1
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Zhang F, Guo H, Zhou X, Deng Z, Xu Q, Wang Q, Yuan H, Luo J. Novel PIP5K1C variant identified in a Chinese pedigree with lethal congenital contractural syndrome 3. BMC Pediatr 2024; 24:182. [PMID: 38491417 PMCID: PMC10941444 DOI: 10.1186/s12887-024-04674-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/26/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Biallelic pathogenic variants in PIP5K1C (MIM #606,102) lead to lethal congenital contractural syndrome 3 (LCCS3, MIM #611,369), a rare autosomal recessive genetic disorder characterized by small gestational age, severe multiple joint contractures and muscle atrophy, early death due to respiratory failure. Currently, 5 individuals with LCCS3 were reported and 5 pathogenic variants in PIP5K1C were identified. Here, we reported the two fetuses in a Chinese pedigree who displayed multiple joint contractures and other congenital anomalies. METHODS Trio-based whole-exome sequencing (WES) was performed for the parents and the recent fetus to detect the genetic cause for fetus phenotype. RESULTS A novel variant, NM_012398.3: c.949_952dup, p.S318Ifs*28 and a previously reported variant, c.688_689del, p.G230Qfs*114 (ClinVar database) in PIP5K1C, were detected in the individuals, and these variants were inherited from the mother and father, respectively. We described the features of multiple joint contractures in our fetuses, including bilateral talipes equinovarus, stiffness in the limbs, extended knees, persistently closed hands and overlapping fingers, which have not been delineated detailedly in previously reported LCCS3 individuals. Furthermore, novel phenotype, bilateral dilated lateral ventricles, was revealed in one fetus. CONCLUSIONS These findings expanded the genetic variant spectrum of PIP5K1C and enriched the clinical features of LCCS3, which will help with the prenatal diagnosis and genetic counseling for this family.
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Affiliation(s)
- Fang Zhang
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
| | - Hongmei Guo
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
| | - Xinlong Zhou
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
- Key Laboratory for Precision Diagnosis and Treatment of Severe Infectious Diseases in Children, Dongguan, 523120, China
| | - Zhengxi Deng
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
| | - Qiuhong Xu
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
| | - Qingming Wang
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
- Department of Medical Genetics, Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China
| | - Haiming Yuan
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China.
- Department of Medical Genetics, Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China.
| | - Jianhua Luo
- Dongguan Maternal and Child Health Care Hospital, Dongguan, 523120, China.
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2
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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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3
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Khan S, Umair M, Abbas S, Ali U, Zaman G, Ansar M, Wang R, Zhang X, Houlden H, Harlalka GV, Gul A. Overlapping neurological phenotypes in two extended consanguineous families with novel variants in the CNTNAP1 and ADGRG1 genes. J Gene Med 2023; 25:e3513. [PMID: 37178061 DOI: 10.1002/jgm.3513] [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: 01/05/2023] [Revised: 03/31/2023] [Accepted: 04/03/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Population diversity is important and rare disease isolates can frequently reveal novel homozygous or biallelic mutations that lead to expanded clinical heterogeneity, with diverse clinical presentations. METHODS The present study describes two consanguineous families with a total of seven affected individuals suffering from a clinically similar severe syndromic neurological disorder, with abnormal development and central nervous system (CNS) and peripheral nervous system (PNS) abnormalities. Whole exome sequencing (WES) and Sanger sequencing followed by 3D protein modeling was performed to identify the disease-causing gene. RNA was extracted from the fresh blood of both families affected and healthy individuals. RESULTS The families were clinically assessed in the field in different regions of Khyber Pakhtunkhwa. Magnetic resonance imagining was obtained in the probands and blood was collected for DNA extraction and WES was performed. Sanger sequencing confirmed a homozygous, likely pathogenic mutation (GRCh38: chr17:42684199G>C; (NM_003632.3): c.333G>C);(NP_003623.1): p.(Trp111Cys) in the CNTNAP1 gene in family A, previously associated with Congenital Hypo myelinating Neuropathy 3 (CHN3; OMIM # 618186) and a novel nonsense variant in family B, (GRCh38: chr16: 57654086C>T; NC_000016.10 (NM_001370440.1): c.721C>T); (NP_001357369.1): p.(Gln241Ter) in the ADGRG1 gene previously associated with bilateral frontoparietal polymicrogyria (OMIM # 606854); both families have extended CNS and PNS clinical manifestations. In addition, 3D protein modeling was performed for the missense variant, p.(Trp111Cys), identified in the CNTNAP1, suggesting extensive secondary structure changes that might lead to improper function or downstream signaling. No RNA expression was observed in both families affected and healthy individuals hence showing that these genes are not expressed in blood. CONCLUSIONS In the present study, two novel biallelic variants in the CNTNAP1 and ADGRG1 genes in two different consanguineous families with a clinical overlap in the phenotype were identified. Thus, the clinical and mutation spectrum is expanded to provide further evidence that CNTNAP1 and ADGRG1 are very important for widespread neurological development.
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Affiliation(s)
- Shazia Khan
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
- Medical Research, RILD Wellcome Wolfson Centre (Level 4), Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
- Hafeez Institute of Medical Sciences, Islamabad, Pakistan
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
- Department of Life Sciences, School of Science, University of Management and Technology (UMT), Lahore, Pakistan
| | - Safdar Abbas
- Department of Biological Science, Dartmouth College, Hanover, NH, USA
| | - Uroba Ali
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Gohar Zaman
- Department of Computer Science, Abbottabad University of Science and Technology, Havelian, Abbottabad, Pakistan
| | - Muhammad Ansar
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Rongrong Wang
- McKusick-Zhang Center for Genetic Medicine, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
- The Research Center for Medical Genomics, China Medical University, Shenyang, China
| | - Henry Houlden
- Department of Neuromuscular Disorder, UCL Institute of Neurology, London, UK
| | - Gaurav V Harlalka
- Medical Research, RILD Wellcome Wolfson Centre (Level 4), Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
- Department of Pharmacology, Samarth College of Pharmacy, Deulgaon Raja, Dist. Buldana, Maharashtra, India
| | - Asma Gul
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
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4
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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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5
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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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6
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Rebelo AP, Cortese A, Abraham A, Eshed-Eisenbach Y, Shner G, Vainshtein A, Buglo E, Camarena V, Gaidosh G, Shiekhattar R, Abreu L, Courel S, Burns DK, Bai Y, Bacon C, Feely SME, Castro D, Peles E, Reilly MM, Shy ME, Zuchner S. A CADM3 variant causes Charcot-Marie-Tooth disease with marked upper limb involvement. Brain 2021; 144:1197-1213. [PMID: 33889941 DOI: 10.1093/brain/awab019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 10/06/2020] [Accepted: 10/30/2020] [Indexed: 01/19/2023] Open
Abstract
The CADM family of proteins consists of four neuronal specific adhesion molecules (CADM1, CADM2, CADM3 and CADM4) that mediate the direct contact and interaction between axons and glia. In the peripheral nerve, axon-Schwann cell interaction is essential for the structural organization of myelinated fibres and is primarily mediated by the binding of CADM3, expressed in axons, to CADM4, expressed by myelinating Schwann cells. We have identified-by whole exome sequencing-three unrelated families, including one de novo patient, with axonal Charcot-Marie-Tooth disease (CMT2) sharing the same private variant in CADM3, Tyr172Cys. This variant is absent in 230 000 control chromosomes from gnomAD and predicted to be pathogenic. Most CADM3 patients share a similar phenotype consisting of autosomal dominant CMT2 with marked upper limb involvement. High resolution mass spectrometry analysis detected a newly created disulphide bond in the mutant CADM3 potentially modifying the native protein conformation. Our data support a retention of the mutant protein in the endoplasmic reticulum and reduced cell surface expression in vitro. Stochastic optical reconstruction microscopy imaging revealed decreased co-localization of the mutant with CADM4 at intercellular contact sites. Mice carrying the corresponding human mutation (Cadm3Y170C) showed reduced expression of the mutant protein in axons. Cadm3Y170C mice showed normal nerve conduction and myelin morphology, but exhibited abnormal axonal organization, including abnormal distribution of Kv1.2 channels and Caspr along myelinated axons. Our findings indicate the involvement of abnormal axon-glia interaction as a disease-causing mechanism in CMT patients with CADM3 mutations.
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Affiliation(s)
- Adriana P Rebelo
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Andrea Cortese
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Amit Abraham
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gal Shner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Anna Vainshtein
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Elena Buglo
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Vladimir Camarena
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Gabriel Gaidosh
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, USA
| | - Ramin Shiekhattar
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, USA
| | - Lisa Abreu
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Steve Courel
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
| | - Dennis K Burns
- Department of Pathology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Yunhong Bai
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Chelsea Bacon
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Shawna M E Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Diana Castro
- Departments of Pediatrics, Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, USA
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, USA
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7
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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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8
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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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9
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Desai D, Stiene D, Song T, Sadayappan S. Distal Arthrogryposis and Lethal Congenital Contracture Syndrome - An Overview. Front Physiol 2020; 11:689. [PMID: 32670090 PMCID: PMC7330016 DOI: 10.3389/fphys.2020.00689] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022] Open
Abstract
Distal arthrogryposis (DA) is a skeletal muscle disorder which can be classified under a broader term as Arthrogryposis multiplex contractures. DA is characterized by the presence of joint contractures at various parts of the body, particularly in distal extremities. It is identified as an autosomal dominant and a rare X-linked recessive disorder associated with increased connective tissue formation around joints in such way that immobilizes muscle movement causing deformities. DA is again classified into various types since it manifests as a range of conditions representing different etiologies. Myopathy is one of the most commonly listed etiologies of DA. The mutations in sarcomeric protein-encoding genes lead to decreased sarcomere integrity, which is often associated with this disorder. Also, skeletal disorders are often associated with cardiac disorders. Some studies mention the presence of cardiomyopathy in patients with skeletal dysfunction. Therefore, it is hypothesized that the congenitally mutated protein that causes DA can also lead to cardiomyopathy. In this review, we will summarize the different forms of DA and their clinical features, along with gene mutations responsible for causing DA in its different forms. We will also examine reports that list mutations also known to cause heart disorders in the presence of DA.
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Affiliation(s)
- Darshini Desai
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Danielle Stiene
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
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10
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Abstract
PURPOSE OF REVIEW Charcot-Marie-Tooth (CMT) disease and related disorders are the commonest group of inherited neuromuscular diseases and represent a heterogeneous group of disorders. This review will cover recent advances in genetic diagnosis and the evolving genetic and phenotype landscape of this disease group. We will review recent evidence of the increasingly recognized phenotypic overlap with other neurodegenerative conditions including hereditary spastic paraplegia, hereditary ataxias and mitochondrial diseases and highlight the importance of deep phenotyping to inform genetic diagnosis and prognosis. RECENT FINDINGS Through whole exome sequencing and multicentre collaboration new genes are being identified as causal for CMT expanding the genetic heterogeneity of this condition. In addition, an increasing number of variants have been identified in genes known to cause complex inherited diseases in which the peripheral neuropathy is part of the disorder and may be the presenting feature. The recent discovery of a repeat expansion in the RFC1 gene in cerebellar ataxia, neuropathy, vestibular areflexia syndrome highlights the prevalence of late-onset recessive conditions which have historically been considered to cause early-onset disease. SUMMARY CMT is an evolving field with considerable phenotypic and genetic heterogeneity and deep phenotyping remains a cornerstone in contemporary CMT diagnostics.
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11
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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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12
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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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13
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Freed AS, Weiss MD, Malouf EA, Hisama FM. CNTNAP1 mutations in an adult with Charcot Marie Tooth disease. Muscle Nerve 2019; 60:E28-E30. [PMID: 31397905 DOI: 10.1002/mus.26658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 07/25/2019] [Accepted: 08/06/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Amanda S Freed
- Medical Genetics and Genomics Residency Program, Washington School of Medicine, University of Washington, Seattle, Washington
| | - Michael D Weiss
- Professor of Neurology and Adjunct Professor of Rehabilitation Medicine, Washington School of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - Emily A Malouf
- Division of Medical Genetics, Washington School of Medicine, University of Washington Medical Center, Seattle, Washington
| | - Fuki M Hisama
- Professor of Medical Genetics and Adjunct Professor of Neurology, Washington School of Medicine, University of Washington School of Medicine, Seattle, Washington
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14
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Dieterich K, Kimber E, Hall JG. Central nervous system involvement in arthrogryposis multiplex congenita: Overview of causes, diagnosis, and care. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2019; 181:345-353. [PMID: 31410997 DOI: 10.1002/ajmg.c.31732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/13/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022]
Abstract
Arthrogryposis or AMC, arthrogryposis multiplex congenita, is defined as multiple congenital joint contractures in more than two joints and in different body areas. The common cause of all AMC is lack of movement in utero, which in turn can have different causes, one of which is CNS involvement. Intellectual disability/CNS involvement is found in approximately 25% of all AMC. AMC with CNS involvement includes a large number of genetic syndromes. So far, more than 400 genes have been identified as linked to AMC, with and without CNS involvement. A number of neonatally lethal syndromes and syndromes resulting in severe disability due to CNS malfunction belong to this group of syndromes. There are several X-linked disorders with AMC, which are primarily related to intellectual disability. A number of neuromuscular disorders may include AMC and CNS/brain involvement. Careful clinical evaluation by a geneticist and a pediatrician/pediatric neurologist is the first step in making a specific diagnosis. Further investigations may include MRI of the brain and spinal cord, electroencephalogram, blood chemistry for muscle enzymes, other organ investigations (ophtalmology, cardiology, gastrointestinal, and genitourinary systems). Nerve conduction studies, electromyogram, and muscle pathology may be of help when there is associated peripheral nervous system involvement. But most importantly, genetic investigations with targeted or rather whole exome or genome sequencing should be performed. A correct diagnosis is important in planning adequate treatment, in genetic counselling and also for future understanding of pathogenic mechanisms and possible new treatments. A multidiciplinary team is needed both in investigation and treatment.
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Affiliation(s)
- Klaus Dieterich
- Univ. Grenoble Alpes, Inserm, U1216, GIN, Grenoble, France.,CHU Grenoble Alpes, Génétique Médicale, Grenoble, France
| | - Eva Kimber
- Department of Women's and Children's Health, Uppsala University Children's Hospital, Uppsala, Sweden.,Department of Paediatrics, Institute of Clinical Sciences, University of Gothenburg, The Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Judith G Hall
- Professor Emerita, Department of Pediatrics and Medical Genetics, University of British Columbia, Vancouver, Canada
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15
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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: 10] [Impact Index Per Article: 2.0] [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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16
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Yermakov LM, Hong LA, Drouet DE, Griggs RB, Susuki K. Functional Domains in Myelinated Axons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:65-83. [PMID: 31760639 DOI: 10.1007/978-981-32-9636-7_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Propagation of action potentials along axons is optimized through interactions between neurons and myelinating glial cells. Myelination drives division of the axons into distinct molecular domains including nodes of Ranvier. The high density of voltage-gated sodium channels at nodes generates action potentials allowing for rapid and efficient saltatory nerve conduction. At paranodes flanking both sides of the nodes, myelinating glial cells interact with axons, forming junctions that are essential for node formation and maintenance. Recent studies indicate that the disruption of these specialized axonal domains is involved in the pathophysiology of various neurological diseases. Loss of paranodal axoglial junctions due to genetic mutations or autoimmune attack against the paranodal proteins leads to nerve conduction failure and neurological symptoms. Breakdown of nodal and paranodal proteins by calpains, the calcium-dependent cysteine proteases, may be a common mechanism involved in various nervous system diseases and injuries. This chapter reviews recent progress in neurobiology and pathophysiology of specialized axonal domains along myelinated nerve fibers.
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Affiliation(s)
- Leonid M Yermakov
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Lulu A Hong
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Domenica E Drouet
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Ryan B Griggs
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, USA.
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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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18
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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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