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Schneider V, Dupont G, Madinier G, Ramond F, Lesca G, Thauvin-Robinet C, Thomas Q. Compound Heterozygous WARS2 Variants Including a Hypomorphic Allele Cause a Milder Phenotype of Complex Dopa Responsive Dystonia: Case Report and Review of the Literature. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01725-7. [PMID: 39073549 DOI: 10.1007/s12311-024-01725-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Biallelic WARS2 pathogenic variants responsible for partial defect in aminoacylation, have recently been reported in subjects presenting with late-onset phenotypes combining dopa-responsive early-onset dystonia parkinsonism with altered DaTSCAN and progressive myoclonus ataxia. Here, we present the case of a 39-year-old male with childhood-onset progressive dopa-responsive dystonia parkinsonism, prominent psychiatric features and ataxia whose genome sequencing identified a p.(Arg36Ter) nonsense variant and a hypomorphic p.(Trp13Gly) missense variant, allowing the diagnosis of WARS2-related disease. The p.(Trp13Gly) missense variant has previously been reported in individuals with less severe phenotypes than those carrying biallelic WARS2 loss-of-function variants. Among these individuals, two subjects had similar genetic backgrounds and almost identical clinical history to our patient. Our report brings additional proof that the p.(Trp13Gly) variant acts as a hypomorphic allele, offering insight on a genotype-phenotype correlation in WARS2-related disorders.
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Affiliation(s)
- Vincent Schneider
- Neurology Department, Dijon University Hospital, 14 rue Paul Gaffarel, 21000, Dijon, Burgundy, France.
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism, EA7270/Inserm, University of Burgundy and Franche-Comté, Dijon, Burgundy, France.
| | - Gwendoline Dupont
- Neurology Department, Dijon University Hospital, 14 rue Paul Gaffarel, 21000, Dijon, Burgundy, France
| | - Guillaume Madinier
- Neurology Department, Dijon University Hospital, 14 rue Paul Gaffarel, 21000, Dijon, Burgundy, France
| | - Francis Ramond
- Department of Medical Genetics, Saint Etienne University Hospital, Saint-Etienne, France
- Auragen Multisite Laboratory, GCS Auragen, Plan France Médecine Génomique, Lyon, 2025, France
| | - Gaetan Lesca
- Auragen Multisite Laboratory, GCS Auragen, Plan France Médecine Génomique, Lyon, 2025, France
- Department of Medical Genetics, competence center for rare neurogenetic diseases, University Hospital of Lyon, Lyon, France
| | - Christel Thauvin-Robinet
- Inserm UMR1231 team GAD "genetics of developmental abnormalities", University of Burgundy, Dijon, Burgundy, France
- Reference center for rare neurogenetic diseases, Genetics Center, FHU-TRANSLAD, Dijon University Hospital, Dijon, Burgundy, France
- Functional Unity of innovative diagnosis for rare diseases, Dijon University Hospital, Dijon, Burgundy, France
| | - Quentin Thomas
- Neurology Department, Dijon University Hospital, 14 rue Paul Gaffarel, 21000, Dijon, Burgundy, France
- Inserm UMR1231 team GAD "genetics of developmental abnormalities", University of Burgundy, Dijon, Burgundy, France
- Reference center for rare neurogenetic diseases, Genetics Center, FHU-TRANSLAD, Dijon University Hospital, Dijon, Burgundy, France
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2
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Thuma TBT, Procopio RA, Jimenez HJ, Gunton KB, Pulido JS. Hypomorphic variants in inherited retinal and ocular diseases: A review of the literature with clinical cases. Surv Ophthalmol 2024; 69:337-348. [PMID: 38036193 DOI: 10.1016/j.survophthal.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
Hypomorphic variants decrease, but do not eliminate, gene function via a reduction in the amount of mRNA or protein product produced by a gene or by production of a gene product with reduced function. Many hypomorphic variants have been implicated in inherited retinal diseases (IRDs) and other genetic ocular conditions; however, there is heterogeneity in the use of the term "hypomorphic" in the scientific literature. We searched for all hypomorphic variants reported to cause IRDs and ocular disorders. We also discuss the presence of hypomorphic variants in the patient population of our ocular genetics department over the past decade. We propose that standardized criteria should be adopted for use of the term "hypomorphic" to describe gene variants to improve genetic counseling and patient care outcomes.
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Affiliation(s)
- Tobin B T Thuma
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | | | - Hiram J Jimenez
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA
| | - Kammi B Gunton
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | - Jose S Pulido
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
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3
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Yeow D, Rudaks LI, Siow SF, Davis RL, Kumar KR. Genetic Testing of Movements Disorders: A Review of Clinical Utility. Tremor Other Hyperkinet Mov (N Y) 2024; 14:2. [PMID: 38222898 PMCID: PMC10785957 DOI: 10.5334/tohm.835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 12/04/2023] [Indexed: 01/16/2024] Open
Abstract
Currently, pathogenic variants in more than 500 different genes are known to cause various movement disorders. The increasing accessibility and reducing cost of genetic testing has resulted in increasing clinical use of genetic testing for the diagnosis of movement disorders. However, the optimal use case(s) for genetic testing at a patient level remain ill-defined. Here, we review the utility of genetic testing in patients with movement disorders and also highlight current challenges and limitations that need to be considered when making decisions about genetic testing in clinical practice. Highlights The utility of genetic testing extends across multiple clinical and non-clinical domains. Here we review different aspects of the utility of genetic testing for movement disorders and the numerous associated challenges and limitations. These factors should be weighed on a case-by-case basis when requesting genetic tests in clinical practice.
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Affiliation(s)
- Dennis Yeow
- Translational Neurogenomics Group, Neurology Department & Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, NSW, Australia
- Concord Clinical School, Sydney Medical School, Faculty of Health & Medicine, University of Sydney, Concord, NSW, Australia
- Rare Disease Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- Department of Neurology, Prince of Wales Hospital, Randwick, NSW, Australia
- Neuroscience Research Australia, Randwick, NSW, Australia
| | - Laura I. Rudaks
- Translational Neurogenomics Group, Neurology Department & Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, NSW, Australia
- Concord Clinical School, Sydney Medical School, Faculty of Health & Medicine, University of Sydney, Concord, NSW, Australia
- Rare Disease Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Sue-Faye Siow
- Department of Clinical Genetics, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Ryan L. Davis
- Rare Disease Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- Neurogenetics Research Group, Kolling Institute, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney and Northern Sydney Local Health District, St Leonards, NSW, Australia
| | - Kishore R. Kumar
- Translational Neurogenomics Group, Neurology Department & Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, NSW, Australia
- Concord Clinical School, Sydney Medical School, Faculty of Health & Medicine, University of Sydney, Concord, NSW, Australia
- Rare Disease Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- School of Clinical Medicine, University of New South Wales, Sydney, NSW, Australia
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4
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Chen Y, Yang B, Zhang XM, Chen S, Wang M, Hu L, Pan N, Li S, Shi W, Yang Z, Wang L, Tan Y, Wang J, Wang Y, Xing Q, Ma Z, Li J, Huang HF, Zhang J, Xu C. Biallelic variants in RBM42 cause a multisystem disorder with neurological, facial, cardiac, and musculoskeletal involvement. Protein Cell 2024; 15:52-68. [PMID: 37294900 PMCID: PMC10762670 DOI: 10.1093/procel/pwad034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/29/2023] [Indexed: 06/11/2023] Open
Abstract
Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of RBM42 with hnRNP K, which is the causative gene for Au-Kline syndrome with overlapping disease characteristics seen in the index patient. The human R102* or A438T mutant protein failed to fully rescue the growth defects of RBM42 ortholog knockout ΔFgRbp1 in Fusarium while it was rescued by the wild-type (WT) human RBM42. A mouse model carrying Rbm42 compound heterozygous variants, c.280C>T (p.Q94*) and c.1306_1308delinsACA (p.A436T), demonstrated gross fetal developmental defects and most of the double mutant animals died by E13.5. RNA-seq data confirmed that Rbm42 was involved in neurological and myocardial functions with an essential role in alternative splicing (AS). Overall, we present clinical, genetic, and functional data to demonstrate that defects in RBM42 constitute the underlying etiology of a new neurodevelopmental disease which links the dysregulation of global AS to abnormal embryonic development.
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Affiliation(s)
- Yiyao Chen
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Bingxin Yang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Xiaoyu Merlin Zhang
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Songchang Chen
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Minhui Wang
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nina Pan
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Shuyuan Li
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Weihui Shi
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
| | - Zhenhua Yang
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, Zhejiang, China
| | - Li Wang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Yajing Tan
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Jian Wang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Yanlin Wang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Qinghe Xing
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- Children’s hospital of Fudan University, Shanghai 201102, China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Jinsong Li
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, Zhejiang, China
| | - He-Feng Huang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
- Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences (No. 2019RU056), Shanghai 200011, China
| | - Jinglan Zhang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
- Shanghai Key Laboratory of Embryo Original Diseases, Shanghai 200030, China
| | - Chenming Xu
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
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5
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Indelicato E, Boesch S, Zech M. Reply to: "Early Onset Nonprogressive Generalized Dystonia Is Caused by Biallelic SHQ1 Variants". Mov Disord 2023; 38:1119-1120. [PMID: 37475612 DOI: 10.1002/mds.29436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 04/20/2023] [Indexed: 07/22/2023] Open
Affiliation(s)
| | - Sylvia Boesch
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
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6
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Ek M, Nilsson D, Engvall M, Malmgren H, Thonberg H, Pettersson M, Anderlid BM, Hammarsjö A, Helgadottir HT, Arnardottir S, Naess K, Nennesmo I, Paucar M, Hjartarson HT, Press R, Solders G, Sejersen T, Lindstrand A, Kvarnung M. Genome sequencing with comprehensive variant calling identifies structural variants and repeat expansions in a large fraction of individuals with ataxia and/or neuromuscular disorders. Front Neurol 2023; 14:1170005. [PMID: 37273706 PMCID: PMC10234573 DOI: 10.3389/fneur.2023.1170005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/21/2023] [Indexed: 06/06/2023] Open
Abstract
Introduction Neuromuscular disorders (NMDs) have a heterogeneous etiology. A genetic diagnosis is key to personalized healthcare and access to targeted treatment for the affected individuals. Methods In this study, 861 patients with NMDs were analyzed with genome sequencing and comprehensive variant calling including single nucleotide variants, small insertions/deletions (SNVs/INDELs), and structural variants (SVs) in a panel of 895 NMD genes, as well as short tandem repeat expansions (STRs) at 28 loci. In addition, for unsolved cases with an unspecific clinical presentation, the analysis of a panel with OMIM disease genes was added. Results In the cohort, 27% (232/861) of the patients harbored pathogenic variants, of which STRs and SVs accounted for one-third of the patients (71/232). The variants were found in 107 different NMD genes. Furthermore, 18 pediatric patients harbored pathogenic variants in non-NMD genes. Discussion Our results highlight that for children with unspecific hypotonia, a genome-wide analysis rather than a disease-based gene panel should be considered as a diagnostic approach. More importantly, our results clearly show that it is crucial to include STR- and SV-analyses in the diagnostics of patients with neuromuscular disorders.
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Affiliation(s)
- Marlene Ek
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
- Science for Life Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet Science Park, Solna, Sweden
| | - Martin Engvall
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Karolinska University Hospital, Centre for Inherited Metabolic Diseases, Stockholm, Sweden
| | - Helena Malmgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Håkan Thonberg
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Pettersson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Hammarsjö
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Hafdis T. Helgadottir
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | | | - Karin Naess
- Karolinska University Hospital, Centre for Inherited Metabolic Diseases, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Inger Nennesmo
- Department of Oncology-Pathology, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Paucar
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Helgi Thor Hjartarson
- Department of Neuropediatrics, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Rayomand Press
- Department of Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden
| | - Göran Solders
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Neurophysiology, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Sejersen
- Department of Neuropediatrics, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Malin Kvarnung
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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7
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Morsy H, Benkirane M, Cali E, Rocca C, Zhelcheska K, Cipriani V, Galanaki E, Maroofian R, Efthymiou S, Murphy D, O'Driscoll M, Suri M, Banka S, Clayton-Smith J, Wright T, Redman M, Bassetti JA, Nizon M, Cogne B, Jamra RA, Bartolomaeus T, Heruth M, Krey I, Gburek-Augustat J, Wieczorek D, Gattermann F, Mcentagart M, Goldenberg A, Guyant-Marechal L, Garcia-Moreno H, Giunti P, Chabrol B, Bacrot S, Buissonnière R, Magry V, Gowda VK, Srinivasan VM, Melegh B, Szabó A, Sümegi K, Cossée M, Ziff M, Butterfield R, Hunt D, Bird-Lieberman G, Hanna M, Koenig M, Stankewich M, Vandrovcova J, Houlden H. Expanding SPTAN1 monoallelic variant associated disorders: From epileptic encephalopathy to pure spastic paraplegia and ataxia. Genet Med 2023; 25:76-89. [PMID: 36331550 PMCID: PMC10620943 DOI: 10.1016/j.gim.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 09/23/2022] [Accepted: 09/25/2022] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Nonerythrocytic αII-spectrin (SPTAN1) variants have been previously associated with intellectual disability and epilepsy. We conducted this study to delineate the phenotypic spectrum of SPTAN1 variants. METHODS We carried out SPTAN1 gene enrichment analysis in the rare disease component of the 100,000 Genomes Project and screened 100,000 Genomes Project, DECIPHER database, and GeneMatcher to identify individuals with SPTAN1 variants. Functional studies were performed on fibroblasts from 2 patients. RESULTS Statistically significant enrichment of rare (minor allele frequency < 1 × 10-5) probably damaging SPTAN1 variants was identified in families with hereditary ataxia (HA) or hereditary spastic paraplegia (HSP) (12/1142 cases vs 52/23,847 controls, p = 2.8 × 10-5). We identified 31 individuals carrying SPTAN1 heterozygous variants or deletions. A total of 10 patients presented with pure or complex HSP/HA. The remaining 21 patients had developmental delay and seizures. Irregular αII-spectrin aggregation was noted in fibroblasts derived from 2 patients with p.(Arg19Trp) and p.(Glu2207del) variants. CONCLUSION We found that SPTAN1 is a genetic cause of neurodevelopmental disorder, which we classified into 3 distinct subgroups. The first comprises developmental epileptic encephalopathy. The second group exhibits milder phenotypes of developmental delay with or without seizures. The final group accounts for patients with pure or complex HSP/HA.
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Affiliation(s)
- Heba Morsy
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom; Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt.
| | - Mehdi Benkirane
- Department of Molecular Genetic, University Institute for Clinical Research, Montpellier University Hospital, PhyMedExp, CNRS UMR 9214, INSERM U1046, Montpellier, France
| | - Elisa Cali
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Clarissa Rocca
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Kristina Zhelcheska
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Valentina Cipriani
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Evangelia Galanaki
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - David Murphy
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Mary O'Driscoll
- West Midlands Regional Clinical Genetics Service, Birmingham Health Partners, Birmingham Women's and Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Mohnish Suri
- Nottingham Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Siddharth Banka
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Jill Clayton-Smith
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Thomas Wright
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Melody Redman
- Department of Clinical Genetics, Chapel Allerton Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | | | - Mathilde Nizon
- Thorax Institute, Nantes University, CNRS, INSERM, Nantes, France
| | - Benjamin Cogne
- Thorax Institute, Nantes University, CNRS, INSERM, Nantes, France; Department of Medical Genetics, Nantes University Hospital, Nantes, France
| | - Rami Abu Jamra
- MVZ for Diagnostic and Therapy, Leipziger Land, Leipzig, Germany; Institute of Human Genetics, University of Leipzig Medical Center, University of Leipzig, Leipzig, Germany
| | - Tobias Bartolomaeus
- MVZ for Diagnostic and Therapy, Leipziger Land, Leipzig, Germany; Institute of Human Genetics, University of Leipzig Medical Center, University of Leipzig, Leipzig, Germany
| | - Marion Heruth
- MVZ for Diagnostic and Therapy, Leipziger Land, Leipzig, Germany
| | - Ilona Krey
- Institute of Human Genetics, University of Leipzig Medical Center, University of Leipzig, Leipzig, Germany
| | - Janina Gburek-Augustat
- Division of Neuropediatrics, Hospital for Children and Adolescents, University Hospital Leipzig, Leipzig, Germany
| | - Dagmar Wieczorek
- Institute of Human Genetics, Medical Faculty, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Felix Gattermann
- Institute of Human Genetics, Medical Faculty, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Meriel Mcentagart
- Medical Genetics, St George's University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Alice Goldenberg
- Department of Medical Genetics, Rouen University Hospital, Rouen, France
| | | | - Hector Garcia-Moreno
- Department of Neurogenetics, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, United Kingdom; Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Paola Giunti
- Department of Neurogenetics, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, United Kingdom; Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Brigitte Chabrol
- Reference Center for Inherited Metabolic Diseases, Marseille University Hospital, Marseille, France
| | - Severine Bacrot
- Department of Molecular Genetics, Versailles Hospital, Versailles, France
| | | | - Virginie Magry
- Department of Molecular Genetics, Amiens-Picardie University Hospital, Amiens, France
| | - Vykuntaraju K Gowda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bangalore, India
| | | | - Béla Melegh
- Department of Medical Genetics, Clinical Centre, School of Medicine, University of Pécs, Pécs, Hungary
| | - András Szabó
- Department of Medical Genetics, Clinical Centre, School of Medicine, University of Pécs, Pécs, Hungary
| | - Katalin Sümegi
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pécs, Pécs, Hungary
| | - Mireille Cossée
- Department of Molecular Genetic, University Institute for Clinical Research, Montpellier University Hospital, PhyMedExp, CNRS UMR 9214, INSERM U1046, Montpellier, France
| | - Monica Ziff
- Clinical Genetics Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Russell Butterfield
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, University of Utah Health, Salt Lake City, UT
| | - David Hunt
- Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, United Kigngdom
| | - Georgina Bird-Lieberman
- Southampton Children's Hospital, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Michael Hanna
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Michel Koenig
- Department of Molecular Genetic, University Institute for Clinical Research, Montpellier University Hospital, PhyMedExp, CNRS UMR 9214, INSERM U1046, Montpellier, France
| | | | - Jana Vandrovcova
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom.
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8
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Benkirane M, Da Cunha D, Marelli C, Larrieu L, Renaud M, Varilh J, Pointaux M, Baux D, Ardouin O, Vangoethem C, Taulan M, Daumas Duport B, Bergougnoux A, Corbillé AG, Cossée M, Juntas Morales R, Tuffery-Giraud S, Koenig M, Isidor B, Vincent MC. RFC1 nonsense and frameshift variants cause CANVAS: clues for an unsolved pathophysiology. Brain 2022; 145:3770-3775. [PMID: 35883251 DOI: 10.1093/brain/awac280] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/13/2022] [Accepted: 07/03/2022] [Indexed: 01/27/2023] Open
Abstract
Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is an inherited late-onset neurological disease caused by bi-allelic AAGGG pentanucleotide expansions within intron 2 of RFC1. Despite extensive studies, the pathophysiological mechanism of these intronic expansions remains elusive. We screened by clinical exome sequencing two unrelated patients presenting with late-onset ataxia. A repeat-primer polymerase chain reaction was used for RFC1 AAGGG intronic expansion identification. RFC1 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction. We identified the first two CANVAS affected patients who are compound heterozygous for RFC1 truncating variants (p.Arg388* and c.575delA, respectively) and a pathological AAGGG expansion. RFC1 expression studies in whole blood showed a significant reduction of RFC1 mRNA for both patients compared to three patients with bi-allelic RFC1 expansions. In conclusion, this observation provides clues that suggest bi-allelic RFC1 conditional loss-of-function as the cause of the disease.
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Affiliation(s)
- Mehdi Benkirane
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France.,Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Dylan Da Cunha
- Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Cecilia Marelli
- Department of Neurology, Montpellier Hospital, Montpellier, France.,Molecular Mechanisms of Neurodegenerative Dementia (MMDN), EPHE University of Montpellier, INSERM, Montpellier, France
| | - Lise Larrieu
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France
| | - Mathilde Renaud
- Department of Medical Genetics, Nancy Hospital, Nancy, France
| | - Jessica Varilh
- Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Morgane Pointaux
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France
| | - David Baux
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France
| | - Olivier Ardouin
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France
| | - Charles Vangoethem
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France
| | - Magali Taulan
- Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | | | - Anne Bergougnoux
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France.,Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | | | - Mireille Cossée
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France.,Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | | | - Sylvie Tuffery-Giraud
- Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Michel Koenig
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France.,Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Bertrand Isidor
- Department of Medical Genetics, Nantes Hospital, Nantes, France
| | - Marie-Claire Vincent
- Department of Molecular Genetics, Institut Universitaire de Recherche Clinique (IURC), Montpellier Hospital, Montpellier, France.,Genetics and Pathophysiology of NeuroMuscular Disorders, PhyMedExp Research Unit, CNRS, INSERM, University of Montpellier, Montpellier, France
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9
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Wu T, Mao L, Chen C, Yin F, Peng J. A novel homozygous missense mutation in the FASTKD2 gene leads to Lennox-Gastaut syndrome. J Hum Genet 2022; 67:589-594. [PMID: 35729327 DOI: 10.1038/s10038-022-01056-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/27/2022] [Accepted: 06/13/2022] [Indexed: 11/09/2022]
Abstract
FASTKD2 encodes an RNA-binding protein, which is a key post-transcriptional regulator of mitochondrial gene expression. Mutations in FASTKD2 have recently been found in mitochondrial encephalomyopathy, which is characterized by a deficiency in mitochondrial function. To date, seven patients have been reported. Six patients were identified with nonsense or frameshift mutations in the FASTKD2 gene, and only one patient harbored a missense mutation and a nonsense mutation. Here, we identified a novel FASTKD2 homozygous mutation, c.911 T > C, in a patient diagnosed with Lennox-Gastaut syndrome. We observed that the expression of FASTKD2 and the levels of mitochondrial 16 S rRNA were lower in the patient than in the unaffected controls. In conclusion, the missense mutation c.911 T > C caused loss of function in FASTKD2, which was associated with a new phenotype, Lennox-Gastaut syndrome.
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Affiliation(s)
- Tenghui Wu
- Department of Pediatrics, Xiangya Hospital Central South University, Changsha, 410008, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, Changsha, 410008, China
| | - Leilei Mao
- Department of Pediatrics, Xiangya Hospital Central South University, Changsha, 410008, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, Changsha, 410008, China
| | - Chen Chen
- Department of Pediatrics, Xiangya Hospital Central South University, Changsha, 410008, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, Changsha, 410008, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital Central South University, Changsha, 410008, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, Changsha, 410008, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital Central South University, Changsha, 410008, China. .,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, Changsha, 410008, China.
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10
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Zhang W, Ye F, Chen S, Peng J, Pang N, Yin F. Splicing Interruption by Intron Variants in CSNK2B Causes Poirier–Bienvenu Neurodevelopmental Syndrome: A Focus on Genotype–Phenotype Correlations. Front Neurosci 2022; 16:892768. [PMID: 35774559 PMCID: PMC9237577 DOI: 10.3389/fnins.2022.892768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
CSNK2B has recently been identified as the causative gene for Poirier–Bienvenu neurodevelopmental syndrome (POBINDS). POBINDS is a rare neurodevelopmental disorder characterized by early-onset epilepsy, developmental delay, hypotonia, and dysmorphism. Limited by the scarcity of patients, the genotype–phenotype correlations in POBINDS are still unclear. In the present study, we describe the clinical and genetic characteristics of eight individuals with POBINDS, most of whom suffered developmental delay, generalized epilepsy, and hypotonia. Minigene experiments confirmed that two intron variants (c.367+5G>A and c.367+6T>C) resulted in the skipping of exon 5, leading to a premature termination of mRNA transcription. Combining our data with the available literature, the types of POBINDS-causing variants included missense, nonsense, frameshift, and splicing, but the variant types do not reflect the clinical severity. Reduced casein kinase 2 holoenzyme activity may represent a unifying pathogenesis. We also found that individuals with missense variants in the zinc finger domain had manageable seizures (p = 0.009) and milder intellectual disability (p = 0.003) than those with missense variants in other domains of CSNK2B. This is the first study of genotype–phenotype correlations in POBINDS, drawing attention to the pathogenicity of intron variants and expanding the understanding of neurodevelopmental disorders.
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Affiliation(s)
- Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Fanghua Ye
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
| | - Nan Pang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Nan Pang,
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Xiangya Hospital, Central South University, Changsha, China
- Fei Yin,
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11
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Nava E, Hartmann B, Boxheimer L, Capone Mori A, Nuoffer JM, Sargsyan Y, Thoms S, Rosewich H, Boltshauser E. How to Detect Isolated PEX10-Related Cerebellar Ataxia? Neuropediatrics 2022; 53:159-166. [PMID: 35038753 DOI: 10.1055/s-0041-1741383] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A 4-year-old boy presented with subacute onset of cerebellar ataxia. Neuroimaging revealed cerebellar atrophy. Metabolic screening tests aiming to detect potentially treatable ataxias showed an increased value (fourfold upper limit of normal) for phytanic acid and elevated very-long-chain fatty acid (VLCFA) ratios (C24:0/C22:0 and C26:0/C22:0), while absolute concentrations of VLCFA were normal. Genetic analysis identified biallelic variants in PEX10. Immunohistochemistry confirmed pathogenicity in the patients' cultured fibroblasts demonstrating peroxisomal mosaicism with a general catalase import deficiency as well as conspicuous peroxisome morphology as an expression of impaired peroxisomal function. We describe for the first time an elongated peroxisome morphology in a patient with PEX10-related cerebellar ataxia.A literature search yielded 14 similar patients from nine families with PEX10-related cerebellar ataxia, most of them presenting their first symptoms between 3 and 8 years of age. In 11/14 patients, the first and main symptom was cerebellar ataxia; in three patients, it was sensorineural hearing impairment. Finally, all 14 patients developed ataxia. Polyneuropathy (9/14) and cognitive impairment (9/14) were common associated findings. In 12/13 patients brain MRI showed cerebellar atrophy. Phytanic acid was elevated in 8/12 patients, while absolute concentrations of VLCFA levels were in normal limits in several patients. VLCFA ratios (C24:0/C22:0 and/or C26:0/C22:0), though, were elevated in 11/11 cases. We suggest including measurement of phytanic acid and VLCFA ratios in metabolic screening tests in unexplained autosomal recessive ataxias with cerebellar atrophy, especially when there is an early onset and symptoms are mild.
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Affiliation(s)
- Esmeralda Nava
- Department of Pediatric Neurology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Britta Hartmann
- Department of Medical Genetics, Cantonal Hospital Aarau, Institute of Laboratory Medicine, Aarau, Switzerland
| | - Larissa Boxheimer
- Department of Neuroradiology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Andrea Capone Mori
- Department of Pediatric Neurology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Jean-Marc Nuoffer
- University Institute of Clinical Chemistry, Bern University Hospital, Bern, Switzerland.,University Children's Hospital Pediatric Endocrinology, Diabetology and Metabolism, Bern, Switzerland
| | - Yelena Sargsyan
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Sven Thoms
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany.,Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, Bielefeld, Germany
| | - Hendrik Rosewich
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Eugen Boltshauser
- Department of Pediatric Neurology (emeritus), University Children's Hospital Zürich, Zürich, Switzerland
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12
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Subramony SH, Burns M, Kugelmann EL, Zingariello CD. Inherited Ataxias in Children. Pediatr Neurol 2022; 131:54-62. [PMID: 35490578 DOI: 10.1016/j.pediatrneurol.2022.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/28/2022] [Accepted: 04/01/2022] [Indexed: 10/18/2022]
Abstract
The purpose of this review is to describe the current diagnostic approach to inherited ataxias during childhood. With the expanding use and availability of gene testing technologies including large sequencing panels, the ability to arrive at a precise genetic diagnosis in this group of disorders has been improving. We have reviewed all the gene sequencing studies of ataxias available by a comprehensive literature search and summarize their results. We provide a logical algorithm for a diagnostic approach in the context of this evolving information. We stress the fact that both autosomal recessive and autosomal dominant mutations can occur in children with ataxias and the need for keeping in mind nucleotide repeat expansions, which cannot be detected by sequencing technologies, as a possible cause of progressive ataxias in children. We discuss the traditional phenotype-based diagnostic approach in the context of gene testing technologies. Finally, we summarize those disorders in which a specific therapy may be indicated.
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Affiliation(s)
- Sub H Subramony
- Department of Neurology, University of Florida College of Medicine, Gainesville, Florida; Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida.
| | - Matthew Burns
- Department of Neurology, University of Florida College of Medicine, Gainesville, Florida
| | - E Lee Kugelmann
- Department of Neurology, University of Florida College of Medicine, Gainesville, Florida
| | - Carla D Zingariello
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida
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13
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Nanetti L, Di Bella D, Magri S, Fichera M, Sarto E, Castaldo A, Mongelli A, Baratta S, Fenu S, Moscatelli M, Bonati MT, Martinuzzi A, Mariotti C, Taroni F. Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature. Front Neurol 2022; 12:793547. [PMID: 35069422 PMCID: PMC8770815 DOI: 10.3389/fneur.2021.793547] [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: 10/12/2021] [Accepted: 12/02/2021] [Indexed: 12/11/2022] Open
Abstract
A wide spectrum of neurodegenerative diseases has been associated with pathogenic variants in the PNPLA6 (patatin-like phospholipase domain-containing protein 6) gene, including spastic paraplegia type 39, Gordon-Holmes, Boucher-Neuhauser, Oliver-Mc Farlane, and Laurence-Moon syndromes. These syndromes present variable and overlapping clinical symptoms, encompassing cerebellar ataxia, hypogonadotropic hypogonadism, chorioretinal dystrophy, spastic paraplegia, muscle wasting, peripheral neuropathy, and cognitive impairment. In the present study, we performed a wide genetic screening in 292 patients presenting with ataxia or spastic paraplegia using a probe-based customized gene panel, covering >200 genes associated with spinocerebellar diseases. We identified six novel and four recurrent PNPLA6 gene variants in eight patients (2.7%). Six patients presented an infantile or juvenile onset (age <18), and two patients had an adult onset. Cerebellar ataxia was observed in seven patients and spastic paraplegia in one patient. Progression of cerebellar symptoms was slow in all patients, who retained ambulation even after a mean disease duration of 15 years. Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII). Additional clinical features included hypogonadotropic hypogonadism (5/8), growth hormone deficiency (2/8), peripheral axonal neuropathy (4/8), cognitive impairment (3/8), chorioretinal dystrophy (2/8), and bilateral vestibular areflexia with a reduced visual vestibule-ocular reflex (1/8). In accordance with previous studies, chorioretinal dystrophy was the most frequent presenting symptom in early onset patients, hypogonadotropic hypogonadism in juvenile onset cases, and cerebellar ataxia in adult patients. One patient had an initial clinical presentation compatible with Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome (CANVAS), but no pathological expansions in the RFC1 gene. In conclusion, patients with PNPLA6 variants present a variable age of onset spanning from infancy to adulthood, and each clinical symptom has an age-dependent manifestation thus requiring a multi-systemic diagnostic approach. The description of patients presenting very late-onset cerebellar ataxia suggests that PNPLA6 genetic screening should also be considered in the diagnostic workout of adult cerebellar ataxia.
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Affiliation(s)
- Lorenzo Nanetti
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Daniela Di Bella
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefania Magri
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Mario Fichera
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elisa Sarto
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Anna Castaldo
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Alessia Mongelli
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silvia Baratta
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silvia Fenu
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marco Moscatelli
- Unit of Neuroradiology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Maria Teresa Bonati
- Unit of Medical Genetics, Institute for Maternal and Child Health Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Burlo Garofalo, Trieste, Italy
| | - Andrea Martinuzzi
- Conegliano Research Center, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Eugenio Medea, Conegliano, Italy
| | - Caterina Mariotti
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Franco Taroni
- Unit of Medical Genetics and Neurogenetics, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
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