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Dobloug S, Kjellström U, Anderson G, Gardner E, Mole SE, Sheth J, Puschmann A. Maculopathy and adult-onset ataxia in patients with biallelic MFSD8 variants. Mol Genet Genomic Med 2024; 12:e2505. [PMID: 39108195 PMCID: PMC11303817 DOI: 10.1002/mgg3.2505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 07/17/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND Biallelic variants in the major facilitator superfamily domain containing 8 gene (MFSD8) are associated with distinct clinical presentations that range from typical late-infantile neuronal ceroid lipofuscinosis type 7 (CLN7 disease) to isolated adult-onset retinal dystrophy. Classic late-infantile CLN7 disease is a severe, rare neurological disorder with an age of onset typically between 2 and 6 years, presenting with seizures and/or cognitive regression. Its clinical course is progressive, leading to premature death, and often includes visual loss due to severe retinal dystrophy. In rare cases, pathogenic variants in MFSD8 can be associated with isolated non-syndromic macular dystrophy with variable age at onset, in which the disease process predominantly or exclusively affects the cones of the macula and where there are no neurological or neuropsychiatric manifestations. METHODS Here we present longitudinal studies on four adult-onset patients who were biallelic for four MFSD8 variants. RESULTS Two unrelated patients who presented with adult-onset ataxia and had macular dystrophy on examination were homozygous for a novel variant in MFSD8 NM_152778.4: c.935T>C p.(Ile312Thr). Two other patients presented in adulthood with visual symptoms, and one of these developed mild to moderate cerebellar ataxia years after the onset of visual symptoms. CONCLUSIONS Our observations expand the knowledge on biallelic pathogenic MFSD8 variants and confirm that these are associated with a spectrum of more heterogeneous clinical phenotypes. In MFSD8-related disease, adult-onset recessive ataxia can be the presenting manifestation or may occur in combination with retinal dystrophy.
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Affiliation(s)
- Sigurd Dobloug
- Department of NeurologyHelsingborg General HospitalHelsingborgSweden
- Department for Clinical Sciences, Lund, NeurologyLund UniversityLundSweden
| | | | - Glenn Anderson
- Department of HistopathologyGreat Ormond Street HospitalLondonUK
| | - Emily Gardner
- Great Ormond Street Institute of Child HealthUniversity College LondonLondonUK
| | - Sara E. Mole
- Great Ormond Street Institute of Child HealthUniversity College LondonLondonUK
| | - Jayesh Sheth
- Foundation for Research in Genetics and EndocrinologyInstitute of Human GeneticsAhmedabadIndia
| | - Andreas Puschmann
- Lund University, Skåne University Hospital, NeurologyLundSweden
- SciLifeLabLund UniversityLundSweden
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Kayani S, Edgar VB, Lowden A, Nettesheim ER, Dahshi H, Messahel S, Minassian BA, Greenberg BM. Neuronal Ceroid Lipofuscinoses Type 7 (CLN7)- A Case Series Reporting Cross Sectional and Retrospective Clinical Data to Evaluate Validity of Standardized Tools to Assess Disease Progression, Quality of Life, and Adaptive Skills. RESEARCH SQUARE 2024:rs.3.rs-3983366. [PMID: 38978590 PMCID: PMC11230482 DOI: 10.21203/rs.3.rs-3983366/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Background This study evaluated the clinical characteristics of neuronal ceroid lipofuscinosis type 7 or CLN7 disease spectrum to characterize the clinical, electrophysiologic and neuroimaging phenotypes. Methods We performed a single-center cross sectional data collection along with retrospective medical chart review in patients with a genetic diagnosis of CLN7. This study received ethical approval by the University of Texas Southwestern Medical Center Institutional Review Board. A total of 8 patients were included between the ages of 4 to 6 years. All patients had a genetic diagnosis of CLN7 with homozygous or compound heterozygous mutations in the MFSD8 gene. The information collected includes patient demographics, developmental history, neurological events including seizures and neurodevelopmental regression along with further evaluation of brain magnetic resonance imaging and electrophysiological findings. The clinical phenotype is described through cross sectional and retrospective data collection and standardized tools assessing quality of life and functional skills. Conclusions Our findings in this cohort of CLN7 patients indicated that development is initially normal with onset of clinical symptoms as early as two years of age. Language problems were noted prior to or at the onset of seizures in all cases. Gait problems were noted prior to seizure onset in 3 of 8 patients, and at or within 6 months after the onset of seizures in 5 of 8 patients. All patients followed a progressive course of language, motor, and neurocognitive deterioration. Congruent with the medical history, our patients had significantly low scores on adaptive abilities. Natural history data such as this can be used to support future clinical trial designs.
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Affiliation(s)
- Saima Kayani
- UT Southwestern: The University of Texas Southwestern Medical Center
| | | | - Andrea Lowden
- UT Southwestern: The University of Texas Southwestern Medical Center
| | | | - Hamza Dahshi
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Souad Messahel
- UT Southwestern: The University of Texas Southwestern Medical Center
| | - Berge A Minassian
- UT Southwestern: The University of Texas Southwestern Medical Center
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Bullock G, Johnson GS, Pattridge SG, Mhlanga-Mutangadura T, Guo J, Cook J, Campbell RS, Vite CH, Katz ML. A Homozygous MAN2B1 Missense Mutation in a Doberman Pinscher Dog with Neurodegeneration, Cytoplasmic Vacuoles, Autofluorescent Storage Granules, and an α-Mannosidase Deficiency. Genes (Basel) 2023; 14:1746. [PMID: 37761886 PMCID: PMC10531151 DOI: 10.3390/genes14091746] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
A 7-month-old Doberman Pinscher dog presented with progressive neurological signs and brain atrophy suggestive of a hereditary neurodegenerative disorder. The dog was euthanized due to the progression of disease signs. Microscopic examination of tissues collected at the time of euthanasia revealed massive accumulations of vacuolar inclusions in cells throughout the central nervous system, suggestive of a lysosomal storage disorder. A whole genome sequence generated with DNA from the affected dog contained a likely causal, homozygous missense variant in MAN2B1 that predicted an Asp104Gly amino acid substitution that was unique among whole genome sequences from over 4000 dogs. A lack of detectable α-mannosidase enzyme activity confirmed a diagnosis of a-mannosidosis. In addition to the vacuolar inclusions characteristic of α-mannosidosis, the dog exhibited accumulations of autofluorescent intracellular inclusions in some of the same tissues. The autofluorescence was similar to that which occurs in a group of lysosomal storage disorders called neuronal ceroid lipofuscinoses (NCLs). As in many of the NCLs, some of the storage bodies immunostained strongly for mitochondrial ATP synthase subunit c protein. This protein is not a substrate for α-mannosidase, so its accumulation and the development of storage body autofluorescence were likely due to a generalized impairment of lysosomal function secondary to the accumulation of α-mannosidase substrates. Thus, it appears that storage body autofluorescence and subunit c accumulation are not unique to the NCLs. Consistent with generalized lysosomal impairment, the affected dog exhibited accumulations of intracellular inclusions with varied and complex ultrastructural features characteristic of autophagolysosomes. Impaired autophagic flux may be a general feature of this class of disorders that contributes to disease pathology and could be a target for therapeutic intervention. In addition to storage body accumulation, glial activation indicative of neuroinflammation was observed in the brain and spinal cord of the proband.
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Affiliation(s)
- Garrett Bullock
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; (G.B.); (G.S.J.); (S.G.P.); (T.M.-M.); (J.G.)
| | - Gary S. Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; (G.B.); (G.S.J.); (S.G.P.); (T.M.-M.); (J.G.)
| | - Savannah G. Pattridge
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; (G.B.); (G.S.J.); (S.G.P.); (T.M.-M.); (J.G.)
| | - Tendai Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; (G.B.); (G.S.J.); (S.G.P.); (T.M.-M.); (J.G.)
| | - Juyuan Guo
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; (G.B.); (G.S.J.); (S.G.P.); (T.M.-M.); (J.G.)
| | - James Cook
- Specialists in Companion Animal Neurology, Clearwater, FL 33765, USA;
| | - Rebecca S. Campbell
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (R.S.C.); (C.H.V.)
| | - Charles H. Vite
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (R.S.C.); (C.H.V.)
| | - Martin L. Katz
- Neurodegenerative Diseases Research Laboratory, Department of Ophthalmology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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Linear Diagnostic Procedure Elicited by Clinical Genetics and Validated by mRNA Analysis in Neuronal Ceroid Lipofuscinosis 7 Associated with a Novel Non-Canonical Splice Site Variant in MFSD8. Genes (Basel) 2023; 14:genes14020245. [PMID: 36833170 PMCID: PMC9956376 DOI: 10.3390/genes14020245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/08/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
Abstract
Neuronal ceroid lipofuscinoses (CNL) are lysosomal storage diseases that represent the most common cause of dementia in children. To date, 13 autosomal recessive (AR) and 1 autosomal dominant (AD) gene have been characterized. Biallelic variants in MFSD8 cause CLN7 type, with nearly 50 pathogenic variants, mainly truncating and missense, reported so far. Splice site variants require functional validation. We detected a novel homozygous non-canonical splice-site variant in MFSD8 in a 5-year-old girl who presented with progressive neurocognitive impairment and microcephaly. The diagnostic procedure was elicited by clinical genetics first, and then confirmed by cDNA sequencing and brain imaging. Inferred by the common geographic origin of the parents, an autosomal recessive inheritance was hypothesized, and SNP-array was performed as the first-line genetic test. Only three AR genes lying within the observed 24 Mb regions of homozygosity were consistent with the clinical phenotype, including EXOSC9, SPATA5 and MFSD8. The cerebral and cerebellar atrophy detected in the meantime by MRI, along with the suspicion of accumulation of ceroid lipopigment in neurons, prompted us to perform targeted MFSD8 sequencing. Following the detection of a splice site variant of uncertain significance, skipping of exon 8 was demonstrated by cDNA sequencing, and the variant was redefined as pathogenic.
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Heinl ES, Lorenz S, Schmidt B, Nasser M Laqtom N, Mazzulli JR, Francelle L, Yu TW, Greenberg B, Storch S, Tegtmeier I, Othmen H, Maurer K, Steinfurth M, Witzgall R, Milenkovic V, Wetzel CH, Reichold M. CLN7/MFSD8 may be an important factor for SARS-CoV-2 cell entry. iScience 2022; 25:105082. [PMID: 36093380 PMCID: PMC9444308 DOI: 10.1016/j.isci.2022.105082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 05/12/2022] [Accepted: 08/31/2022] [Indexed: 11/12/2022] Open
Abstract
The SARS-CoV-2 virus has triggered a worldwide pandemic. According to the BioGrid database, CLN7 (MFSD8) is thought to interact with several viral proteins. The aim of this work was to investigate a possible involvement of CLN7 in the infection process. Experiments on a CLN7-deficient HEK293T cell line exhibited a 90% reduced viral load compared to wild-type cells. This observation may be linked to the finding that CLN7 ko cells have a significantly reduced GM1 content in their cell membrane. GM1 is found highly enriched in lipid rafts, which are thought to play an important role in SARS-CoV-2 infection. In contrast, overexpression of CLN7 led to an increase in viral load. This study provides evidence that CLN7 is involved in SARS-CoV-2 infection. This makes it a potential pharmacological target for drug development against COVID-19. Furthermore, it provides insights into the physiological function of CLN7 where still only little is known about.
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Affiliation(s)
- Elena-Sofia Heinl
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
| | - Sebastian Lorenz
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
| | - Barbara Schmidt
- Institute of Clinical Microbiology and Hygiene, University of Regensburg, 93053 Regensburg, Germany
| | - Nouf Nasser M Laqtom
- Departments of Chemical Engineering and Genetics, Stanford University, Stanford, CA 94305, USA
| | - Joseph R. Mazzulli
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Laetitia Francelle
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Timothy W. Yu
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Benjamin Greenberg
- Department of Neurology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Stephan Storch
- Children’s Hospital Biochemistry, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Ines Tegtmeier
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
| | - Helga Othmen
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
- Institute for Molecular and Cellular Anatomy, University Regensburg, 93053 Regensburg, Germany
| | - Katja Maurer
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
| | - Malin Steinfurth
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
| | - Ralph Witzgall
- Institute for Molecular and Cellular Anatomy, University Regensburg, 93053 Regensburg, Germany
| | - Vladimir Milenkovic
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Christian H. Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Markus Reichold
- Medical Cell Biology, University Regensburg, 93053 Regensburg, Germany
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6
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Poncet AF, Grunewald O, Vaclavik V, Meunier I, Drumare I, Pelletier V, Bocquet B, Todorova MG, Le Moing AG, Devos A, Schorderet DF, Jobic F, Defoort-Dhellemmes S, Dollfus H, Smirnov VM, Dhaenens CM. Contribution of Whole-Genome Sequencing and Transcript Analysis to Decipher Retinal Diseases Associated with MFSD8 Variants. Int J Mol Sci 2022; 23:ijms23084294. [PMID: 35457110 PMCID: PMC9032189 DOI: 10.3390/ijms23084294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 01/01/2023] Open
Abstract
Biallelic gene defects in MFSD8 are not only a cause of the late-infantile form of neuronal ceroid lipofuscinosis, but also of rare isolated retinal degeneration. We report clinical and genetic data of seven patients compound heterozygous or homozygous for variants in MFSD8, issued from a French cohort with inherited retinal degeneration, and two additional patients retrieved from a Swiss cohort. Next-generation sequencing of large panels combined with whole-genome sequencing allowed for the identification of twelve variants from which seven were novel. Among them were one deep intronic variant c.998+1669A>G, one large deletion encompassing exon 9 and 10, and a silent change c.750A>G. Transcript analysis performed on patients’ lymphoblastoid cell lines revealed the creation of a donor splice site by c.998+1669A>G, resulting in a 140 bp pseudoexon insertion in intron 10. Variant c.750A>G produced exon 8 skipping. In silico and in cellulo studies of these variants allowed us to assign the pathogenic effect, and showed that the combination of at least one severe variant with a moderate one leads to isolated retinal dystrophy, whereas the combination in trans of two severe variants is responsible for early onset severe retinal dystrophy in the context of late-infantile neuronal ceroid lipofuscinosis.
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Affiliation(s)
- Anaïs F. Poncet
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Veronika Vaclavik
- University of Lausanne, Jules-Gonin Eye Hospital, 1004 Lausanne, Switzerland;
- Cantonal Hospital, Department of Ophthalmology, 1700 Fribourg, Switzerland
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Isabelle Drumare
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Margarita G. Todorova
- Department of Ophthalmology, Cantonal Hospital, 9007 St. Gallen, Switzerland;
- Department of Ophthalmology, University of Zürich, 8091 Zürich, Switzerland
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland
| | - Anne-Gaëlle Le Moing
- Department of Child Neurology, Amiens-Picardy University Hospital, F-80000 Amiens, France;
| | - Aurore Devos
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Daniel F. Schorderet
- Faculty of Biology and Medicine, University of Lausanne and Faculty of Life Sciences, Ecole Polytechnique Fédérale of Lausanne, 1004 Lausanne, Switzerland;
| | - Florence Jobic
- Unité de Génétique Médicale et Oncogénétique, Centre Hospitalier Universitaire Amiens Picardie, F-80000 Amiens, France;
| | - Sabine Defoort-Dhellemmes
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Vasily M. Smirnov
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
- Université de Lille, Faculté de Médecine, F-59000 Lille, France
| | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
- Correspondence: ; Tel.: +33-320444953
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7
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Garanto A, Ferreira CR, Boon CJF, van Karnebeek CDM, Blau N. Clinical and biochemical footprints of inherited metabolic disorders. VII. Ocular phenotypes. Mol Genet Metab 2022; 135:311-319. [PMID: 35227579 PMCID: PMC10518078 DOI: 10.1016/j.ymgme.2022.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/19/2022] [Accepted: 02/11/2022] [Indexed: 12/11/2022]
Abstract
Ocular manifestations are observed in approximately one third of all inherited metabolic disorders (IMDs). Although ocular involvement is not life-threatening, it can result in severe vision loss, thereby leading to an additional burden for the patient. Retinal degeneration with or without optic atrophy is the most frequent phenotype, followed by oculomotor problems, involvement of the cornea and lens, and refractive errors. These phenotypes can provide valuable clues that contribute to its diagnosis. In this issue we found 577 relevant IMDs leading to ophthalmologic manifestations. This article is the seventh of a series attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnoses according to system involvement.
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Affiliation(s)
- Alejandro Garanto
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands and Amsterdam University Medical Centers, Academic Medical Center, Department of Ophthalmology, University of Amsterdam, Amsterdam, the Netherlands.
| | - Clara D M van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Departments of Pediatrics and Human Genetics, Emma Children's Hospital, Amsterdam Reproduction and Development, Amsterdam University Medical Centers, Amsterdam, the Netherlands.
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital, Zürich, Switzerland.
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8
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Chen X, Dong T, Hu Y, Shaffo FC, Belur NR, Mazzulli JR, Gray SJ. AAV9/MFSD8 gene therapy is effective in preclinical models of neuronal ceroid lipofuscinosis type 7 disease. J Clin Invest 2022; 132:146286. [PMID: 35025759 PMCID: PMC8884910 DOI: 10.1172/jci146286] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Neuronal ceroid lipofuscinosis type 7 (CLN7) disease is a lysosomal storage disease caused by mutations in the facilitator superfamily domain containing 8 (MFSD8) gene, which encodes a membrane-bound lysosomal protein, MFSD8. To test the effectiveness and safety of adeno-associated viral (AAV) gene therapy, an in vitro study demonstrated that AAV2/MFSD8 dose dependently rescued lysosomal function in fibroblasts from a CLN7 patient. An in vivo efficacy study using intrathecal administration of AAV9/MFSD8 to Mfsd8- /- mice at P7-P10 or P120 with high or low dose led to clear age- and dose-dependent effects. A high dose of AAV9/MFSD8 at P7-P10 resulted in widespread MFSD8 mRNA expression, tendency of amelioration of subunit c of mitochondrial ATP synthase accumulation and glial fibrillary acidic protein immunoreactivity, normalization of impaired behaviors, doubled median life span, and extended normal body weight gain. In vivo safety studies in rodents concluded that intrathecal administration of AAV9/MFSD8 was safe and well tolerated. In summary, these results demonstrated that the AAV9/MFSD8 vector is both effective and safe in preclinical models.
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Affiliation(s)
- Xin Chen
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Thomas Dong
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Yuhui Hu
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Frances C Shaffo
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
| | - Nandkishore R Belur
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Joseph R Mazzulli
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Steven J Gray
- Department of Pediatrics, University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA
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9
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A Novel, Apparently Silent Variant in MFSD8 Causes Neuronal Ceroid Lipofuscinosis with Marked Intrafamilial Variability. Int J Mol Sci 2022; 23:ijms23042271. [PMID: 35216386 PMCID: PMC8877174 DOI: 10.3390/ijms23042271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Variants in MFSD8 can cause neuronal ceroid lipofuscinoses (NCLs) as well as nonsyndromic retinopathy. The mutation spectrum includes mainly missense and stop variants, but splice sites and frameshift variants have also been reported. To date, apparently synonymous substitutions have not been shown to cause MFSD8-associated diseases. We report two closely related subjects from a consanguineous Turkish family who presented classical features of NCLs but demonstrated marked intrafamilial variability in age at the onset and severity of symptoms. In fact, the difference in the onset of first neurologic symptoms was 15 years and that of ophthalmologic symptoms was 12 years. One subject presented an intellectual disability and a considerable cerebellar ataxia syndrome, while the other subject showed no intellectual disability and only a mild atactic syndrome. The diagnostic genetic testing of both subjects based on genome sequencing prioritized a novel, apparently synonymous variant in MFSD8, which was found in homozygosity in both subjects. The variant was not located within an integral part of the splice site consensus sequences. However, the bioinformatic analyses suggested that the mutant allele is more likely to cause exon skipping due to an altered ratio of exonic splice enhancer and silencer motifs. Exon skipping was confirmed in vitro by minigene assays and in vivo by RNA analysis from patient lymphocytes. The mutant transcript is predicted to result in a frameshift and, if translated, in a truncated protein. Synonymous variants are often given a low priority in genetic diagnostics because of their expected lack of functional impact. This study highlights the importance of investigating the impact of synonymous variants on splicing.
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10
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Rossi M, van der Veen S, Merello M, Tijssen MAJ, van de Warrenburg B. Myoclonus-Ataxia Syndromes: A Diagnostic Approach. Mov Disord Clin Pract 2020; 8:9-24. [PMID: 33426154 DOI: 10.1002/mdc3.13106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/30/2020] [Accepted: 10/14/2020] [Indexed: 12/30/2022] Open
Abstract
Background A myriad of disorders combine myoclonus and ataxia. Most causes are genetic and an increasing number of genes are being associated with myoclonus-ataxia syndromes (MAS), due to recent advances in genetic techniques. A proper etiologic diagnosis of MAS is clinically relevant, given the consequences for genetic counseling, treatment, and prognosis. Objectives To review the causes of MAS and to propose a diagnostic algorithm. Methods A comprehensive and structured literature search following PRISMA criteria was conducted to identify those disorders that may combine myoclonus with ataxia. Results A total of 135 causes of combined myoclonus and ataxia were identified, of which 30 were charted as the main causes of MAS. These include four acquired entities: opsoclonus-myoclonus-ataxia syndrome, celiac disease, multiple system atrophy, and sporadic prion diseases. The distinction between progressive myoclonus epilepsy and progressive myoclonus ataxia poses one of the main diagnostic dilemmas. Conclusions Diagnostic algorithms for pediatric and adult patients, based on clinical manifestations including epilepsy, are proposed to guide the differential diagnosis and corresponding work-up of the most important and frequent causes of MAS. A list of genes associated with MAS to guide genetic testing strategies is provided. Priority should be given to diagnose or exclude acquired or treatable disorders.
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Affiliation(s)
- Malco Rossi
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina
| | - Sterre van der Veen
- Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina.,Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands
| | - Marcelo Merello
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina.,Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina
| | - Marina A J Tijssen
- Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands.,Expertise Center Movement Disorders Groningen University Medical Center Groningen (UMCG) Groningen The Netherlands
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition & Behaviour Radboud University Medical Center Nijmegen The Netherlands
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11
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Bauwens M, Storch S, Weisschuh N, Ceuterick‐de Groote C, De Rycke R, Guillemyn B, De Jaegere S, Coppieters F, Van Coster R, Leroy BP, De Baere E. Functional characterization of novel MFSD8 pathogenic variants anticipates neurological involvement in juvenile isolated maculopathy. Clin Genet 2020; 97:426-436. [PMID: 31721179 PMCID: PMC7064892 DOI: 10.1111/cge.13673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/22/2022]
Abstract
Biallelic MFSD8 variants are an established cause of severe late-infantile subtype of neuronal ceroid lipofuscinosis (v-LINCL), a severe lysosomal storage disorder, but have also been associated with nonsyndromic adult-onset maculopathy. Here, we functionally characterized two novel MFSD8 variants found in a child with juvenile isolated maculopathy, in order to establish a refined prognosis. ABCA4 locus resequencing was followed by the analysis of other inherited retinal disease genes by whole exome sequencing (WES). Minigene assays and cDNA sequencing were used to assess the effect of a novel MFSD8 splice variant. MFSD8 expression was quantified with qPCR and overexpression studies were analyzed by immunoblotting. Transmission electron microscopy (TEM) was performed on a skin biopsy and ophthalmological and neurological re-examinations were conducted. WES revealed two novel MFSD8 variants: c.[590del];[439+3A>C] p.[Gly197Valfs*2];[Ile67Glufs*3]. Characterization of the c.439+3A>C variant via splice assays showed exon-skipping (p.Ile67Glufs*3), while overexpression studies of the corresponding protein indicated expression of a truncated polypeptide. In addition, a significantly reduced MFSD8 RNA expression was noted in patient's lymphocytes. TEM of a skin biopsy revealed typical v-LINCL lipopigment inclusions while neurological imaging of the proband displayed subtle cerebellar atrophy. Functional characterization demonstrated the pathogenicity of two novel MFSD8 variants, found in a child with an initial diagnosis of juvenile isolated maculopathy but likely evolving to v-LINCL with a protracted disease course. Our study allowed a refined neurological prognosis in the proband and expands the natural history of MFSD8-associated disease.
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Affiliation(s)
| | - Stephan Storch
- Department of Biochemistry, Children's HospitalUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Nicole Weisschuh
- Molecular Genetics Laboratory, Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
| | | | - Riet De Rycke
- Department of Biomedical Molecular BiologyGhent UniversityGhentBelgium
- VIB‐UGent Center for Inflammation ResearchGhentBelgium
- Ghent University Expertise Centre for Transmission Electron Microscopy and VIB BioImaging CoreGhentBelgium
| | | | - Sarah De Jaegere
- Center for Medical GeneticsGhent University HospitalGhentBelgium
| | | | - Rudy Van Coster
- Department of Pediatrics, Division of Pediatric Neurology and MetabolismGhent University HospitalGhentBelgium
| | - Bart P. Leroy
- Center for Medical GeneticsGhent University HospitalGhentBelgium
- Department of OphthalmologyGhent University and Ghent University HospitalGhentBelgium
- Division of Ophthalmology and Center for Cellular & Molecular TherapeuticsThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Elfride De Baere
- Center for Medical GeneticsGhent UniversityGhentBelgium
- Center for Medical GeneticsGhent University HospitalGhentBelgium
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12
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Zare-Abdollahi D, Bushehri A, Alavi A, Dehghani A, Mousavi-Mirkala M, Effati J, Miratashi SAM, Dehani M, Jamali P, Khorram Khorshid HR. MFSD8 gene mutations; evidence for phenotypic heterogeneity. Ophthalmic Genet 2019; 40:141-145. [PMID: 31006324 DOI: 10.1080/13816810.2019.1592200] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Cone-rod dystrophies are a group of genetically and phenotypically heterogeneous inherited degenerative retinal diseases primarily affecting macular and cone system function. MFSD8 loss-of-function variants are mainly related to the variant late-infantile neuronal ceroid lipofuscinoses which present with progressive motor and mental regression in combination with seizures, ataxia, and visual impairment. MATERIAL AND METHODS Clinical examination and genomic DNA extraction were collected from two unrelated Iranian families presenting with autosomal recessive cone-rod dystrophy. The candidate disease-causing variant was screened with whole-exome sequencing and bioinformatics analyses. Sanger sequencing was used for validation and co-segregation analysis. RESULTS Two previously reported variants (c.1361T>C; p.M454T and c.1235C>T; p.P412L) and in a compound heterozygous pattern in one family and a homozygous variant (c.1361T>C; p.M454T) identical to one of the variants in the first family in MFSD8 gene were identified. Both confirmed by Sanger sequencing and co-segregated with disease status. CONCLUSIONS Here and for the first time, we reported on two previously variant late-infantile neuronal ceroid lipofuscinoses-associated variants in MFSD8 but in association with a form of cone-rod dystrophy known as non-syndromic macular dystrophy with central cone involvement. Our results support this concept that variant late-infantile neuronal ceroid lipofuscinoses and non-syndromic macular dystrophy with central cone involvement are not different disease entities, but rather allelic diseases and phenotypic variants of the same mutation. Consideration of the milder MFSD8 phenotypes is important against the potentially severe consequences of life-threatening conditions associated with MFSD8 mutations in order to prevent the danger of misdiagnosis as well as the accuracy of genetic counseling.
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Affiliation(s)
- Davood Zare-Abdollahi
- a Genetics Research Center , University of Social Welfare and Rehabilitation Sciences , Tehran , Iran
| | - Ata Bushehri
- a Genetics Research Center , University of Social Welfare and Rehabilitation Sciences , Tehran , Iran
| | - Afagh Alavi
- a Genetics Research Center , University of Social Welfare and Rehabilitation Sciences , Tehran , Iran
| | - Alireza Dehghani
- b Department of Ophthalmology , Eye Research Center, Isfahan University of Medical Sciences , Isfahan , Iran
| | | | - Jalil Effati
- d Meybod Genetic Research Center, State Welfare Organization of Yazd , Yazd , Iran
| | | | - Mohammad Dehani
- a Genetics Research Center , University of Social Welfare and Rehabilitation Sciences , Tehran , Iran
| | - Payman Jamali
- f Shahrood Genetic Counseling Center , Welfare Office , Semnan , Iran
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13
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Geier EG, Bourdenx M, Storm NJ, Cochran JN, Sirkis DW, Hwang JH, Bonham LW, Ramos EM, Diaz A, Van Berlo V, Dokuru D, Nana AL, Karydas A, Balestra ME, Huang Y, Russo SP, Spina S, Grinberg LT, Seeley WW, Myers RM, Miller BL, Coppola G, Lee SE, Cuervo AM, Yokoyama JS. Rare variants in the neuronal ceroid lipofuscinosis gene MFSD8 are candidate risk factors for frontotemporal dementia. Acta Neuropathol 2019; 137:71-88. [PMID: 30382371 PMCID: PMC6371791 DOI: 10.1007/s00401-018-1925-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 12/21/2022]
Abstract
Pathogenic variation in MAPT, GRN, and C9ORF72 accounts for at most only half of frontotemporal lobar degeneration (FTLD) cases with a family history of neurological disease. This suggests additional variants and genes that remain to be identified as risk factors for FTLD. We conducted a case-control genetic association study comparing pathologically diagnosed FTLD patients (n = 94) to cognitively normal older adults (n = 3541), and found suggestive evidence that gene-wide aggregate rare variant burden in MFSD8 is associated with FTLD risk. Because homozygous mutations in MFSD8 cause neuronal ceroid lipofuscinosis (NCL), similar to homozygous mutations in GRN, we assessed rare variants in MFSD8 for relevance to FTLD through experimental follow-up studies. Using post-mortem tissue from middle frontal gyrus of patients with FTLD and controls, we identified increased MFSD8 protein levels in MFSD8 rare variant carriers relative to non-variant carrier patients with sporadic FTLD and healthy controls. We also observed an increase in lysosomal and autophagy-related proteins in MFSD8 rare variant carrier and sporadic FTLD patients relative to controls. Immunohistochemical analysis revealed that MFSD8 was expressed in neurons and astrocytes across subjects, without clear evidence of abnormal localization in patients. Finally, in vitro studies identified marked disruption of lysosomal function in cells from MFSD8 rare variant carriers, and identified one rare variant that significantly increased the cell surface levels of MFSD8. Considering the growing evidence for altered autophagy in the pathogenesis of neurodegenerative disorders, our findings support a role of NCL genes in FTLD risk and suggest that MFSD8-associated lysosomal dysfunction may contribute to FTLD pathology.
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Affiliation(s)
- Ethan G Geier
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Mathieu Bourdenx
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Nadia J Storm
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | | | - Daniel W Sirkis
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Ji-Hye Hwang
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Luke W Bonham
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Eliana Marisa Ramos
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Antonio Diaz
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Victoria Van Berlo
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Deepika Dokuru
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Alissa L Nana
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Anna Karydas
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | | | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Silvia P Russo
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Salvatore Spina
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Lea T Grinberg
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - William W Seeley
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Richard M Myers
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA
| | - Bruce L Miller
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Giovanni Coppola
- Department of Psychiatry and Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Suzee E Lee
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Ana Maria Cuervo
- Department of Development and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Jennifer S Yokoyama
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA.
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14
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Birtel J, Gliem M, Mangold E, Müller PL, Holz FG, Neuhaus C, Lenzner S, Zahnleiter D, Betz C, Eisenberger T, Bolz HJ, Charbel Issa P. Next-generation sequencing identifies unexpected genotype-phenotype correlations in patients with retinitis pigmentosa. PLoS One 2018; 13:e0207958. [PMID: 30543658 PMCID: PMC6292620 DOI: 10.1371/journal.pone.0207958] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited degenerative disease causing severe retinal dystrophy and visual impairment mainly with onset in infancy or adolescence. Targeted next-generation sequencing (NGS) has become an efficient tool to encounter the enormous genetic heterogeneity of diverse retinal dystrophies, including RP. To identify disease-causing mutations in unselected, consecutive RP patients, we conducted Sanger sequencing of genes commonly involved in the suspected genetic RP subtype, followed by targeted large-panel NGS if no mutation was identified, or NGS as primary analysis. A high (70%) detection rate of disease-causing mutations was achieved in a large cohort of 116 unrelated patients. About half (48%) of the solved RP cases were explained by mutations in four genes: RPGR, EYS, PRPF31 and USH2A. Overall, 110 different mutations distributed across 30 different genes were detected, and 46 of these mutations were novel. A molecular diagnosis was achieved in the majority (82–100%) of patients if the family history was suggestive for a particular mode of inheritance, but only in 60% in cases of sporadic RP. The diagnostic potential of extensive molecular analysis in a routine setting is also illustrated by the identification of unexpected genotype-phenotype correlations for RP patients with mutations in CRX, CEP290, RPGRIP1, MFSD8. Furthermore, we identified numerous mutations in autosomal dominant (PRPF31, PRPH2, CRX) and X-linked (RPGR) RP genes in patients with sporadic RP. Variants in RP2 and RPGR were also found in female RP patients with apparently sporadic or dominant disease. In summary, this study demonstrates that massively parallel sequencing of all known retinal dystrophy genes is a valuable diagnostic approach for RP patients.
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Affiliation(s)
- Johannes Birtel
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | - Martin Gliem
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | | | - Philipp L. Müller
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | - Frank G. Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | | | | | | | - Christian Betz
- Bioscientia Center for Human Genetics, Ingelheim, Germany
| | | | - Hanno J. Bolz
- Bioscientia Center for Human Genetics, Ingelheim, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Peter Charbel Issa
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- * E-mail:
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15
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Kozina AA, Okuneva EG, Baryshnikova NV, Krasnenko AY, Tsukanov KY, Klimchuk OI, Kondakova OB, Larionova AN, Batysheva TT, Surkova EI, Shatalov PA, Ilinsky VV. A novel MFSD8 mutation in a Russian patient with neuronal ceroid lipofuscinosis type 7: a case report. BMC MEDICAL GENETICS 2018; 19:151. [PMID: 30144815 PMCID: PMC6109285 DOI: 10.1186/s12881-018-0669-7] [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: 06/01/2018] [Accepted: 08/17/2018] [Indexed: 12/30/2022]
Abstract
Background Neuronal ceroid lipofuscinoses (NCLs) are the most common autosomal recessive neurodegenerative disorders in children. Clinical manifestations include progressive cognitive decline, motor impairment, ataxia, visual loss, seizures and early death. To date more than 440 NCL-causing mutations in 13 genes are known. Case presentation We report clinical and genetic characteristics of a 5-year-old girl affected by ceroid lipofuscinosis type 7 (NCL7). She had progressive motor and mental deterioration since the age of 2,5 years. Later she developed progressive vision loss, stereotypies, action myoclonus and epilepsy. By the age of 5 years she stopped walking. Based on symptoms, diagnosis of Rett syndrome was suggested, but no abnormalities were detected in MeCP2. We identified a novel homozygous mutation in MFSD8 gene (c.525 T > A, p.Cys175Ter). To our knowledge, this is the first report of MFSD8 gene mutation in a Russian patient with variant late-infantile NCL. Conclusions Our results enlarge mutational spectrum of ceroid lipofuscinosis type 7 and demonstrate tremendous diagnosis value of exome sequencing for pediatric NCLs. Also we confirmed that NCL should be suspected in patients with Rett-like phenotype at onset and negative MECP2 mutation.
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Affiliation(s)
- Anastasiya Aleksandrovna Kozina
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia
| | | | - Natalia Vladimirovna Baryshnikova
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia
| | - Anna Yurievna Krasnenko
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia
| | | | | | - Olga Borisovna Kondakova
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | - Anna Nikolaevna Larionova
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | - Tatyana Timofeevna Batysheva
- Scientific and Practical Centre of Pediatric psychoneurology of Moscow Healthcare Department, Michurinsky prospect, 74, 119602, Moscow, Russia
| | | | - Peter Alekseevich Shatalov
- Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Taldomskaya str 2, 125412, Moscow, Russia
| | - Valery Vladimirovich Ilinsky
- Institute of Biomedical Chemistry, Pogodinskaya street 10 building 8, 119121, Moscow, Russia.,Genotek Ltd, Nastavnicheskii pereulok 17/1, 105120, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianova street 1, 117997, Moscow, Russia.,Vavilov Institute of General Genetics, Gubkina street 3, 119333, Moscow, Russia
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16
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Danyukova T, Ariunbat K, Thelen M, Brocke-Ahmadinejad N, Mole SE, Storch S. Loss of CLN7 results in depletion of soluble lysosomal proteins and impaired mTOR reactivation. Hum Mol Genet 2018; 27:1711-1722. [PMID: 29514215 PMCID: PMC5932567 DOI: 10.1093/hmg/ddy076] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/15/2022] Open
Abstract
Defects in the MFSD8 gene encoding the lysosomal membrane protein CLN7 lead to CLN7 disease, a neurodegenerative lysosomal storage disorder belonging to the group of neuronal ceroid lipofuscinoses. Here, we have performed a SILAC-based quantitative analysis of the lysosomal proteome using Cln7-deficient mouse embryonic fibroblasts (MEFs) from a Cln7 knockout (ko) mouse model. From 3335 different proteins identified, we detected 56 soluble lysosomal proteins and 29 highly abundant lysosomal membrane proteins. Quantification revealed that the amounts of 12 different soluble lysosomal proteins were significantly reduced in Cln7 ko MEFs compared with wild-type controls. One of the most significantly depleted lysosomal proteins was Cln5 protein that underlies another distinct neuronal ceroid lipofuscinosis disorder. Expression analyses showed that the mRNA expression, biosynthesis, intracellular sorting and proteolytic processing of Cln5 were not affected, whereas the depletion of mature Cln5 protein was due to increased proteolytic degradation by cysteine proteases in Cln7 ko lysosomes. Considering the similar phenotypes of CLN5 and CLN7 patients, our data suggest that depletion of CLN5 may play an important part in the pathogenesis of CLN7 disease. In addition, we found a defect in the ability of Cln7 ko MEFs to adapt to starvation conditions as shown by impaired mammalian target of rapamycin complex 1 reactivation, reduced autolysosome tubulation and increased perinuclear accumulation of autolysosomes compared with controls. In summary, depletion of multiple soluble lysosomal proteins suggest a critical role of CLN7 for lysosomal function, which may contribute to the pathogenesis and progression of CLN7 disease.
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Affiliation(s)
- Tatyana Danyukova
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Khandsuren Ariunbat
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Melanie Thelen
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | | | - Sara E Mole
- MRC Laboratory for Molecular Cell Biology, Department of Genetics, Evolution and Environment & UCL GOSH Institute of Child Health, University College London, London WC1E 6BT, UK
| | - Stephan Storch
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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