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Ouahed JD, Griffith A, Collen LV, Snapper SB. Breaking Down Barriers: Epithelial Contributors to Monogenic IBD Pathogenesis. Inflamm Bowel Dis 2024; 30:1189-1206. [PMID: 38280053 DOI: 10.1093/ibd/izad319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Indexed: 01/29/2024]
Abstract
Monogenic causes of inflammatory bowel diseases (IBD) are increasingly being discovered. To date, much attention has been placed in those resulting from inborn errors of immunity. Therapeutic efforts have been largely focused on offering personalized immune modulation or curative bone marrow transplant for patients with IBD and underlying immune disorders. To date, less emphasis has been placed on monogenic causes of IBD that pertain to impairment of the intestinal epithelial barrier. Here, we provide a comprehensive review of monogenic causes of IBD that result in impaired intestinal epithelial barrier that are categorized into 6 important functions: (1) epithelial cell organization, (2) epithelial cell intrinsic functions, (3) epithelial cell apoptosis and necroptosis, (4) complement activation, (5) epithelial cell signaling, and (6) control of RNA degradation products. We illustrate how impairment of any of these categories can result in IBD. This work reviews the current understanding of the genes involved in maintaining the intestinal barrier, the inheritance patterns that result in dysfunction, features of IBD resulting from these disorders, and pertinent translational work in this field.
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Affiliation(s)
- Jodie D Ouahed
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexandra Griffith
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Lauren V Collen
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Scott B Snapper
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
- Division of Gastroenterology, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA
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Hall CHT, de Zoeten EF. Understanding very early onset inflammatory bowel disease (VEOIBD) in relation to inborn errors of immunity. Immunol Rev 2024; 322:329-338. [PMID: 38115672 PMCID: PMC11044353 DOI: 10.1111/imr.13302] [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: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 12/21/2023]
Abstract
Inflammatory bowel diseases (IBD) are multifactorial diseases which are caused by the combination of genetic predisposition, exposure factors (environmental and dietary), immune status, and dysbiosis. IBD is a disease which presents at any age, ranging from newborns to the elderly. The youngest of the pediatric IBD population have a more unique presentation and clinical course and may have a different etiology. Very early onset IBD (VEOIBD) patients, designated as those diagnosed prior the age of 6, have distinct features which are more frequent in this patient population including increased incidence of monogenetic causes for IBD (0%-33% depending on the study). This proportion is increased in the youngest subsets, which is diagnosed prior to the age of 2. To date, there are approximately 80 monogenic causes of VEOIBD that have been identified and published. Many of these monogenic causes are inborn errors of immunity yet the majority of VEOIBD patients do not have an identifiable genetic cause for their disease. In this review, we will focus on the clinical presentation, evaluation, and monogenic categories which have been associated with VEOIBD including (1) Epithelial cell defects (2) Adaptive immune defects, (3) Innate Immune/Bacterial Clearance and Recognition defects, and (4) Hyperinflammatory and autoinflammatory disorders. We will highlight differential diagnosis of VEOIBD presentations, as well as evaluation and treatment, which will be helpful for those who study and care for VEOIBD patients outside of the pediatric gastroenterology field. This is a fast-moving field of research which has grown significantly based on knowledge that we gain from our patients. These scientific findings have identified novel mucosal biology pathways and will continue to inform our understanding of gastrointestinal biology.
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Affiliation(s)
- Caroline H. T. Hall
- Mucosal Inflammation Program University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Edwin F. de Zoeten
- Mucosal Inflammation Program University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA
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Dinges SS, Amini K, Notarangelo LD, Delmonte OM. Primary and secondary defects of the thymus. Immunol Rev 2024; 322:178-211. [PMID: 38228406 PMCID: PMC10950553 DOI: 10.1111/imr.13306] [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] [Indexed: 01/18/2024]
Abstract
The thymus is the primary site of T-cell development, enabling generation, and selection of a diverse repertoire of T cells that recognize non-self, whilst remaining tolerant to self- antigens. Severe congenital disorders of thymic development (athymia) can be fatal if left untreated due to infections, and thymic tissue implantation is the only cure. While newborn screening for severe combined immune deficiency has allowed improved detection at birth of congenital athymia, thymic disorders acquired later in life are still underrecognized and assessing the quality of thymic function in such conditions remains a challenge. The thymus is sensitive to injury elicited from a variety of endogenous and exogenous factors, and its self-renewal capacity decreases with age. Secondary and age-related forms of thymic dysfunction may lead to an increased risk of infections, malignancy, and autoimmunity. Promising results have been obtained in preclinical models and clinical trials upon administration of soluble factors promoting thymic regeneration, but to date no therapy is approved for clinical use. In this review we provide a background on thymus development, function, and age-related involution. We discuss disease mechanisms, diagnostic, and therapeutic approaches for primary and secondary thymic defects.
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Affiliation(s)
- Sarah S. Dinges
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kayla Amini
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Luigi D. Notarangelo
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ottavia M. Delmonte
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Chen J, Chen M, Lin Y, Li X. Meconium peritonitis in multiple intestinal atresia with combined immune deficiency caused by a TTC7A mutation: A case report. SAGE Open Med Case Rep 2024; 12:2050313X241227129. [PMID: 38292879 PMCID: PMC10826389 DOI: 10.1177/2050313x241227129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/01/2024] [Indexed: 02/01/2024] Open
Abstract
Multiple intestinal atresia with combined immune deficiency is a severe autosomal recessive disorder caused by the tetratricopeptide repeat domain 7A (TTC7A) gene deficiency, which is characterized by extensive intestinal defects with immune deficiency. This report describes a fetus with TTC7A deficiency who developed meconium peritonitis in utero. Evidence suggests that patients with TTC7A deficiency present with intestinal defects as early as in utero. In this case, intestinal abnormalities were considered during the prenatal examination at week 28, and chromosome and genetic tests were performed. The results indicated that the fetus had a TTC7A complex heterozygous mutation. The male infant underwent surgical treatment after birth and developed severe infection and sepsis, which confirmed the presence of multiple intestinal atresia with combined immune deficiency. Our case suggests an association between meconium peritonitis and the TTC7A gene deficiency, indicating the possibility of severe intestinal defects and immune deficiencies after birth and guiding subsequent fetal treatment choices.
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Affiliation(s)
- Jiongfei Chen
- Obstetric and Gynecologic, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Meiwen Chen
- Obstetric and Gynecologic, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Ya Lin
- Obstetric and Gynecologic, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xiangjuan Li
- Obstetric and Gynecologic, Hangzhou Women’s Hospital, Hangzhou, Zhejiang, China
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Babcock SJ, Flores-Marin D, Thiagarajah JR. The genetics of monogenic intestinal epithelial disorders. Hum Genet 2023; 142:613-654. [PMID: 36422736 PMCID: PMC10182130 DOI: 10.1007/s00439-022-02501-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 11/27/2022]
Abstract
Monogenic intestinal epithelial disorders, also known as congenital diarrheas and enteropathies (CoDEs), are a group of rare diseases that result from mutations in genes that primarily affect intestinal epithelial cell function. Patients with CoDE disorders generally present with infantile-onset diarrhea and poor growth, and often require intensive fluid and nutritional management. CoDE disorders can be classified into several categories that relate to broad areas of epithelial function, structure, and development. The advent of accessible and low-cost genetic sequencing has accelerated discovery in the field with over 45 different genes now associated with CoDE disorders. Despite this increasing knowledge in the causal genetics of disease, the underlying cellular pathophysiology remains incompletely understood for many disorders. Consequently, clinical management options for CoDE disorders are currently limited and there is an urgent need for new and disorder-specific therapies. In this review, we provide a general overview of CoDE disorders, including a historical perspective of the field and relationship to other monogenic disorders of the intestine. We describe the genetics, clinical presentation, and known pathophysiology for specific disorders. Lastly, we describe the major challenges relating to CoDE disorders, briefly outline key areas that need further study, and provide a perspective on the future genetic and therapeutic landscape.
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Affiliation(s)
- Stephen J Babcock
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA
| | - David Flores-Marin
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Jay R Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA.
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Ouahed JD. Understanding inborn errors of immunity: A lens into the pathophysiology of monogenic inflammatory bowel disease. Front Immunol 2022; 13:1026511. [PMID: 36248828 PMCID: PMC9556666 DOI: 10.3389/fimmu.2022.1026511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Inflammatory bowel diseases (IBD) are chronic inflammatory conditions of the gastrointestinal tract, including Crohn’s disease, ulcerative colitis and inflammatory bowel disease-undefined (IBD-U). IBD are understood to be multifactorial, involving genetic, immune, microbial and environmental factors. Advances in next generation sequencing facilitated the growing identification of over 80 monogenic causes of IBD, many of which overlap with Inborn errors of immunity (IEI); Approximately a third of currently identified IEI result in gastrointestinal manifestations, many of which are inflammatory in nature, such as IBD. Indeed, the gastrointestinal tract represents an opportune system to study IEI as it consists of the largest mass of lymphoid tissue in the body and employs a thin layer of intestinal epithelial cells as the critical barrier between the intestinal lumen and the host. In this mini-review, a selection of pertinent IEI resulting in monogenic IBD is described involving disorders in the intestinal epithelial barrier, phagocytosis, T and B cell defects, as well as those impairing central and peripheral tolerance. The contribution of disrupted gut-microbiota-host interactions in disturbing intestinal homeostasis among patients with intestinal disease is also discussed. The molecular mechanisms driving pathogenesis are reviewed along with the personalized therapeutic interventions and investigational avenues this growing knowledge has enabled.
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