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Armirola-Ricaurte C, Zonnekein N, Koutsis G, Amor-Barris S, Pelayo-Negro AL, Atkinson D, Efthymiou S, Turchetti V, Dinopoulos A, Garcia A, Karakaya M, Moris G, Polat AI, Yiş U, Espinos C, Van de Vondel L, De Vriendt E, Karadima G, Wirth B, Hanna M, Houlden H, Berciano J, Jordanova A. Alternative splicing expands the clinical spectrum of NDUFS6-related mitochondrial disorders. Genet Med 2024; 26:101117. [PMID: 38459834 DOI: 10.1016/j.gim.2024.101117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 03/10/2024] Open
Abstract
PURPOSE We describe 3 families with Charcot-Marie-Tooth neuropathy (CMT), harboring a homozygous NDUFS6 NM_004553.6:c.309+5G>A variant previously linked to fatal Leigh syndrome. We aimed to characterize clinically and molecularly the newly identified patients and understand the mechanism underlying their milder phenotype. METHODS The patients underwent extensive clinical examinations. Exome sequencing was done in 4 affected individuals. The functional effect of the c.309+5G>A variant was investigated in patient-derived EBV-transformed lymphoblasts at the complementary DNA, protein, and mitochondrial level. Alternative splicing was evaluated using complementary DNA long-read sequencing. RESULTS All patients presented with early-onset, slowly progressive axonal CMT, and nystagmus; some exhibited additional central nervous system symptoms. The c.309+5G>A substitution caused the expression of aberrantly spliced transcripts and negligible levels of the canonical transcript. Immunoblotting showed reduced levels of mutant isoforms. No detectable defects in mitochondrial complex stability or bioenergetics were found. CONCLUSION We expand the clinical spectrum of NDUFS6-related mitochondrial disorders to include axonal CMT, emphasizing the clinical and pathophysiologic overlap between these 2 clinical entities. This work demonstrates the critical role that alternative splicing may play in modulating the severity of a genetic disorder, emphasizing the need for careful consideration when interpreting splice variants and their implications on disease prognosis.
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Affiliation(s)
- Camila Armirola-Ricaurte
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Noortje Zonnekein
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Georgios Koutsis
- Neurogenetics Unit, 1st Department of Neurology, Eginitio Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Silvia Amor-Barris
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Ana Lara Pelayo-Negro
- University Hospital Marqués de Valdecilla (IFIMAV), University of Cantabria, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain
| | - Derek Atkinson
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Valentina Turchetti
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Argyris Dinopoulos
- 3rd Department of Pediatrics, Attiko Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Antonio Garcia
- Service of Clinical Neurophysiology, University Hospital Marqués de Valdecilla, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain
| | - Mert Karakaya
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases, University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - German Moris
- Service of Neurology, University Hospital Central de Asturias, University of Oviedo, Oviedo, Spain
| | - Ayşe Ipek Polat
- Department of Pediatric Neurology, Dokuz Eylül University, Izmir, Turkey
| | - Uluç Yiş
- Department of Pediatric Neurology, Dokuz Eylül University, Izmir, Turkey
| | - Carmen Espinos
- Rare Neurodegenerative Disease Laboratory, Centro de Investigación Príncipe Felipe (CIPF), CIBER on Rare Diseases (CIBERER), Valencia, Spain
| | - Liedewei Van de Vondel
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Els De Vriendt
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Georgia Karadima
- Neurogenetics Unit, 1st Department of Neurology, Eginitio Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases, University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Michael Hanna
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Jose Berciano
- University Hospital Marqués de Valdecilla (IFIMAV), University of Cantabria, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Santander, Spain
| | - Albena Jordanova
- Molecular Neurogenomics group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Molecular Neurogenomics group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Sofia, Bulgaria.
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Higuchi Y, Ando M, Kojima F, Yuan J, Hashiguchi A, Yoshimura A, Hiramatsu Y, Nozuma S, Fukumura S, Yahikozawa H, Abe E, Toyoshima I, Sugawara M, Okamoto Y, Matsuura E, Takashima H. Dystonia and Parkinsonism in COA7-related disorders: expanding the phenotypic spectrum. J Neurol 2024; 271:419-430. [PMID: 37750949 PMCID: PMC10769979 DOI: 10.1007/s00415-023-11998-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/27/2023]
Abstract
BACKGROUND AND OBJECTIVE Biallelic mutations in the COA7 gene have been associated with spinocerebellar ataxia with axonal neuropathy type 3 (SCAN3), and a notable clinical diversity has been observed. We aim to identify the genetic and phenotypic spectrum of COA7-related disorders. METHODS We conducted comprehensive genetic analyses on the COA7 gene within a large group of Japanese patients clinically diagnosed with inherited peripheral neuropathy or cerebellar ataxia. RESULTS In addition to our original report, which involved four patients until 2018, we identified biallelic variants of the COA7 gene in another three unrelated patients, and the variants were c.17A > G (p.D6G), c.115C > T (p.R39W), and c.449G > A (p.C150Y; novel). Patient 1 presented with an infantile-onset generalized dystonia without cerebellar ataxia. Despite experiencing an initial transient positive response to levodopa and deep brain stimulation, he became bedridden by the age of 19. Patient 2 presented with cerebellar ataxia, neuropathy, as well as parkinsonism, and showed a slight improvement upon levodopa administration. Dopamine transporter SPECT showed decreased uptake in the bilateral putamen in both patients. Patient 3 exhibited severe muscle weakness, respiratory failure, and feeding difficulties. A haplotype analysis of the mutation hotspot in Japan, c.17A > G (p.D6G), uncovered a common haplotype block. CONCLUSION COA7-related disorders typically encompass a spectrum of conditions characterized by a variety of major (cerebellar ataxia and axonal polyneuropathy) and minor (leukoencephalopathy, dystonia, and parkinsonism) symptoms, but may also display a dystonia-predominant phenotype. We propose that COA7 should be considered as a new causative gene for infancy-onset generalized dystonia, and COA7 gene screening is recommended for patients with unexplained dysfunctions of the central and peripheral nervous systems.
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Affiliation(s)
- Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Masahiro Ando
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Fumikazu Kojima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Junhui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Yu Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Satoshi Nozuma
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Shinobu Fukumura
- Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan
| | | | - Erika Abe
- Department of Neurology, National Hospital Organization Akita National Hospital, Yurihonjo, Japan
| | - Itaru Toyoshima
- Department of Neurology, National Hospital Organization Akita National Hospital, Yurihonjo, Japan
| | - Masashiro Sugawara
- Department of Neurology, Akita University Graduate School of Medicine, Akita, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
- Department of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Kagoshima, Japan
| | - Eiji Matsuura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima City, Kagoshima, 890-8520, Japan.
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Kim J, Lee J, Jang DH. NDUFAF6-Related Leigh Syndrome Caused by Rare Pathogenic Variants: A Case Report and the Focused Review of Literature. Front Pediatr 2022; 10:812408. [PMID: 35664867 PMCID: PMC9157758 DOI: 10.3389/fped.2022.812408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Leigh syndrome is a neurodegenerative disorder that presents with fluctuation and stepwise deterioration, such as neurodevelopmental delay and regression, dysarthria, dysphagia, hypotonia, dystonia, tremor, spasticity, epilepsy, and respiratory problems. The syndrome characteristically presents symmetric necrotizing lesions in the basal ganglia, brainstem, cerebellum, thalamus, and spinal cord on cranial magnetic resonance imaging. To date, more than 85 genes are known to be associated with Leigh syndrome. Here, we present a rare case of a child who developed Leigh syndrome due to pathogenic variants of NDUFAF6, which encodes an assembly factor of complex I, a respiratory chain subunit. A targeted next-generation sequencing analysis related to mitochondrial disease revealed a missense variant (NM_152416.4:c.371T > C; p.Ile124Thr) and a frameshift variant (NM_152416.4:c.233_242del; p.Leu78GInfs*10) inherited biparentally. The proband underwent physical therapy and nutrient cocktail therapy, but his physical impairment gradually worsened.
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Affiliation(s)
- Jaewon Kim
- Department of Rehabilitation Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Jaewoong Lee
- Department of Laboratory Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Dae-Hyun Jang
- Department of Rehabilitation Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
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