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Hsiao C, Tsai T, Shen T, Tsai Y, Liao Y, Lee Y, Tsai P. Characterization of a novel TFG variant causing autosomal recessive pure hereditary spastic paraplegia. Ann Clin Transl Neurol 2024; 11:1909-1920. [PMID: 38837630 PMCID: PMC11251477 DOI: 10.1002/acn3.52113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/03/2024] [Accepted: 05/15/2024] [Indexed: 06/07/2024] Open
Abstract
OBJECTIVE TFG mutations have previously been implicated in autosomal recessive hereditary spastic paraplegia (HSP), also known as SPG57. This study aimed to investigate the clinical and molecular features of TFG mutations in a Taiwanese HSP cohort. METHODS Genetic analysis of TFG was conducted in 242 unrelated Taiwanese HSP patients using a targeted resequencing panel covering the entire coding regions of TFG. Functional assays were performed using an in vitro cell model to assess the impact of TFG variants on protein function. Additionally, other representative TFG mutant proteins were examined to understand the broader implications of TFG mutations in HSP. RESULTS The study identified a novel homozygous TFG c.177A>C (p.(Lys59Asn)) variant in a family with adolescent-onset, pure form HSP. Functional analysis revealed that the Lys59Asn TFG variant, similar to other HSP-associated TFG mutants, exhibited a low affinity between TFG monomers and abnormal assembly of TFG homo-oligomers. These structural alterations led to aberrant intracellular distribution, compromising TFG's protein secretion function and resulting in decreased cellular viability. INTERPRETATION These findings confirm that the homozygous TFG c.177A>C (p.(Lys59Asn)) variant is a novel cause of SPG57. The study expands our understanding of the clinical and mutational spectrum of TFG-associated diseases, highlighting the functional defects associated with this specific TFG variant. Overall, this research contributes to the broader comprehension of the genetic and molecular mechanisms underlying HSP.
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Affiliation(s)
- Cheng‐Tsung Hsiao
- Department of NeurologyTaipei Veterans General HospitalTaipeiTaiwan
- Department of NeurologyNational Yang Ming Chiao Tung University School of MedicineTaipeiTaiwan
| | - Tzu‐Yun Tsai
- Department of Life SciencesNational Chung Hsing UniversityTaichungTaiwan
| | - Ting‐Yi Shen
- Department of Life SciencesNational Chung Hsing UniversityTaichungTaiwan
| | - Yu‐Shuen Tsai
- Cancer and Immunology Research CenterNational Yang Ming Chiao Tung UniversityTaipeiTaiwan
| | - Yi‐Chu Liao
- Department of NeurologyTaipei Veterans General HospitalTaipeiTaiwan
- Department of NeurologyNational Yang Ming Chiao Tung University School of MedicineTaipeiTaiwan
- Brain Research CenterNational Yang Ming Chiao Tung UniversityTaipeiTaiwan
| | - Yi‐Chung Lee
- Department of NeurologyTaipei Veterans General HospitalTaipeiTaiwan
- Department of NeurologyNational Yang Ming Chiao Tung University School of MedicineTaipeiTaiwan
- Brain Research CenterNational Yang Ming Chiao Tung UniversityTaipeiTaiwan
- Center for Intelligent Drug Systems and Smart Bio‐devices (IDS2B)National Yang Ming Chiao Tung UniversityHsinchuTaiwan
| | - Pei‐Chien Tsai
- Department of Life SciencesNational Chung Hsing UniversityTaichungTaiwan
- The iEGG and Animal Biotechnology Research CenterNational Chung Hsing UniversityTaichungTaiwan
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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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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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Odake Y, Koh K, Takiyama Y, Ishiura H, Tsuji S, Yamada M, Yoshita M. Identification of a novel mutation in ATP13A2 associated with a complicated form of hereditary spastic paraplegia. NEUROLOGY-GENETICS 2020; 6:e514. [PMID: 33134512 PMCID: PMC7577544 DOI: 10.1212/nxg.0000000000000514] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/07/2020] [Indexed: 01/30/2023]
Abstract
Objective To establish molecular diagnosis for a family with a complicated form of autosomal recessive hereditary spastic paraplegia with intellectual disability, cognitive decline, psychosis, peripheral neuropathy, upward gaze palsy, and thin corpus callosum (TCC). Methods Physical examinations, laboratory tests, structural neuroimaging studies, and exome sequence analysis were carried out. Results The 3 patients exhibited intellectual disability and progressive intellectual decline accompanied by psychiatric symptoms. Gait difficulty with spasticity and pyramidal weakness appeared at the ages of 20s–30s. Brain MRI revealed TCC with atrophic changes in the frontotemporal lobes, caudate nuclei, and cerebellum. Exome sequence analysis revealed a novel homozygous c.2654C>A (p. Ala885Asp) variant in the ATP13A2, a gene responsible for a complicated form of hereditary spastic paraplegia (SPG78), Kufor-Rakeb syndrome, and neuronal ceroid lipofuscinosis. The predominant clinical presentations of the patients include progressive intellectual disability and gait difficulty with spasticity and pyramidal weakness, consistent with the diagnosis of SPG78. Of note, prominent psychiatric symptoms and extrapyramidal signs including rigidity, dystonia, and involuntary movements preceded the spastic paraparesis. Conclusions Our study further broadens the clinical spectrum associated with ATP13A2 mutations.
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Affiliation(s)
- Yasuko Odake
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Kishin Koh
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Yoshihisa Takiyama
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Hiroyuki Ishiura
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Shoji Tsuji
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Masahito Yamada
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
| | - Mitsuhiro Yoshita
- Department of Clinical Research (Y.O., M. Yoshita), National Hospital Organization, Hokuriku National Hospital, Nanto; Department of Neurology (K.K., Y.T.), Graduate School of Medical Science, University of Yamanashi, Tyuo; Department of Neurology (H.I.), The University of Tokyo; Department of Molecular Neurology (S.T.), Graduate School of Medicine, The University of Tokyo; Institute of Medical Genomics (S.T.), International University of Health and Welfare, Chiba; and Department of Neurology and Neurobiology of Aging (M. Yamada), Kanazawa University Graduate School of Medical Sciences, Japan
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