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Xu L, Wang Y, Wang W, Zhang R, Zhao D, Yun Y, Liu F, Zhao Y, Yan C, Lin P. Novel TFG mutation causes autosomal-dominant spastic paraplegia and defects in autophagy. J Med Genet 2024; 61:325-331. [PMID: 37890998 DOI: 10.1136/jmg-2023-109485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/14/2023] [Indexed: 10/29/2023]
Abstract
BACKGROUND Mutations in the tropomyosin receptor kinase fused (TFG) gene are associated with various neurological disorders, including autosomal recessive hereditary spastic paraplegia (HSP), autosomal dominant hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) and autosomal dominant type of Charcot-Marie-Tooth disease type 2. METHODS Whole genome sequencing and whole-exome sequencing were used, followed by Sanger sequencing for validation. Haplotype analysis was performed to confirm the inheritance mode of the novel TFG mutation in a large Chinese family with HSP. Additionally, another family diagnosed with HMSN-P and carrying the reported TFG mutation was studied. Clinical data and muscle pathology comparisons were drawn between patients with HSP and patients with HMSN-P. Furthermore, functional studies using skin fibroblasts derived from patients with HSP and patients with HMSN-P were conducted to investigate the pathomechanisms of TFG mutations. RESULTS A novel heterozygous TFG variant (NM_006070.6: c.125G>A (p.R42Q)) was identified and caused pure HSP. We further confirmed that the well-documented recessively inherited spastic paraplegia, caused by homozygous TFG mutations, exists in a dominantly inherited form. Although the clinical features and muscle pathology between patients with HSP and patients with HMSN-P were distinct, skin fibroblasts derived from both patient groups exhibited reduced levels of autophagy-related proteins and the presence of TFG-positive puncta. CONCLUSIONS Our findings suggest that autophagy impairment may serve as a common pathomechanism among different clinical phenotypes caused by TFG mutations. Consequently, targeting autophagy may facilitate the development of a uniform treatment for TFG-related neurological disorders.
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Affiliation(s)
- Ling Xu
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Yaru Wang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Wenqing Wang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Rui Zhang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Dandan Zhao
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Yan Yun
- Department of Radiology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Fuchen Liu
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Yuying Zhao
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Chuanzhu Yan
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Pengfei Lin
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
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2
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Fink JK. The hereditary spastic paraplegias. HANDBOOK OF CLINICAL NEUROLOGY 2023; 196:59-88. [PMID: 37620092 DOI: 10.1016/b978-0-323-98817-9.00022-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The hereditary spastic paraplegias (HSPs) are a group of more than 90 genetic disorders in which lower extremity spasticity and weakness are either the primary neurologic impairments ("uncomplicated HSP") or when accompanied by other neurologic deficits ("complicated HSP"), important features of the clinical syndrome. Various genetic types of HSP are inherited such as autosomal dominant, autosomal recessive, X-linked, and maternal (mitochondrial) traits. Symptoms that begin in early childhood may be nonprogressive and resemble spastic diplegic cerebral palsy. Symptoms that begin later, typically progress insidiously over a number of years. Genetic testing is able to confirm the diagnosis for many subjects. Insights from gene discovery indicate that abnormalities in diverse molecular processes underlie various forms of HSP, including disturbance in axon transport, endoplasmic reticulum morphogenesis, vesicle transport, lipid metabolism, and mitochondrial function. Pathologic studies in "uncomplicated" HSP have shown axon degeneration particularly involving the distal ends of corticospinal tracts and dorsal column fibers. Treatment is limited to symptom reduction including amelioration of spasticity, reducing urinary urgency, proactive physical therapy including strengthening, stretching, balance, and agility exercise.
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Affiliation(s)
- John K Fink
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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3
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Peotter JL, Pustova I, Lettman MM, Shatadal S, Bradberry MM, Winter-Reed AD, Charan M, Sharkey EE, Alvin JR, Bren AM, Oie AK, Chapman ER, Salamat MS, Audhya A. TFG regulates secretory and endosomal sorting pathways in neurons to promote their activity and maintenance. Proc Natl Acad Sci U S A 2022; 119:e2210649119. [PMID: 36161950 PMCID: PMC9546632 DOI: 10.1073/pnas.2210649119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/18/2022] [Indexed: 02/01/2023] Open
Abstract
Molecular pathways that intrinsically regulate neuronal maintenance are poorly understood, but rare pathogenic mutations that underlie neurodegenerative disease can offer important insights into the mechanisms that facilitate lifelong neuronal function. Here, we leverage a rat model to demonstrate directly that the TFG p.R106C variant implicated previously in complicated forms of hereditary spastic paraplegia (HSP) underlies progressive spastic paraparesis with accompanying ventriculomegaly and thinning of the corpus callosum, consistent with disease phenotypes identified in adolescent patients. Analyses of primary cortical neurons obtained from CRISPR-Cas9-edited animals reveal a kinetic delay in biosynthetic secretory protein transport from the endoplasmic reticulum (ER), in agreement with prior induced pluripotent stem cell-based studies. Moreover, we identify an unexpected role for TFG in the trafficking of Rab4A-positive recycling endosomes specifically within axons and dendrites. Impaired TFG function compromises the transport of at least a subset of endosomal cargoes, which we show results in down-regulated inhibitory receptor signaling that may contribute to excitation-inhibition imbalances. In contrast, the morphology and trafficking of other organelles, including mitochondria and lysosomes, are unaffected by the TFG p.R106C mutation. Our findings demonstrate a multifaceted role for TFG in secretory and endosomal protein sorting that is unique to cells of the central nervous system and highlight the importance of these pathways to maintenance of corticospinal tract motor neurons.
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Affiliation(s)
- Jennifer L. Peotter
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Iryna Pustova
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Molly M. Lettman
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Shalini Shatadal
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Mazdak M. Bradberry
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Allison D. Winter-Reed
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Maya Charan
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Erin E. Sharkey
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - James R. Alvin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Alyssa M. Bren
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Annika K. Oie
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Edwin R. Chapman
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
- HHMI, University of Wisconsin-Madison, Madison, WI 53705
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - M. Shahriar Salamat
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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4
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Cecconi F, Nazio F. TFG: a novel regulator of ULK1-dependent autophagy. Mol Cell Oncol 2021; 8:1945895. [PMID: 34616872 PMCID: PMC8489955 DOI: 10.1080/23723556.2021.1945895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
TRK-fused gene (TFG) is a protein implicated in multiple neurodegenerative diseases and oncogenesis. We have recently shown that, under starvation conditions, TFG contributes to spatial control of autophagy by facilitating Unc-51 like autophagy activating kinase 1 (ULK1)-microtubule-associated protein 1 light chain 3 gamma (MAP1LC3C) interaction to modulate omegasome and autophagosome formation. Defective TFG-mediated autophagy could thus be postulated as a possible contributor to ontogenesis or progression of TFG-related diseases.
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Affiliation(s)
- Francesco Cecconi
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy.,Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Francesca Nazio
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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5
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Carinci M, Testa B, Bordi M, Milletti G, Bonora M, Antonucci L, Ferraina C, Carro M, Kumar M, Ceglie D, Eck F, Nardacci R, le Guerroué F, Petrini S, Soriano ME, Caruana I, Doria V, Manifava M, Peron C, Lambrughi M, Tiranti V, Behrends C, Papaleo E, Pinton P, Giorgi C, Ktistakis NT, Locatelli F, Nazio F, Cecconi F. TFG binds LC3C to regulate ULK1 localization and autophagosome formation. EMBO J 2021; 40:e103563. [PMID: 33932238 PMCID: PMC8126910 DOI: 10.15252/embj.2019103563] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/17/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
The early secretory pathway and autophagy are two essential and evolutionarily conserved endomembrane processes that are finely interlinked. Although growing evidence suggests that intracellular trafficking is important for autophagosome biogenesis, the molecular regulatory network involved is still not fully defined. In this study, we demonstrate a crucial effect of the COPII vesicle-related protein TFG (Trk-fused gene) on ULK1 puncta number and localization during autophagy induction. This, in turn, affects formation of the isolation membrane, as well as the correct dynamics of association between LC3B and early ATG proteins, leading to the proper formation of both omegasomes and autophagosomes. Consistently, fibroblasts derived from a hereditary spastic paraparesis (HSP) patient carrying mutated TFG (R106C) show defects in both autophagy and ULK1 puncta accumulation. In addition, we demonstrate that TFG activity in autophagy depends on its interaction with the ATG8 protein LC3C through a canonical LIR motif, thereby favouring LC3C-ULK1 binding. Altogether, our results uncover a link between TFG and autophagy and identify TFG as a molecular scaffold linking the early secretion pathway to autophagy.
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Affiliation(s)
- Marianna Carinci
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Medical Sciences, University of Ferrara, Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | - Beatrice Testa
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Matteo Bordi
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Giacomo Milletti
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Massimo Bonora
- Department of Medical Sciences, University of Ferrara, Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | - Laura Antonucci
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Caterina Ferraina
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Marta Carro
- Department of Biology, University of Padua, Padua, Italy
| | - Mukesh Kumar
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Donatella Ceglie
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Franziska Eck
- Munich Cluster for Systems Neurology (SyNergy), Ludwig-Maximilians-Universität (LMU), München, Germany
| | - Roberta Nardacci
- Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases IRCCS "L. Spallanzani", Rome, Italy
| | - Francois le Guerroué
- Munich Cluster for Systems Neurology (SyNergy), Ludwig-Maximilians-Universität (LMU), München, Germany
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Ignazio Caruana
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Valentina Doria
- Confocal Microscopy Core Facility, Research Laboratories, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Camille Peron
- UO Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Matteo Lambrughi
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Valeria Tiranti
- UO Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Christian Behrends
- Munich Cluster for Systems Neurology (SyNergy), Ludwig-Maximilians-Universität (LMU), München, Germany
| | - Elena Papaleo
- Computational Biology Laboratory, Danish Cancer Society Research Center, Copenhagen, Denmark.,Translational Disease Systems Biology, Faculty of Health and Medical Sciences, Novo Nordisk Foundation Center for Protein Research University of Copenhagen, Copenhagen, Denmark
| | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | - Carlotta Giorgi
- Department of Medical Sciences, University of Ferrara, Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | | | - Franco Locatelli
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Gynecology/Obstetrics and Pediatrics, Sapienza University, Rome, Italy
| | - Francesca Nazio
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Francesco Cecconi
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy.,Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
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6
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Khorrami M, Tabatabaiefar MA, Khorram E, Yaghini O, Rezaei M, Hejazifar A, Riahinezhad M, Kheirollahi M. Homozygous TFG gene variants expanding the mutational and clinical spectrum of hereditary spastic paraplegia 57 and a review of literature. J Hum Genet 2021; 66:973-981. [PMID: 33767317 DOI: 10.1038/s10038-021-00919-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/20/2021] [Accepted: 03/04/2021] [Indexed: 01/17/2023]
Abstract
In recent years, the tropomyosin-receptor kinase fused gene (TFG) has been linked to diverse hereditary neurodegenerative disorders, including a very rare complex hereditary spastic paraplegia, named spastic paraplegia type 57 (SPG57). Until now, four pathogenic homozygous variants of the TFG gene have been reported associated with SPG57. Two consanguineous Iranian families (1 and 2), the first one with two affected members and the second one with one, all with an early-onset progressive muscle weakness, spasticity, and several neurological symptoms were examined via the whole-exome sequencing. Two homozygous missense variants including c.41A>G (p.Lys14Arg) and c.316C>T (p.Arg106Cys) have been found in the related families. The candidate variants were confirmed by Sanger sequencing and found to co-segregate with the disease in families. The bioinformatics analysis showed the deleterious effects of these nucleotide changes and the variants were classified as pathogenic according to ACMG guidelines. A comparison of the clinical presentation of the patients harboring c.41A>G (p.Lys14Arg) with previously reported SPG57 revealed variability in the severity state and unreported clinical presentation, including, facial atrophy, nystagmus, hyperelastic skin, cryptorchidism, hirsutism, kyphoscoliosis, and pectus excavatum. The affected member of the second family carried a previously reported homozygous c.316C>T (p.Arg106Cys) variant and displayed a complex HSP including optic atrophy. Remarkable clinical differences were observed between the family 1 and 2 harboring the c.41A>G (p.Lys14Arg) and c.316C>T (p.Arg106Cys) variants, which could be attributed to the distinct affected domains (PB1 domains and coiled-coil domains), and therefore, SPG57 might have been representing phenotype vs. variant position correlation.
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Affiliation(s)
- Mehdi Khorrami
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Erfan Khorram
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Omid Yaghini
- Department of Pediatrics, School of Medicine, Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mojgan Rezaei
- Department of Biology, Faculty of Science, Yazd University, Yazd, Iran
| | - Arash Hejazifar
- Department of Biology, School of Sciences, The University of Isfahan, Isfahan, Iran
| | - Maryam Riahinezhad
- Department of Radiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Majid Kheirollahi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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7
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Wu DW, Li Y, Yin X, Zhang B. A novel TFG c.793C>G mutation in a Chinese pedigree with Charcot-Marie-Tooth disease 2. Brain Behav 2020; 10:e01724. [PMID: 32666699 PMCID: PMC7507360 DOI: 10.1002/brb3.1724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/20/2020] [Accepted: 05/25/2020] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION Mutations within TFG gene were recently reported to cause Charcot-Marie-Tooth disease 2 (CMT2). However, only few pedigrees were documented so far. Here, we reported a Chinese CMT2 pedigree with 8 affected cases and a novel TFG mutation. METHODS Clinical evaluation and electrophysiological study were performed in all the affected individuals. Whole-exome sequencing was conducted, followed by the Sanger sequencing and co-segregation analysis to verify the variants. RESULTS All cases presented with a phenotype of CMT2, including slowly progressive symmetrical muscle atrophy and weakness predominantly in the distal limbs. Sensory loss in the distal limbs was present in the proband and his father. Age at onset ranged from 37 to 44 years, and was younger in male cases, compared with female cases. Nerve conduction study revealed normal motor nerve conduction velocity but decreased compound muscle action potential. Electromyography test revealed fibrillation potential and positive sharp waves. The creatine kinase activity was increased in all cases. After genetic investigations, we identified a novel TFG c.793C>G (p.Pro265Ala) mutation in the family. This mutation alters the conserved amino acid residue and is absent in 1000G, ExAC, dbSNP, EP6500, and 200 in-house controls. It co-segregated with the disease in the family. CONCLUSIONS Our report provided additional evidence that the heterozygous TFG mutations were associated with CMT2.
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Affiliation(s)
- Ding-Wen Wu
- Department of Genetics and Metabolism, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Diagnosis and Treatment of Neonatal Diseases of Zhejiang Province, Hangzhou, China
| | - Yanfang Li
- Department of Pediatrics, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xinzhen Yin
- Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Baorong Zhang
- Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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8
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Inherited motor-sensory neuropathy with upper limb predominance associated with the tropomyosin-receptor kinase fused gene. Neuromuscul Disord 2020; 30:227-231. [PMID: 32085962 DOI: 10.1016/j.nmd.2019.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 02/01/2023]
Abstract
The Tropomyosin-receptor kinase fused gene (TFG) encodes TFG which is expressed in spinal motor neurons, dorsal root ganglia and cranial nerve nuclei, and plays a role in the dynamics of the endoplasmic reticulum. Two dominant missense TFG mutations have previously been reported in limited geographical areas (Far East, Iran, China) in association with hereditary motor sensory neuropathy with proximal involvement (HMSN-P) of the four limbs, or with Charcot-Marie-Tooth disease type 2 (CMT2). The 60-year-old female proband belonging to a three-generation Italian family presented with an atypical neuropathy characterized by diffuse painful cramps and prominent motor-sensory impairment of the distal upper limbs. Her sural nerve biopsy showed chronic axonal neuropathy without active degeneration or regeneration. Targeted next-generation sequencing of a panel with 98 genes associated with inherited peripheral neuropathies/neuromuscular disorders identified three candidate genes: TFG, DHTKD1 and DCTN2. In the family, the disease co-segregated with the TFG p.(Gly269Val) variant. TFG should be considered in genetic testing of patients with heterogeneous inherited neuropathy, independently of their ethnic origin.
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Khani M, Taheri H, Shamshiri H, Houlden H, Efthymiou S, Alavi A, Nafissi S, Elahi E. Continuum of phenotypes in hereditary motor and sensory neuropathy with proximal predominance and Charcot-Marie-Tooth patients with TFG
mutation. Am J Med Genet A 2019; 179:1507-1515. [DOI: 10.1002/ajmg.a.61184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/12/2019] [Accepted: 04/23/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Marzieh Khani
- School of Biology; College of Science, University of Tehran; Tehran Iran
| | - Hanieh Taheri
- School of Biology; College of Science, University of Tehran; Tehran Iran
| | - Hosein Shamshiri
- Department of Neurology; Tehran University of Medical Sciences; Tehran Iran
| | - Henry Houlden
- Department of Molecular Neuroscience; UCL Institute of Neurology; London United Kingdom
| | - Stephanie Efthymiou
- Department of Molecular Neuroscience; UCL Institute of Neurology; London United Kingdom
| | - Afagh Alavi
- Genetics Research Center; University of Social Welfare and Rehabilitation Sciences; Tehran Iran
| | - Shahriar Nafissi
- Department of Neurology; Tehran University of Medical Sciences; Tehran Iran
| | - Elahe Elahi
- School of Biology; College of Science, University of Tehran; Tehran Iran
- Department of Biotechnology; College of Science, University of Tehran; Tehran Iran
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10
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Li J, Meng L, Wu R, Xie Z, Gang Q, Zhang W, Wang Z, Yuan Y. Sural nerve pathology in TFG-associated motor neuron disease with sensory neuropathy. Neuropathology 2019; 39:194-199. [PMID: 30957313 DOI: 10.1111/neup.12555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 12/11/2022]
Abstract
The tropomyosin-receptor kinase fused gene (TFG) functions in vesicles formation and egress at the endoplasmic reticulum (ER). A heterozygous missense mutation c.854C > T (p.Pro285Leu) within TFG has been reported as causative for hereditary motor and sensory neuropathy with proximal predominance. Here, we describe two unrelated Chinese pedigrees with 13 affected members harboring the same variant. The clinical, electrophysiological and pathological findings are consistent with motor neuron disease with sensory neuropathy. The main symptoms were painful muscle cramps, slowly progressive proximal predominant weakness, muscle atrophy, fasciculation and distal sensory disturbance. Electromyography revealed widespread denervation and reinnervation. Sural nerve biopsy revealed severe loss of myelinated fibers. Electron microscopy revealed aggregation of ER with enlarged lumen and small vesicles in the remaining myelinated and unmyelinated axons. The mitochondria are smaller in Schwann cells and axons. Some unmyelinated axons showed disappearance of neurofilament and microtubular structures. This is the first report of c.854C > T mutation within TFG in Chinese population. Our findings not only extend the geographical and phenotypic spectrum of TFG-related neurological disorders, but also confirm the abnormalities of ER and mitochondria in sural nerves.
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Affiliation(s)
- Jia Li
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Lingchao Meng
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Rui Wu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhiying Xie
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Qiang Gang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
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