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Kimball TN, García-Rueda AG, Rivero-García P, Pérez-Segovia AH, Mayoral-Carrasco LE. Recognizing Lipofuscinosis as a Guide in Antiepileptic Treatment: Clinical Description of the First Mexican Case With Neuronal Ceroid Lipofuscinosis Type 7 (NCL7). Cureus 2024; 16:e56914. [PMID: 38659533 PMCID: PMC11042739 DOI: 10.7759/cureus.56914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
Neuronal ceroid lipofuscinosis type 7 (NCL7) is a rare form of childhood dementia; it is part of a group of diseases characterized by rapid progressive cognitive decline, blindness associated with retinitis pigmentosa, and seizures. We report the clinical and molecular characteristics of the first Mexican patient with NCL7, highlighting a particularly atypical disease course. The typical presentation form is expected to have reduced life expectancy and an average age of ambulation loss at 12 years. Our 27-year-old patient retains the ability to walk. The patient's unique presentation could, in part, be attributed to her genetic profile: a hypomorphic allele carrying a missense variant (c.1390G>A) and an almost null allele with a frameshift variant (c.1086del), contributing to the preservation of some protein function. Throughout her childhood and early adulthood, our patient experienced a variable response to antiseizure drugs, attributed to a lack of recognition of the disease and the specific efficacy of certain antiseizure medications. Our findings underscore the significance of considering this genetic condition and acknowledging its clinical heterogeneity.
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Affiliation(s)
- Tamara N Kimball
- Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, MEX
| | - Andrea G García-Rueda
- Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, MEX
| | - Pamela Rivero-García
- Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, MEX
| | - Aarón H Pérez-Segovia
- Radiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, MEX
| | - Luis E Mayoral-Carrasco
- Genetics, Instituto Nacional de Neurologia y Neurocirugia Manuel Velasco Suarez, Mexico City, MEX
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2
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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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3
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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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4
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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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Rashmi R, Majumdar S. Pan-Cancer Analysis Reveals the Prognostic Potential of the THAP9/THAP9-AS1 Sense-Antisense Gene Pair in Human Cancers. Noncoding RNA 2022; 8:ncrna8040051. [PMID: 35893234 PMCID: PMC9326536 DOI: 10.3390/ncrna8040051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/11/2022] [Accepted: 06/13/2022] [Indexed: 11/18/2022] Open
Abstract
Human THAP9, which encodes a domesticated transposase of unknown function, and lncRNA THAP9-AS1 (THAP9-antisense1) are arranged head-to-head on opposite DNA strands, forming a sense and antisense gene pair. We predict that there is a bidirectional promoter that potentially regulates the expression of THAP9 and THAP9-AS1. Although both THAP9 and THAP9-AS1 are reported to be involved in various cancers, their correlative roles on each other’s expression has not been explored. We analyzed the expression levels, prognosis, and predicted biological functions of the two genes across different cancer datasets (TCGA, GTEx). We observed that although the expression levels of the two genes, THAP9 and THAP9-AS1, varied in different tumors, the expression of the gene pair was strongly correlated with patient prognosis; higher expression of the gene pair was usually linked to poor overall and disease-free survival. Thus, THAP9 and THAP9-AS1 may serve as potential clinical biomarkers of tumor prognosis. Further, we performed a gene co-expression analysis (using WGCNA) followed by a differential gene correlation analysis (DGCA) across 22 cancers to identify genes that share the expression pattern of THAP9 and THAP9-AS1. Interestingly, in both normal and cancer samples, THAP9 and THAP9-AS1 often co-express; moreover, their expression is positively correlated in each cancer type, suggesting the coordinated regulation of this H2H gene pair.
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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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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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8
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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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9
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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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10
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Magliyah M, AlRaddadi O, Balbaid A, Schatz P. Multimodal retinal imaging in MFSD8-neuronal ceroid lipofuscinosis. Ophthalmic Genet 2020; 40:588-590. [PMID: 31909682 DOI: 10.1080/13816810.2019.1709125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Moustafa Magliyah
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Ophthalmology Department, Prince Mohammed Medical City, AlJouf, Saudi Arabia
| | - Osama AlRaddadi
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Ophthalmology Department, Ohud Hospital, Madinah, Saudi Arabia
| | - Abdullah Balbaid
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Retina Department, Jeddah Eye Hospital, Jeddah, Saudi Arabia
| | - Patrik Schatz
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Department of Ophthalmology, Clinical Sciences, Skane County University Hospital, Lund University, Lund, Sweden
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11
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Ravooru N, Paul OS, Nagendra HG, Sathyanarayanan N. Data enabled prediction analysis assigns folate/biopterin transporter (BT1) family to 36 hypothetical membrane proteins in Leishmania donovani. Bioinformation 2019; 15:697-708. [PMID: 31831951 PMCID: PMC6900323 DOI: 10.6026/97320630015697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 11/23/2022] Open
Abstract
Leishmaniasis is a neglected tropical disease caused by the pathogenic protozoan Leishmania donovani and it is transmitted by an infected sand fly. Approximately 0.4 million cases of Visceral Leishmaniasis are reported across the globe every year, of which 67% is from the Indian subcontinent. The currently available drugs have not been effective owing to their high toxicity levels, inadequate specificity, drug resistance, extended treatment periods and/or prohibitive prices. For this reason, hypothetical proteins in this pathogen, which constitute about 67% of its proteome, must be distinctly characterized and studied for their potential role as drug targets for Leishmaniasis. Domain information from PFAM and functional information from GO has been used to assign putative functions to 36 hypothetical membrane proteins in this protozoan. Furthermore, as a case study, we have performed a thorough sequence level characterization of a hypothetical protein E9BPD7 from the BT1 family of membrane proteins that transports folate/biopterin. Phylogenetic analyses of E9BPD7 have revealed interesting evolutionary correlations to BT1 family and MFS superfamily, which have significant roles in a number of diseases and drug resistance pathways.
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Affiliation(s)
- Nithin Ravooru
- Department of Biotechnology, Sir M Visvesvaraya Institute of Technology,Bangalore
- University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Ojal Sarah Paul
- Department of Biotechnology, Sir M Visvesvaraya Institute of Technology,Bangalore
| | | | - Nitish Sathyanarayanan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research,Bangalore
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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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von Kleist L, Ariunbat K, Braren I, Stauber T, Storch S, Danyukova T. A newly generated neuronal cell model of CLN7 disease reveals aberrant lysosome motility and impaired cell survival. Mol Genet Metab 2019; 126:196-205. [PMID: 30301600 DOI: 10.1016/j.ymgme.2018.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/26/2018] [Accepted: 09/26/2018] [Indexed: 01/11/2023]
Abstract
Mutations in the CLN7/MFSD8 gene encoding the lysosomal membrane protein CLN7 are causative of CLN7 disease, an inherited neurodegenerative disorder that typically affects children. To gain insight into the pathomechanisms of CLN7 disease, we established an immortalized cell line based on cerebellar (Cb) granule neuron precursors isolated from Cln7-/- mice. Here, we demonstrate that Cln7-deficient neuron-derived Cb cells display an abnormal phenotype that includes increased size and defective outward movement of late endosomes and lysosomes as well as impaired lysosomal exocytosis. Whereas Cln7-/- Cb cells appeared to be autophagy-competent, loss of Cln7 resulted in enhanced cell death under prolonged nutrient deprivation. Furthermore, reduced cell survival of Cln7-deficient cells was accompanied by a significantly impaired protein kinase B/Akt phosphorylation at Ser473 during long-term starvation. In summary, our data demonstrate for the first time that the putative lysosomal transporter CLN7 is relevant for lysosome motility and plays an important role for neuronal cell survival under conditions of starvation.
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Affiliation(s)
- Lisa von Kleist
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Khandsuren Ariunbat
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Ingke Braren
- Vector Core Unit, Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Stephan Storch
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Tatyana Danyukova
- Section Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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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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15
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Guo J, O'Brien DP, Mhlanga-Mutangadura T, Olby NJ, Taylor JF, Schnabel RD, Katz ML, Johnson GS. A rare homozygous MFSD8 single-base-pair deletion and frameshift in the whole genome sequence of a Chinese Crested dog with neuronal ceroid lipofuscinosis. BMC Vet Res 2015; 10:960. [PMID: 25551667 PMCID: PMC4298050 DOI: 10.1186/s12917-014-0181-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 08/06/2014] [Indexed: 02/02/2023] Open
Abstract
Background The neuronal ceroid lipofuscinoses are heritable lysosomal storage diseases characterized by progressive neurological impairment and the accumulation of autofluorescent storage granules in neurons and other cell types. Various forms of human neuronal ceroid lipofuscinosis have been attributed to mutations in at least 13 different genes. So far, mutations in the canine orthologs of 7 of these genes have been identified in DNA from dogs with neuronal ceroid lipofuscinosis. The identification of new causal mutations could lead to the establishment of canine models to investigate the pathogenesis of the corresponding human neuronal ceroid lipofuscinoses and to evaluate and optimize therapeutic interventions for these fatal human diseases. Case presentation We obtained blood and formalin-fixed paraffin-embedded brain sections from a rescue dog that was reported to be a young adult Chinese Crested. The dog was euthanized at approximately 19 months of age as a consequence of progressive neurological decline that included blindness, anxiety, and cognitive impairment. A diagnosis of neuronal ceroid lipofuscinosis was made based on neurological signs, magnetic resonance imaging of the brain, and fluorescence microscopic and electron microscopic examination of brain sections. We isolated DNA from the blood and used it to generate a whole genome sequence with 33-fold average coverage. Among the 7.2 million potential sequence variants revealed by aligning the sequence reads to the canine genome reference sequence was a homozygous single base pair deletion in the canine ortholog of one of 13 known human NCL genes: MFSD8:c.843delT. MFSD8:c.843delT is predicted to cause a frame shift and premature stop codon resulting in a truncated protein, MFSD8:p.F282Lfs13*, missing its 239 C-terminal amino acids. The MFSD8:c.843delT allele is absent from the whole genome sequences of 101 healthy canids or dogs with other diseases. The genotyping of archived DNA from 1478 Chinese Cresteds did not identify any additional MFSD8:c.843delT homozygotes and found only one heterozygote. Conclusion We conclude that the neurodegenerative disease of the Chinese Crested rescue dog was neuronal ceroid lipofuscinosis and that homozygosity for the MFSD8:c.843delT sequence variant was very likely to be the molecular-genetic cause of the disease. Electronic supplementary material The online version of this article (doi:10.1186/s12917-014-0181-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juyuan Guo
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Dennis P O'Brien
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Tendai Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
| | - Natasha J Olby
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
| | - Jeremy F Taylor
- Division of Animal Science, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA.
| | - Robert D Schnabel
- Division of Animal Science, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA.
| | - Martin L Katz
- Mason Eye Institute, School of Medicine, University of Missouri, Columbia, MO, USA.
| | - Gary S Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
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Roosing S, van den Born LI, Sangermano R, Banfi S, Koenekoop RK, Zonneveld-Vrieling MN, Klaver CCW, van Lith-Verhoeven JJC, Cremers FPM, den Hollander AI, Hoyng CB. Mutations in MFSD8, encoding a lysosomal membrane protein, are associated with nonsyndromic autosomal recessive macular dystrophy. Ophthalmology 2015; 122:170-9. [PMID: 25227500 DOI: 10.1016/j.ophtha.2014.07.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/21/2014] [Accepted: 07/21/2014] [Indexed: 01/09/2023] Open
Abstract
PURPOSE This study aimed to identify the genetic defects in 2 families with autosomal recessive macular dystrophy with central cone involvement. DESIGN Case series. PARTICIPANTS Two families and a cohort of 244 individuals with various inherited maculopathies and cone disorders. METHODS Genome-wide linkage analysis and exome sequencing were performed in 1 large family with 5 affected individuals. In addition, exome sequencing was performed in the proband of a second family. Subsequent analysis of the identified mutations in 244 patients was performed by Sanger sequencing or restriction enzyme digestion. The medical history of individuals carrying the MFSD8 variants was reviewed and additional ophthalmic examinations were performed, including electroretinography (ERG), multifocal ERG (mfERG), perimetry, optical coherence tomography (OCT), fundus autofluorescence, and fundus photography. MAIN OUTCOME MEASURES MFSD8 variants, age at diagnosis, visual acuity, fundus appearance, color vision defects, visual field, ERG, mfERG, fundus autofluorescence, and OCT findings. RESULTS Compound heterozygous variants in MFSD8, a gene encoding a lysosomal transmembrane protein, were identified in 2 families with macular dystrophy with a normal or subnormal ERG, but reduced mfERG. In both families, a heterozygous missense variant p.Glu336Gln was identified, which was predicted to have a mild effect on the protein. In the first family, a protein-truncating variant (p.Glu381*) was identified on the other allele, and in the second family, a variant (c.1102G>C) was identified that results in a splicing defect leading to skipping of exon 11 (p.Lys333Lysfs*3). The p.Glu336Gln allele was found to be significantly enriched in patients with maculopathies and cone disorders (6/488) compared with ethnically matched controls (35/18 682; P < 0.0001), suggesting that it may act as a genetic modifier. CONCLUSIONS In this study, we identified variants in MFSD8 as a novel cause of nonsyndromic autosomal recessive macular dystrophy with central cone involvement. Affected individuals showed no neurologic features typical for variant late-infantile neuronal ceroid lipofuscinosis (vLINCL), a severe and devastating multisystem lysosomal storage disease previously associated with mutations in MFSD8. We propose a genotype-phenotype model in which a combination of a severe and a mild variant cause nonsyndromic macular dystrophy with central cone involvement, and 2 severe mutations cause vLINCL.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands; Current affiliation: Howard Hughes Medical Institute, The Rockefeller University, Department for Pediatric Brain Diseases, New York, New York
| | | | - Riccardo Sangermano
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Naples, Italy; Medical Genetics, Department of Biochemistry, Biophysics, and General Pathology, Second University of Naples, Naples, Italy
| | - Robert K Koenekoop
- McGill Ocular Genetics Laboratory, McGill University Health Centre, Montreal, Quebec, Canada
| | | | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Centre, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | | | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
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Craiu D, Dragostin O, Dica A, Hoffman-Zacharska D, Gos M, Bastian AE, Gherghiceanu M, Rolfs A, Nahavandi N, Craiu M, Iliescu C. Rett-like onset in late-infantile neuronal ceroid lipofuscinosis (CLN7) caused by compound heterozygous mutation in the MFSD8 gene and review of the literature data on clinical onset signs. Eur J Paediatr Neurol 2015; 19:78-86. [PMID: 25439737 DOI: 10.1016/j.ejpn.2014.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 07/16/2014] [Accepted: 07/27/2014] [Indexed: 02/05/2023]
Abstract
BACKGROUND We present clinical and molecular findings of a patient with ceroid-lipofuscinosis CLN7, with a compound heterozygous mutation of the MFSD8 gene, with Rett syndrome clinical signs onset and a later development of full picture of vLINCL. CASE PRESENTATION A 7 years-old female patient with normal development until the age 12 months, developed Rett like clinical picture (psychomotor regression, microcephaly, stereotypic hands movements in the midline, hyperventilation episodes) present at the onset of her condition (age 18 months), features still present at the initial evaluation in our clinic at age 5 years. RESULTS MECP2 (methyl CpG binding protein 2) gene mutation was negative. At age 6 years she was readmitted for severe ataxia and blindness, seizures, and severe developmental regression leading to NCL (neuronal ceroid lipofuscinosis) suspicion. EEG showed slow background with IRDA (intermittent rhythmic delta activity). A conjunctive biopsy showed abnormal curvilinear and fingerprint lysosomal deposits, and genetic analysis revealed two heterozygous mutations of MFSD8 gene (c.881C > A p.Thr294Lys and c.754 + 2T > A) each inherited from carrier parents and a heterozygous variant (c.470A>C p.Asp157Ala) of CLN5 gene. CONCLUSION NCL should be suspected and MFSD8 genetic testing should also be considered in patients with Rett like phenotype at onset and negative MECP2 mutation. Such cases should be carefully and frequently re-evaluated in order to avoid delayed diagnosis and offer proper genetic advice to the family. In our knowledge, this might be the first case of CLN7 disease with Rett like onset described in the literature, which developed typical vLINCL clinical phenotype after age 5.5 years. A short review of the literature showing NCL onset modalities is presented.
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Affiliation(s)
- Dana Craiu
- "Carol Davila" University of Medicine Bucharest, Department of Neurology, Pediatric Neurology, Psychiatry, Neurosurgery, Discipline Pediatric Neurology, Romania; Pediatric Neurology Clinic, "Alexandru Obregia" Clinical Psychiatric Hospital, Şos. Berceni 10-12, Sector 4, Bucharest, Romania.
| | - Octavia Dragostin
- Pediatric Neurology Clinic, "Alexandru Obregia" Clinical Psychiatric Hospital, Şos. Berceni 10-12, Sector 4, Bucharest, Romania.
| | - Alice Dica
- Pediatric Neurology Clinic, Research Department, "Alexandru Obregia" Clinical Psychiatric Hospital, Şos. Berceni 10-12, Sector 4, Bucharest, Romania.
| | - Dorota Hoffman-Zacharska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01-211 Warsaw, Poland.
| | - Monika Gos
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17A, 01-211 Warsaw, Poland.
| | - Alexandra Eugenia Bastian
- "Carol Davila" University of Medicine Bucharest, Department II, Dental Medicine, Pathology Discpline, Romania; Pathology Lab., Colentina University Hospital, Sos Stefan cel Mare 19-21, Sector 2, 020125 Bucharest, Romania.
| | - Mihaela Gherghiceanu
- Ultrastructural Pathology Lab., 'Victor Babes' National Institute of Pathology, 99-101 Spl. Independentei, 050096 Bucharest 5, Romania.
| | - Arndt Rolfs
- Albrecht-Kossel-Institute for Neurogenetics, Medical Faculty, University of Rostock, Gehlsheimerstrasse 20, 18157 Rostock, Germany; Centogene AG, Schillingallee 69, 18057 Rostock, Germany.
| | | | - Mihai Craiu
- "Carol Davila" University of Medicine Bucharest, Department of Pediatrics and Medical Genetics, Discipline Pediatrics, Romania; Pediatric II Clinic, "Alfred Rusescu" Clinical Pediatric Hospital, Institute of Mother and Child Health, B-dul Lacul Tei No. 120, Sector 2, Bucharest, Romania.
| | - Catrinel Iliescu
- "Carol Davila" University of Medicine Bucharest, Department of Neurology, Pediatric Neurology, Psychiatry, Neurosurgery, Discipline Pediatric Neurology, Romania; Pediatric Neurology Clinic, "Alexandru Obregia" Clinical Psychiatric Hospital, Şos. Berceni 10-12, Sector 4, Bucharest, Romania.
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Clinico-pathological manifestations of variant late infantile neuronal ceroid lipofuscinosis (vLINCL) caused by a novel mutation in MFSD8 gene. Eur J Med Genet 2014; 57:607-12. [PMID: 25270050 DOI: 10.1016/j.ejmg.2014.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/15/2014] [Indexed: 11/21/2022]
Abstract
Neuronal ceroid lipofuscinosis (NCL) refers to a growing heterogeneous group of neurodegenerative disorders characterized by lysosomal accumulation of abnormal autofluorescent material. NCLs are traditionally classified clinically according to their age of onset. Variable late infantile NCL (vLINCL) is the most genetically heterogeneous subtype as it has been shown to be caused by mutations in at least six genes. We report on 5 patients of a consanguineous family who presented in early childhood with intractable seizures, severe cognitive and motor decline, behavioral impairment and progressive retinal degeneration. Disease course was severe; all patients were in a vegetative state by the second decade of life, and eventually die prematurely (except in one case). Ultrastructural studies of brain and rectal mucosa disclosed accumulation of storage material in various patterns including fingerprint, curvilinear, and granular osmiophilic deposits consistent with the diagnosis of NCL. Brain pathologic features from a living patient are first reported here and shed light on disease progression and pathogenesis. Using a combination of whole genome autozygosity mapping and candidate gene direct sequencing, we identified a mutation in MFSD8, c.472G>A (p.Gly158Ser), which was found to segregate with the disease phenotype in the family. This study underscores the importance of a combined clinic-molecular workup in NCLs and other neurodegenerative conditions.
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Steenhuis P, Froemming J, Reinheckel T, Storch S. Proteolytic cleavage of the disease-related lysosomal membrane glycoprotein CLN7. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1822:1617-28. [PMID: 22668694 DOI: 10.1016/j.bbadis.2012.05.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 05/08/2012] [Accepted: 05/29/2012] [Indexed: 12/15/2022]
Abstract
CLN7 is a polytopic lysosomal membrane glycoprotein of unknown function and is deficient in variant late infantile neuronal ceroid lipofuscinosis. Here we show that full-length CLN7 is proteolytically cleaved twice, once proximal to the used N-glycosylation sites in lumenal loop L9 and once distal to these sites. Cleavage occurs by cysteine proteases in acidic compartments and disruption of lysosomal targeting of CLN7 results in inhibition of proteolytic cleavage. The apparent molecular masses of the CLN7 fragments suggest that both cleavage sites are located within lumenal loop L9. The known disease-causing mutations, p.T294K and p.P412L, localized in lumenal loops L7 and L9, respectively, did not interfere with correct lysosomal targeting of CLN7 but enhanced its proteolytic cleavage in lysosomes. Incubation of cells with selective cysteine protease inhibitors and expression of CLN7 in gene-targeted mouse embryonic fibroblasts revealed that cathepsin L is required for one of the two proteolytic cleavage events. Our findings suggest that CLN7 is inactivated by proteolytic cleavage and that enhanced CLN7 proteolysis caused by missense mutations in selected luminal loops is associated with disease.
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Affiliation(s)
- Pieter Steenhuis
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
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Al-Owain M, Al-Zaidan H, Al-Hassnan Z. Map of autosomal recessive genetic disorders in Saudi Arabia: Concepts and future directions. Am J Med Genet A 2012; 158A:2629-40. [DOI: 10.1002/ajmg.a.35551] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 06/06/2012] [Indexed: 12/23/2022]
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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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22
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Kohan R, Cismondi IA, Oller-Ramirez AM, Guelbert N, Anzolini TV, Alonso G, Mole SE, de Kremer DR, de Halac NI. Therapeutic approaches to the challenge of neuronal ceroid lipofuscinoses. Curr Pharm Biotechnol 2011; 12:867-83. [PMID: 21235444 PMCID: PMC3632406 DOI: 10.2174/138920111795542633] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Accepted: 07/07/2010] [Indexed: 12/22/2022]
Abstract
The Neuronal Ceroid Lipofuscinoses (NCLs) are lysosomal storage diseases (LSDs) affecting the central nervous system (CNS), with generally recessive inheritance. They are characterized by pathological lipofuscin-like material accumulating in cells. The clinical phenotypes at all onset ages show progressive loss of vision, decreasing cognitive and motor skills, epileptic seizures and premature death, with dementia without visual loss prominent in the rarer adult forms. Eight causal genes, CLN10/CTSD, CLN1/PPT1, CLN2/TPP1, CLN3, CLN5, CLN6, CLN7/MFSD8, CLN8, with more than 265 mutations and 38 polymorphisms (http://www.ucl.ac.uk/ncl) have been described. Other NCL genes are hypothesized, including CLN4 and CLN9; CLCN6, CLCN7 and possibly SGSH are under study. Some therapeutic strategies applied to other LSDs with significant systemic involvement would not be effective in NCLs due to the necessity of passing the blood brain barrier to prevent the neurodegeneration, repair or restore the CNS functionality. There are therapies for the NCLs currently at preclinical stages and under phase 1 trials to establish safety in affected children. These approaches involve enzyme replacement, gene therapy, neural stem cell replacement, immune therapy and other pharmacological approaches. In the next decade, progress in the understanding of the natural history and the biochemical and molecular cascade of events relevant to the pathogenesis of these diseases in humans and animal models will be required to achieve significant therapeutic advances.
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Affiliation(s)
- R Kohan
- Center for the Study of Inherited Metabolic Diseases (CEMECO),Children's Hospital, Department of Medical Sciences, National University Cordoba, Argentina.
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Al-Kowari MK, Hassan S, El-Said MF, Ben-Omran T, Hedin L, Mole SE, Badii R. Neuronal ceroid lipofuscinosis in Qatar: report of a novel mutation in ceroid-lipofuscinosis, neuronal 5 in the Arab population. J Child Neurol 2011; 26:625-9. [PMID: 21447811 DOI: 10.1177/0883073810387298] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study sought to genetically define the first family diagnosed with neuronal ceroid lipofuscinosis from Qatar. Onset was in late infancy (3 years), and sequencing in the affected children revealed a novel homozygous c.613C>T change in exon 3 of ceroid-lipofuscinosis, neuronal 5, corresponding to a missense mutation of a conserved amino acid, p.Pro205Ser. The clinical manifestations of the disease in this family largely resemble those of ceroid-lipofuscinosis, neuronal 5 disease, variant late infantile that was first described in Finland and include mental decline, visual deterioration, ataxia, and epileptic seizures. This description of ceroid-lipofuscinosis, neuronal 5 disease in an Arab family adds to the clinical and molecular diversity of the variant late-infantile neuronal ceroid lipofuscinoses, which were originally reported in Europe and are increasingly recognized in other populations.
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Affiliation(s)
- Moza K Al-Kowari
- Molecular Genetics Laboratory, Hamad Medical Corporation, Doha, Qatar
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Wang P, Ju W, Wu D, Wang L, Yan M, Zou J, He B, Jenkins EC, Brown WT, Zhong N. A two-dimensional protein fragmentation-proteomic study of neuronal ceroid lipofuscinoses: Identification and characterization of differentially expressed proteins. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:304-16. [DOI: 10.1016/j.jchromb.2010.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 12/02/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
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Sharifi A, Kousi M, Sagné C, Bellenchi GC, Morel L, Darmon M, Hulková H, Ruivo R, Debacker C, El Mestikawy S, Elleder M, Lehesjoki AE, Jalanko A, Gasnier B, Kyttälä A. Expression and lysosomal targeting of CLN7, a major facilitator superfamily transporter associated with variant late-infantile neuronal ceroid lipofuscinosis. Hum Mol Genet 2010; 19:4497-514. [PMID: 20826447 DOI: 10.1093/hmg/ddq381] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neuronal ceroid lipofuscinoses (NCLs) constitute a group of progressive neurodegenerative disorders resulting from mutations in at least eight different genes. Mutations in the most recently identified NCL gene, MFSD8/CLN7, underlie a variant of late-infantile NCL (vLINCL). The MFSD8/CLN7 gene encodes a polytopic protein with unknown function, which shares homology with ion-coupled membrane transporters. In this study, we confirmed the lysosomal localization of the native CLN7 protein. This localization of CLN7 is not impaired by the presence of pathogenic missense mutations or after genetic ablation of the N-glycans. Expression of chimeric and full-length constructs showed that lysosomal targeting of CLN7 is mainly determined by an N-terminal dileucine motif, which specifically binds to the heterotetrameric adaptor AP-1 in vitro. We also show that CLN7 mRNA is more abundant in neurons than astrocytes and microglia, and that it is expressed throughout rat brain, with increased levels in the granular layer of cerebellum and hippocampal pyramidal cells. Interestingly, this cellular and regional distribution is in good agreement with the autofluorescent lysosomal storage and cell loss patterns found in brains from CLN7-defective patients. Overall, these data highlight lysosomes as the primary site of action for CLN7, and suggest that the pathophysiology underpinning CLN7-associated vLINCL is a cell-autonomous process.
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Affiliation(s)
- A Sharifi
- Institut de Biologie Physico-Chimique, Université Paris Descartes, Centre National de la Recherche Scientifique, UMR 8192, Institut de Biologie Physico-Chimique, 13 Rue P. et M. Curie, Paris, France
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Abstract
Consanguinity increases the coefficient of inbreeding, which increases the likelihood of presence of pathogenic mutations in a homoallelic state. Although this is known to have an adverse outcome by increasing the risk of autosomal recessive disorders, this very phenomenon has also made homozygosity mapping the most robust gene discovery strategy in the recent history of human genetics. However, homozygosity mapping can also serve as an extremely powerful tool in the clinical genetics setting as well. In particular, this method is highly suited in the setting of genetically heterogeneous conditions and inborn errors of metabolism that require sophisticated biochemical testing that may not be readily available. This article is meant to highlight the clinical utility of this strategy using illustrative clinical examples from the author's own clinical genetics practice.
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