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Marakhonov A, Serebryakova E, Mukhina A, Vechkasova A, Prokhorov N, Efimova I, Balinova N, Lobenskaya A, Vasilyeva T, Zabnenkova V, Ryzhkova O, Rodina Y, Pershin D, Soloveva N, Fomenko A, Saydaeva D, Ibisheva A, Irbaieva T, Koroteev A, Zinchenko R, Voronin S, Shcherbina A, Kutsev S. A Rare Case of TP63-Associated Lymphopenia Revealed by Newborn Screening Using TREC. Int J Mol Sci 2024; 25:10844. [PMID: 39409174 PMCID: PMC11482481 DOI: 10.3390/ijms251910844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2024] [Revised: 09/30/2024] [Accepted: 10/07/2024] [Indexed: 10/19/2024] Open
Abstract
The expanded newborn screening (NBS) program in the Russian Federation was initiated in 2023, among which severe combined immunodeficiency (SCID) is screened using TREC/KREC assays. Here, we report a rare case of a TP63-associated disease identified through this NBS program. Dried blood spots from newborns were initially screened for TREC/KREC levels, and those with values below the cut-off underwent confirmatory testing and further genetic analysis, including whole-exome sequencing (WES). A male newborn was identified with significantly reduced TREC values, indicative of T cell lymphopenia. Genetic analysis revealed a heterozygous NM_003722.5:c.1027C>T variant in TP63, leading to the p.(Arg343Trp) substitution within the DNA binding domain. This mutation has been previously associated with Ectrodactyly-Ectodermal Dysplasia-Cleft lip/palate syndrome (EEC) syndrome and shown to reduce the transactivation activity of TP63 in a dominant-negative manner. This case represents one of the few instances of immune system involvement in a patient with a TP63 mutation, highlighting the need for further investigation into the immunological aspects of TP63-associated disorders. Our findings suggest that comprehensive immunological evaluation should be considered for patients with TP63 mutations to better understand and manage potential immune dysfunctions.
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Affiliation(s)
- Andrey Marakhonov
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Elena Serebryakova
- Saint-Petersburg State Medical Diagnostic Center (Medical Genetic Center), 194044 Saint-Petersburg, Russia; (E.S.); (A.V.); (A.L.); (A.K.)
| | - Anna Mukhina
- Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, 117198 Moscow, Russia; (A.M.); (Y.R.); (D.P.); (A.S.)
| | - Anastasia Vechkasova
- Saint-Petersburg State Medical Diagnostic Center (Medical Genetic Center), 194044 Saint-Petersburg, Russia; (E.S.); (A.V.); (A.L.); (A.K.)
| | - Nikolai Prokhorov
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA;
| | - Irina Efimova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Natalia Balinova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Anastasia Lobenskaya
- Saint-Petersburg State Medical Diagnostic Center (Medical Genetic Center), 194044 Saint-Petersburg, Russia; (E.S.); (A.V.); (A.L.); (A.K.)
| | - Tatyana Vasilyeva
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Victoria Zabnenkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Oxana Ryzhkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Yulia Rodina
- Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, 117198 Moscow, Russia; (A.M.); (Y.R.); (D.P.); (A.S.)
| | - Dmitry Pershin
- Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, 117198 Moscow, Russia; (A.M.); (Y.R.); (D.P.); (A.S.)
| | - Nadezhda Soloveva
- Department of Neonatal and Infantile Pathology, Saint-Petersburg State Pediatric Medical University, 194100 Saint-Petersburg, Russia; (N.S.); (A.F.)
| | - Anna Fomenko
- Department of Neonatal and Infantile Pathology, Saint-Petersburg State Pediatric Medical University, 194100 Saint-Petersburg, Russia; (N.S.); (A.F.)
| | - Djamila Saydaeva
- State Budgetary Institution “Maternity Hospital” of the Ministry of Healthcare of the Chechen Republic, 364017 Grozny, Russia; (D.S.); (A.I.)
| | - Aset Ibisheva
- State Budgetary Institution “Maternity Hospital” of the Ministry of Healthcare of the Chechen Republic, 364017 Grozny, Russia; (D.S.); (A.I.)
| | - Taisiya Irbaieva
- Department of Maternity and Childhood, Ministry of Healthcare of the Chechen Republic, 364061 Grozny, Russia;
| | - Alexander Koroteev
- Saint-Petersburg State Medical Diagnostic Center (Medical Genetic Center), 194044 Saint-Petersburg, Russia; (E.S.); (A.V.); (A.L.); (A.K.)
| | - Rena Zinchenko
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Sergey Voronin
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
| | - Anna Shcherbina
- Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, 117198 Moscow, Russia; (A.M.); (Y.R.); (D.P.); (A.S.)
| | - Sergey Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (I.E.); (N.B.); (T.V.); (V.Z.); (O.R.); (R.Z.); (S.V.); (S.K.)
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2
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Borovikov A, Marakhonov A, Murtazina A, Davydenko K, Filatova A, Galeeva N, Kadnikova V, Ogorodova N, Gorodilova D, Kanivets I, Pyankov D, Zherdev K, Petel’guzov A, Zubkov P, Polyakov A, Shchagina O, Skoblov M. Cases report: Mosaic structural variants of the EXT1 gene in previously genetically unconfirmed multiple osteochondromas. Front Genet 2024; 15:1435493. [PMID: 39192890 PMCID: PMC11347319 DOI: 10.3389/fgene.2024.1435493] [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: 05/20/2024] [Accepted: 07/26/2024] [Indexed: 08/29/2024] Open
Abstract
Multiple osteochondromas (MO) is a rare autosomal dominant skeletal disorder characterized by the development of multiple benign tumors known as osteochondromas. The condition is predominantly caused by loss-of-function variants in the EXT1 or EXT2 genes, facilitating relatively precise clinical diagnosis through established diagnostic criteria. Despite this, a notable percentage of MO cases (10%-20%) remains unresolved after sequencing coding regions and copy number analysis of both genes. In our study, we identified mosaic structural variants in two patients who initially yielded negative results on standard genetic analysis for MO. Specifically, mosaic deletions affecting exons 8-11 and exons 2-11 in the EXT1 gene were detected. RNA analysis was performed in one case, while both cases underwent genome sequencing. To date, only six mosaic copy number variations have been reported in association with MO, representing a minority among known variants in both genes. Our report provides a detailed analysis of these findings, highlighting the significance of advanced genetic testing techniques in detecting mosaic variants in the EXT1/2 genes.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ilya Kanivets
- Genomed, Moscow, Russia
- Federal State Budgetary Educational Institution, Further Professional Education, Russian Medical Academy of Continuous Professional Education, Ministry of Healthcare of the Russian Federation, Moscow, Russia
| | | | - Konstantin Zherdev
- National Medical Research Center of Children’s Health, Moscow, Russia
- Department of Pediatric Surgery and Urology-Andrology, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
| | | | - Pavel Zubkov
- National Medical Research Center of Children’s Health, Moscow, Russia
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3
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Madsen HB, Pease LI, Scanlan RL, Akbari M, Rasmussen LJ, Shanley DP, Bohr VA. The DNA repair enzyme, aprataxin, plays a role in innate immune signaling. Front Aging Neurosci 2023; 15:1290681. [PMID: 38161589 PMCID: PMC10754971 DOI: 10.3389/fnagi.2023.1290681] [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] [Received: 09/07/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
Ataxia with oculomotor apraxia type 1 (AOA1) is a progressive neurodegenerative disorder characterized by a gradual loss of coordination of hand movements, speech, and eye movements. AOA1 is caused by an inactivation mutation in the APTX gene. APTX resolves abortive DNA ligation intermediates. APTX deficiency may lead to the accumulation of 5'-AMP termini, especially in the mitochondrial genome. The consequences of APTX deficiency includes impaired mitochondrial function, increased DNA single-strand breaks, elevated reactive oxygen species production, and altered mitochondrial morphology. All of these processes can cause misplacement of nuclear and mitochondrial DNA, which can activate innate immune sensors to elicit an inflammatory response. This study explores the impact of APTX knockout in microglial cells, the immune cells of the brain. RNA-seq analysis revealed significant differences in the transcriptomes of wild-type and APTX knockout cells, especially in response to viral infections and innate immune pathways. Specifically, genes and proteins involved in the cGAS-STING and RIG-I/MAVS pathways were downregulated in APTX knockout cells, which suggests an impaired immune response to cytosolic DNA and RNA. The clinical relevance of these findings was supported by analyzing publicly available RNA-seq data from AOA1 patient cell lines. Comparisons between APTX-deficient patient cells and healthy control cells also revealed altered immune responses and dysregulated DNA- and RNA-sensing pathways in the patient cells. Overall, this study highlights the critical role of APTX in regulating innate immunity, particularly in DNA- and RNA-sensing pathways. Our findings contribute to a better understanding of the underlying molecular mechanisms of AOA1 pathology and highlights potential therapeutic targets for this disease.
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Affiliation(s)
- Helena B. Madsen
- Center for Healthy Aging, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Louise I. Pease
- CAMPUS for Ageing and Vitality, Newcastle University, Newcastle, United Kingdom
| | | | - Mansour Akbari
- Center for Healthy Aging, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lene J. Rasmussen
- Center for Healthy Aging, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daryl P. Shanley
- CAMPUS for Ageing and Vitality, Newcastle University, Newcastle, United Kingdom
| | - Vilhelm A. Bohr
- Center for Healthy Aging, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
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4
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Islam A, Chakraborty A, Gambardella S, Campopiano R, Sarker AH, Boldogh I, Hazra T. Functional analysis of a conserved site mutation in the DNA end processing enzyme PNKP leading to ataxia with oculomotor apraxia type 4 in humans. J Biol Chem 2023; 299:104714. [PMID: 37061005 PMCID: PMC10197107 DOI: 10.1016/j.jbc.2023.104714] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 04/17/2023] Open
Abstract
Polynucleotide kinase 3'-phosphatase (PNKP), an essential DNA end-processing enzyme in mammals with 3'-phosphatase and 5'-kinase activities, plays a pivotal role in multiple DNA repair pathways. Its functional deficiency has been etiologically linked to various neurological disorders. Recent reports have shown that mutation at a conserved glutamine (Gln) in PNKP leads to late-onset ataxia with oculomotor apraxia type 4 (AOA4) in humans and embryonic lethality in pigs. However, the molecular mechanism underlying such phenotypes remains elusive. Here, we report that the enzymatic activities of the mutant versus WT PNKP are comparable; however, cells expressing mutant PNKP and peripheral blood mononuclear cells (PBMCs) of AOA4 patients showed a significant amount of DNA double-strand break accumulation and consequent activation of the DNA damage response. Further investigation revealed that the nuclear localization of mutant PNKP is severely abrogated, and the mutant proteins remain primarily in the cytoplasm. Western blot analysis of AOA4 patient-derived PBMCs also revealed the presence of mutated PNKP predominantly in the cytoplasm. To understand the molecular determinants, we identified that mutation at a conserved Gln residue impedes the interaction of PNKP with importin alpha but not with importin beta, two highly conserved proteins that mediate the import of proteins from the cytoplasm into the nucleus. Collectively, our data suggest that the absence of PNKP in the nucleus leads to constant activation of the DNA damage response due to persistent accumulation of double-strand breaks in the mutant cells, triggering death of vulnerable brain cells-a potential cause of neurodegeneration in AOA4 patients.
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Affiliation(s)
- Azharul Islam
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Stefano Gambardella
- IRCCS Neuromed & Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Rosa Campopiano
- IRCCS Neuromed & Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Altaf H Sarker
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Tapas Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA.
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5
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Lange LM, Gonzalez-Latapi P, Rajalingam R, Tijssen MAJ, Ebrahimi-Fakhari D, Gabbert C, Ganos C, Ghosh R, Kumar KR, Lang AE, Rossi M, van der Veen S, van de Warrenburg B, Warner T, Lohmann K, Klein C, Marras C. Nomenclature of Genetic Movement Disorders: Recommendations of the International Parkinson and Movement Disorder Society Task Force - An Update. Mov Disord 2022; 37:905-935. [PMID: 35481685 DOI: 10.1002/mds.28982] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/28/2022] [Accepted: 02/14/2022] [Indexed: 12/13/2022] Open
Abstract
In 2016, the Movement Disorder Society Task Force for the Nomenclature of Genetic Movement Disorders presented a new system for naming genetically determined movement disorders and provided a criterion-based list of confirmed monogenic movement disorders. Since then, a substantial number of novel disease-causing genes have been described, which warrant classification using this system. In addition, with this update, we further refined the system and propose dissolving the imaging-based categories of Primary Familial Brain Calcification and Neurodegeneration with Brain Iron Accumulation and reclassifying these genetic conditions according to their predominant phenotype. We also introduce the novel category of Mixed Movement Disorders (MxMD), which includes conditions linked to multiple equally prominent movement disorder phenotypes. In this article, we present updated lists of newly confirmed monogenic causes of movement disorders. We found a total of 89 different newly identified genes that warrant a prefix based on our criteria; 6 genes for parkinsonism, 21 for dystonia, 38 for dominant and recessive ataxia, 5 for chorea, 7 for myoclonus, 13 for spastic paraplegia, 3 for paroxysmal movement disorders, and 6 for mixed movement disorder phenotypes; 10 genes were linked to combined phenotypes and have been assigned two new prefixes. The updated lists represent a resource for clinicians and researchers alike and they have also been published on the website of the Task Force for the Nomenclature of Genetic Movement Disorders on the homepage of the International Parkinson and Movement Disorder Society (https://www.movementdisorders.org/MDS/About/Committees--Other-Groups/MDS-Task-Forces/Task-Force-on-Nomenclature-in-Movement-Disorders.htm). © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.
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Affiliation(s)
- Lara M Lange
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Paulina Gonzalez-Latapi
- The Edmond J. Safra Program in Parkinson's Disease and The Morton and Gloria Shulman Movement Disorder Clinic, Toronto Western Hospital, University of Toronto, Toronto, Canada.,Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Rajasumi Rajalingam
- The Edmond J. Safra Program in Parkinson's Disease and The Morton and Gloria Shulman Movement Disorder Clinic, Toronto Western Hospital, University of Toronto, Toronto, Canada
| | - Marina A J Tijssen
- UMCG Expertise Centre Movement Disorders, Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Carolin Gabbert
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Christos Ganos
- Department of Neurology, Charité University Hospital Berlin, Berlin, Germany
| | - Rhia Ghosh
- Huntington's Disease Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Kishore R Kumar
- Molecular Medicine Laboratory and Department of Neurology, Concord Repatriation General Hospital, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Anthony E Lang
- The Edmond J. Safra Program in Parkinson's Disease and The Morton and Gloria Shulman Movement Disorder Clinic, Toronto Western Hospital, University of Toronto, Toronto, Canada
| | - Malco Rossi
- Movement Disorders Section, Neuroscience Department, Raul Carrea Institute for Neurological Research (FLENI), Buenos Aires, Argentina
| | - Sterre van der Veen
- UMCG Expertise Centre Movement Disorders, Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Center of Expertise for Parkinson and Movement Disorders, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Tom Warner
- Department of Clinical & Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Connie Marras
- The Edmond J. Safra Program in Parkinson's Disease and The Morton and Gloria Shulman Movement Disorder Clinic, Toronto Western Hospital, University of Toronto, Toronto, Canada
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6
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Dragašević-Mišković N, Stanković I, Milovanović A, Kostić VS. Autosomal recessive adult onset ataxia. J Neurol 2021; 269:504-533. [PMID: 34499204 DOI: 10.1007/s00415-021-10763-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 11/24/2022]
Abstract
Autosomal recessive ataxias (ARCA) represent a complex group of diseases ranging from primary ataxias to rare and complex metabolic disorders in which ataxia is a part of the clinical picture. Small number of ARCA manifest exclusively in adulthood, while majority of typical childhood onset ARCA may also start later with atypical clinical presentation. We have systematically searched the literature for ARCA with adult onset, both in the group of primary ataxias including those that are less frequently described in isolated or in a small number of families, and also in the group of complex and metabolic diseases in which ataxia is only part of the clinical picture. We propose an algorithm that could be used when encountering a patient with adult onset sporadic or recessive ataxia in whom the acquired causes are excluded. ARCA are frequently neglected in the differential diagnosis of adult-onset ataxias. Rising awareness of their clinical significance is important, not only because some of these disorders may be potentially treatable, but also for prognostic implications and inclusion of patients to future clinical trials with disease modifying agents.
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Affiliation(s)
- Nataša Dragašević-Mišković
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia.
| | - Iva Stanković
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
| | - Andona Milovanović
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
| | - Vladimir S Kostić
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
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7
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Kalasova I, Hailstone R, Bublitz J, Bogantes J, Hofmann W, Leal A, Hanzlikova H, Caldecott KW. Pathological mutations in PNKP trigger defects in DNA single-strand break repair but not DNA double-strand break repair. Nucleic Acids Res 2020; 48:6672-6684. [PMID: 32504494 PMCID: PMC7337934 DOI: 10.1093/nar/gkaa489] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/30/2020] [Accepted: 06/04/2020] [Indexed: 12/20/2022] Open
Abstract
Hereditary mutations in polynucleotide kinase-phosphatase (PNKP) result in a spectrum of neurological pathologies ranging from neurodevelopmental dysfunction in microcephaly with early onset seizures (MCSZ) to neurodegeneration in ataxia oculomotor apraxia-4 (AOA4) and Charcot-Marie-Tooth disease (CMT2B2). Consistent with this, PNKP is implicated in the repair of both DNA single-strand breaks (SSBs) and DNA double-strand breaks (DSBs); lesions that can trigger neurodegeneration and neurodevelopmental dysfunction, respectively. Surprisingly, however, we did not detect a significant defect in DSB repair (DSBR) in primary fibroblasts from PNKP patients spanning the spectrum of PNKP-mutated pathologies. In contrast, the rate of SSB repair (SSBR) is markedly reduced. Moreover, we show that the restoration of SSBR in patient fibroblasts collectively requires both the DNA kinase and DNA phosphatase activities of PNKP, and the fork-head associated (FHA) domain that interacts with the SSBR protein, XRCC1. Notably, however, the two enzymatic activities of PNKP appear to affect different aspects of disease pathology, with reduced DNA phosphatase activity correlating with neurodevelopmental dysfunction and reduced DNA kinase activity correlating with neurodegeneration. In summary, these data implicate reduced rates of SSBR, not DSBR, as the source of both neurodevelopmental and neurodegenerative pathology in PNKP-mutated disease, and the extent and nature of this reduction as the primary determinant of disease severity.
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Affiliation(s)
- Ilona Kalasova
- Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, 142 20, Czech Republic
| | - Richard Hailstone
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Janin Bublitz
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Jovel Bogantes
- Servicio de Cirugía Reconstructiva, Hospital Rafael Ángel Calderón Guardia, Caja Costarricense de Seguro Social, San José, Costa Rica
| | - Winfried Hofmann
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Alejandro Leal
- Section of Genetics and Biotechnology, School of Biology, University of Costa Rica, San José, Costa Rica
| | - Hana Hanzlikova
- Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, 142 20, Czech Republic.,Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Keith W Caldecott
- Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, 142 20, Czech Republic.,Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK
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8
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Campopiano R, Ferese R, Buttari F, Femiano C, Centonze D, Fornai F, Biagioni F, Chiaravalloti MA, Magnani M, Giardina E, Ruzzo A, Gambardella S. A Novel Homozygous Variant in the Fork-Head-Associated Domain of Polynucleotide Kinase Phosphatase in a Patient Affected by Late-Onset Ataxia With Oculomotor Apraxia Type 4. Front Neurol 2020; 10:1331. [PMID: 32010037 PMCID: PMC6974581 DOI: 10.3389/fneur.2019.01331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 12/02/2019] [Indexed: 11/13/2022] Open
Abstract
Ataxia with oculomotor apraxia (AOA) is a clinical syndrome featuring a group of genetic diseases including at least four separate autosomal-recessive cerebellar ataxias. All these disorders are due to altered genes involved in DNA repair. AOA type 4 (AOA4) is caused by mutations in DNA repair factor polynucleotide kinase phosphatase (PNKP), which encodes for a DNA processing enzyme also involved in other syndromes featured by microcephaly or neurodegeneration. To date, only a few AOA4 patients have been reported worldwide. All these patients are homozygous or compound heterozygous carriers for mutations in the kinase domain of PNKP. In this report, we describe a 56 years old patient affected by AOA4 characterized by ataxia, polyneuropathy, oculomotor apraxia, and cognitive impairment with the absence of dystonia. The disease is characterized by a very late onset (50 years) when compared with other AOA4 patients described so far (median age of onset at 4 years). In this proband, Clinical Exome Analysis through Next Generation Sequencing (NGS) consisting of 4,800 genes, identified the PNKP homozygous mutation p.Gln50Glu. This variant, classified as a likely pathogenic variant according to American College of Medical Genetics (ACMG) guidelines, does not involve the kinase domain but falls in the fork-head-associated (FHA) domain. So far, mutations in such a domain were reported to associate only with a pure seizure syndrome without the classic AOA4 features. Therefore, this is the first report of patients carrying a mutation of the FHA domain within the PNKP gene which expresses the clinical phenotype known as the AOA4 syndrome and the lack of any seizure activity. Further studies are required to investigate specifically the significance of various mutations within the FHA domain, and it would be worth to correlate these variants with the age of onset of the AOA4 syndrome.
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Affiliation(s)
| | | | | | | | - Diego Centonze
- IRCCS Neuromed, Pozzilli, Italy.,Dipartimento di Medicina dei Sistemi, Università di Roma Tor Vergata, Rome, Italy
| | - Francesco Fornai
- IRCCS Neuromed, Pozzilli, Italy.,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | | | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Emiliano Giardina
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.,Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | - Anna Ruzzo
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Stefano Gambardella
- IRCCS Neuromed, Pozzilli, Italy.,Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
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