genetic defects underlying PIDs, expanding our knowledge of the complex clinical phenotypes associated with PIDs, and in shifting paradigms of PID pathogenesis. Once considered Mendelian, monogenic, and completely penetrant disorders, genomic studies have redefined PIDs as a heterogeneous group of diseases found in the global population that may arise through multigenic defects, non-germline transmission, and with variable penetrance. This review examines the uses of next-generation DNA sequencing (NGS) in the diagnosis of PIDs. While whole genome sequencing identifies variants throughout the genome, whole exome sequencing sequences only the protein-coding regions within a genome, and targeted gene panels sequence only a specific cohort of genes. The advantages and limitations of each sequencing approach are compared. The complexities of variant interpretation and variant validation remain the major challenge in wide-spread implementation of these technologies. Lastly, the roles of NGS in newborn screening and precision therapeutics for individuals with PID are also addressed.
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Affiliation(s)
- Michael Seleman
- Division of Immunology, Boston Children's Hospital, Boston, MA, United States
| | | | - Raif S Geha
- Division of Immunology, Boston Children's Hospital, Boston, MA, United States
| | - Janet Chou
- Division of Immunology, Boston Children's Hospital, Boston, MA, United States
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52
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Al-Mousa H, Al-Saud B. Primary Immunodeficiency Diseases in Highly Consanguineous Populations from Middle East and North Africa: Epidemiology, Diagnosis, and Care. Front Immunol 2017; 8:678. [PMID: 28694805 PMCID: PMC5483440 DOI: 10.3389/fimmu.2017.00678] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/24/2017] [Indexed: 12/27/2022] Open
Abstract
Middle East and North Africa region (MENA)1 populations are of different ethnic origins. Consanguineous marriages are common practice with an overall incidence ranging between 20 and 50%. Primary immunodeficiency diseases (PIDs) are a group of heterogeneous genetic disorders caused by defects in the immune system that predisposes patients to recurrent infections, autoimmune diseases, and malignancies. PIDs are more common in areas with high rates of consanguineous marriage since most have an autosomal recessive mode of inheritance. Studies of PIDs in the region had contributed into the discovery and the understanding of several novel immunodeficiency disorders. Few MENA countries have established national registries that helped in estimating the prevalence and defining common PID phenotypes. Available reports from those registries suggest a predominance of combined immunodeficiency disorders in comparison to antibody deficiencies seen in other populations. Access to a comprehensive clinical immunology management services is limited in most MENA countries. Few countries had established advanced clinical immunology service, capable to provide extensive genetic testing and stem cell transplantation for various immunodeficiency disorders. Newborn screening for PIDs is an essential need in this population considering the high incidence of illness and can be implemented and incorporated into existing newborn screening programs in some MENA countries. Increased awareness, subspecialty training in clinical immunology, and establishing collaborating research centers are necessary to improve patient care. In this review, we highlight some of the available epidemiological data, challenges in establishing diagnosis, and available therapy for PID patients in the region.
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Affiliation(s)
- Hamoud Al-Mousa
- Department of Pediatrics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia.,Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Bandar Al-Saud
- Department of Pediatrics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with no known cure that affects at least five million people worldwide. Monozygotic twin concordance and familial aggregation studies strongly suggest that lupus results from genetic predisposition along with environmental exposures including UV light. The majority of the common risk alleles associated with genetic predisposition to SLE map to genes associated with the immune system. However, evidence is emerging that implicates a role for aberrant DNA repair in the development of lupus. Here we summarize our current knowledge of the potential association of lupus with mutations in DNA repair genes. We also discuss how defective or aberrant DNA repair could lead to the development of lupus.
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Affiliation(s)
- Rithy Meas
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Matthew J Burak
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA
| | - Joann B Sweasy
- Department of Therapeutic Radiology, Yale University, New Haven, CT, USA; Department of Genetics, Yale University, New Haven, CT, USA.
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54
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Repair of oxidatively induced DNA damage by DNA glycosylases: Mechanisms of action, substrate specificities and excision kinetics. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 771:99-127. [PMID: 28342455 DOI: 10.1016/j.mrrev.2017.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Indexed: 02/07/2023]
Abstract
Endogenous and exogenous reactive species cause oxidatively induced DNA damage in living organisms by a variety of mechanisms. As a result, a plethora of mutagenic and/or cytotoxic products are formed in cellular DNA. This type of DNA damage is repaired by base excision repair, although nucleotide excision repair also plays a limited role. DNA glycosylases remove modified DNA bases from DNA by hydrolyzing the glycosidic bond leaving behind an apurinic/apyrimidinic (AP) site. Some of them also possess an accompanying AP-lyase activity that cleaves the sugar-phosphate chain of DNA. Since the first discovery of a DNA glycosylase, many studies have elucidated the mechanisms of action, substrate specificities and excision kinetics of these enzymes present in all living organisms. For this purpose, most studies used single- or double-stranded oligodeoxynucleotides with a single DNA lesion embedded at a defined position. High-molecular weight DNA with multiple base lesions has been used in other studies with the advantage of the simultaneous investigation of many DNA base lesions as substrates. Differences between the substrate specificities and excision kinetics of DNA glycosylases have been found when these two different substrates were used. Some DNA glycosylases possess varying substrate specificities for either purine-derived lesions or pyrimidine-derived lesions, whereas others exhibit cross-activity for both types of lesions. Laboratory animals with knockouts of the genes of DNA glycosylases have also been used to provide unequivocal evidence for the substrates, which had previously been found in in vitro studies, to be the actual substrates in vivo as well. On the basis of the knowledge gained from the past studies, efforts are being made to discover small molecule inhibitors of DNA glycosylases that may be used as potential drugs in cancer therapy.
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Bakhtiar S, Gámez-Díaz L, Jarisch A, Soerensen J, Grimbacher B, Belohradsky B, Keller KM, Rietschel C, Klingebiel T, Koletzko S, Albert MH, Bader P. Treatment of Infantile Inflammatory Bowel Disease and Autoimmunity by Allogeneic Stem Cell Transplantation in LPS-Responsive Beige-Like Anchor Deficiency. Front Immunol 2017; 8:52. [PMID: 28197149 PMCID: PMC5281554 DOI: 10.3389/fimmu.2017.00052] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/12/2017] [Indexed: 01/21/2023] Open
Abstract
Inflammatory bowel disease (IBD) in young children can be a clinical manifestation of various primary immunodeficiency syndromes. Poor clinical outcome is associated with poor quality of life and high morbidity from the complications of prolonged immunosuppressive treatment and malabsorption. In 2012, mutations in the lipopolysaccharide-responsive beige-like anchor (LRBA) gene were identified as the cause of an autoimmunity and immunodeficiency syndrome. Since then, several LRBA-deficient patients have been reported with a broad spectrum of clinical manifestations without reliable predictive prognostic markers. Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been performed in a few severely affected patients with complete or partial response. Herein, we present a detailed course of the disease and the transplantation procedure used in a LRBA-deficient patient suffering primarily from infantile IBD with immune enteropathy since the age of 6 weeks, and progressive autoimmunity with major complications following long-term immunosuppressive treatment. At 12 years of age, alloHSCT using bone marrow of a fully matched sibling donor—a healthy heterozygous LRBA mutant carrier—was performed after conditioning with a reduced-intensity regimen. During the 6-year follow-up, we observed a complete remission of enteropathy, autoimmunity, and skin vitiligo, with complete donor chimerism. The genetic diagnosis of LRBA deficiency was made post-alloHSCT by detection of two compound heterozygous mutations, using targeted sequencing of DNA samples extracted from peripheral blood before the transplantation.
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Affiliation(s)
- Shahrzad Bakhtiar
- Division for Pediatric Stem-Cell Transplantation and Immunology, University Hospital Frankfurt , Frankfurt/Main , Germany
| | - Laura Gámez-Díaz
- Center for Chronic Immunodeficiency, University Hospital , Freiburg , Germany
| | - Andrea Jarisch
- Division for Pediatric Stem-Cell Transplantation and Immunology, University Hospital Frankfurt , Frankfurt/Main , Germany
| | - Jan Soerensen
- Division for Pediatric Stem-Cell Transplantation and Immunology, University Hospital Frankfurt , Frankfurt/Main , Germany
| | - Bodo Grimbacher
- Center for Chronic Immunodeficiency, University Hospital , Freiburg , Germany
| | - Bernd Belohradsky
- Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University , Munich , Germany
| | | | | | - Thomas Klingebiel
- Division for Pediatric Stem-Cell Transplantation and Immunology, University Hospital Frankfurt , Frankfurt/Main , Germany
| | - Sibylle Koletzko
- Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University , Munich , Germany
| | - Michael H Albert
- Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University , Munich , Germany
| | - Peter Bader
- Division for Pediatric Stem-Cell Transplantation and Immunology, University Hospital Frankfurt , Frankfurt/Main , Germany
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56
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Abstract
Some autoimmune disorders are monogenetic diseases; however, clinical manifestations among individuals vary, despite the presence of identical mutations in the disease-causing gene. In this issue of the JCI, Massaad and colleagues characterized a seemingly monogenic autoimmune disorder in a family that was linked to homozygous loss-of-function mutations in the gene encoding the endonuclease Nei endonuclease VIII-like 3 (NEIL3), which has not been previously associated with autoimmunity. The identification of an unrelated healthy individual with the same homozygous mutation spurred more in-depth analysis of the data and revealed the presence of a second mutation in a known autoimmune-associated gene. Animals lacking Neil3 had no overt phenotype, but were predisposed to autoantibody production and nephritis following exposure to the TLR3 ligand poly(I:C). Together, these results support further evaluation of the drivers of autoimmunity in supposedly monogenic disorders.
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