1
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Tangeraas T, Constante JR, Backe PH, Oyarzábal A, Neugebauer J, Weinhold N, Boemer F, Debray FG, Ozturk-Hism B, Evren G, Tuba EF, Ummuhan O, Footitt E, Davison J, Martinez C, Bueno C, Machado I, Rodríguez-Pombo P, Al-Sannaa N, De Los Santos M, Muchart López J, Ozturkmen-Akay H, Karaca M, Tekin M, Pajares S, Ormazabal A, Stoway SD, Artuch R, Dixon M, Mørkrid L, García-Cazorla A. BCKDK deficiency: a treatable neurodevelopmental disease amenable to newborn screening. Brain 2023:7024722. [PMID: 36729635 DOI: 10.1093/brain/awad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/13/2022] [Accepted: 11/27/2022] [Indexed: 02/03/2023] Open
Abstract
There are few causes of treatable neurodevelopmental diseases described to date. Branched Chain Ketoacid Dehydrogenase Kinase (BCKDK) deficiency causes branched-chain amino acid (BCAA) depletion and is linked to a neurodevelopmental disorder characterized by autism, intellectual disability, and microcephaly. We report the largest cohort of patients studied, broadening the phenotypic and genotypic spectrum. Moreover, this is the first study to present newborn screening findings and mid-term clinical outcome. In this cross-sectional study, patients with a diagnosis of BCKDK deficiency were recruited via investigators' practices through a MetabERN initiative. Clinical, biochemical and genetic data were collected. Dried blood spot (DBS) newborn screening (NBS) amino acid profiles were retrieved from collaborating centers and compared to a healthy newborn reference population. Twenty-one patients with BCKDK mutations were included from 13 families. Patients were diagnosed between 8 months and 16 years (mean: 5.8 years, 43% female). At diagnosis, BCAA levels (leucine, valine, and isoleucine) were below reference values in plasma and in cerebrospinal fluid. All patients had global neurodevelopmental delay; 18/21 had gross motor function (GMF) impairment with GMF III or worse in 5/18, 16/16 intellectual disability, 17/17 language impairment, 12/17 autism spectrum disorder, 9/21 epilepsy, 12/15 clumsiness, 3/21 had sensorineural hearing loss and 4/20 feeding difficulties. No microcephaly was observed at birth, but 17/20 developed microcephaly during follow-up. Regression was reported in 6 patients. Movement disorder was observed in 3/21 patients: hyperkinetic movements (1), truncal ataxia (1) and dystonia (2). After treatment with high protein diet (≥ 2 g/kg/day) and BCAA supplementation (100-250 mg/kg/day), plasma BCAA increased significantly (p < 0.001), motor functions and head circumference stabilized/improved in 13/13 and in 11/15 patients, respectively. Amongst cases with follow-up data, none of the 3 patients starting treatment before 2 years of age developed autism at follow-up. The patient with the earliest age of treatment initiation (8 months) showed normal development at 3 years of age. NBS in DBS identified BCAA levels significantly lower than those of the normal population. This work highlights the potential benefits of dietetic treatment, in particular early introduction of BCAA. Therefore, it is of utmost importance to increase awareness about this treatable disease and consider it as a candidate for early detection by NBS programs.
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Affiliation(s)
- Trine Tangeraas
- Paediatric and Adolescent Medicine, Oslo University Hospital, 0424, Oslo, Norway.,European Reference Network for Hereditary Metabolic Diseases (MetabERN)
| | - Juliana R Constante
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Neurometabolic Unit and Synaptic Metabolism Laboratory, Neurology Department Sant Joan de Déu Hospital, IPR, Barcelona 08950, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Paul Hoff Backe
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Department of Medical Biochemistry, Oslo University Hospital-Rikshospitalet, PO Box 4950 Nydalen, OUS HF Rikshospitalet, 0424 Oslo Norway.,Department of Microbiology, Clinic for Diagnostics and Intervention, Oslo University Hospital, Rikshospitalet, PO Box 4950, Nydalen, N-0424, Oslo, Norway
| | - Alfonso Oyarzábal
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Neurometabolic Unit and Synaptic Metabolism Laboratory, Neurology Department Sant Joan de Déu Hospital, IPR, Barcelona 08950, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Julia Neugebauer
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Department of Pediatric Gastroenterology, Nephrology and Metabolic Medicine. Charité - Universitätsmedizin Berlin, Berlin 13353, Germany.,Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, Berlin 13353, Germany
| | - Natalie Weinhold
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Department of Pediatric Gastroenterology, Nephrology and Metabolic Medicine. Charité - Universitätsmedizin Berlin, Berlin 13353, Germany.,Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, Berlin 13353, Germany
| | - Francois Boemer
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Biochemical Genetics Laboratory, Human Genetics, CHU of Liege, University of Liège, Liège, 4000, Belgium
| | - François G Debray
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Department of Human Genetics, CHU of Liege, University of Liège, Liège, 4000, Belgium
| | - Burcu Ozturk-Hism
- Department of Pediatric Metabolic Diseases, Marmara University School of Medicine, Istanbul 34854, Turkey
| | - Gumus Evren
- Medical Genetics Department, University of Harran 63000 Sanliurfa, Turkey
| | - Eminoglu F Tuba
- Pediatric Metabolism Department, Ankara University School of Medicine, 06100 Ankara, Turkey
| | - Oncul Ummuhan
- Pediatric Metabolism Department, Ankara University School of Medicine, 06100 Ankara, Turkey
| | - Emma Footitt
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Metabolic Medicine Department, Great Ormond Street Hospital for Children, London WC1N 3JH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre (NIHR GOSH BRC), London WC1N 3JH, UK
| | - James Davison
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Metabolic Medicine Department, Great Ormond Street Hospital for Children, London WC1N 3JH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre (NIHR GOSH BRC), London WC1N 3JH, UK
| | - Caroline Martinez
- Department of Pediatrics and Psychiatry, The Mount Sinai Hospital, New York 1468, USA
| | - Clarissa Bueno
- Neurology Department, Clinical Hospital of the Faculty of Medicine, University of São Paulo, São Paulo 05403-010, Brazil
| | - Irene Machado
- Hospital Universitario Clínico San Cecilio, Granada, 18016, Spain
| | - Pilar Rodríguez-Pombo
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, CBM-CSIC, Departamento de Biología Molecular, Institute for Molecular Biology-IUBM, Universidad Autónoma Madrid, CIBERER, IDIPAZ, 28049 Madrid, Spain
| | - Nouriya Al-Sannaa
- Pediatric Services Division, Johns Hopkins Aramco Healthcare, Dhahran 34465, Saudi Arabia
| | - Mariela De Los Santos
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain.,Neurometabolic Unit, Gastroenterology and Nutrition Department, Sant Joan de Déu Hospital, Barcelona 08950, Spain
| | - Jordi Muchart López
- Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Pediatric Radiology Department Esplugues de Llobregat, 08950 Barcelona, Spain
| | | | - Meryem Karaca
- Pediatric Metabolic Diseases Department, University of Harran, Sanliurfa 63000, Turkey
| | - Mustafa Tekin
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P.Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami 33136, USA
| | - Sonia Pajares
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain.,Section of Inborn Errors of Metabolism-IBC, Department of Biochemistry and Molecular Genetics, Hospital Clínic, Barcelona 08036, Spain
| | - Aida Ormazabal
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain.,Clinical Biochemistry Department, Sant Joan de Déu Hospital, Barcelona 08950, Spain
| | - Stephanie D Stoway
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo 0424, Norway.,Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester 55905, USA
| | - Rafael Artuch
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain.,Clinical Biochemistry Department, Sant Joan de Déu Hospital, Barcelona 08950, Spain
| | - Marjorie Dixon
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Dietetics, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, WC1N, 3JH, UK
| | - Lars Mørkrid
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Department of Medical Biochemistry, Oslo University Hospital-Rikshospitalet, PO Box 4950 Nydalen, OUS HF Rikshospitalet, 0424 Oslo Norway.,Institute of Clinical Medicine, University of Oslo, PO Box 4950, Nydalen, N-0424, Norway
| | - Angeles García-Cazorla
- European Reference Network for Hereditary Metabolic Diseases (MetabERN).,Neurometabolic Unit and Synaptic Metabolism Laboratory, Neurology Department Sant Joan de Déu Hospital, IPR, Barcelona 08950, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid 28029, Spain
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2
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Ørstavik K, Arntzen KA, Mathisen P, Backe PH, Tangeraas T, Rasmussen M, Kristensen E, Van Ghelue M, Jonsrud C, Bliksrud YT. Novel mutations in the
HADHB
gene causing a mild phenotype of mitochondrial trifunctional protein (
MTP
) deficiency. JIMD Rep 2022; 63:193-198. [PMID: 35433169 PMCID: PMC8995838 DOI: 10.1002/jmd2.12276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/08/2022] [Accepted: 02/11/2022] [Indexed: 11/11/2022] Open
Abstract
Mitochondrial trifunctional protein (MTP) deficiency is an ultrarare hereditary recessive disorder causing a broad spectrum of phenotypes with lethal infantile cardiomyopathy at the most severe end. Attenuated forms with polyneuropathy have been reported combined with myoglobinuria or rhabdomyolysis as key features. We here report three young adults (two siblings) in which three variants in the HADHB‐gene were identified. All three cases had a similar mild phenotype with axonal neuropathy and frequent intermittent weakness episodes but without myoglobinuria. Special dietary precautions were recommended to minimize complications especially during infections and other catabolic states. MTP deficiency is therefore an important differential diagnosis in patients with milder fluctuating neuromuscular symptoms.
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Affiliation(s)
- Kristin Ørstavik
- Department of Neurology, Section for Rare Neuromuscular disorders and EMAN Oslo University Hospital, Rikshospitalet Oslo Norway
| | - Kjell Arne Arntzen
- National Neuromuscular Centre Norway and Department of Neurology University Hospital of North Norway Tromsø Norway
| | - Per Mathisen
- Department of Cardiology Oslo University Hospital, Rikshospitalet Oslo Norway
| | - Paul Hoff Backe
- Department of Microbiology Oslo University Hospital, Rikshospitalet and University of Oslo Oslo Norway
- Department of Medical Biochemistry Institute for Clinical Medicine, University of Oslo Oslo Norway
| | - Trine Tangeraas
- Norwegian National Unit for Newborn Screening, Division of Pediatric and Adolescent Medicine Oslo University Hospital Oslo Norway
| | - Magnhild Rasmussen
- Department of Neurology, Section for Rare Neuromuscular disorders and EMAN Oslo University Hospital, Rikshospitalet Oslo Norway
- Department of Clinical Neurosciences for Children Oslo University Hospital, Rikshospitalet Oslo Norway
| | - Erle Kristensen
- Department of Medical Biochemistry Oslo University Hospital, Rikshospitalet Oslo Norway
| | - Marijke Van Ghelue
- Department of Medical Genetics, Division of Child and Adolescent Health University Hospital of North Norway Tromsø Norway
| | - Christoffer Jonsrud
- Department of Medical Genetics, Division of Child and Adolescent Health University Hospital of North Norway Tromsø Norway
| | - Yngve Thomas Bliksrud
- Department of Medical Biochemistry Oslo University Hospital, Rikshospitalet Oslo Norway
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3
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Sumathipala D, Strømme P, Fattahi Z, Lüders T, Sheng Y, Kahrizi K, Einarsen IH, Sloan JL, Najmabadi H, van den Heuvel L, Wevers RA, Guerrero-Castillo S, Mørkrid L, Valayannopoulos V, Backe PH, Venditti CP, van Karnebeek CD, Nilsen H, Frengen E, Misceo D. ZBTB11 dysfunction: spectrum of brain abnormalities, biochemical signature and cellular consequences. Brain 2022; 145:2602-2616. [PMID: 35104841 PMCID: PMC9337812 DOI: 10.1093/brain/awac034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 12/07/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Bi-allelic pathogenic variants in ZBTB11 have been associated with intellectual developmental disorder, autosomal recessive 69 (MRT69; OMIM 618383). We report five patients from three families with novel, bi-allelic variants in ZBTB11. We have expanded the clinical phenotype of MRT69, documenting varied severity of atrophy affecting different brain regions and described combined malonic and methylmalonic aciduria as a biochemical manifestation. As ZBTB11 encodes for a transcriptional regulator, we performeded chromatin immunoprecipitation-sequencing targeting ZBTB11 in fibroblasts from patients and controls. Chromatin immunoprecipitation-sequencing revealed binding of wild-type ZBTB11 to promoters in 238 genes, among which genes encoding proteins involved in mitochondrial functions and RNA processing are over-represented. Mutated ZBTB11 showed reduced binding to 61 of the targeted genes, indicating that the variants act as loss of function. Most of these genes are related to mitochondrial functions. Transcriptome analysis of the patient fibroblasts revealed dysregulation of mitochondrial functions. In addition, we uncovered that reduced binding of the mutated ZBTB11 to ACSF3 leads to decreased ACSF3 transcript level, explaining combined malonic and methylmalonic aciduria. Collectively, these results expand the clinical spectrum of ZBTB11-related neurological disease and give insight into the pathophysiology in which the dysfunctional ZBTB11 affect mitochondrial functions and RNA processing contributing to the neurological and biochemical phenotypes.
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Affiliation(s)
| | | | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Torben Lüders
- Department of Clinical Molecular Biology, Section of Clinical Molecular Biology (EpiGen), University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Ingunn Holm Einarsen
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jennifer L Sloan
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, NHGRI, NIH, Bethesda, MD, USA
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Lambert van den Heuvel
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands,United for Metabolic Disease—UMD, The Netherlands
| | - Sergio Guerrero-Castillo
- University Children’s Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Lars Mørkrid
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | - Paul Hoff Backe
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway,Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Charles P Venditti
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, NHGRI, NIH, Bethesda, MD, USA
| | - Clara D van Karnebeek
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands,United for Metabolic Disease—UMD, The Netherlands,Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, Section of Clinical Molecular Biology (EpiGen), University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | | | - Doriana Misceo
- Correspondence to: Doriana Misceo Department of Medical Genetics Oslo University Hospital and University of Oslo Postboks 4956 Nydalen, 0424 Oslo, Norway E-mail:
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4
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Liu X, Risbakk S, Almeida Carvalho P, Yang M, Hoff Backe P, Bjørås M, Norby T, Chatzitakis A. Immobilization of FeFe-hydrogenase on black TiO2 nanotubes as biocathodes for the hydrogen evolution reaction. Electrochem commun 2022. [DOI: 10.1016/j.elecom.2022.107221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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5
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Ahmadi A, Till K, Backe PH, Blicher P, Diekmann R, Schüttpelz M, Glette K, Tørresen J, Bjørås M, Rowe AD, Dalhus B. Non-flipping DNA glycosylase AlkD scans DNA without formation of a stable interrogation complex. Commun Biol 2021; 4:876. [PMID: 34267321 PMCID: PMC8282808 DOI: 10.1038/s42003-021-02400-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 06/25/2021] [Indexed: 11/09/2022] Open
Abstract
The multi-step base excision repair (BER) pathway is initiated by a set of enzymes, known as DNA glycosylases, able to scan DNA and detect modified bases among a vast number of normal bases. While DNA glycosylases in the BER pathway generally bend the DNA and flip damaged bases into lesion specific pockets, the HEAT-like repeat DNA glycosylase AlkD detects and excises bases without sequestering the base from the DNA helix. We show by single-molecule tracking experiments that AlkD scans DNA without forming a stable interrogation complex. This contrasts with previously studied repair enzymes that need to flip bases into lesion-recognition pockets and form stable interrogation complexes. Moreover, we show by design of a loss-of-function mutant that the bimodality in scanning observed for the structural homologue AlkF is due to a key structural differentiator between AlkD and AlkF; a positively charged β-hairpin able to protrude into the major groove of DNA.
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Affiliation(s)
- Arash Ahmadi
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway
| | - Katharina Till
- FOM Institute AMOLF, Science Park 104, Amsterdam, The Netherlands.,Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Paul Hoff Backe
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway
| | - Pernille Blicher
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway
| | - Robin Diekmann
- Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Mark Schüttpelz
- Biomolecular Photonics, Department of Physics, University of Bielefeld, Bielefeld, Germany
| | - Kyrre Glette
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Jim Tørresen
- Department of Informatics, University of Oslo, Oslo, Norway
| | - Magnar Bjørås
- Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway.,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Alexander D Rowe
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Newborn Screening, Division of Child and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Bjørn Dalhus
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Oslo, Norway. .,Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway.
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6
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Fjær R, Marciniak K, Sundnes O, Hjorthaug H, Sheng Y, Hammarström C, Sitek JC, Vigeland MD, Backe PH, Øye AM, Fosse JH, Stav-Noraas TE, Uchiyama Y, Matsumoto N, Comi A, Pevsner J, Haraldsen G, Selmer KK. A novel somatic mutation in GNB2 provides new insights to the pathogenesis of Sturge-weber syndrome. Hum Mol Genet 2021; 30:1919-1931. [PMID: 34124757 PMCID: PMC8522634 DOI: 10.1093/hmg/ddab144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/30/2022] Open
Abstract
Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterised by vascular malformations affecting skin, eyes and leptomeninges of the brain, which can lead to glaucoma, seizures and intellectual disability. The discovery of a disease-causing somatic missense mutation in the GNAQ gene, encoding an alpha chain of heterotrimeric G-proteins, has initiated efforts to understand how G-proteins contribute to SWS pathogenesis. The mutation is predominantly detected in endothelial cells and is currently believed to affect downstream MAPK-signalling. In this study of six Norwegian patients with classical SWS, we aimed to identify somatic mutations through deep sequencing of DNA from skin biopsies. Surprisingly, one patient was negative for the GNAQ mutation, but instead harboured a somatic mutation in GNB2 (NM_005273.3:c.232A > G, p.Lys78Glu) which encodes a beta chain of the same G-protein complex. The positions of the mutant amino acids in the G-protein are essential for complex reassembly. Therefore, failure of reassembly and continuous signalling is a likely consequence of both mutations. Ectopic expression of mutant proteins in endothelial cells revealed that expression of either mutant reduced cellular proliferation, yet regulated MAPK-signalling differently, suggesting that dysregulated MAPK-signalling cannot fully explain the SWS phenotype. Instead, both mutants reduced synthesis of YAP, a transcriptional co-activator of the Hippo signalling pathway, suggesting a key role for this pathway in the vascular pathogenesis of SWS. The discovery of the GNB2 mutation sheds novel light on the pathogenesis of SWS and suggests that future research on targets of treatment should be directed towards the YAP, rather than the MAPK, signalling pathway.
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Affiliation(s)
- Roar Fjær
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway.,Department of Neurology and Clinical Neurophysiology, St. Olavs University Hospital, Trondheim.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Katarzyna Marciniak
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Olav Sundnes
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway.,Department of Dermatology, Oslo University Hospital, Oslo, Norway
| | - Hanne Hjorthaug
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Clara Hammarström
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Jan Cezary Sitek
- Department of Dermatology, Oslo University Hospital, Oslo, Norway
| | - Magnus Dehli Vigeland
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway.,Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ane-Marte Øye
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Johanna Hol Fosse
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | | | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.,Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Anne Comi
- Department of Neurology, Hugo Moser Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Neurology and Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jonathan Pevsner
- Department of Neurology, Hugo Moser Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guttorm Haraldsen
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Kaja Kristine Selmer
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway.,National Centre for Rare Epilepsy-Related Disorders, Oslo University Hospital and the University of Oslo, Oslo, Norway.,Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway
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7
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Andersen E, Chollet ME, Sletten M, Stavik B, Skarpen E, Backe PH, Thiede B, Glosli H, Henriksson CE, Iversen N. Molecular Characterization of Two Homozygous Factor VII Variants Associated with Intracranial Bleeding. Thromb Haemost 2021; 121:1588-1598. [PMID: 33742435 DOI: 10.1055/a-1450-8568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Clinical parameters have been extensively studied in factor (F) VII deficiency, but the knowledge of molecular mechanisms of this disease is scarce. We report on three probands with intracranial bleeds at an early age, one of which had concomitant high titer of FVII inhibitor. The aim of the present study was to identify the causative mutations and to elucidate the underlying molecular mechanisms. All nine F7 exons were sequenced in the probands and the closest family members. A homozygous deletion in exon 1, leading to a frame shift and generation of a premature stop codon (p.C10Pfs*16), was found in proband 1. Probands 2 and 3 (siblings) were homozygous for a missense mutation in exon 8, resulting in a glycine (G) to arginine (R) substitution at amino acid 240 (p.G240R). All probands had severely reduced FVII activity (FVII:C < 1 IU/dL). Treatment consisted of recombinant FVIIa and/or plasma concentrate, and proband 1 developed a FVII inhibitor shortly after initiation of treatment. The FVII variants were overexpressed in mammalian cell lines. No FVII protein was produced in cells expressing the p.C10Pfs*16 variant, and the inhibitor development in proband 1 was likely linked to the complete absence of circulating FVII. Structural analysis suggested that the G to R substitution in FVII found in probands 2 and 3 would destabilize the protein structure, and cell studies demonstrated a defective intracellular transport and increased endoplasmic reticulum stress. The molecular mechanism underlying the p.G240R variant could be reduced secretion caused by protein destabilization and misfolding.
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Affiliation(s)
- Elisabeth Andersen
- Department of Hematology, Oslo University Hospital, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway
| | - Maria Eugenia Chollet
- Department of Hematology, Oslo University Hospital, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway
| | - Marit Sletten
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Benedicte Stavik
- Department of Hematology, Oslo University Hospital, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Oslo, Norway
| | - Ellen Skarpen
- Core Facility for Advanced Light Microscopy, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital, Oslo, Norway.,Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Bernd Thiede
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Heidi Glosli
- Department of Pediatric Research, Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway.,Centre for Rare Disorders, Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Carola Elisabeth Henriksson
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Nina Iversen
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
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8
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Xu K, Chatzitakis A, Risbakk S, Yang M, Backe PH, Grandcolas M, Bjørås M, Norby T. High performance and toxicity assessment of Ta3N5 nanotubes for photoelectrochemical water splitting. Catal Today 2021. [DOI: 10.1016/j.cattod.2019.12.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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9
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Andersen TCB, Kristiansen PE, Huszenicza Z, Johansson MU, Gopalakrishnan RP, Kjelstrup H, Boyken S, Sundvold-Gjerstad V, Granum S, Sørli M, Backe PH, Fulton DB, Karlsson BG, Andreotti AH, Spurkland A. The SH3 domains of the protein kinases ITK and LCK compete for adjacent sites on T cell-specific adapter protein. J Biol Chem 2019; 294:15480-15494. [PMID: 31484725 DOI: 10.1074/jbc.ra119.008318] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/22/2019] [Indexed: 12/22/2022] Open
Abstract
T-cell activation requires stimulation of specific intracellular signaling pathways in which protein-tyrosine kinases, phosphatases, and adapter proteins interact to transmit signals from the T-cell receptor to the nucleus. Interactions of LCK proto-oncogene, SRC family tyrosine kinase (LCK), and the IL-2-inducible T cell kinase (ITK) with the T cell-specific adapter protein (TSAD) promotes LCK-mediated phosphorylation and thereby ITK activation. Both ITK and LCK interact with TSAD's proline-rich region (PRR) through their Src homology 3 (SH3) domains. Whereas LCK may also interact with TSAD through its SH2 domain, ITK interacts with TSAD only through its SH3 domain. To begin to understand on a molecular level how the LCK SH3 and ITK SH3 domains interact with TSAD in human HEK293T cells, here we combined biochemical analyses with NMR spectroscopy. We found that the ITK and LCK SH3 domains potentially have adjacent and overlapping binding sites within the TSAD PRR amino acids (aa) 239-274. Pulldown experiments and NMR spectroscopy revealed that both domains may bind to TSAD aa 239-256 and aa 257-274. Co-immunoprecipitation experiments further revealed that both domains may also bind simultaneously to TSAD aa 242-268. Accordingly, NMR spectroscopy indicated that the SH3 domains may compete for these two adjacent binding sites. We propose that once the associations of ITK and LCK with TSAD promote the ITK and LCK interaction, the interactions among TSAD, ITK, and LCK are dynamically altered by ITK phosphorylation status.
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Affiliation(s)
- Thorny Cesilie Bie Andersen
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
| | | | - Zsuzsa Huszenicza
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
| | - Maria U Johansson
- Swedish NMR Centre at the University of Gothenburg, Gothenburg 413 90, Sweden
| | | | - Hanna Kjelstrup
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
| | - Scott Boyken
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011-1079
| | - Vibeke Sundvold-Gjerstad
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
| | - Stine Granum
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
| | - Morten Sørli
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1432 Ås, Norway
| | - Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway.,Department of Medical Biochemistry, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011-1079
| | - B Göran Karlsson
- Swedish NMR Centre at the University of Gothenburg, Gothenburg 413 90, Sweden
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011-1079
| | - Anne Spurkland
- Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, 0317 Oslo, Norway
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10
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Lundin KE, Hamasy A, Backe PH, Moens LN, Falk-Sörqvist E, Elgstøen KB, Mørkrid L, Bjørås M, Granert C, Norlin AC, Nilsson M, Christensson B, Stenmark S, Smith CIE. Susceptibility to infections, without concomitant hyper-IgE, reported in 1976, is caused by hypomorphic mutation in the phosphoglucomutase 3 (PGM3) gene. Clin Immunol 2015; 161:366-72. [PMID: 26482871 PMCID: PMC4695917 DOI: 10.1016/j.clim.2015.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/17/2015] [Accepted: 10/13/2015] [Indexed: 10/28/2022]
Abstract
Phosphoglucomutase 3 (PGM3) is an enzyme converting N-acetyl-glucosamine-6-phosphate to N-acetyl-glucosamine-1-phosphate, a precursor important for glycosylation. Mutations in the PGM3 gene have recently been identified as the cause of novel primary immunodeficiency with a hyper-IgE like syndrome. Here we report the occurrence of a homozygous mutation in the PGM3 gene in a family with immunodeficient children, described already in 1976. DNA from two of the immunodeficient siblings was sequenced and shown to encode the same homozygous missense mutation, causing a destabilized protein with reduced enzymatic capacity. Affected individuals were highly prone to infections, but lack the developmental defects in the nervous and skeletal systems, reported in other families. Moreover, normal IgE levels were found. Thus, belonging to the expanding group of congenital glycosylation defects, PGM3 deficiency is characterized by immunodeficiency, with or without increased IgE levels, and with variable forms of developmental defects affecting other organ systems.
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Affiliation(s)
- Karin E Lundin
- Clinical Research Center, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, S-141 86 Huddinge, Sweden.
| | - Abdulrahman Hamasy
- Clinical Research Center, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, S-141 86 Huddinge, Sweden
| | - Paul Hoff Backe
- Department of Microbiology, Clinic for Diagnostics and Intervention, Oslo University Hospital, Rikshospitalet, Box 4950, Nydalen, N-0424 Oslo, Norway; Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Box 4950, Nydalen, N-0424 Oslo, Norway
| | - Lotte N Moens
- Department of Immunology, Genetics and Pathology, Uppsala University, S-751 85 Uppsala, Sweden
| | - Elin Falk-Sörqvist
- Department of Immunology, Genetics and Pathology, Uppsala University, S-751 85 Uppsala, Sweden
| | - Katja B Elgstøen
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Box 4950, Nydalen, N-0424 Oslo, Norway
| | - Lars Mørkrid
- Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, Box 4950, Nydalen, N-0424 Oslo, Norway
| | - Magnar Bjørås
- Department of Microbiology, Clinic for Diagnostics and Intervention, Oslo University Hospital, Rikshospitalet, Box 4950, Nydalen, N-0424 Oslo, Norway; Institute for Cancer Research and Molecular Medicine, NTNU, 8905, N-7491 Trondheim, Norway
| | - Carl Granert
- Immunodeficiency Unit, Section of Clinical Immunology, Karolinska University Hospital, S-14186, Stockholm, Sweden
| | - Anna-Carin Norlin
- Immunodeficiency Unit, Section of Clinical Immunology, Karolinska University Hospital, S-14186, Stockholm, Sweden; Clinical Immunology and Transfusion Medicine, Karolinska University Laboratory, Karolinska University Hospital, S-14186, Stockholm, Sweden
| | - Mats Nilsson
- Department of Immunology, Genetics and Pathology, Uppsala University, S-751 85 Uppsala, Sweden; Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, S-171 21, Stockholm, Sweden
| | - Birger Christensson
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, S-141 86, Stockholm, Sweden
| | | | - C I Edvard Smith
- Clinical Research Center, Karolinska Institutet, Department of Laboratory Medicine, Karolinska University Hospital, S-141 86 Huddinge, Sweden; Immunodeficiency Unit, Section of Clinical Immunology, Karolinska University Hospital, S-14186, Stockholm, Sweden.
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11
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Fjaer R, Brodtkorb E, Øye AM, Sheng Y, Vigeland MD, Kvistad KA, Backe PH, Selmer KK. Generalized epilepsy in a family with basal ganglia calcifications and mutations in SLC20A2 and CHRNB2. Eur J Med Genet 2015; 58:624-8. [PMID: 26475232 DOI: 10.1016/j.ejmg.2015.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 07/15/2015] [Accepted: 10/05/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND The genetic understanding of primary familial brain calcification (PFBC) has increased considerably in recent years due to the finding of causal genes like SLC20A2, PDGFRB and PDGFB. The phenotype of PFBC is complex and has as of yet been poorly delineated. The most common clinical presentations include movement disorders, cognitive symptoms and psychiatric conditions. We report a family including two sisters with brain calcifications due to a variant in SLC20A2 and generalized tonic-clonic seizures as the principal phenotypic trait. METHODS The affected siblings underwent whole exome sequencing and candidate variants and cosegregation in the family were validated by Sanger sequencing. RESULTS Both siblings and their asymptomatic father were heterozygous for a variant in SLC20A2. The siblings also had a variant in CHRNB2, a known epilepsy gene associated with autosomal dominant frontal lobe epilepsy, which they had inherited from the mother. CONCLUSIONS To our knowledge, the reported siblings represent the third and fourth subjects with confirmed SLC20A2 variants exhibiting epilepsy as a phenotypic trait. Our findings support seizures as part of the phenotypic spectrum of SLC20A2-related PFBC. However, the present phenotype may also result from additional genetic influence, such as the identified missense variant in CHRNB2.
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Affiliation(s)
- Roar Fjaer
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Kirkeveien 166, Bygg 25, Avdeling for Medisinsk Genetikk, Postboks 4956 Nydalen 0424 Oslo, Norway.
| | - Eylert Brodtkorb
- Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway; Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ane-Marte Øye
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Kirkeveien 166, Bygg 25, Avdeling for Medisinsk Genetikk, Postboks 4956 Nydalen 0424 Oslo, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Kirkeveien 166, Bygg 25, Avdeling for Medisinsk Genetikk, Postboks 4956 Nydalen 0424 Oslo, Norway
| | - Magnus Dehli Vigeland
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Kirkeveien 166, Bygg 25, Avdeling for Medisinsk Genetikk, Postboks 4956 Nydalen 0424 Oslo, Norway
| | - Kjell Arne Kvistad
- Department of Medical Imaging, St. Olav's University Hospital, Trondheim, Norway
| | - Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway; Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
| | - Kaja Kristine Selmer
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Kirkeveien 166, Bygg 25, Avdeling for Medisinsk Genetikk, Postboks 4956 Nydalen 0424 Oslo, Norway
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12
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Backe PH, Ytre-Arne M, Røhr AK, Brodtkorb E, Fowler B, Rootwelt H, Bjørås M, Mørkrid L. Novel Deletion Mutation Identified in a Patient with Late-Onset Combined Methylmalonic Acidemia and Homocystinuria, cblC Type. JIMD Rep 2013; 11:79-85. [PMID: 23580368 DOI: 10.1007/8904_2013_225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/12/2013] [Accepted: 03/14/2013] [Indexed: 01/04/2023] Open
Abstract
Combined methylmalonic aciduria and homocystinuria, cblC type (MMACHC), is the most common inborn error of cellular vitamin B12 metabolism and is caused by mutations in the MMACHC gene. This metabolic disease results in impaired intracellular synthesis of adenosylcobalamin and methylcobalamin, coenzymes for the methylmalonyl-CoA mutase and methionine synthase enzymes, respectively. The inability to produce normal levels of these two coenzymes leads to increased concentrations of methylmalonic acid and homocysteine in plasma and urine, together with normal or decreased concentration of methionine in plasma. Here, we report a novel homozygous deletion mutation (NM_015506.2:c.392_394del) resulting in an in-frame deletion of amino acid Gln131 and late-onset disease in a 23-year-old male. The patient presented with sensory and motoric disabilities, urine and fecal incontinence, and light cognitive impairment. There was an excessive urinary excretion of methylmalonic acid and greatly elevated plasma homocysteine. The clinical symptoms and the laboratory abnormalities responded partly to treatment with hydroxycobalamin, folinic acid, methionine, and betaine. Studies on patient fibroblasts together with spectroscopic activity assays on recombinant MMACHC protein reveal that Gln131 is crucial in order to maintain enzyme activity. Furthermore, structural analyses show that Gln131 is one of only two residues making hydrogen bonds to the tail of cobalamin. Circular dichroism spectroscopy indicates that the 3D structure of the deletion mutant is folded but perturbed compared to the wild-type protein.
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Affiliation(s)
- Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital and University of Oslo, 4950, 0424, Oslo, Nydalen, Norway,
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13
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Ranneberg-Nilsen T, Rollag H, Slettebakk R, Backe PH, Olsen Ø, Luna L, Bjørås M. The chromatin remodeling factor SMARCB1 forms a complex with human cytomegalovirus proteins UL114 and UL44. PLoS One 2012; 7:e34119. [PMID: 22479537 PMCID: PMC3313996 DOI: 10.1371/journal.pone.0034119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 02/22/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Human cytomegalovirus (HCMV) uracil DNA glycosylase, UL114, is required for efficient viral DNA replication. Presumably, UL114 functions as a structural partner to other factors of the DNA-replication machinery and not as a DNA repair protein. UL114 binds UL44 (HCMV processivity factor) and UL54 (HCMV-DNA-polymerase). In the present study we have searched for cellular partners of UL114. METHODOLOGY/PRINCIPAL FINDINGS In a yeast two-hybrid screen SMARCB1, a factor of the SWI/SNF chromatin remodeling complex, was found to be an interacting partner of UL114. This interaction was confirmed in vitro by co-immunoprecipitation and pull-down. Immunofluorescence microscopy revealed that SMARCB1 along with BRG-1, BAF170 and BAF155, which are the core SWI/SNF components required for efficient chromatin remodeling, were present in virus replication foci 24-48 hours post infection (hpi). Furthermore a direct interaction was also demonstrated for SMARCB1 and UL44. CONCLUSIONS/SIGNIFICANCE The core SWI/SNF factors required for efficient chromatin remodeling are present in the HCMV replication foci throughout infection. The proteins UL44 and UL114 interact with SMARCB1 and may participate in the recruitment of the SWI/SNF complex to the chromatinized virus DNA. Thus, the presence of the SWI/SNF chromatin remodeling complex in replication foci and its association with UL114 and with UL44 might imply its involvement in different DNA transactions.
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Affiliation(s)
- Toril Ranneberg-Nilsen
- Department of Microbiology, University of Oslo and Oslo University Hospital HF, Oslo, Norway
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14
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Dalhus B, Forsbring M, Helle IH, Vik ES, Forstrøm RJ, Backe PH, Alseth I, Bjørås M. Separation-of-function mutants unravel the dual-reaction mode of human 8-oxoguanine DNA glycosylase. Structure 2011; 19:117-27. [PMID: 21220122 DOI: 10.1016/j.str.2010.09.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 08/31/2010] [Accepted: 09/30/2010] [Indexed: 11/16/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8oxoG) is a major mutagenic base lesion formed when reactive oxygen species react with guanine in DNA. The human 8oxoG DNA glycosylase (hOgg1) recognizes and initiates repair of 8oxoG. hOgg1 is acknowledged as a bifunctional DNA glycosylase catalyzing removal of the damaged base followed by cleavage of the backbone of the intermediate abasic DNA (AP lyase/β-elimination). When acting on 8oxoG-containing DNA, these two steps in the hOgg1 catalysis are considered coupled, with Lys249 implicated as a key residue. However, several lines of evidence point to a concurrent and independent monofunctional hydrolysis of the N-glycosylic bond being the in vivo relevant reaction mode of hOgg1. Here, we present biochemical and structural evidence for the monofunctional mode of hOgg1 by design of separation-of-function mutants. Asp268 is identified as the catalytic residue, while Lys249 appears critical for the specific recognition and final alignment of 8oxoG during the hydrolysis reaction.
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Affiliation(s)
- Bjørn Dalhus
- Centre for Molecular Biology and Neuroscience and Institute of Medical Microbiology, Rikshospitalet, Oslo University Hospital, N-0027 Oslo, Norway.
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15
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Brodtkorb E, Strand J, Backe PH, Lund AM, Bjørås M, Rootwelt T, Rootwelt H, Woldseth B, Eide L. Four novel mutations identified in Norwegian patients result in intermittent maple syrup urine disease when combined with the R301C mutation. Mol Genet Metab 2010; 100:324-32. [PMID: 20570198 DOI: 10.1016/j.ymgme.2010.04.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 04/26/2010] [Indexed: 01/03/2023]
Abstract
Maple syrup urine disease (MSUD) is caused by a defect in branched chain alpha-ketoacid dehydrogenase complex (BCKD), an essential metabolon for the catabolism of the branched chain amino acids. Here, we report four novel mutations in the DBT gene, encoding the transacylase subunit (E2) of BCKD, resulting in intermittent MSUD in seven Norwegian patients. The patients had episodes with neurological symptoms including lethargy and/or ataxia during childhood infections. All seven patients were heterozygous for the annotated R301C mutation. The second allelic mutations were identified in five patients; one nonsense mutation (G62X), two missense mutations (W84C and R376C) and a mutation in the 3' untranslated region (UTR; c. *358A>C) in two patients. These four novel mutations result in near depletion of E2 protein, and the common R301C protein contributes predominantly to the residual (14%) cellular BCKD activity. Structural analyses of the mutations implied that the W84C and R376C mutations affect stability of intramolecular domains in E2, while the R301C mutation likely disturbs E2 trimer assembly as previously reported. The UTR mutated allele coincided with a strong reduction in mRNA levels, as did the non-R301C specific allele in two patients where the second mutation could not be identified. In summary, the pathogenic effect of the novel mutations is depletion of cellular protein, and the intermittent form of MSUD appears to be attributed to the residual R301C mutant protein in these patients.
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Affiliation(s)
- Else Brodtkorb
- Institute of Clinical Biochemistry, Institute of Clinical Medicine, University of Oslo, Centre of Molecular Biology and Neuroscience, Sognsvannsveien 20, Oslo, Norway
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16
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Görbitz CH, Backe PH. L-Isoleucyl- L-asparagine 1.094-hydrate: a hybrid hydrogen-bonding pattern. Acta Crystallogr C 2010; 66:o349-52. [DOI: 10.1107/s0108270110020895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 06/01/2010] [Indexed: 11/11/2022] Open
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