1
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Chang C, Sell LB, Shi Q, Bhat MA. Mouse models of human CNTNAP1-associated congenital hypomyelinating neuropathy and genetic restoration of murine neurological deficits. Cell Rep 2023; 42:113274. [PMID: 37862170 PMCID: PMC10873044 DOI: 10.1016/j.celrep.2023.113274] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/14/2023] [Accepted: 09/28/2023] [Indexed: 10/22/2023] Open
Abstract
The Contactin-associated protein 1 (Cntnap1) mouse mutants fail to establish proper axonal domains in myelinated axons. Human CNTNAP1 mutations are linked to hypomyelinating neuropathy-3, which causes severe neurological deficits. To understand the human neuropathology and to model human CNTNAP1C323R and CNTNAP1R764C mutations, we generated Cntnap1C324R and Cntnap1R765C mouse mutants, respectively. Both Cntnap1 mutants show weight loss, reduced nerve conduction, and progressive motor dysfunction. The paranodal ultrastructure shows everted myelin loops and the absence of axo-glial junctions. Biochemical analysis reveals that these Cntnap1 mutant proteins are nearly undetectable in the paranodes, have reduced surface expression and stability, and are retained in the neuronal soma. Postnatal transgenic expression of Cntnap1 in the mutant backgrounds rescues the phenotypes and restores the organization of axonal domains with improved motor function. This study uncovers the mechanistic impact of two human CNTNAP1 mutations in a mouse model and provides proof of concept for gene therapy for CNTNAP1 patients.
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Affiliation(s)
- Cheng Chang
- Department of Cellular and Integrative Physiology University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, China
| | - Lacey B Sell
- Department of Cellular and Integrative Physiology University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Qian Shi
- Department of Cellular and Integrative Physiology University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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2
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Garel P, Lesca G, Ville D, Poulat AL, Chatron N, Sanlaville D, Des Portes V, Arzimanoglou A, Lion-François L. CNTNAP1-encephalopathy: Six novel patients surviving the neonatal period. Eur J Paediatr Neurol 2022; 37:98-104. [PMID: 35182943 DOI: 10.1016/j.ejpn.2022.01.015] [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: 04/01/2021] [Revised: 12/29/2021] [Accepted: 01/26/2022] [Indexed: 11/29/2022]
Abstract
CNTNAP1 encodes CASPR1, involved in the paranodal junction. Thirty-three patients, with CNTNAP1 biallelic mutations have been described previously. Most of them had a very severe neurological impairment and passed away in the first months of life. We identified four patients, from two unrelated families, who survived over the neonatal period. Exome sequencing showed compound heterozygous or homozygous variants. Severe hypotonia was a constant feature. When compared to previous reports, the most important clinical differences observed in our patients were the absence of antenatal problems and, in two of them, the lack of respiratory distress. Less commonly reported characteristics such as epileptic seizures, dystonia, and impaired communication skills were also observed. MRIs revealed hypomyelination or abnormal white matter signal, cerebral or cerebellar atrophy. The present observations support a wider than initially reported clinical spectrum, including survival after the neonatal period and additional neurological features. They contribute to better delineate the phenotype-genotype correlations for CNTNAP1. In addition, we report one more family with two sibs who carry a missense variant of uncertain significance which we propose could be associated with a milder phenotype.
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Affiliation(s)
- Pauline Garel
- Department of Pediatrics, Centre Hospitalier Universitaire de Saint Etienne, Saint-Priest-en-Jarez, France.
| | - Gaetan Lesca
- Genetics Department, Member of the ERN EpiCARE, HFME, University Hospitals of Lyon (HCL), Lyon, France; INMG (Institut Neuromyogene), Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Dorothée Ville
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Anne-Lise Poulat
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Nicolas Chatron
- Department of Biology and Pathology, University Hospitals of Lyon (HCL), Lyon, France; INMG (Institut Neuromyogene), Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Damien Sanlaville
- Department of Biology and Pathology, University Hospitals of Lyon (HCL), Lyon, France; INMG (Institut Neuromyogene), Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Vincent Des Portes
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Alexis Arzimanoglou
- Department of Paediatric Clinical Epileptology, Sleep Disorders and Functional Neurology, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
| | - Laurence Lion-François
- Pediatric Neurology Department, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL), Lyon, France
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3
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Malavasi EL, Ghosh A, Booth DG, Zagnoni M, Sherman DL, Brophy PJ. Dynamic early clusters of nodal proteins contribute to node of Ranvier assembly during myelination of peripheral neurons. eLife 2021; 10:68089. [PMID: 34240706 PMCID: PMC8289411 DOI: 10.7554/elife.68089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/07/2021] [Indexed: 12/31/2022] Open
Abstract
Voltage-gated sodium channels cluster in macromolecular complexes at nodes of Ranvier to promote rapid nerve impulse conduction in vertebrate nerves. Node assembly in peripheral nerves is thought to be initiated at heminodes at the extremities of myelinating Schwann cells, and fusion of heminodes results in the establishment of nodes. Here we show that assembly of 'early clusters' of nodal proteins in the murine axonal membrane precedes heminode formation. The neurofascin (Nfasc) proteins are essential for node assembly, and the formation of early clusters also requires neuronal Nfasc. Early clusters are mobile and their proteins are dynamically recruited by lateral diffusion. They can undergo fusion not only with each other but also with heminodes, thus contributing to the development of nodes in peripheral axons. The formation of early clusters constitutes the earliest stage in peripheral node assembly and expands the repertoire of strategies that have evolved to establish these essential structures.
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Affiliation(s)
- Elise Lv Malavasi
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Aniket Ghosh
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel G Booth
- Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Michele Zagnoni
- Centre for Microsystems & Photonics, Dept. Electronic and Electrical Engineering, University of Strathclyde, Strathclyde, United Kingdom
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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4
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Abstract
The nodes of Ranvier have clustered Na+ and K+ channels necessary for rapid and efficient axonal action potential conduction. However, detailed mechanisms of channel clustering have only recently been identified: they include two independent axon-glia interactions that converge on distinct axonal cytoskeletons. Here, we discuss how glial cell adhesion molecules and the extracellular matrix molecules that bind them assemble combinations of ankyrins, spectrins and other cytoskeletal scaffolding proteins, which cluster ion channels. We present a detailed molecular model, incorporating these overlapping mechanisms, to explain how the nodes of Ranvier are assembled in both the peripheral and central nervous systems.
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5
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Li W, Yang L, Tang C, Liu K, Lu Y, Wang H, Yan K, Qiu Z, Zhou W. Mutations of CNTNAP1 led to defects in neuronal development. JCI Insight 2020; 5:135697. [PMID: 33148880 PMCID: PMC7710280 DOI: 10.1172/jci.insight.135697] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 09/30/2020] [Indexed: 12/20/2022] Open
Abstract
Mutations of CNTNAP1 were associated with myelination disorders, suggesting the role of CNTNAP1 in myelination processes. Whether CNTNAP1 may have a role in early cortical neuronal development is largely unknown. In this study, we identified 4 compound heterozygous mutations of CNTNAP1 in 2 Chinese families. Using mouse models, we found that CNTNAP1 is highly expressed in neurons and is located predominantly in MAP2+ neurons during the early developmental stage. Importantly, Cntnap1 deficiency results in aberrant dendritic growth and spine development in vitro and in vivo, and it delayed migration of cortical neurons during early development. Finally, we found that the number of parvalbumin+ neurons in the cortex and hippocampus of Cntnap1–/– mice is strikingly increased by P15, suggesting that excitation/inhibition balance is impaired. Together, this evidence elucidates a critical function of CNTNAP1 in cortical development, providing insights underlying molecular and circuit mechanisms of CNTNAP1-related disease. Deficiency of CNTNAP1 causes severe cortical developmental deficits, leading to human lethal perinatal symptoms.
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Affiliation(s)
| | - Lin Yang
- Key Laboratory of Birth Defects.,Division of Endocrinology, Genetics and Metabolic Disease, and
| | - Chuanqing Tang
- Stem Cell Research Center, Institute of Pediatrics, Children's Hospital, Fudan University, Shanghai, China
| | | | | | | | | | - Zilong Qiu
- Institute of Neuroscience, State Key Laboratory of Neuroscience.,CAS Center for Excellence in Brain Science and Intelligence Technology.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology.,Chinese Academy of Sciences, and.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Wenhao Zhou
- Division of Neonatology.,Key Laboratory of Birth Defects.,Key Laboratory of Neonatal Diseases, Ministry of Health, Children's Hospital of Fudan University, Shanghai, China
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6
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Roston A, Evans D, Gill H, McKinnon M, Isidor B, Cogné B, Mwenifumbo J, van Karnebeek C, An J, Jones SJM, Farrer M, Demos M, Connolly M, Gibson WT. SETD1B-associated neurodevelopmental disorder. J Med Genet 2020; 58:196-204. [PMID: 32546566 DOI: 10.1136/jmedgenet-2019-106756] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/11/2020] [Accepted: 04/14/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND Dysfunction of histone methyltransferases and chromatin modifiers has been implicated in complex neurodevelopmental syndromes and cancers. SETD1B encodes a lysine-specific methyltransferase that assists in transcriptional activation of genes by depositing H3K4 methyl marks. Previous reports of patients with rare variants in SETD1B describe a distinctive phenotype that includes seizures, global developmental delay and intellectual disability. METHODS Two of the patients described herein were identified via genome-wide and exome-wide testing, with microarray and research-based exome, through the CAUSES (Clinical Assessment of the Utility of Sequencing and Evaluation as a Service) Research Clinic at the University of British Columbia. The third Vancouver patient had clinical trio exome sequencing through Blueprint Genetics. The fourth patient underwent singleton exome sequencing in Nantes, with subsequent recruitment to this cohort through GeneMatcher. RESULTS Here we present clinical reports of four patients with rare coding variants in SETD1B that demonstrate a shared phenotype, including intellectual disability, language delay, conserved musculoskeletal findings and seizures that may be treatment-refractory. We include supporting evidence from next-generation sequencing among a cohort of paediatric patients with epilepsy. CONCLUSION Rare coding variants in SETD1B can cause a diagnosable syndrome and could contribute as a risk factor for epilepsy, autism and other neurodevelopmental phenotypes. In the long term, some patients may also be at increased risk for cancers and other complex diseases. Thus, longitudinal studies are required to further elucidate the precise role of SETD1B in neurodevelopmental disorders and other systemic disease.
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Affiliation(s)
- Alexandra Roston
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Dan Evans
- Centre for Applied Neurogenetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Harinder Gill
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada.,Provincial Medical Genetics Program, BC Women's Hospital and Health Centre, Vancouver, British Columbia, Canada
| | - Margaret McKinnon
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Bertrand Isidor
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, Pays de la Loire, France
| | - Benjamin Cogné
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, Pays de la Loire, France.,INSERM, CNRS, UNIV Nantes, l'institut du thorax, Nantes, Frances
| | - Jill Mwenifumbo
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Clara van Karnebeek
- Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology and Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatrics, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jianghong An
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Matthew Farrer
- Centre for Applied Neurogenetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Michelle Demos
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mary Connolly
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - William T Gibson
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
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7
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CNTNAP1 Mutations and Their Clinical Presentations: New Case Report and Systematic Review. Case Rep Med 2020; 2020:8795607. [PMID: 32328110 PMCID: PMC7174947 DOI: 10.1155/2020/8795607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/23/2020] [Accepted: 03/27/2020] [Indexed: 01/11/2023] Open
Abstract
Lethal congenital contracture syndrome type 7 (LCCS7) and congenital hypomyelinating neuropathy type 3 (CHN3) are rare autosomal recessive diseases, characterized by severe neonatal hypotonia, polyhydramnios, arthrogryposis, facial diplegia, and severe motor paralysis, leading to death in early infancy. They are related to mutations in the CNTNAP1 (contactin associated protein 1) gene, playing an important role in myelination. Recent studies have shown that both diseases could present with a wide phenotypic spectrum, with promising survival up to early childhood. We report on a 7-year-old boy from a nonconsanguineous Lebanese family presenting with neonatal hypotonia, respiratory distress, and arthrogryposis. Molecular analysis revealed the presence of a pathogenic variant in the CNTNAP1 gene leading to a premature stop codon: NM_003632.2:c.3361C>T p.(Arg1121∗). A review of the literature is discussed.
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8
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Morelli KH, Hatton CL, Harper SQ, Burgess RW. Gene therapies for axonal neuropathies: Available strategies, successes to date, and what to target next. Brain Res 2020; 1732:146683. [PMID: 32001243 DOI: 10.1016/j.brainres.2020.146683] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022]
Abstract
Nearly one-hundred loci in the human genome have been associated with different forms of Charcot-Marie-Tooth disease (CMT) and related inherited neuropathies. Despite this wealth of gene targets, treatment options are still extremely limited, and clear "druggable" pathways are not obvious for many of these mutations. However, recent advances in gene therapies are beginning to circumvent this challenge. Each type of CMT is a monogenic disorder, and the cellular targets are usually well-defined and typically include peripheral neurons or Schwann cells. In addition, the genetic mechanism is often also clear, with loss-of-function mutations requiring restoration of gene expression, and gain-of-function or dominant-negative mutations requiring silencing of the mutant allele. These factors combine to make CMT a good target for developing genetic therapies. Here we will review the state of relatively established gene therapy approaches, including viral vector-mediated gene replacement and antisense oligonucleotides for exon skipping, altering splicing, and gene knockdown. We will also describe earlier stage approaches for allele-specific knockdown and CRIPSR/Cas9 gene editing. We will next describe how these various approaches have been deployed in clinical and preclinical studies. Finally, we will evaluate various forms of CMT as candidates for gene therapy based on the current understanding of their genetics, cellular/tissue targets, validated animal models, and availability of patient populations and natural history data.
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Affiliation(s)
- Kathryn H Morelli
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | - Scott Q Harper
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA.
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9
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Lesmana H, Vawter Lee M, Hosseini SA, Burrow TA, Hallinan B, Bove K, Schapiro M, Hopkin RJ. CNTNAP1-Related Congenital Hypomyelinating Neuropathy. Pediatr Neurol 2019; 93:43-49. [PMID: 30686628 DOI: 10.1016/j.pediatrneurol.2018.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 12/13/2018] [Accepted: 12/24/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND Congenital hypomyelinating neuropathy is a rare form of hereditary peripheral neuropathy characterized by nonprogressive weakness, areflexia, hypotonia, severely reduced nerve conduction velocities, and hypomyelination. Mutations in contactin-associated protein 1 (CNTNAP1) were recently described as a cause of congenital hypomyelinating neuropathy. CNTNAP1-associated congenital hypomyelinating neuropathy is characterized by severe hypotonia, multiple distal joint contractures, and high mortality in the first few months of life. METHODS Whole-exome sequencing was performed in two siblings with congenital hypotonia. Detailed phenotyping data were compared with previously reported cases. RESULTS A novel, heterozygous compound mutation of CNTNAP1 was identified in both siblings. We also reviewed 17 patients harboring 10 distinct mutations from previously published studies. All patients presented with severe hypotonia, respiratory distress, and multiple cranial nerve palsies at birth. Six of 19 patients survived beyond infancy and required chronic mechanical ventilation. Seizures were common in the surviving patients. CONCLUSIONS These findings suggest that CNTNAP1-related congenital hypomyelinating neuropathy is a distinct form of hereditary neuropathy that affects both the central and peripheral nervous systems with no clear phenotype-genotype correlation. Our findings also indicate that arthrogryposis multiplex congenita and early lethality are not universal outcomes for patients with congenital hypomyelinating neuropathy.
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Affiliation(s)
- Harry Lesmana
- Department of Hematology, St. Jude Children's Research Hospital, University of Tennessee Health Science Center, Memphis, Tennessee; Department of Oncology, St. Jude Children's Research Hospital, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Marissa Vawter Lee
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | | | - T Andrew Burrow
- Section of Genetics and Metabolism, Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Barbara Hallinan
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | - Kevin Bove
- Division of Pathology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio; Division of Laboratory Medicine, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | - Mark Schapiro
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio
| | - Robert J Hopkin
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio.
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10
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Conant A, Curiel J, Pizzino A, Sabetrasekh P, Murphy J, Bloom M, Evans SH, Helman G, Taft RJ, Simons C, Whitehead MT, Moore SA, Vanderver A. Absence of Axoglial Paranodal Junctions in a Child With CNTNAP1 Mutations, Hypomyelination, and Arthrogryposis. J Child Neurol 2018; 33:642-650. [PMID: 29882456 PMCID: PMC6800098 DOI: 10.1177/0883073818776157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Leukodystrophies and genetic leukoencephalopathies are a heterogeneous group of heritable disorders that affect the glial-axonal unit. As more patients with unsolved leukodystrophies and genetic leukoencephalopathies undergo next generation sequencing, causative mutations in genes leading to central hypomyelination are being identified. Two such individuals presented with arthrogryposis multiplex congenita, congenital hypomyelinating neuropathy, and central hypomyelination with early respiratory failure. Whole exome sequencing identified biallelic mutations in the CNTNAP1 gene: homozygous c.1163G>C (p.Arg388Pro) and compound heterozygous c.967T>C (p.Cys323Arg) and c.319C>T (p.Arg107*). Sural nerve and quadriceps muscle biopsies demonstrated progressive, severe onion bulb and axonal pathology. By ultrastructural evaluation, septate axoglial paranodal junctions were absent from nodes of Ranvier. Serial brain magnetic resonance images revealed hypomyelination, progressive atrophy, and reduced diffusion in the globus pallidus in both patients. These 2 families illustrate severe progressive peripheral demyelinating neuropathy due to the absence of septate paranodal junctions and central hypomyelination with neurodegeneration in CNTNAP1-associated arthrogryposis multiplex congenita.
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Affiliation(s)
- Alexander Conant
- 1 Department of Neurology, Children's National Health System, Washington, DC, USA
| | - Julian Curiel
- 2 Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Amy Pizzino
- 1 Department of Neurology, Children's National Health System, Washington, DC, USA
| | - Parisa Sabetrasekh
- 1 Department of Neurology, Children's National Health System, Washington, DC, USA
| | - Jennifer Murphy
- 3 National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miriam Bloom
- 4 Department of Pediatric Hospitalist Medicine, Children's National Health System, Washington, DC, USA
| | - Sarah H Evans
- 5 Department of Physical Medicine and Rehabilitation, Children's National Health System, Washington, DC, USA
| | - Guy Helman
- 1 Department of Neurology, Children's National Health System, Washington, DC, USA.,6 Center for Genetic Medicine, Children's National Health System, Washington DC, USA.,7 Murdoch Children's Research Institute, Parkville, Melbourne, Australia
| | - Ryan J Taft
- 8 Illumina, San Diego, CA, USA.,9 Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Cas Simons
- 7 Murdoch Children's Research Institute, Parkville, Melbourne, Australia.,9 Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew T Whitehead
- 10 Neuroradiology Department, Children's National Health System, Washington, DC, USA.,11 George Washington University School of Medicine, Washington, DC, USA
| | - Steven A Moore
- 12 Department of Pathology, University of Iowa Carver College of Medicine and Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, Iowa City, IA, USA
| | - Adeline Vanderver
- 1 Department of Neurology, Children's National Health System, Washington, DC, USA.,2 Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,3 National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.,11 George Washington University School of Medicine, Washington, DC, USA
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11
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Low KJ, Stals K, Caswell R, Wakeling M, Clayton-Smith J, Donaldson A, Foulds N, Norman A, Splitt M, Urankar K, Vijayakumar K, Majumdar A, Study D, Ellard S, Smithson SF. Phenotype of CNTNAP1: a study of patients demonstrating a specific severe congenital hypomyelinating neuropathy with survival beyond infancy. Eur J Hum Genet 2018; 26:796-807. [PMID: 29511323 PMCID: PMC5974240 DOI: 10.1038/s41431-018-0110-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 11/18/2022] Open
Abstract
CHN is genetically heterogeneous and its genetic basis is difficult to determine on features alone. CNTNAP1 encodes CASPR, integral in the paranodal junction high molecular mass complex. Nineteen individuals with biallelic variants have been described in association with severe congenital hypomyelinating neuropathy, respiratory compromise, profound intellectual disability and death within the first year. We report 7 additional patients ascertained through exome sequencing. We identified 9 novel CNTNAP1 variants in 6 families: three missense variants, four nonsense variants, one frameshift variant and one splice site variant. Significant polyhydramnios occurred in 6/7 pregnancies. Severe respiratory compromise was seen in 6/7 (tracheostomy in 5). A complex neurological phenotype was seen in all patients who had marked brain hypomyelination/demyelination and profound developmental delay. Additional neurological findings included cranial nerve compromise: orobulbar dysfunction in 5/7, facial nerve weakness in 4/7 and vocal cord paresis in 5/7. Dystonia occurred in 2/7 patients and limb contractures in 5/7. All had severe gastroesophageal reflux, and a gastrostomy was required in 5/7. In contrast to most previous reports, only one patient died in the first year of life. Protein modelling was performed for all detected CNTNAP1 variants. We propose a genotype-phenotype correlation, whereby hypomorphic missense variants partially ameliorate the phenotype, prolonging survival. This study suggests that biallelic variants in CNTNAP1 cause a distinct recognisable syndrome, which is not caused by other genes associated with CHN. Neonates presenting with this phenotype will benefit from early genetic definition to inform clinical management and enable essential genetic counselling for their families.
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Affiliation(s)
- K J Low
- Department of Clinical Genetics, St Michaels Hospital, Bristol, UK
- School of Clinical Sciences, University of Bristol, Bristol, UK
| | - K Stals
- Department of Molecular Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
| | - R Caswell
- Institute for Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - M Wakeling
- Institute for Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - J Clayton-Smith
- Manchester Centre for Genomic Medicine, St Marys' Hospital, Manchester, UK
- Institute of Human Development, University of Manchester, Manchester, UK
| | - A Donaldson
- Department of Clinical Genetics, St Michaels Hospital, Bristol, UK
| | - N Foulds
- Wessex Clinical Genetics Service, Southampton, UK
| | - A Norman
- Department of Clinical Genetics, St Michaels Hospital, Bristol, UK
| | - M Splitt
- Northern Genetics Service, Institute of Genetics Medicine, Newcastle upon Tyne, UK
| | - K Urankar
- Department of Neuropathology, North Bristol NHS Trust, Bristol, UK
| | - K Vijayakumar
- Paediatric Neuromuscular Service, Bristol Royal Hospital for Children, Bristol, UK
| | - A Majumdar
- Paediatric Neuromuscular Service, Bristol Royal Hospital for Children, Bristol, UK
| | - Ddd Study
- Wellcome Trust Sanger Institute, Cambridge, UK
| | - S Ellard
- Department of Molecular Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
- Institute for Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - S F Smithson
- Department of Clinical Genetics, St Michaels Hospital, Bristol, UK.
- School of Clinical Sciences, University of Bristol, Bristol, UK.
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