1
|
Boyarchuk O, Kostyuchenko L, Akopyan H, Bondarenko A, Volokha A, Hilfanova A, Savchak I, Nazarenko L, Yarema N, Urbas O, Hrabovska I, Lysytsia O, Budzyn A, Tykholaz O, Ivanchuk M, Bastanohova O, Patskun E, Vasylenko N, Stepanovskyy Y, Chernyshova L, Makukh H. Nijmegen breakage syndrome: 25-year experience of diagnosis and treatment in Ukraine. Front Immunol 2024; 15:1428724. [PMID: 39007137 PMCID: PMC11239363 DOI: 10.3389/fimmu.2024.1428724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 06/17/2024] [Indexed: 07/16/2024] Open
Abstract
Introduction Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder, characterized by microcephaly, immunodeficiency, and impaired DNA repair. NBS is most prevalent among Slavic populations, including Ukraine. Our study aimed to comprehensively assess the prevalence, diagnosis, clinical data, immunological parameters, and treatment of NBS patients in Ukraine. Methods We conducted a retrospective review that included 84 NBS patients from different regions of Ukraine who were diagnosed in 1999-2023. Data from the Ukrainian Registry of NBS and information from treating physicians, obtained using a developed questionnaire, were utilized for analysis. Results Among 84 NBS patients, 55 (65.5%) were alive, 25 (29.8%) deceased, and 4 were lost to follow-up. The median age of patients was 11 years, ranging from 1 to 34 years. Most patients originate from western regions of Ukraine (57.8%), although in recent years, there has been an increase in diagnoses from central and southeastern regions, expanding our knowledge of NBS prevalence. The number of diagnosed patients per year averaged 3.4 and increased from 2.7 to 4.8 in recent years. The median age of NBS diagnosis was 4.0 years (range 0.1-16) in 1999-2007 and decreased to 2.7 in the past 6 years. Delayed physical development was observed in the majority of children up to the age of ten years. All children experienced infections, and 41.3% of them had recurrent infections. Severe infections were the cause of death in 12%. The second most common clinical manifestation of NBS was malignancies (37.5%), with the prevalence of lymphomas (63.3%). Malignancies have been the most common cause of death in NBS patients (72% of cases). Decreased levels of CD4+ and CD19+ were observed in 89.6%, followed by a reduction of CD3+ (81.8%) and CD8+ (62.5%). The level of NK cells was elevated at 62.5%. IgG concentration was decreased in 72.9%, and IgA - in 56.3%. Immunoglobulin replacement therapy was administered to 58.7% of patients. Regular immunoglobulin replacement therapy has helped reduce the frequency and severity of severe respiratory tract infections. Conclusion Improvements in diagnosis, including prenatal screening, newborn screening, monitoring, and expanding treatment options, will lead to better outcomes for NBS patients.
Collapse
Affiliation(s)
- Oksana Boyarchuk
- Department of Children’s Diseases and Pediatric Surgery, I.Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Larysa Kostyuchenko
- Clinic of Pediatric Immunology and Rheumatology, Western Ukrainian Specialized Children’s Medical Centre, Lviv, Ukraine
| | - Hayane Akopyan
- Department of Diagnostic of Hereditary Pathology, Institute of Hereditary Pathology of the National Academy of Medical Sciences of Ukraine, Lviv, Ukraine
| | - Anastasiia Bondarenko
- Department of Pediatrics, Immunology, Infectious and Rare Diseases, European Medical School, International European University, Kyiv, Ukraine
| | - Alla Volokha
- Department of Pediatrics, Pediatric Infectious Diseases, Immunology and Allergology, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Anna Hilfanova
- Department of Pediatrics, Immunology, Infectious and Rare Diseases, European Medical School, International European University, Kyiv, Ukraine
| | - Ihor Savchak
- Clinic of Pediatric Immunology and Rheumatology, Western Ukrainian Specialized Children’s Medical Centre, Lviv, Ukraine
| | - Liliia Nazarenko
- Department of Pediatrics, Cherkasy Regional Children’s Hospital, Cherkasy, Ukraine
| | - Nataliia Yarema
- Department of Children’s Diseases and Pediatric Surgery, I.Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Olha Urbas
- Department of Pediatrics, Ivano-Frankivsk National Medical University, Ivano-Frankivsk, Ukraine
| | - Iryna Hrabovska
- Department of Pediatrics Oncohematology, Volyn Regional Territorial Mother and Child Health Care Center, Lutsk, Ukraine
| | - Oleksandr Lysytsia
- Department of Bone Marrow Transplantation and Intensive Megadose Chemotherapy and Immunotherapy, National Specialized Children’s Hospital “OHMATDYT”, Kyiv, Ukraine
| | - Andrii Budzyn
- Department of Bone Marrow Transplantation and Intensive Megadose Chemotherapy and Immunotherapy, National Specialized Children’s Hospital “OHMATDYT”, Kyiv, Ukraine
| | - Oksana Tykholaz
- Department of Propedeutics of Pediatric Diseases with Patient Care, National Pirogov Memorial Medical University, Vinnytsya, Ukraine
| | - Mariana Ivanchuk
- Department of Pediatrics Oncohematology, Volyn Regional Territorial Mother and Child Health Care Center, Lutsk, Ukraine
| | - Olha Bastanohova
- Center of Specialized Pediatric Care, Poltava Regional Clinical Hospital named after M. V. Sklifosovsky, Poltava, Ukraine
| | - Erika Patskun
- Department of Faculty Therapy, Uzhhorod National University, Uzhhorod, Ukraine
| | - Nataliia Vasylenko
- Outpatient Department, Kherson Regional Children’s Hospital, Kherson, Ukraine
| | - Yuriy Stepanovskyy
- Department of Pediatrics, Immunology, Infectious and Rare Diseases, European Medical School, International European University, Kyiv, Ukraine
| | - Liudmyla Chernyshova
- Department of Pediatrics, Pediatric Infectious Diseases, Immunology and Allergology, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Halyna Makukh
- Department of the Research and Biotechnology, Scientific Medical Genetic Center LeoGENE, Lviv, Ukraine
| |
Collapse
|
2
|
Escherich CS, Chen W, Li Y, Yang W, Nishii R, Li Z, Raetz EA, Devidas M, Wu G, Nichols KE, Inaba H, Pui CH, Jeha S, Camitta BM, Larsen E, Hunger SP, Loh ML, Yang JJ. Germ line genetic NBN variation and predisposition to B-cell acute lymphoblastic leukemia in children. Blood 2024; 143:2270-2283. [PMID: 38446568 PMCID: PMC11443573 DOI: 10.1182/blood.2023023336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024] Open
Abstract
ABSTRACT Biallelic mutation in the DNA-damage repair gene NBN is the genetic cause of Nijmegen breakage syndrome, which is associated with predisposition to lymphoid malignancies. Heterozygous carriers of germ line NBN variants may also be at risk for leukemia development, although this is much less characterized. By sequencing 4325 pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL), we systematically examined the frequency of germ line NBN variants and identified 25 unique, putatively damaging NBN coding variants in 50 patients. Compared with the frequency of NBN variants in gnomAD noncancer controls (189 unique, putatively damaging NBN coding variants in 472 of 118 479 individuals), we found significant overrepresentation in pediatric B-ALL (P = .004; odds ratio, 1.8). Most B-ALL-risk variants were missense and cluster within the NBN N-terminal domains. Using 2 functional assays, we verified 14 of 25 variants with severe loss-of-function phenotypes and thus classified these as nonfunctional or partially functional. Finally, we found that germ line NBN variant carriers, all of whom were identified as heterozygous genotypes, showed similar survival outcomes relative to those with wild type status. Taken together, our findings provide novel insights into the genetic predisposition to B-ALL, and the impact of NBN variants on protein function and suggest that heterozygous NBN variant carriers may safely receive B-ALL therapy. These trials were registered at www.clinicaltrials.gov as #NCT01225874, NCT00075725, NCT00103285, NCI-T93-0101D, and NCT00137111.
Collapse
Affiliation(s)
- Carolin S Escherich
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
- Department for Pediatric Oncology, Hematology, and Clinical Immunology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Wenan Chen
- Department of Pathology, Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN
| | - Yizhen Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Wenjian Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Rina Nishii
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Zhenhua Li
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| | - Elizabeth A Raetz
- Department of Pediatrics and Perlmutter Cancer Center, New York University Langone Health, New York, NY
| | - Meenakshi Devidas
- Department of Global Pediatric Medicine, St. Jude Children's Research Hospital, Memphis, TN
| | - Gang Wu
- Department of Pathology, Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN
| | - Kim E Nichols
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Hiroto Inaba
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Ching-Hon Pui
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Sima Jeha
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - Bruce M Camitta
- Department of Pediatrics, Midwest Center for Cancer and Blood Disorders, Medical College of Wisconsin, Milwaukee, WI
| | - Eric Larsen
- Department of Pediatrics, Maine Children's Cancer Program, Scarborough, ME
| | - Stephen P Hunger
- Department of Pediatrics and Center for Childhood Cancer Research, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Mignon L Loh
- Department of Pediatrics and the Ben Towne Center for Childhood Cancer Research, Seattle Children's Hospital, University of Washington, Seattle, WA
| | - Jun J Yang
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN
| |
Collapse
|
3
|
Naumova E, Lesichkova S, Milenova V, Yankova P, Murdjeva M, Mihailova S. Primary immunodeficiencies in Bulgaria - achievements and challenges of the PID National Expert Center. Front Immunol 2022; 13:922752. [PMID: 36211402 PMCID: PMC9535737 DOI: 10.3389/fimmu.2022.922752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/09/2022] [Indexed: 11/24/2022] Open
Abstract
Tremendous progress has been made in the recognition of primary immune deficiencies (PIDs) in Bulgaria since in 2005 we have joined the J Project Central-Eastern European collaborative program. Ten years later an Expert Centre (ExpC) for Rare Diseases - Primary Immune Deficiencies at the University Hospital “Alexandrovska”- Sofia was established. In May 2017 The National Register of Patients with Rare Diseases also became operational as a database containing clinical and genetic information for Bulgarian patients with PID. The transfer of data and information on Bulgarian PID patients to the European Primary Immunodeficiency Database, managed by the European Society for Primary Immunodeficiency (ESID) has started in 2020. The total number of registered patients now is 191 (100 men and 91 women), with more than half of them being children (106; 55.5%). Regular updating of the information in the register showed that 5.2% of patients are deceased and the majority (94.8%) is a subject to continuous monitoring as it has been reported for other European countries as well. With the establishment of the ExpC, the dynamics in the diagnosis and registration of patients with PID significantly intensified. For a period of 5 years (2016-2021) 101 patients were evaluated and registered in comparison with previous period - before ExpC establishment when only 89 patients were diagnosed. The most common pathology was humoral immune deficiency (85 patients; 44.5%). Ninety-six (50.3%) of the patients underwent genetic testing, and 66. 7% had genetically confirmed diagnosis. Three of the variants have not been reported in population databases. Following genetic investigation confirmation of the initial phenotypic diagnosis was achieved in 82.8% of cases and change in the diagnosis - in 17%. Sixty-two patients were on regular replacement or specific therapy, and the rest received symptomatic and supportive treatment. In summary, we present the first epidemiological report of PIDs in Bulgaria, based on the National PID register. Data on the clinical, phenotypic and genetic characteristics of PID patients provided important information about the nature of primary immunodeficiency diseases in our country.
Collapse
Affiliation(s)
- Elissaveta Naumova
- Clinic of Clinical Immunology with Stem Cell Bank, Expert Center for Rare Diseases-PID, University Hospital “Alexandrovska”, Sofia, Bulgaria
- Department of Clinical Immunology, Faculty of Medicine, Medical University, Sofia, Bulgaria
- *Correspondence: Elissaveta Naumova,
| | - Spaska Lesichkova
- Clinic of Clinical Immunology with Stem Cell Bank, Expert Center for Rare Diseases-PID, University Hospital “Alexandrovska”, Sofia, Bulgaria
- Department of Clinical Immunology, Faculty of Medicine, Medical University, Sofia, Bulgaria
| | - Veneta Milenova
- Clinic of Clinical Immunology with Stem Cell Bank, Expert Center for Rare Diseases-PID, University Hospital “Alexandrovska”, Sofia, Bulgaria
| | - Petya Yankova
- Clinic of Clinical Immunology with Stem Cell Bank, Expert Center for Rare Diseases-PID, University Hospital “Alexandrovska”, Sofia, Bulgaria
- Department of Clinical Immunology, Faculty of Medicine, Medical University, Sofia, Bulgaria
| | - Marianna Murdjeva
- Department of Microbiology and Immunology, Faculty of Pharmacy, Research Institute, Medical University, Plovdiv, Bulgaria
| | - Snezhina Mihailova
- Clinic of Clinical Immunology with Stem Cell Bank, Expert Center for Rare Diseases-PID, University Hospital “Alexandrovska”, Sofia, Bulgaria
- Department of Clinical Immunology, Faculty of Medicine, Medical University, Sofia, Bulgaria
| |
Collapse
|
4
|
Wieland J, Buchan S, Sen Gupta S, Mantzouratou A. Genomic instability and the link to infertility: A focus on microsatellites and genomic instability syndromes. Eur J Obstet Gynecol Reprod Biol 2022; 274:229-237. [PMID: 35671666 DOI: 10.1016/j.ejogrb.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 12/01/2022]
Abstract
Infertility is associated to multiple types of different genomic instabilities and is a genetic feature of genomic instability syndromes. While the mismatch repair machinery contributes to the maintenance of genome integrity, surprisingly its potential role in infertility is overlooked. Defects in mismatch repair mechanisms contribute to microsatellite instability and genomic instability syndromes, due to the inability to repair newly replicated DNA. This article reviews the literature to date to elucidate the contribution of microsatellite instability to genomic instability syndromes and infertility. The key findings presented reveal microsatellite instability is poorly researched in genomic instability syndromes and infertility.
Collapse
Affiliation(s)
- Jack Wieland
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK.
| | - Sarah Buchan
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK.
| | - Sioban Sen Gupta
- Institute for Women's Health, 86-96 Chenies Mews, University College London, London WC1E 6HX, UK.
| | - Anna Mantzouratou
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK.
| |
Collapse
|
5
|
The Slavic NBN Founder Mutation: A Role for Reproductive Fitness? PLoS One 2016; 11:e0167984. [PMID: 27936167 PMCID: PMC5148078 DOI: 10.1371/journal.pone.0167984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 11/23/2016] [Indexed: 01/21/2023] Open
Abstract
The vast majority of patients with Nijmegen Breakage Syndrome (NBS) are of Slavic origin and carry a deleterious deletion (c.657del5; rs587776650) in the NBN gene on chromosome 8q21. This mutation is essentially confined to Slavic populations and may thus be considered a Slavic founder mutation. Notably, not a single parenthood of a homozygous c.657del5 carrier has been reported to date, while heterozygous carriers do reproduce but have an increased cancer risk. These observations seem to conflict with the considerable carrier frequency of c.657del5 of 0.5% to 1% as observed in different Slavic populations because deleterious mutations would be eliminated quite rapidly by purifying selection. Therefore, we propose that heterozygous c.657del5 carriers have increased reproductive success, i.e., that the mutation confers heterozygote advantage. In fact, in our cohort study of the reproductive history of 24 NBS pedigrees from the Czech Republic, we observed that female carriers gave birth to more children on average than female non-carriers, while no such reproductive differences were observed for males. We also estimate that c.657del5 likely occurred less than 300 generations ago, thus supporting the view that the original mutation predated the historic split and subsequent spread of the ‘Slavic people’. We surmise that the higher fertility of female c.657del5 carriers reflects a lower miscarriage rate in these women, thereby reflecting the role of the NBN gene product, nibrin, in the repair of DNA double strand breaks and their processing in immune gene rearrangements, telomere maintenance, and meiotic recombination, akin to the previously described role of the DNA repair genes BRCA1 and BRCA2.
Collapse
|
6
|
Malkin D, Nichols KE, Zelley K, Schiffman JD. Predisposition to pediatric and hematologic cancers: a moving target. Am Soc Clin Oncol Educ Book 2014:e44-e55. [PMID: 24857136 DOI: 10.14694/edbook_am.2014.34.e44] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Our understanding of hereditary cancer syndromes in children, adolescents, and young adults continues to grow. In addition, we now recognize the wide variation in tumor spectrum found within each specific cancer predisposition syndrome including the risk for hematologic malignancies. An increased understanding of the genetic mutations, biologic consequences, tumor risk, and clinical management of these syndromes will improve patient outcome. In this article, we illustrate the diversity of molecular mechanisms by which these disorders develop in both children and adults with a focus on Li-Fraumeni syndrome, hereditary paraganglioma syndrome, DICER1 syndrome, and multiple endocrine neoplasia syndrome. This is followed by a detailed discussion of adult-onset tumors that can occur in the pediatric population including basal cell carcinoma, colorectal cancer, medullary thyroid cancer, and adrenal cortical carcinoma, and the underlying hereditary cancer syndromes that these tumors could indicate. Finally, the topic of leukemia predisposition syndromes is explored with a specific focus on the different categories of syndromes associated with leukemia risk (genetic instability/DNA repair syndromes, cell cycle/differentiation, bone marrow failure syndromes, telomere maintenance, immunodeficiency syndromes, and transcription factors/pure familial leukemia syndromes). Throughout this article, special attention is made to clinical recognition of these syndromes, genetic testing, and management with early tumor surveillance and screening.
Collapse
Affiliation(s)
- David Malkin
- From the Division of Hematology/Oncology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, PA; and Division of Pediatric Hematology/Oncology, Department of Pediatrics and Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| | - Kim E Nichols
- From the Division of Hematology/Oncology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, PA; and Division of Pediatric Hematology/Oncology, Department of Pediatrics and Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| | - Kristin Zelley
- From the Division of Hematology/Oncology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, PA; and Division of Pediatric Hematology/Oncology, Department of Pediatrics and Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| | - Joshua D Schiffman
- From the Division of Hematology/Oncology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, PA; and Division of Pediatric Hematology/Oncology, Department of Pediatrics and Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| |
Collapse
|
7
|
Germline mutations 657del5 and 643C>T (R215W) in NBN are not likely to be associated with increased risk of breast cancer in Czech women. Breast Cancer Res Treat 2012; 133:809-11. [PMID: 22491912 DOI: 10.1007/s10549-012-2049-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
|
8
|
Borte S, Wang N, Oskarsdóttir S, von Döbeln U, Hammarström L. Newborn screening for primary immunodeficiencies: beyond SCID and XLA. Ann N Y Acad Sci 2012; 1246:118-30. [PMID: 22236436 DOI: 10.1111/j.1749-6632.2011.06350.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary immunodeficiencies (PID) encompass more than 250 disease entities, including phagocytic disorders, complement deficiencies, T cell defects, and antibody deficiencies. While differing in clinical severity, early diagnosis and treatment is of considerable importance for all forms of PID to prevent organ damage and life-threatening infections. During the past few years, neonatal screening assays have been developed to detect diseases hallmarked by the absence of T or B lymphocytes, classically seen in severe combined immunodeficiencies (SCID) and X-linked agammaglobulinemia (XLA). As described in this review, a reduction or lack of T and B cells in newborns is also frequently found in several other forms of PID, requiring supplemental investigation and involving the development of additional technical platforms in order to help classify abnormal screening results.
Collapse
Affiliation(s)
- Stephan Borte
- Division of Clinical Immunology and Transfusion Medicine, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | | | | | | | | |
Collapse
|
9
|
Abstract
Nijmegen breakage syndrome (NBS) is a rare autosomal recessive syndrome of chromosomal instability mainly characterized by microcephaly at birth, combined immunodeficiency and predisposition to malignancies. Due to a founder mutation in the underlying NBN gene (c.657_661del5) the disease is encountered most frequently among Slavic populations. The principal clinical manifestations of the syndrome are: microcephaly, present at birth and progressive with age, dysmorphic facial features, mild growth retardation, mild-to-moderate intellectual disability, and, in females, hypergonadotropic hypogonadism. Combined cellular and humoral immunodeficiency with recurrent sinopulmonary infections, a strong predisposition to develop malignancies (predominantly of lymphoid origin) and radiosensitivity are other integral manifestations of the syndrome. The NBN gene codes for nibrin which, as part of a DNA repair complex, plays a critical nuclear role wherever double-stranded DNA ends occur, either physiologically or as a result of mutagenic exposure. Laboratory findings include: (1) spontaneous chromosomal breakage in peripheral T lymphocytes with rearrangements preferentially involving chromosomes 7 and 14, (2) sensitivity to ionizing radiation or radiomimetics as demonstrated in vitro by cytogenetic methods or by colony survival assay, (3) radioresistant DNA synthesis, (4) biallelic hypomorphic mutations in the NBN gene, and (5) absence of full-length nibrin protein. Microcephaly and immunodeficiency are common to DNA ligase IV deficiency (LIG4 syndrome) and severe combined immunodeficiency with microcephaly, growth retardation, and sensitivity to ionizing radiation due to NHEJ1 deficiency (NHEJ1 syndrome). In fact, NBS was most commonly confused with Fanconi anaemia and LIG4 syndrome. Genetic counselling should inform parents of an affected child of the 25% risk for further children to be affected. Prenatal molecular genetic diagnosis is possible if disease-causing mutations in both alleles of the NBN gene are known. No specific therapy is available for NBS, however, hematopoietic stem cell transplantation may be one option for some patients. Prognosis is generally poor due to the extremely high rate of malignancies. Zespół Nijmegen (Nijmegen breakage syndrome; NBS) jest rzadkim schorzeniem z wrodzoną niestabilnością chromosomową dziedziczącym się w sposób autosomalny recesywny, charakteryzującym się przede wszystkim wrodzonym małogłowiem, złożonymi niedoborami odporności i predyspozycją do rozwoju nowotworów. Choroba występuje najczęściej w populacjach słowiańskich, w których uwarunkowana jest mutacją założycielską w genie NBN (c.657_661del5). Do najważniejszych objawów zespołu zalicza się: małogłowie obecne od urodzenia i postępujące z wiekiem, charakterystyczne cechy dysmorfii twarzy, opóźnienie wzrastania, niepełnosprawność intelektualną w stopniu lekkim do umiarkowanego oraz hipogonadyzm hipogonadotropowy u dziewcząt. Na obraz choroby składają się także: niedobór odporności komórkowej i humoralnej, który jest przyczyną nawracających infekcji, znaczna predyspozycja do rozwoju nowotworów złośliwych (zwłaszcza układu chłonnego), a także zwiększona wrażliwość na promieniowanie jonizujące. Wyniki badań laboratoryjnych wykazują: (1) spontaniczną łamliwość chromosomów w limfocytach T krwi obwodowej, z preferencją do rearanżacji chromosomów 7 i 14, (2) nadwrażliwość na promieniowanie jonizujące lub radiomimetyki, co można wykazać metodami in vitro, (3) radiooporność syntezy DNA, (4) hipomorficzne mutacje na obu allelach genu NBN, oraz (5) brak w komórkach pełnej cząsteczki białka, nibryny. Małogłowie i niedobór odporności występują także w zespole niedoboru ligazy IV (LIG4) oraz w zespole niedoboru NHEJ1. Rodzice powinni otrzymać poradę genetyczną ze względu na wysokie ryzyko (25%) powtórzenia się choroby u kolejnego potomstwa. Możliwe jest zaproponowanie molekularnej diagnostyki prenatalnej jeżeli znane są obie mutacje będące przyczyną choroby. Nie ma możliwości zaproponowania specyficznej terapii, ale przeszczep szpiku może być alternatywą dla niektórych pacjentów. Generalnie prognoza nie jest pomyślna z uwagi na wysokie ryzyko rozwoju nowotworu.
Collapse
|