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Gürbüz AF, Eryılmaz MK, Yıldız O, Kılınç F, Araz M, Artaç M. Rare case of myelodysplastic syndrome with excess blasts 2 developing after adjuvant chemoradiotherapy for triple-negative breast cancer in a patient with Bloom syndrome. Strahlenther Onkol 2024:10.1007/s00066-024-02257-z. [PMID: 38995367 DOI: 10.1007/s00066-024-02257-z] [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: 02/27/2024] [Accepted: 06/13/2024] [Indexed: 07/13/2024]
Abstract
INTRODUCTION Bloom syndrome (BS) is a rare autosomal recessive disorder caused by a loss-of-function mutation in the BLM gene encoding an RecQ helicase involved in DNA repair and maintenance of chromosomal stability. In patients with BS, significant sensitivity to both DNA-damaging chemotherapy (CT) and ionizing radiation complicates the management of neoplasms by exacerbating comorbidities and predisposing to toxicities and poor outcomes. CASE REPORT A 30-year-old female patient diagnosed with BS who presented with early-stage triple-negative breast cancer was treated with four cycles of doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) followed by weekly paclitaxel (80 mg/m2) for 12 weeks as the chemotherapy protocol and a total of 5000 cGy curative radiotherapy (RT). Due to pancytopenia 8 months after completion of therapy, bone marrow biopsy and aspiration were performed, and a diagnosis of myelodysplastic syndrome with excess blasts 2 (MDS-EB2) was made. Two courses of the azacitidine (75 mg/m2) protocol were administered every 28 days in the hematology clinic. Two weeks after CT the patient was transferred from the emergency department to the hematology clinic with the diagnosis of pancytopenia and febrile neutropenia. She died at the age of 33 due to sepsis that developed during follow-up. CONCLUSION Due to the rarity of BS, there is no prospective trial in patients with cancer and no evidence base upon which to design treatment programs. For these reasons, it is strongly recommended that patients receive multidisciplinary care, with precise assessment and discussion of the indication and an adequate dose of DNA-damaging agents such as chemotherapy and ionizing radiation.
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Affiliation(s)
- Ali Fuat Gürbüz
- Department of Medical Oncology, Faculty of Medicine, Necmettin Erbakan University, 14280, Konya, Turkey.
| | - Melek Karakurt Eryılmaz
- Department of Medical Oncology, Faculty of Medicine, Necmettin Erbakan University, 14280, Konya, Turkey
| | - Oğuzhan Yıldız
- Department of Medical Oncology, Faculty of Medicine, Necmettin Erbakan University, 14280, Konya, Turkey
| | - Fahriye Kılınç
- Department of Pathology, Faculty of Medicine, Necmettin Erbakan University, Konya, Turkey
| | - Murat Araz
- Department of Medical Oncology, Faculty of Medicine, Necmettin Erbakan University, 14280, Konya, Turkey
| | - Mehmet Artaç
- Department of Medical Oncology, Faculty of Medicine, Necmettin Erbakan University, 14280, Konya, Turkey
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2
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Gould NJ, Holjak EJB, Barat J, Tay KY, Dar AR. Bloom Syndrome Complicated by Low-Grade Lymphoma and Non-small Cell Lung Cancer: A Case Report. Cureus 2024; 16:e60107. [PMID: 38860091 PMCID: PMC11164565 DOI: 10.7759/cureus.60107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2024] [Indexed: 06/12/2024] Open
Abstract
Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by photosensitivity, rashes on the nose and cheeks, short stature, and a predisposition to develop cancers. In this report, we discuss the diagnosis and management of a 34-year-old Canadian male BS patient, originally from Honduras, who developed B-cell lymphoma and a subsequent non-small cell lung carcinoma (NSCLC). Given the radiosensitivity of the patient due to his BS diagnosis and the early stage of the low-grade B-cell lymphoma, we relied on surveillance as the clinical approach to his management. The treatment for NSCLC was initiated in stage III of the disease and was palliative in intent. Chemotherapy (12 rounds of paclitaxel, with the dosage gradually increasing from 48 mg to 58 mg and finally to 72 mg) was employed to shrink the left upper lobe (LUL) lung mass. Subsequently, radiotherapy (3000 cGY in 20 fractions) was administered to improve symptoms further. The radiotherapy dose schedule was modified given the patient's BS diagnosis to avoid excessive toxicity. The palliative treatment course was well tolerated by the patient and resulted in symptom relief. However, his cancer progressed over the course of the treatment, ultimately resulting in his death 18 months after the initial diagnosis of NSCLC; no autopsy was performed. We believe this report will spur clinicians to engage in fruitful discussions about tailoring chemotherapy and radiation therapy regimens for treating cancer in BS patients.
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Affiliation(s)
- Nathan J Gould
- Schulich School of Medicine and Dentistry, Western University, London, CAN
| | - Emma J B Holjak
- Schulich School of Medicine and Dentistry, Western University, London, CAN
| | - Jalal Barat
- Schulich School of Medicine and Dentistry, Western University, London, CAN
| | - Keng Yeow Tay
- Radiology, Victoria Hospital, London, CAN
- Radiology, London Health Sciences Centre, London, CAN
| | - A Rashid Dar
- Radiation Oncology, London Health Sciences Centre, London, CAN
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3
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Wojtara MS, Kang J, Zaman M. Congenital Telangiectatic Erythema: Scoping Review. JMIR DERMATOLOGY 2023; 6:e48413. [PMID: 37796556 PMCID: PMC10587801 DOI: 10.2196/48413] [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: 04/22/2023] [Revised: 08/19/2023] [Accepted: 09/15/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Congenital telangiectatic erythema (CTE), also known as Bloom syndrome, is a rare autosomal recessive disorder characterized by below-average height, a narrow face, a red skin rash occurring on sun-exposed areas of the body, and an increased risk of cancer. CTE is one of many genodermatoses and photodermatoses associated with defects in DNA repair. CTE is caused by a mutation occurring in the BLM gene, which causes abnormal breaks in chromosomes. OBJECTIVE We aimed to analyze the existing literature on CTE to provide additional insight into its heredity, the spectrum of clinical presentations, and the management of this disorder. In addition, the gaps in current research and the use of artificial intelligence to streamline clinical diagnosis and the management of CTE are outlined. METHODS A literature search was conducted on PubMed, DOAJ, and Scopus using search terms such as "congenital telangiectatic erythema," "bloom syndrome," and "bloom-torre-machacek." Due to limited current literature, studies published from January 2000 to January 2023 were considered for this review. A total of 49 sources from the literature were analyzed. RESULTS Through this scoping review, the researchers were able to identify several publications focusing on Bloom syndrome. Some common subject areas included the heredity of CTE, clinical presentations of CTE, and management of CTE. In addition, the literature on rare diseases shows the potential advancements in understanding and treatment with artificial intelligence. Future studies should address the causes of heterogeneity in presentation and examine potential therapeutic candidates for CTE and similarly presenting syndromes. CONCLUSIONS This review illuminated current advances in potential molecular targets or causative pathways in the development of CTE as well as clinical features including erythema, increased cancer risk, and growth abnormalities. Future studies should continue to explore innovations in this space, especially in regard to the use of artificial intelligence, including machine learning and deep learning, for the diagnosis and clinical management of rare diseases such as CTE.
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Affiliation(s)
- Magda Sara Wojtara
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jayne Kang
- Department of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Mohammed Zaman
- Department of Biology, Stony Brook University, Stony Brook, NY, United States
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4
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Sacco KA, Gazzin A, Notarangelo LD, Delmonte OM. Granulomatous inflammation in inborn errors of immunity. Front Pediatr 2023; 11:1110115. [PMID: 36891233 PMCID: PMC9986611 DOI: 10.3389/fped.2023.1110115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/23/2023] [Indexed: 02/22/2023] Open
Abstract
Granulomas have been defined as inflammatory infiltrates formed by recruitment of macrophages and T cells. The three-dimensional spherical structure typically consists of a central core of tissue resident macrophages which may merge into multinucleated giant cells surrounded by T cells at the periphery. Granulomas may be triggered by infectious and non-infectious antigens. Cutaneous and visceral granulomas are common in inborn errors of immunity (IEI), particularly among patients with chronic granulomatous disease (CGD), combined immunodeficiency (CID), and common variable immunodeficiency (CVID). The estimated prevalence of granulomas in IEI ranges from 1%-4%. Infectious agents causing granulomas such Mycobacteria and Coccidioides presenting atypically may be 'sentinel' presentations for possible underlying immunodeficiency. Deep sequencing of granulomas in IEI has revealed non-classical antigens such as wild-type and RA27/3 vaccine-strain Rubella virus. Granulomas in IEI are associated with significant morbidity and mortality. The heterogeneity of granuloma presentation in IEI presents challenges for mechanistic approaches to treatment. In this review, we discuss the main infectious triggers for granulomas in IEI and the major forms of IEI presenting with 'idiopathic' non-infectious granulomas. We also discuss models to study granulomatous inflammation and the impact of deep-sequencing technology while searching for infectious triggers of granulomatous inflammation. We summarize the overarching goals of management and highlight the therapeutic options reported for specific granuloma presentations in IEI.
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Affiliation(s)
- Keith A Sacco
- Department of Pulmonology, Section of Allergy-Immunology, Phoenix Children's Hospital, Phoenix, AZ, United States
| | - Andrea Gazzin
- Laboratory of Clinical Immunology and Microbiology, Immune Deficiency Genetics Section, National Institutes of Health, Bethesda, MD, United States
| | - Luigi D Notarangelo
- Laboratory of Clinical Immunology and Microbiology, Immune Deficiency Genetics Section, National Institutes of Health, Bethesda, MD, United States
| | - Ottavia M Delmonte
- Laboratory of Clinical Immunology and Microbiology, Immune Deficiency Genetics Section, National Institutes of Health, Bethesda, MD, United States
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Kasap B, Guclu-Geyik F, Uludag Alkaya D, Cetin G, Tuysuz B. Two novel variants and follow-up findings in four children with Bloom syndrome from two families. Clin Dysmorphol 2022; 31:31-35. [PMID: 34538859 DOI: 10.1097/mcd.0000000000000391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Busra Kasap
- Department of Pediatric Genetics, Istanbul University-Cerrahpaşa, Cerrahpaşa Medical Faculty
| | - Filiz Guclu-Geyik
- Department of Genetics, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul
| | - Dilek Uludag Alkaya
- Department of Pediatric Genetics, Istanbul University-Cerrahpaşa, Cerrahpaşa Medical Faculty
| | - Güven Cetin
- Department of Hematology-Oncology, Bezmialem Boundation University, Medical Faculty, Istanbul, Turkey
| | - Beyhan Tuysuz
- Department of Pediatric Genetics, Istanbul University-Cerrahpaşa, Cerrahpaşa Medical Faculty
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6
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Pinti E, Nemeth K, Staub K, Lengyel A, Fekete G, Haltrich I. Diagnostic difficulties and possibilities of NF1-like syndromes in childhood. BMC Pediatr 2021; 21:331. [PMID: 34325699 PMCID: PMC8320045 DOI: 10.1186/s12887-021-02791-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 06/30/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1), which is caused by heterozygous inactivating pathogenic variants in the NF1, has poor phenotypic expressivity in the early years of life and there are numerous conditions, including many other tumor predisposition syndromes, that can mimic its appearance. These are collectively termed NF1-like syndromes and are also connected by their genetic background. Therefore, the NF1's clinical diagnostic efficiency in childhood could be difficult and commonly should be completed with genetic testing. METHODS To estimate the number of syndromes/conditions that could mimic NF1, we compiled them through an extensive search of the scientific literature. To test the utility of NF1's National Institutes of Health (NIH) clinical diagnostic criteria, which have been in use for a long time, we analyzed the data of a 40-member pediatric cohort with symptoms of the NF1-like syndromes' overlapping phenotype and performed NF1 genetic test, and established the average age when diagnostic suspicion arises. To facilitate timely identification, we compiled strongly suggestive phenotypic features and anamnestic data. RESULTS In our cohort the utility of NF1's clinical diagnostic criteria were very limited (sensitivity: 80%, specificity: 30%). Only 53% of children with clinically diagnosed NF1 had a detectable NF1 pathogenic variation, whereas 40% of patients without fulfilled clinical criteria tested positive. The average age at first genetic counseling was 9 years, and 40% of children were referred after at least one tumor had already been diagnosed. These results highlight the need to improve NF1-like syndromes' diagnostic efficiency in childhood. We collected the most extensive spectrum of NF1-like syndromes to help the physicians in differential diagnosis. We recommend the detailed, non-invasive clinical evaluation of patients before referring them to a clinical geneticist. CONCLUSIONS Early diagnosis of NF1-like syndromes can help to prevent severe complications by appropriate monitoring and management. We propose a potential screening, diagnostic and management strategy based on our findings and recent scientific knowledge.
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Affiliation(s)
- Eva Pinti
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary.
| | - Krisztina Nemeth
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Krisztina Staub
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Anna Lengyel
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Gyorgy Fekete
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
| | - Iren Haltrich
- II. Department of Pediatrics, Semmelweis University, Tuzolto utca 7-9, Budapest, 1094, Hungary
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7
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Xue C, Molnarova L, Steinfeld JB, Zhao W, Ma C, Spirek M, Kaniecki K, Kwon Y, Beláň O, Krejci K, Boulton S, Sung P, Greene EC, Krejci L. Single-molecule visualization of human RECQ5 interactions with single-stranded DNA recombination intermediates. Nucleic Acids Res 2021; 49:285-305. [PMID: 33332547 PMCID: PMC7797033 DOI: 10.1093/nar/gkaa1184] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/03/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
RECQ5 is one of five RecQ helicases found in humans and is thought to participate in homologous DNA recombination by acting as a negative regulator of the recombinase protein RAD51. Here, we use kinetic and single molecule imaging methods to monitor RECQ5 behavior on various nucleoprotein complexes. Our data demonstrate that RECQ5 can act as an ATP-dependent single-stranded DNA (ssDNA) motor protein and can translocate on ssDNA that is bound by replication protein A (RPA). RECQ5 can also translocate on RAD51-coated ssDNA and readily dismantles RAD51-ssDNA filaments. RECQ5 interacts with RAD51 through protein-protein contacts, and disruption of this interface through a RECQ5-F666A mutation reduces translocation velocity by ∼50%. However, RECQ5 readily removes the ATP hydrolysis-deficient mutant RAD51-K133R from ssDNA, suggesting that filament disruption is not coupled to the RAD51 ATP hydrolysis cycle. RECQ5 also readily removes RAD51-I287T, a RAD51 mutant with enhanced ssDNA-binding activity, from ssDNA. Surprisingly, RECQ5 can bind to double-stranded DNA (dsDNA), but it is unable to translocate. Similarly, RECQ5 cannot dismantle RAD51-bound heteroduplex joint molecules. Our results suggest that the roles of RECQ5 in genome maintenance may be regulated in part at the level of substrate specificity.
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Affiliation(s)
- Chaoyou Xue
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Lucia Molnarova
- Department of Biology, Masaryk University, Brno 62500, Czech Republic
| | - Justin B Steinfeld
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Weixing Zhao
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Chujian Ma
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Mario Spirek
- Department of Biology, Masaryk University, Brno 62500, Czech Republic
| | - Kyle Kaniecki
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Ondrej Beláň
- DSB Repair Metabolism Lab, The Francis Crick Institute, Midland Road, London NW1 1AT, UK
| | - Katerina Krejci
- Department of Biology, Masaryk University, Brno 62500, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno 65691, Czech Republic
| | - Simon J Boulton
- DSB Repair Metabolism Lab, The Francis Crick Institute, Midland Road, London NW1 1AT, UK
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Lumir Krejci
- Department of Biology, Masaryk University, Brno 62500, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Brno 65691, Czech Republic
- National Centre for Biomolecular Research, Masaryk, Brno 62500, Czech Republic
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8
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Kleinwuchssyndrome – potenziell lebensbedrohliche Erkrankungen. Monatsschr Kinderheilkd 2020. [DOI: 10.1007/s00112-020-01030-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Zusammenfassung
Hintergrund
Es gibt viele Ursachen für einen Kleinwuchs. Kleinwuchs in Kombination mit einer intrauterinen Wachstumsretardierung (IUGR), einer Entwicklungsverzögerung und/oder ungewöhnlichen Stigmata sollte immer auch an eine syndromale Ursache denken lassen.
Fragestellung
Diese Arbeit soll für Kleinwuchssyndrome sensibilisieren, deren Diagnose aufgrund der potenziell lebensbedrohlichen Folgen möglichst frühzeitig gestellt werden sollte.
Material und Methoden
Die vorliegende Arbeit wurde auf Basis klinikinterner Fallberichte vor dem Hintergrund der aktuellen Literatur erstellt.
Ergebnisse
Das PTEN-Hamartom-Tumor-Syndrom (PHTS), das Bloom-Syndrom (BS), der mikrozephale osteodysplastische primordiale Kleinwuchs Typ II (MOPD-II-Syndrom) sowie das Ligase-IV-Syndrom (Lig4-Syndrom) sind seltene Kleinwuchssyndrome mit potenziell letalem Ausgang. Gemeinsame Merkmale liegen in einer Abweichung des Kopfumfangs (KU) und einer Entwicklungsverzögerung. Die Verdachtsdiagnose wird molekulargenetisch gesichert. Die Behandlung erfolgt in erster Linie symptomorientiert, für das PHTS und das Ligase-IV-Syndrom existieren darüber hinaus bereits kausale Therapieansätze. Für alle Syndrome gibt es Empfehlungen im Hinblick auf gezielte Vorsorgeuntersuchungen.
Schlussfolgerung
Bei entsprechenden Hinweisen auf einen syndromalen Kleinwuchs sollte zügig eine molekulargenetisch gestützte Diagnostik erfolgen, um rechtzeitig geeignete Therapieoptionen und Vorsorgeprogramme initiieren zu können.
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9
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Schnabel F, Kornak U, Wollnik B. Premature aging disorders: A clinical and genetic compendium. Clin Genet 2020; 99:3-28. [PMID: 32860237 DOI: 10.1111/cge.13837] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/22/2022]
Abstract
Progeroid disorders make up a heterogeneous group of very rare hereditary diseases characterized by clinical signs that often mimic physiological aging in a premature manner. Apart from Hutchinson-Gilford progeria syndrome, one of the best-investigated progeroid disorders, a wide spectrum of other premature aging phenotypes exist, which differ significantly in their clinical presentation and molecular pathogenesis. Next-generation sequencing (NGS)-based approaches have made it feasible to determine the molecular diagnosis in the early stages of a disease. Nevertheless, a broad clinical knowledge on these disorders and their associated symptoms is still fundamental for a comprehensive patient management and for the interpretation of variants of unknown significance from NGS data sets. This review provides a detailed overview on characteristic clinical features and underlying molecular genetics of well-known as well as only recently identified premature aging disorders and also highlights novel findings towards future therapeutic options.
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Affiliation(s)
- Franziska Schnabel
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Uwe Kornak
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable cells" (MBExC), University of Göttingen, Göttingen, Germany
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10
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Xue C, Daley JM, Xue X, Steinfeld J, Kwon Y, Sung P, Greene EC. Single-molecule visualization of human BLM helicase as it acts upon double- and single-stranded DNA substrates. Nucleic Acids Res 2019; 47:11225-11237. [PMID: 31544923 PMCID: PMC6868385 DOI: 10.1093/nar/gkz810] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/06/2019] [Accepted: 09/17/2019] [Indexed: 11/12/2022] Open
Abstract
Bloom helicase (BLM) and its orthologs are essential for the maintenance of genome integrity. BLM defects represent the underlying cause of Bloom Syndrome, a rare genetic disorder that is marked by strong cancer predisposition. BLM deficient cells accumulate extensive chromosomal aberrations stemming from dysfunctions in homologous recombination (HR). BLM participates in several HR stages and helps dismantle potentially harmful HR intermediates. However, much remains to be learned about the molecular mechanisms of these BLM-mediated regulatory effects. Here, we use DNA curtains to directly visualize the activity of BLM helicase on single molecules of DNA. Our data show that BLM is a robust helicase capable of rapidly (∼70-80 base pairs per second) unwinding extensive tracts (∼8-10 kilobases) of double-stranded DNA (dsDNA). Importantly, we find no evidence for BLM activity on single-stranded DNA (ssDNA) that is bound by replication protein A (RPA). Likewise, our results show that BLM can neither associate with nor translocate on ssDNA that is bound by the recombinase protein RAD51. Moreover, our data reveal that the presence of RAD51 also blocks BLM translocation on dsDNA substrates. We discuss our findings within the context of potential regulator roles for BLM helicase during DNA replication and repair.
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Affiliation(s)
- Chaoyou Xue
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - James M Daley
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Xiaoyu Xue
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Justin Steinfeld
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Youngho Kwon
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
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11
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Tzfoni I, Chayo J, Shaked M, Bernstein E, Dekel R, Arber N, Shapira S. Pancreatic cancer in bloom syndrome. SAGE Open Med Case Rep 2019; 7:2050313X19855587. [PMID: 31210938 PMCID: PMC6552343 DOI: 10.1177/2050313x19855587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 05/09/2019] [Indexed: 11/15/2022] Open
Abstract
Bloom syndrome is a rare autosomal recessive disorder characterized by distinct physical features, such as short stature, genomic instability, and predisposition to numerous cancers. The BLM gene encodes for the RecQ helicase that plays an important role in genome editing, maintenance, and stability. Mutations in the BLM gene cause genomic instability that exposes the carriers to a variety of cancers, and in particular hematological and gastrointestinal cancers. Herein, we report the first case of pancreatic cancer in a 32-year-old patient with bloom syndrome.
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Affiliation(s)
- Itai Tzfoni
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Jennifer Chayo
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Meital Shaked
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Ezra Bernstein
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Roy Dekel
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Nadir Arber
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
| | - Shiran Shapira
- Health Promotion Center and Integrated Cancer Prevention Center, Tel Aviv Sourasky Medical Center and Tel Aviv University, Tel Aviv, Israel
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12
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Crickard J, Xue C, Wang W, Kwon Y, Sung P, Greene E. The RecQ helicase Sgs1 drives ATP-dependent disruption of Rad51 filaments. Nucleic Acids Res 2019; 47:4694-4706. [PMID: 30916344 PMCID: PMC6511845 DOI: 10.1093/nar/gkz186] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/06/2019] [Accepted: 03/20/2019] [Indexed: 12/21/2022] Open
Abstract
DNA helicases of the RecQ family are conserved among the three domains of life and play essential roles in genome maintenance. Mutations in several human RecQ helicases lead to diseases that are marked by cancer predisposition. The Saccharomyces cerevisiae RecQ helicase Sgs1 is orthologous to human BLM, defects in which cause the cancer-prone Bloom's Syndrome. Here, we use single-molecule imaging to provide a quantitative mechanistic understanding of Sgs1 activities on single stranded DNA (ssDNA), which is a central intermediate in all aspects of DNA metabolism. We show that Sgs1 acts upon ssDNA bound by either replication protein A (RPA) or the recombinase Rad51. Surprisingly, we find that Sgs1 utilizes a novel motor mechanism for disrupting ssDNA intermediates bound by the recombinase protein Rad51. The ability of Sgs1 to disrupt Rad51-ssDNA filaments may explain some of the defects engendered by RECQ helicase deficiencies in human cells.
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Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Chaoyou Xue
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Weibin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Youngho Kwon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Eric C Greene
- Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY 10032, USA
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Crickard JB, Greene EC. Helicase Mechanisms During Homologous Recombination in Saccharomyces cerevisiae. Annu Rev Biophys 2019; 48:255-273. [PMID: 30857400 DOI: 10.1146/annurev-biophys-052118-115418] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicases are enzymes that move, manage, and manipulate nucleic acids. They can be subdivided into six super families and are required for all aspects of nucleic acid metabolism. In general, all helicases function by converting the chemical energy stored in the bond between the gamma and beta phosphates of adenosine triphosphate into mechanical work, which results in the unidirectional movement of the helicase protein along one strand of a nucleic acid. The results of this translocation activity can range from separation of strands within duplex nucleic acids to the physical remodeling or removal of nucleoprotein complexes. In this review, we focus on describing key helicases from the model organism Saccharomyces cerevisiae that contribute to the regulation of homologous recombination, which is an essential DNA repair pathway for fixing damaged chromosomes.
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Affiliation(s)
- J Brooks Crickard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; ,
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