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Cook S, Hooser BN, Williams DC, Kortz G, Aleman M, Minor K, Koziol J, Friedenberg SG, Cullen JN, Shelton GD, Ekenstedt KJ. Canine models of Charcot-Marie-Tooth: MTMR2, MPZ, and SH3TC2 variants in golden retrievers with congenital hypomyelinating polyneuropathy. Neuromuscul Disord 2023; 33:677-691. [PMID: 37400349 PMCID: PMC10530471 DOI: 10.1016/j.nmd.2023.06.007] [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: 03/23/2023] [Revised: 06/06/2023] [Accepted: 06/19/2023] [Indexed: 07/05/2023]
Abstract
Congenital hypomyelinating polyneuropathy (HPN) restricted to the peripheral nervous system was reported in 1989 in two Golden Retriever (GR) littermates. Recently, four additional cases of congenital HPN in young, unrelated GRs were diagnosed via neurological examination, electrodiagnostic evaluation, and peripheral nerve pathology. Whole-genome sequencing was performed on all four GRs, and variants from each dog were compared to variants found across >1,000 other dogs, all presumably unaffected with HPN. Likely causative variants were identified for each HPN-affected GR. Two cases shared a homozygous splice donor site variant in MTMR2, with a stop codon introduced within six codons following the inclusion of the intron. One case had a heterozygous MPZ isoleucine to threonine substitution. The last case had a homozygous SH3TC2 nonsense variant predicted to truncate approximately one-half of the protein. Haplotype analysis using 524 GR established the novelty of the identified variants. Each variant occurs within genes that are associated with the human Charcot-Marie-Tooth (CMT) group of heterogeneous diseases, affecting the peripheral nervous system. Testing a large GR population (n = >200) did not identify any dogs with these variants. Although these variants are rare within the general GR population, breeders should be cautious to avoid propagating these alleles.
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Affiliation(s)
- Shawna Cook
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.
| | - Blair N Hooser
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
| | - D Colette Williams
- The William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA, USA
| | - Gregg Kortz
- VCA Sacramento Veterinary Referral Center, Sacramento CA, USA
| | - Monica Aleman
- The William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA, USA
| | - Katie Minor
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Jennifer Koziol
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, USA
| | - Steven G Friedenberg
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Jonah N Cullen
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kari J Ekenstedt
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
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Shchagina O, Orlova M, Murtazina A, Filatova A, Skoblov M, Dadali E. Evaluation of Pathogenicity and Causativity of Variants in the MPZ and SH3TC2 Genes in a Family Case of Hereditary Peripheral Neuropathy. Int J Mol Sci 2023; 24:9786. [PMID: 37372933 DOI: 10.3390/ijms24129786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
The implementation of NGS methods into clinical practice allowed researchers effectively to establish the molecular cause of a disorder in cases of a genetically heterogeneous pathology. In cases of several potentially causative variants, we need additional analysis that can help in choosing a proper causative variant. In the current study, we described a family case of hereditary motor and sensory neuropathy (HMSN) type 1 (Charcot-Marie-Tooth disease). DNA analysis revealed two variants in the SH3TC2 gene (c.279G>A and c.1177+5G>A), as well as a previously described variant c.449-9C>T in the MPZ gene, in a heterozygous state. This family segregation study was incomplete because of the proband's father's unavailability. To evaluate the variants' pathogenicity, minigene splicing assay was carried out. This study showed no effect of the MPZ variant on splicing, but the c.1177+5G>A variant in the SH3TC2 gene leads to the retention of 122 nucleotides from intron 10 in the RNA sequence, causing a frameshift and an occurrence of a premature stop codon (NP_078853.2:p.Ala393GlyfsTer2).
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Affiliation(s)
- Olga Shchagina
- Research Centre for Medical Genetics, Moscow 115522, Russia
| | - Mariya Orlova
- Research Centre for Medical Genetics, Moscow 115522, Russia
| | | | | | | | - Elena Dadali
- Research Centre for Medical Genetics, Moscow 115522, Russia
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Higuchi Y, Takashima H. Clinical genetics of Charcot-Marie-Tooth disease. J Hum Genet 2023; 68:199-214. [PMID: 35304567 DOI: 10.1038/s10038-022-01031-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/02/2022] [Accepted: 03/06/2022] [Indexed: 02/08/2023]
Abstract
Recent research in the field of inherited peripheral neuropathies (IPNs) such as Charcot-Marie-Tooth (CMT) disease has helped identify the causative genes provided better understanding of the pathogenesis, and unraveled potential novel therapeutic targets. Several reports have described the epidemiology, clinical characteristics, molecular pathogenesis, and novel causative genes for CMT/IPNs in Japan. Based on the functions of the causative genes identified so far, the following molecular and cellular mechanisms are believed to be involved in the causation of CMTs/IPNs: myelin assembly, cytoskeletal structure, myelin-specific transcription factor, nuclear related, endosomal sorting and cell signaling, proteasome and protein aggregation, mitochondria-related, motor proteins and axonal transport, tRNA synthetases and RNA metabolism, and ion channel-related mechanisms. In this article, we review the epidemiology, genetic diagnosis, and clinicogenetic characteristics of CMT in Japan. In addition, we discuss the newly identified novel causative genes for CMT/IPNs in Japan, namely MME and COA7. Identification of the new causes of CMT will facilitate in-depth characterization of the underlying molecular mechanisms of CMT, leading to the establishment of therapeutic approaches such as drug development and gene therapy.
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Affiliation(s)
- Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
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Fargeot G, Gitiaux C, Magy L, Pereon Y, Delmont E, Viala K, Echaniz-Laguna A. French recommendations for the management of adult & pediatric chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Rev Neurol (Paris) 2022; 178:953-968. [PMID: 36182621 DOI: 10.1016/j.neurol.2022.06.004] [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: 10/06/2021] [Revised: 05/31/2022] [Accepted: 06/05/2022] [Indexed: 11/22/2022]
Abstract
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system, primarily affecting the myelin sheath. The pathophysiology of CIDP is complex, involving both humoral and cellular immunity. The diagnosis of CIDP should be suspected in patients with symmetrical proximal and distal motor weakness and distal sensory symptoms of progressive onset, associated with decreased/abolished tendon reflexes. Treatments include intraveinous immunoglobulins, steroids and plasma exchange, with usually an induction phase followed by a maintenance therapy with progressive weaning. Treatment should be rapidly initiated to prevent axonal degeneration, which may compromise recovery. CIDP outcome is variable, ranging from mild distal paresthesiae to complete loss of ambulation. There have been several breakthroughs in the diagnosis and management of CIDP the past ten years, e.g. discovery of antibodies against the node of Ranvier, contribution of nerve ultrasound and magnetic resonance imaging to diagnosis, and demonstration of subcutaneous immunoglobulins efficiency. This led us to elaborate French recommendations for the management of adult & pediatric CIDP patients. These recommendations include diagnosis assessment, treatment, and follow-up.
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Affiliation(s)
- G Fargeot
- Neurophysiology Department, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.
| | - C Gitiaux
- Department of Paediatric Neurophysiology, Necker-Enfants-Malades Hospital, AP-HP, Paris University, Paris, France
| | - L Magy
- Department of Neurology, National Reference Center for 'Rare Peripheral Neuropathies', University Hospital of Limoges, Limoges, France
| | - Y Pereon
- CHU Nantes, Centre de Référence Maladies Neuromusculaires AOC, Filnemus, Euro-NMD, Explorations Fonctionnelles, Hôtel-Dieu, Nantes, France
| | - E Delmont
- Reference Center for Neuromuscular Diseases and ALS Timone University Hospital, Aix-Marseille University, Marseille, France
| | - K Viala
- Neurophysiology Department, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | - A Echaniz-Laguna
- Neurology Department, CHU de Bicêtre, AP-HP, Le-Kremlin-Bicêtre, France; French National Reference Center for Rare Neuropathies (NNERF), Le-Kremlin-Bicêtre, France; Inserm U1195, Paris-Saclay University, Le-Kremlin-Bicêtre, France
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