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Uribe-Carretero E, Rey V, Fuentes JM, Tamargo-Gómez I. Lysosomal Dysfunction: Connecting the Dots in the Landscape of Human Diseases. BIOLOGY 2024; 13:34. [PMID: 38248465 PMCID: PMC10813815 DOI: 10.3390/biology13010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
Lysosomes are the main organelles responsible for the degradation of macromolecules in eukaryotic cells. Beyond their fundamental role in degradation, lysosomes are involved in different physiological processes such as autophagy, nutrient sensing, and intracellular signaling. In some circumstances, lysosomal abnormalities underlie several human pathologies with different etiologies known as known as lysosomal storage disorders (LSDs). These disorders can result from deficiencies in primary lysosomal enzymes, dysfunction of lysosomal enzyme activators, alterations in modifiers that impact lysosomal function, or changes in membrane-associated proteins, among other factors. The clinical phenotype observed in affected patients hinges on the type and location of the accumulating substrate, influenced by genetic mutations and residual enzyme activity. In this context, the scientific community is dedicated to exploring potential therapeutic approaches, striving not only to extend lifespan but also to enhance the overall quality of life for individuals afflicted with LSDs. This review provides insights into lysosomal dysfunction from a molecular perspective, particularly in the context of human diseases, and highlights recent advancements and breakthroughs in this field.
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Affiliation(s)
- Elisabet Uribe-Carretero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Verónica Rey
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Jose Manuel Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Isaac Tamargo-Gómez
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
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Simonati A, Williams RE. Neuronal Ceroid Lipofuscinosis: The Multifaceted Approach to the Clinical Issues, an Overview. Front Neurol 2022; 13:811686. [PMID: 35359645 PMCID: PMC8961688 DOI: 10.3389/fneur.2022.811686] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/11/2022] [Indexed: 01/04/2023] Open
Abstract
The main aim of this review is to summarize the current state-of-art in the field of childhood Neuronal Ceroid Lipofuscinosis (NCL), a group of rare neurodegenerative disorders. These are genetic diseases associated with the formation of toxic endo-lysosomal storage. Following a brief historical review of the evolution of NCL definition, a clinically-oriented approach is used describing how the early symptoms and signs affecting motor, visual, cognitive domains, and including seizures, may lead clinicians to a rapid molecular diagnosis, avoiding the long diagnostic odyssey commonly observed. We go on to focus on recent advances in NCL research and summarize contributions to knowledge of the pathogenic mechanisms underlying NCL. We describe the large variety of experimental models which have aided this research, as well as the most recent technological developments which have shed light on the main mechanisms involved in the cellular pathology, such as apoptosis and autophagy. The search for innovative therapies is described. Translation of experimental data into therapeutic approaches is being established for several of the NCLs, and one drug is now commercially available. Lastly, we show the importance of palliative care and symptomatic treatments which are still the main therapeutic interventions.
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Affiliation(s)
- Alessandro Simonati
- Departments of Surgery, Dentistry, Paediatrics, and Gynaecology, School of Medicine, University of Verona, Verona, Italy
- Department of Clinical Neuroscience, AOUI-VR, Verona, Italy
- *Correspondence: Alessandro Simonati
| | - Ruth E. Williams
- Department of Children's Neuroscience, Evelina London Children's Hospital, London, United Kingdom
- Ruth E. Williams
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3
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Shiro Y, Yamashita A, Watanabe K, Yamazaki T. CLN6's luminal tail-mediated functional interference between CLN6 mutants as a novel pathomechanism for the neuronal ceroid lipofuscinoses. Biomed Res 2021; 42:129-138. [PMID: 34380921 DOI: 10.2220/biomedres.42.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
CLN6 (Ceroid Lipofuscinosis, Neuronal, 6) is a 311-amino acid protein spanning the endoplasmic reticulum membrane. Mutations in CLN6 are linked to CLN6 disease, a hereditary neurodegenerative disorder categorized into the neuronal ceroid lipofuscinoses. CLN6 disease is an autosomal recessive disorder and individuals affected with this disease have two identical (homozygous) or two distinct (compound heterozygous) CLN6 mutant alleles. Little has been known about CLN6's physiological roles and the disease mechanism. We recently found that CLN6 prevents protein aggregate formation, pointing to impaired CLN6's anti-aggregate activity as a cause for the disease. To comprehensively understand the pathomechanism, overall anti-aggregate activity derived from two different CLN6 mutants needs to be investigated, considering patients compound heterozygous for CLN6 alleles. We focused on mutant combinations involving the S132CfsX18 (132fsX) prematurely terminated protein, produced from the most frequent mutation in CLN6. The 132fsX mutant nullified anti-aggregate activity of the P299L CLN6 missense mutant but not of wild-type CLN6. Wild-type CLN6's resistance to the 132fsX mutant was abolished by replacement of amino acids 297-301, including Pro297 and Pro299, with five alanine residues. Given that removal of CLN6's C-terminal fifteen amino acids 297-311 (luminal tail) did not affect the resistance, we suggested that CLN6's luminal tail, when unleashed from Pro297/299-mediated conformational constraints, is improperly positioned by the 132fsX mutant, thereby blocking the induction of anti- aggregate activity. We here reveal a novel mechanism for dissipating CLN6 mutants' residual functions, providing an explanation for the compound heterozygosity-driven pathogenesis.
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Affiliation(s)
- Yuki Shiro
- Department of Molecular Cell Biology and Medicine, Graduate School of Biomedical Sciences, Tokushima University
| | - Arisa Yamashita
- Department of Molecular Cell Biology and Medicine, Graduate School of Biomedical Sciences, Tokushima University
| | - Kana Watanabe
- Department of Molecular Cell Biology and Medicine, Graduate School of Biomedical Sciences, Tokushima University
| | - Tetsuo Yamazaki
- Department of Molecular Cell Biology and Medicine, Graduate School of Biomedical Sciences, Tokushima University
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4
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LOU T, HUANG Y, DONG M. [Genetic study of a family of neuronal ceroid lipofuscinosis caused by a heterozygous mutation of CLN6 gene]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2019; 48:373-377. [PMID: 31901039 PMCID: PMC8800761 DOI: 10.3785/j.issn.1008-9292.2019.08.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 04/15/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To analyze the genetic cause of a family with autosomal recessive neuronal ceroid lipofuscinoses (NCL). METHODS The proband was screened for mutations within the coding region of the candidate genes through high-throughput targeted sequencing. Potential causative mutations were verified by PCR and Sanger sequencing in the proband and his parents. RT-PCR and TA clone sequencing were performed to investigate whether the mRNAs were abnormally spliced. RESULTS The sequencing results revealed compound heterozygous mutations of CLN6:c.486+2T>C and c.486+4A>T, which were respectively inherited from his parents. RT-PCR and TA cloning sequencing suggested that the mRNAs were abnormally spliced in two forms due to both mutations. CONCLUSIONS The compound heterozygous mutations of CLN6:c.486+2T>C and c.486+4A>T are possibly the genetic causes of the NCL family. Detection of the novel mutation has extended mutation spectrum of CLN6.
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Affiliation(s)
| | | | - Minyue DONG
- 董旻岳(1964—), 男, 博士, 主任医师, 博士生导师, 主要从事生殖遗传学研究; E-mail:
;
https://orcid.org/0000-0002-4344-7924
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5
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Chin JJ, Behnam B, Davids M, Sharma P, Zein WM, Wang C, Chepa-Lotrea X, Gallantine WB, Toro C, Adams DR, Tifft CJ, Gahl WA, Malicdan MCV. Novel mutations in CLN6 cause late-infantile neuronal ceroid lipofuscinosis without visual impairment in two unrelated patients. Mol Genet Metab 2019; 126:188-195. [PMID: 30528883 DOI: 10.1016/j.ymgme.2018.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/02/2018] [Accepted: 12/02/2018] [Indexed: 12/25/2022]
Abstract
CLN6 is a transmembrane protein located in the endoplasmic reticulum that is involved in lysosomal acidification. Mutations in CLN6 cause late-infantile neuronal ceroid lipofuscinosis (LINCL), and teenage and adult onset NCL without visual impairment. Here we describe two pediatric patients with LINCL from unrelated families who were evaluated at the National Institutes of Health. Both children exhibited typical phenotypes associated with LINCL except that they lacked the expected visual impairment. Whole exome sequencing identified novel biallelic mutations in CLN6, i.e., c.218-220dupGGT (p.Trp73dup) and c.296A > G (p.Lys99Arg) in Proband 1 and homozygous c.723G > T (p.Met241Ile) in Proband 2. Expression analysis in dermal fibroblasts showed a small increase in CLN6 protein levels. Electron micrographs of these fibroblasts demonstrated large numbers of small membrane-bound vesicles, in addition to lipofuscin deposits. LysoTracker™ Red intensity was increased in fibroblasts from both patients. This study supports a role for CLN6 in lysosomal homeostasis, and highlights the importance of considering CLN6 mutations in the diagnosis of Batten Disease even in patients with normal vision.
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Affiliation(s)
- Joseph J Chin
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Babak Behnam
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Mariska Davids
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Prashant Sharma
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Wadih M Zein
- National Eye Institute, National Institute of Health, Bethesda, MD, United States
| | - Camille Wang
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Xenia Chepa-Lotrea
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | | | - Camilo Toro
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - David R Adams
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Cynthia J Tifft
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - William A Gahl
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - May Christine V Malicdan
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States.
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6
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Nafi O, Ramadan B, Riess O, Buchert R, Froukh T. Two cases of variant late infantile ceroid lipofuscinosis in Jordan. World J Clin Cases 2019; 7:203-208. [PMID: 30705896 PMCID: PMC6354087 DOI: 10.12998/wjcc.v7.i2.203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/26/2018] [Accepted: 12/15/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Late infantile ceroid lipofuscinosis is a rare neurodegenerative disorder that appears between the ages of 2 and 4 years and is difficult to diagnose. In this report we present two sisters with this condition, and the clinical course consisted of delayed developmental skills initially and later regression of previously acquired skills. The cases were initially considered as childhood disintegrative disorder (CDD); however, when whole exome sequencing (WES) genetic testing was done, they proved to be variant late infantile ceroid lipofuscinosis. This is the first report from Jordan.
CASE SUMMARY Clinical presentation included developmental delay and initially speech delay, followed by lose of sphincter control. Motor development was normal until 4 years of age, then they developed ataxia (fear of going downstairs) and weakness while walking. Atonic and myoclonic seizures become intractable, and this was followed by inability to stand or sit and loss of expressive language. In addition to complete blood count test, liver function test, kidney function test, serum electrolyte test, and blood sugar test, serum amino acid profile, B12 level test, thyroid function test, and a brain computed tomography scan were also normal. An electroencephalogram showed a generalized spike and wave pattern, and magnetic resonance imaging showed little to no abnormalities. After dealing with the cases as CDD, WES testing proved a final diagnosis of variant late infantile ceroid lipofuscinosis. Current treatment is anti-epileptic drugs and supportive care at home, and they are now in vegetative state.
CONCLUSION This report highlights the importance of WES for the identification of genetic diseases, especially neurodegenerative disorders.
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Affiliation(s)
- Omar Nafi
- Department of Pediatrics, Faculty of Medicine, Mutah University, Al Karak 61710, Jordan
| | - Bashar Ramadan
- Department of Pediatrics, Faculty of Medicine, Mutah University, Al Karak 61710, Jordan
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, Rare Disease Center, University of Tübingen, Tübingen 72076, Germany
| | - Rebecca Buchert
- Institute of Medical Genetics and Applied Genomics, Rare Disease Center, University of Tübingen, Tübingen 72076, Germany
| | - Tawfiq Froukh
- Department of Biotechnology and Genetic Engineering, Philadelphia University, Amman 11118, Jordan
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7
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Poppens MJ, Cain JT, Johnson TB, White KA, Davis SS, Laufmann R, Kloth AD, Weimer JM. Tracking sex-dependent differences in a mouse model of CLN6-Batten disease. Orphanet J Rare Dis 2019; 14:19. [PMID: 30665444 PMCID: PMC6341540 DOI: 10.1186/s13023-019-0994-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 01/07/2019] [Indexed: 02/08/2023] Open
Abstract
Background CLN6-Batten disease is a rare neurodevelopmental disorder characterized pathologically by the accumulation of lysosomal storage material, glial activation and neurodegeneration, and phenotypically by loss of vision, motor coordination, and cognitive ability, with premature death occurring in the second decade of life. In this study, we investigate whether sex differences in a mouse model of CLN6-Batten disease impact disease onset and progression. Results A number of noteworthy differences were observed including elevated accumulation of mitochondrial ATP synthase subunit C in the thalamus and cortex of female Cln6 mutant mice at 2 months of age. Moreover, female mutant mice showed more severe behavioral deficits. Beginning at 9 months of age, female mice demonstrated learning and memory deficits and suffered a more severe decline in motor coordination. Further, compared to their male counterparts, female animals succumbed to the disease at a slightly younger age, indicating an accelerated disease progression. Conversely, males showed a marked increase in microglial activation at 6 months of age in the cortex relative to females. Conclusions Thus, as female Cln6 mutant mice exhibit cellular and behavioral deficits that precede similar pathologies in male mutant mice, our findings suggest the need for consideration of sex-based differences in CLN6 disease progression during development of preclinical and clinical studies. Electronic supplementary material The online version of this article (10.1186/s13023-019-0994-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- McKayla J Poppens
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Jacob T Cain
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Tyler B Johnson
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Katherine A White
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Samantha S Davis
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Rachel Laufmann
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | | | - Jill M Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA. .,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA.
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8
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Berkovic SF, Oliver KL, Canafoglia L, Krieger P, Damiano JA, Hildebrand MS, Morbin M, Vears DF, Sofia V, Giuliano L, Garavaglia B, Simonati A, Santorelli FM, Gambardella A, Labate A, Belcastro V, Castellotti B, Ozkara C, Zeman A, Rankin J, Mole SE, Aguglia U, Farrell M, Rajagopalan S, McDougall A, Brammah S, Andermann F, Andermann E, Dahl HHM, Franceschetti S, Carpenter S. Kufs disease due to mutation ofCLN6: clinical, pathological and molecular genetic features. Brain 2018; 142:59-69. [DOI: 10.1093/brain/awy297] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/02/2018] [Indexed: 01/22/2023] Open
Affiliation(s)
- Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Karen L Oliver
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Laura Canafoglia
- Department of Neurophysiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Penina Krieger
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Michael S Hildebrand
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Michela Morbin
- Neuropathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Danya F Vears
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Vito Sofia
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, Section of Neurosciences, University of Catania, Catania, Italy
| | - Loretta Giuliano
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, Section of Neurosciences, University of Catania, Catania, Italy
| | - Barbara Garavaglia
- Medical Genetics and Neurogenetics Unit, Bicocca Laboratories, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Alessandro Simonati
- Department of Neuroscience, Biomedicine, Movement-Neurology and Neuropathology, Policlinico GB Rossi, P.le LA Scuro, Verona, Italy
| | | | - Antonio Gambardella
- Institute of Neurology, University Magna Græcia Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR) Germaneto, CZ, Italy
| | - Angelo Labate
- Institute of Neurology, University Magna Græcia Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR) Germaneto, CZ, Italy
| | | | - Barbara Castellotti
- Unit Genetics of Neurodegenerative and Metabolic Diseases, IRCCS Foundation C. Besta Neurological Institute, Milan, Italy
| | - Cigdem Ozkara
- Istanbul University-Cerrahpaşa, Medical Faculty, Department of Neurology, Istanbul, Turkey
| | - Adam Zeman
- University of Exeter Medical School, St Luke’s Campus, Magdalen Road, Exeter EX1 2LU, UK
| | - Julia Rankin
- Clinical Genetics, Royal Devon and Exeter Hospital, Gladstone Road, Exeter, UK
| | - Sara E Mole
- MRC Laboratory for Molecular Cell Biology and UCL GOS Institute of Child Health, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Umberto Aguglia
- Department of Medical and Surgical Sciences, University Magna Græcia Catanzaro, Italy
- Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR) Germaneto, CZ, Italy
| | - Michael Farrell
- Department of Neuropathology, Beaumont Hospital, Dublin 9, Ireland
| | - Sulekha Rajagopalan
- Department of Clinical Genetics, Liverpool Hospital, Liverpool, New South Wales Australia
| | - Alan McDougall
- Department of Neurology, Liverpool Hospital, Liverpool, New South Wales Australia
| | - Susan Brammah
- Central Sydney Electron Microscope Unit, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Frederick Andermann
- Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, Quebec, Canada
- Departments of Neurology and Neurosurgery and Paediatrics, McGill University, Montreal, Quebec, Canada
| | - Eva Andermann
- Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, Quebec, Canada
- Departments of Neurology and Neurosurgery and Paediatrics, McGill University, Montreal, Quebec, Canada
| | - Hans-Henrik M Dahl
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Silvana Franceschetti
- Department of Neurophysiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stirling Carpenter
- Consultant in Neuropathology, Centro Hospitalar São João, Porto, Portugal
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Sun G, Yao F, Tian Z, Ma T, Yang Z. A first CLN6 variant case of late infantile neuronal ceroid lipofuscinosis caused by a homozygous mutation in a boy from China: a case report. BMC MEDICAL GENETICS 2018; 19:177. [PMID: 30285654 PMCID: PMC6167792 DOI: 10.1186/s12881-018-0690-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/20/2018] [Indexed: 01/14/2023]
Abstract
Background Neuronal ceroid lipofuscinosis (NCLs) are lysosomal storage disorders characterized by seizures, motor impairment, and loss of vision. Ceroid lipofuscinosis (CLN) gene mutations are the cause, but NCL cases arising from CLN6 mutations have not been described in China to date. The CLN6 protein, which plays a role in lysosomal function, is an endoplasmic reticulum (ER) membrane protein with seven transmembrane (TM) domains. It has a cytosolic-facing amino terminal domain and a luminal-facing carboxyl terminal domain, with six loops between the TM domains. Case presentation Here we report a case involving a Chinese boy whose suspected diagnosis was a hereditary leukoencephalopathy, based on brain MRI imaging and epilepsy symptoms, language articulation disorders, ataxia, and unstable gait. The electroencephalogram showed epileptic discharges, and the brain MRI scan showed high signal intensity adjacent to the bilateral posterior horns of the lateral ventricles on T2-weighted images, along with cerebellar atrophy. Using next-generation sequencing for the genes in a panel for hereditary leukoencephalopathies, we detected a homozygous missense point mutation c.892G > A(p.Glu298Lys) in CLN6, and the variant was interpreted as pathogenic on in silico analysis. Absence of this mutation was confirmed in 259 controls. Late infantile NCL and secondary epilepsy were diagnosed, and oral sodium valproate was prescribed. The epilepsy was not well controlled, however, and the other signs had not improved at the 6-month follow-up. We also analyzed the loci of 31 CLN6 missense mutations, including those previously reported and the current one. We found that 22.6% (7/31) of the mutations are in the cytoplasmic domains, about 32.2% (10/31) are in the TM domains, and about 45.2% (14/31) are in the luminal domains. These mutations were mostly located in the TM3-TM4 loop (6/31), TM1-TM2 loop (4/31), and C-terminus (4/31), with none found in the TM4-TM5 loop, TM5-TM6 loop, or TM7. Conclusions We report the first case in China of NCL caused by a CLN6 mutation, expanding the genotype options for NCLs. In practice, NCLs generally are not the initial suspected diagnosis for such cases. Use of a gene sequencing panel for investigating unexplained seizures or leukoencephalopathies can help confirm the diagnosis. Electronic supplementary material The online version of this article (10.1186/s12881-018-0690-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guilian Sun
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Fang Yao
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Zhuoling Tian
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Tianjiao Ma
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China
| | - Zhiliang Yang
- Department of Pediatrics, The First Hospital of China Medical University, No. 155 Nanjing North Street, Heping District, Shenyang, 110001, Liaoning Province, People's Republic of China.
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10
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Sato R, Inui T, Endo W, Okubo Y, Takezawa Y, Anzai M, Morita H, Saitsu H, Matsumoto N, Haginoya K. First Japanese variant of late infantile neuronal ceroid lipofuscinosis caused by novel CLN6 mutations. Brain Dev 2016; 38:852-6. [PMID: 27165443 DOI: 10.1016/j.braindev.2016.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/16/2016] [Accepted: 04/12/2016] [Indexed: 01/02/2023]
Abstract
The clinical phenotypes of neuronal ceroid lipofuscinoses (NCLs) have been determined based on the age of onset and clinical symptoms. NCLs with onset between age 2 and 4years are known as late infantile neuronal ceroid lipofuscinoses (LINCLs). The clinical features of LINCLs include visual loss and progressive myoclonus epilepsy (PME) characterized by myoclonus, seizures, ataxia, and both mental and motor deterioration. There have been reports of several genes associated with LINCLs, with mutations in the CLN6 gene reported to cause variant forms of LINCLs (vLINCLs). Here, we report the first Japanese vLINCL caused by novel CLN6 mutations, found in a patient diagnosed by whole-exome sequencing. Visual acuity in our patient was preserved until the early teens. It remains to be elucidated if preserved visual function is related to the novel mutations of CLN6. Our case reveals the efficacy of whole-exome sequencing for examination of PMEs and highlights the existence of the CLN6 mutation in the Japanese population.
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Affiliation(s)
- Ryo Sato
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan; Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.
| | - Takehiko Inui
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan
| | - Wakaba Endo
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan
| | - Yukimune Okubo
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan; Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Yusuke Takezawa
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan; Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Mai Anzai
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan
| | - Hiroyuki Morita
- Departmetn of Pediatrics, Fukushima Rehabilitation Center for Children, Koriyama, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Haginoya
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Japan
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Bennett MJ, Rakheja D. The neuronal ceroid-lipofuscinoses. ACTA ACUST UNITED AC 2014; 17:254-9. [PMID: 23798013 DOI: 10.1002/ddrr.1118] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2012] [Indexed: 12/15/2022]
Abstract
The neuronal ceroid-lipofuscinoses (NCL's, Batten disease) represent a group of severe neurodegenerative diseases, which mostly present in childhood. The phenotypes are similar and include visual loss, seizures, loss of motor and cognitive function, and early death. At autopsy, there is massive neuronal loss with characteristic storage in remaining neurons. Neurons appear to die because of increased rates of apoptosis and altered autophagy. Ten genes have been identified so far that result in an NCL (CLN1-10). The most common forms are CLN1, CLN2, and CLN3, which were previously known as Infantile, Late-Infantile, and Juvenile NCL's, respectively. CLN1 and CLN2 result from mutations in soluble lysosomal enzymes palmitoyl-protein thioesterase (PPT) and tripeptidyl peptidase 1 (TPP1), which can be measured in white blood cells for clinical diagnosis. Molecular diagnostic testing is routinely available for CLN1, CLN2, and CLN3. Sequencing of other NCL genes may be required to establish a diagnosis when the common forms are ruled out. The pathogenesis of NCL neuronal loss resulting from loss of function of any of the NCL gene products remains unknown and no treatment options are presently available.
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Affiliation(s)
- Michael J Bennett
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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12
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A murine model of variant late infantile ceroid lipofuscinosis recapitulates behavioral and pathological phenotypes of human disease. PLoS One 2013; 8:e78694. [PMID: 24223841 PMCID: PMC3815212 DOI: 10.1371/journal.pone.0078694] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 09/24/2013] [Indexed: 01/07/2023] Open
Abstract
Neuronal ceroid lipofuscinoses (NCLs; also known collectively as Batten Disease) are a family of autosomal recessive lysosomal storage disorders. Mutations in as many as 13 genes give rise to ∼10 variants of NCL, all with overlapping clinical symptomatology including visual impairment, motor and cognitive dysfunction, seizures, and premature death. Mutations in CLN6 result in both a variant late infantile onset neuronal ceroid lipofuscinosis (vLINCL) as well as an adult-onset form of the disease called Type A Kufs. CLN6 is a non-glycosylated membrane protein of unknown function localized to the endoplasmic reticulum (ER). In this study, we perform a detailed characterization of a naturally occurring Cln6 mutant (Cln6nclf) mouse line to validate its utility for translational research. We demonstrate that this Cln6nclf mutation leads to deficits in motor coordination, vision, memory, and learning. Pathologically, we demonstrate loss of neurons within specific subregions and lamina of the cortex that correlate to behavioral phenotypes. As in other NCL models, this model displays selective loss of GABAergic interneuron sub-populations in the cortex and the hippocampus with profound, early-onset glial activation. Finally, we demonstrate a novel deficit in memory and learning, including a dramatic reduction in dendritic spine density in the cerebral cortex, which suggests a reduction in synaptic strength following disruption in CLN6. Together, these findings highlight the behavioral and pathological similarities between the Cln6nclf mouse model and human NCL patients, validating this model as a reliable format for screening potential therapeutics.
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Getty AL, Rothberg PG, Pearce DA. Diagnosis of neuronal ceroid lipofuscinosis: mutation detection strategies. ACTA ACUST UNITED AC 2013; 1:351-62. [PMID: 23489355 DOI: 10.1517/17530059.1.3.351] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCL) are a group of rare genetically inherited neurodegenerative disorders in children. These diseases are classified by age of onset (congenital, infantile, late-infantile, juvenile and adult-onset) and by the gene bearing mutations (CLN10/CTSD, CLN1/PPT1, CLN2/TPP1, CLN3, CLN5, CLN6, CLN7/MFSD8 and CLN8). Enzyme activity assays are helpful in identifying several of these disorders; however confirmation of the mutation in the gene causing these diseases is vital for definitive diagnosis. There exists considerable heterogeneity in the NCLs as a whole and within each type of NCL both in phenotype (disease manifestation and progression) and genotype (type of mutation), which complicates NCL diagnosis. In order to streamline the diagnostic process, the age of symptom onset, geography and/or ethnicity, and enzyme activity may be considered together. However, these ultimately serve to guide targeting the correct route to genetic confirmation of an NCL through mutational analysis. Herein, an effective protocol to diagnose NCLs using these criteria is presented.
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Affiliation(s)
- Amanda L Getty
- University of Rochester School of Medicine and Dentistry, Center for Neural Development and Disease, Aab Institute of Biomedical Sciences, Box 645, Rochester, New York 14642, USA +1 585 506 1972 ;
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Kousi M, Lehesjoki AE, Mole SE. Update of the mutation spectrum and clinical correlations of over 360 mutations in eight genes that underlie the neuronal ceroid lipofuscinoses. Hum Mutat 2011; 33:42-63. [DOI: 10.1002/humu.21624] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Accepted: 08/29/2011] [Indexed: 12/17/2022]
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Arsov T, Smith K, Damiano J, Franceschetti S, Canafoglia L, Bromhead C, Andermann E, Vears D, Cossette P, Rajagopalan S, McDougall A, Sofia V, Farrell M, Aguglia U, Zini A, Meletti S, Morbin M, Mullen S, Andermann F, Mole S, Bahlo M, Berkovic S. Kufs disease, the major adult form of neuronal ceroid lipofuscinosis, caused by mutations in CLN6. Am J Hum Genet 2011; 88:566-73. [PMID: 21549341 DOI: 10.1016/j.ajhg.2011.04.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022] Open
Abstract
The molecular basis of Kufs disease is unknown, whereas a series of genes accounting for most of the childhood-onset forms of neuronal ceroid lipofuscinosis (NCL) have been identified. Diagnosis of Kufs disease is difficult because the characteristic lipopigment is largely confined to neurons and can require a brain biopsy or autopsy for final diagnosis. We mapped four families with Kufs disease for whom there was good evidence of autosomal-recessive inheritance and found two peaks on chromosome 15. Three of the families were affected by Kufs type A disease and presented with progressive myoclonus epilepsy, and one was affected by type B (presenting with dementia and motor system dysfunction). Sequencing of a candidate gene in one peak shared by all four families identified no mutations, but sequencing of CLN6, found in the second peak and shared by only the three families affected by Kufs type A disease, revealed pathogenic mutations in all three families. We subsequently sequenced CLN6 in eight other families, three of which were affected by recessive Kufs type A disease. Mutations in both CLN6 alleles were found in the three type A cases and in one family affected by unclassified Kufs disease. Mutations in CLN6 are the major cause of recessive Kufs type A disease. The phenotypic differences between variant late-infantile NCL, previously found to be caused by CLN6, and Kufs type A disease are striking; there is a much later age at onset and lack of visual involvement in the latter. Sequencing of CLN6 will provide a simple diagnostic strategy in this disorder, in which definitive identification usually requires invasive biopsy.
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Cln6 mutants associated with neuronal ceroid lipofuscinosis are degraded in a proteasome-dependent manner. Biosci Rep 2009; 29:173-81. [PMID: 18811591 DOI: 10.1042/bsr20080143] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
NCLs (neuronal ceroid lipofuscinoses), a group of inherited neurodegenerative lysosomal storage diseases that predominantly affect children, are the result of autosomal recessive mutations within one of the nine cln genes. The wild-type cln gene products are composed of membrane and soluble proteins that localize to the lysosome or the ER (endoplasmic reticulum). However, the destiny of the Cln variants has not been fully characterized. To explore a possible link between ER quality control and processing of Cln mutants, we investigated the fate of two NCL-related Cln6 mutants found in patient samples (Cln6(G123D) and Cln6(M241T)) in neuronal-derived human cells. The point mutations are predicted to be in the putative transmembrane domains and most probably generate misfolded membrane proteins that are subjected to ER quality control. Consistent with this paradigm, both mutants underwent rapid proteasome-mediated degradation and complexed with components of the ER extraction apparatus, Derlin-1 and p97. In addition, knockdown of SEL1L [sel-1 suppressor of lin-12-like (Caenorhabditis elegans)], a member of an E3 ubiquitin ligase complex involved in ER protein extraction, rescued significant amounts of Cln6(G123D) and Cln6(M241T) polypeptides. The results implicate ER quality control in the instability of the Cln variants that probably contributes to the development of NCL.
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Affiliation(s)
- Dinesh Rakheja
- Department of Pathology, University of Texas Southwestern Medical Center and Children's Medical Center, MC 9073, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
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18
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Tammen I, Houweling PJ, Frugier T, Mitchell NL, Kay GW, Cavanagh JAL, Cook RW, Raadsma HW, Palmer DN. A missense mutation (c.184C>T) in ovine CLN6 causes neuronal ceroid lipofuscinosis in Merino sheep whereas affected South Hampshire sheep have reduced levels of CLN6 mRNA. Biochim Biophys Acta Mol Basis Dis 2006; 1762:898-905. [PMID: 17046213 DOI: 10.1016/j.bbadis.2006.09.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 08/27/2006] [Accepted: 09/06/2006] [Indexed: 11/24/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are a group of fatal recessively inherited neurodegenerative diseases of humans and animals characterised by common clinical signs and pathology. These include blindness, ataxia, dementia, behavioural changes, seizures, brain and retinal atrophy and accumulation of fluorescent lysosome derived organelles in most cells. A number of different variants have been suggested and seven different causative genes identified in humans (CLN1, CLN2, CLN3, CLN5, CLN6, CLN8 and CTSD). Animal models have played a central role in the investigation of this group of diseases and are extremely valuable for developing a better understanding of the disease mechanisms and possible therapeutic approaches. Ovine models include flocks of affected New Zealand South Hampshires and Borderdales and Australian Merinos. The ovine CLN6 gene has been sequenced in a representative selection of these sheep. These investigations unveiled the mutation responsible for the disease in Merino sheep (c.184C>T; p.Arg62Cys) and three common ovine allelic variants (c.56A>G, c.822G>A and c.933_934insCT). Linkage analysis established that CLN6 is the gene most likely to cause NCL in affected South Hampshire sheep, which do not have the c.184C>T mutation but show reduced expression of CLN6 mRNA in a range of tissues as determined by real-time PCR. Lack of linkage precludes CLN6 as a candidate for NCL in Borderdale sheep.
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Affiliation(s)
- Imke Tammen
- Centre for Advanced Technologies in Animal Genetics and Reproduction (Reprogen), Faculty of Veterinary Science, The University of Sydney, PMB3, Camden, NSW, Australia.
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19
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Teixeira CAF, Lin S, Mangas M, Quinta R, Bessa CJP, Ferreira C, Sá Miranda MC, Boustany RMN, Ribeiro MG. Gene expression profiling in vLINCL CLN6-deficient fibroblasts: Insights into pathobiology. Biochim Biophys Acta Mol Basis Dis 2006; 1762:637-46. [PMID: 16857350 DOI: 10.1016/j.bbadis.2006.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 05/31/2006] [Accepted: 06/01/2006] [Indexed: 11/29/2022]
Abstract
The CLN6 vLINCL is caused by molecular defects in CLN6 gene coding for an ER resident transmembrane protein whose function is unknown. In the present study gene expression profiling of CLN6-deficient fibroblasts using cDNA microarray was undertaken in order to provide novel insights into the molecular mechanisms underlying this neurodegenerative fatal disease. Data were validated by qRT-PCR. Statistically significant alterations of expression were observed for 12 transcripts. The two most overexpressed genes, versican and tissue factor pathway inhibitor 2, are related to extracellular matrix (ECM), predicting changes in ECM-related proteins in CLN6-deficient cells. Transcript profiling also suggested alterations in signal transduction pathways, apoptosis and the immune/inflammatory response. Up-regulated genes related to steroidogenesis or signalling, and the relationship between cholesterol dynamics and glycosphingolipid sorting, led to investigation of free cholesterol and gangliosides in CLN6-deficient fibroblasts. Cholesterol accumulation in lysosomes suggests a homeostasis block as a result of CLN6p deficiency. The cholesterol imbalance may affect structure/function of caveolae and lipid rafts, disrupting signalling transduction pathways and sorting cell mechanisms. Alterations in protein/lipid intracellular trafficking would affect the composition and function of endocytic compartments, including lysosomes. Dysfunctional endosomal/lysosomal vesicles may act as one of the triggers for apoptosis and cell death, and for a secondary protective inflammatory response. In conclusion, the data reported provide novel clues into molecular pathophysiological mechanisms of CLN6-deficiency, and may also help in developing disease biomarkers and therapies for this and other neurodegenerative diseases.
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Affiliation(s)
- C A F Teixeira
- Unidade de Enzimologia, Instituto de Genética Médica Jacinto Magalhães, Porto, Portugal
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20
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Siintola E, Lehesjoki AE, Mole SE. Molecular genetics of the NCLs -- status and perspectives. Biochim Biophys Acta Mol Basis Dis 2006; 1762:857-64. [PMID: 16828266 DOI: 10.1016/j.bbadis.2006.05.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Accepted: 05/23/2006] [Indexed: 11/19/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders characterized by the accumulation of autofluorescent storage material in many cell types, including neurons. Most NCL subtypes are inherited in an autosomal recessive manner and characterized clinically by epileptic seizures, progressive psychomotor decline, visual failure, variable age of onset, and premature death. To date, seven genes underlying human NCLs have been identified. Most of the mutations in these genes are associated with specific disease subtypes, while some result in variable disease onset, severity and progression. In addition to these, there are still disease subgroups with unknown molecular genetic backgrounds. Although apparent clinical homogeneity exists within some of these subgroups, actual genetic heterogeneity may complicate gene identification. Additional clues to the identification of these unknown genes may come from animal models of NCL and from functional studies of already known genes which may suggest further candidates.
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Affiliation(s)
- Eija Siintola
- Folkhälsan Institute of Genetics, Department of Medical Genetics and Neuroscience Center, Biomedicum Helsinki, University of Helsinki, Finland.
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Siintola E, Topcu M, Kohlschütter A, Salonen T, Joensuu T, Anttonen AK, Lehesjoki AE. Two novel CLN6 mutations in variant late-infantile neuronal ceroid lipofuscinosis patients of Turkish origin. Clin Genet 2005; 68:167-73. [PMID: 15996215 DOI: 10.1111/j.1399-0004.2005.00471.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuronal ceroid lipofuscinoses (NCLs) are the most common neurodegenerative childhood-onset disorders characterized by autosomal recessive inheritance, epileptic seizures, progressive psychomotor deterioration, visual failure, and premature death. At least seven subtypes of childhood-onset NCLs have been identified of which the late-infantile-onset forms (LINCLs) are genetically the most heterogeneous with four underlying genes identified. A variant form of LINCL (vLINCL) present in Turkish patients has been considered a distinct clinical and genetic entity (CLN7). However, we recently showed that mutations in the CLN8 gene account for a subset of Turkish vLINCL. Toward identifying the CLN7 gene we here screened the known NCL loci for homozygosity in nine Turkish vLINCL families. These loci were excluded in seven families that are likely to represent the 'true' Turkish vLINCL. In two families, we identified two novel homozygous mutations in the CLN6 gene: an intronic base substitution (c.542+5G>T) affecting the splicing of the transcript and a nonsense mutation (c.663C>G) creating a stop codon at tyrosine 221. These data indicate that CLN6 mutations, in addition to those of CLN8, should be considered a diagnostic alternative in Turkish vLINCL patients. The genetic background of the 'true' Turkish vLINCL, CLN7, remains to be defined.
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Affiliation(s)
- E Siintola
- Folkhälsan Institute of Genetics, Department of Medical Genetics and Neuroscience Center, Biomedicum Helsinki, University of Helsinki, Finland
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22
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Mole SE, Williams RE, Goebel HH. Correlations between genotype, ultrastructural morphology and clinical phenotype in the neuronal ceroid lipofuscinoses. Neurogenetics 2005; 6:107-26. [PMID: 15965709 DOI: 10.1007/s10048-005-0218-3] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 02/03/2005] [Indexed: 12/23/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of severe neurodegenerative diseases with onset usually in childhood and characterised by the intracellular accumulation of autofluorescent storage material. Within the last decade, mutations that cause NCL have been found in six human genes (CLN1, CLN2, CLN3, CLN5, CLN6 and CLN8). Mutations in two additional genes cause disease in animal models that share features with NCL-CTSD in sheep and mice and PPT2 in mice. Approximately 160 NCL disease-causing mutations have now been described (listed and fully cited in the NCL Mutation Database, http://www.ucl.ac.uk/ncl/ ). Most mutations result in a classic morphology and disease phenotype, but some mutations are associated with disease that is of later onset, less severe or protracted in its course, or with atypical morphology. Seven common mutations exist, some having a worldwide distribution and others associated with families originating from specific geographical regions. This review attempts to correlate the gene, disease-causing mutation, morphology and clinical phenotype for each type of NCL.
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Affiliation(s)
- Sara E Mole
- MRC Laboratory for Molecular Cell Biology and Department of Paediatrics and Child Health, University College London, Gower Street, London, WC1E 6BT, UK.
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Mole SE, Michaux G, Codlin S, Wheeler RB, Sharp JD, Cutler DF. CLN6, which is associated with a lysosomal storage disease, is an endoplasmic reticulum protein. Exp Cell Res 2004; 298:399-406. [PMID: 15265688 DOI: 10.1016/j.yexcr.2004.04.042] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Revised: 04/21/2004] [Indexed: 11/25/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are severe inherited neurodegenerative disorders affecting children. In this disease, lysosomes accumulate autofluorescent storage material and there is death of neurons. Five types of NCL are caused by mutations in lysosomal proteins (CTSD, CLN1/PPT1, CLN2/TTPI, CLN3 and CLN5), and one type is caused by mutations in a protein that recycles between the ER and ERGIC (CLN8). The CLN6 gene underlying a variant of late infantile NCL (vLINCL) was recently identified. It encodes a novel 311 amino acid transmembrane protein. Antisera raised against CLN6 peptides detected a protein of 30 kDa by Western blotting of human cells, which was missing in cells from some CLN6 deficient patients. Using immunofluorescence microscopy, CLN6 was shown to reside in the endoplasmic reticulum (ER). CLN6 protein tagged with GFP at the C-terminus and expressed in HEK293 cells was also found within the ER. Investigation of the effect of five CLN6 disease mutations that affect single amino acids showed that the mutant proteins were retained in the ER. These data suggest that CLN6 is an ER resident protein, the activity of which, despite this location, must contribute to lysosomal function.
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Affiliation(s)
- Sara E Mole
- Department of Paediatrics and Child Health, Royal Free and University College Medical School, University College London, London WC1E 6JJ, UK.
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Schulz A, Dhar S, Rylova S, Dbaibo G, Alroy J, Hagel C, Artacho I, Kohlschütter A, Lin S, Boustany RM. Impaired cell adhesion and apoptosis in a novel CLN9 Batten disease variant. Ann Neurol 2004; 56:342-50. [PMID: 15349861 DOI: 10.1002/ana.20187] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We describe the ninth variant of neuronal ceroid lipofuscinosis (NCL) or Batten disease, due to defects in a putative new gene, CLN9. We therefore refer to the new variant as CLN9-deficient. Two Serbian sisters and two German brothers are described. Their clinical history is characteristic for juvenile NCL. They show similar gene expression patterns. The existence of this variant is supported by the presence of curvilinear inclusions, fingerprint profiles, and granular osmiophilic deposits in neurons, lymphocytes, and conjunctival cells. Enzyme screening and sequencing of the coding regions of other NCL genes was negative. CLN9-deficient cells have a distinctive phenotype. They have rounded cell bodies, have prominent nucleoli, attach poorly to the culture dish, and are sensitive to apoptosis but have increased growth rates. Gene expression of proteins involved in cell adhesion and apoptosis is altered in these cells. Sphingolipid metabolism is also perturbed. They have decreased levels of ceramide, sphingomyelin, lactosylceramide, ceramide trihexoside, and globoside and increased activity of serine palmitoyl transferase.
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Affiliation(s)
- Angela Schulz
- Departments of Pediatrics and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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Ezaki J, Kominami E. The intracellular location and function of proteins of neuronal ceroid lipofuscinoses. Brain Pathol 2004; 14:77-85. [PMID: 14997940 PMCID: PMC8095780 DOI: 10.1111/j.1750-3639.2004.tb00501.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Neuronal ceroid lipofuscinoses are a group of diseases characterized by accumulation of hydrophobic proteins in lysosomes of neurons and other types of cells. NCLs are caused by at least 8 mutant genes (CLN1-CLN8), though CLN4 and CLN7 have not yet been identified. Except for Cln1p, the protein encoded by CLN1, the defective proteins are associated with lysosomal accumulation of mitochondrial ATP synthase subunit c. Cln1p and Cln2p are soluble lysosomal enzymes, targeted to lysosomes in a mannose 6-phosphate dependent manner. Mutations in the lysosomal protease cathepsin D cause another NCL. Cln3p, Cln5p, Cln6p and Cln8p are thought to be transmembrane proteins. Cln3p and Cln5p are localized in the endosome-lysosomal compartment. Deficiency of endosomal membrane protein CLC-3, a member of the chloride channel family, causes NCL-like phenotype and lysosomal storage of subunit c. Herein, we review the features of NCL and NCL-related proteins and discuss the involvement of the proteins in lysosomal degradation of subunit c.
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Affiliation(s)
- Junji Ezaki
- Department of Biochemistry, Juntendo University School of Medicine, 2‐1‐1 Hongo, Bunkyo‐ku, Tokyo 113‐8421, Japan
| | - Eiki Kominami
- Department of Biochemistry, Juntendo University School of Medicine, 2‐1‐1 Hongo, Bunkyo‐ku, Tokyo 113‐8421, Japan
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Heine C, Koch B, Storch S, Kohlschütter A, Palmer DN, Braulke T. Defective endoplasmic reticulum-resident membrane protein CLN6 affects lysosomal degradation of endocytosed arylsulfatase A. J Biol Chem 2004; 279:22347-52. [PMID: 15010453 DOI: 10.1074/jbc.m400643200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Variant late infantile neuronal ceroid lipofuscinosis, a lysosomal storage disorder characterized by progressive mental deterioration and blindness, is caused by mutations in a polytopic membrane protein (CLN6) with unknown intracellular localization and function. In this study, transient transfection of BHK21 cells with CLN6 cDNA and immunoblot analysis using peptide-specific CLN6 antibodies demonstrated the expression of a approximately 27-kDa protein that does not undergo proteolytic processing. Cross-linking experiments revealed the presence of CLN6 dimers. Using double immunofluorescence microscopy, epitope-tagged CLN6 was shown to be retained in the endoplasmic reticulum (ER) with no colocalization with the cis-Golgi or lysosomal markers. The translocation into the ER and proper folding were confirmed by the N-linked glycosylation of a mutant CLN6 polypeptide. Pulse-chase labeling of fibroblasts from CLN6 patients and from sheep (OCL6) and mouse (nclf) models of the disease followed by immunoprecipitation of cathepsin D indicated that neither the synthesis, sorting nor the proteolytic processing of this lysosomal enzyme was affected in CLN6-defective cells. However, the degradation of the endocytosed index protein arylsulfatase A was strongly reduced in all of the mutant CLN6 cell lines compared with controls. These data suggest that defects in the ER-resident CLN6 protein lead to lysosomal dysfunctions, which may result in lysosomal accumulation of storage material.
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Affiliation(s)
- Claudia Heine
- Department of Biochemistry, Children's Hospital, University of Hamburg, D-20246 Hamburg, Germany
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Abstract
The neuronal ceroid lipofuscinoses (NCL), also known as Batten disease, are a group of inherited severe neurodegenerative disorders primarily affecting children. They are characterised by the accumulation of autofluorescent storage material in many cells. Children suffer from visual failure, seizures, progressive physical and mental decline and premature death, associated with the loss of cortical neurones. Six genes have been identified that cause human NCL (CLN1, CLN2, CLN3, CLN5, CLN6, CLN8), and approximately 150 mutations have been described. The majority of mutations result in a characteristic disease course for each gene. However, mutations associated with later disease onset or a more protracted disease course have also been described. At least seven common mutations exist, either with a world-wide distribution or associated with families from specific countries. All mutations are described in the NCL Mutation Database (http://www.uc.ac.uk/ncl).
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Affiliation(s)
- Sara E Mole
- Department of Paediatrics and Child Health, Royal Free and University College Medical School, University College, London, United Kingdom.
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Abstract
The neuronal ceroid lipofuscinoses (NCL) are a large group of autosomal recessive lysosomal storage disorders with both enzymatic deficiency and structural protein dysfunction. Previously, diagnosis of NCL was based on age at onset and clinicopathological (C-P) findings described 4 forms, classified as infantile (INCL) (2), late-infantile (LINCL) (5), juvenile (JNCL) (6), and adult (ANCL) (12). Most patients with NCL have progressive ocular and cerebral dysfunction, including cognitive/motor dysfunction and uncontrolled seizures. After reviewing 520 patients with NCL, we found that about 104 (20%) did not fit this classification of NCL. With further research, 4 additional forms have been recognized: Finnish (13), Gypsy/Indian (14), Turkish (15)--variants of LINCL, and Northern epilepsy (16), also known as progressive epilepsy with mental retardation. These eight NCL forms resulted from 151 different mutations in genes CLN1 to CLN8 causing different phenotypes (http://www.ucl.ac.uk/ncl). The genes CLN1 and CLN2 encode lysosomal palmitoyl protein thioesterase and tripeptidyl peptidase 1. The diagnosis of NCL is based on clinicopathological (C-P) findings, enzymatic assay, and molecular genetic testing. Ultrastructural studies must be performed to confirm the presence and nature of lysosomal storage material (fingerprint or curvilinear profiles, or granular osmiophilic deposits) before doing biochemical testing. Pheno/genotypic correlation studies are discussed.
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Affiliation(s)
- Hans H Goebel
- Department of Neuropathology, Johannes Gutenberg University, Mainz, Germany.
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Sharp JD, Wheeler RB, Parker KA, Gardiner RM, Williams RE, Mole SE. Spectrum of CLN6 mutations in variant late infantile neuronal ceroid lipofuscinosis. Hum Mutat 2003; 22:35-42. [PMID: 12815591 DOI: 10.1002/humu.10227] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative diseases of childhood. CLN6, the gene mutated in variant late infantile NCL (vLINCL), was recently cloned. We report the identification of eight further mutations in CLN6 making a total of 18 reported mutations. These mutations include missense, nonsense, small deletions or insertions, and two splice-site mutations. Ten mutations affect single amino acids, all of which are conserved across vertebrate species. Minor differences in the pattern of disease symptom evolution can be identified. One patient with a more protracted disease progression was a compound heterozygote for a missense mutation and an unidentified mutation. Fifteen CLN6 mutations occur in one or two families only, and families from the same country do not all share the same mutation. Unlike NCLs caused by mutations in CLN1, CLN3, CLN5, and CLN8, there is no major founder mutation in CLN6. However, one mutation (E72X) is significantly more common in patients from Costa Rica than two other mutations present in that same population. In addition, a 1-bp insertion (c.316insC) is associated with families from Pakistan and I154del may be common in Portugal. A group of Roma Gypsy families from the Czech Republic share two disease-associated haplotypes, one of which is also present in a Pakistani family, consistent with the proposed migration of the Roma from the Indian subcontinent 1,000 years ago. All mutations are recorded in the NCL Mutation Database together with their country of origin for use in the development of rapid screening assays to confirm diagnosis and to facilitate carrier testing appropriate to a population.
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Affiliation(s)
- Julie D Sharp
- Department of Paediatrics and Child Health, Royal Free and University College Medical School, University College London, London, UK
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