1
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Čunátová K, Fernández-Vizarra E. Pathological variants in nuclear genes causing mitochondrial complex III deficiency: An update. J Inherit Metab Dis 2024. [PMID: 39053894 DOI: 10.1002/jimd.12751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/24/2024] [Accepted: 05/02/2024] [Indexed: 07/27/2024]
Abstract
Mitochondrial disorders are a group of clinically and biochemically heterogeneous genetic diseases within the group of inborn errors of metabolism. Primary mitochondrial diseases are mainly caused by defects in one or several components of the oxidative phosphorylation system (complexes I-V). Within these disorders, those associated with complex III deficiencies are the least common. However, thanks to a deeper knowledge about complex III biogenesis, improved clinical diagnosis and the implementation of next-generation sequencing techniques, the number of pathological variants identified in nuclear genes causing complex III deficiency has expanded significantly. This updated review summarizes the current knowledge concerning the genetic basis of complex III deficiency, and the main clinical features associated with these conditions.
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Affiliation(s)
- Kristýna Čunátová
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Erika Fernández-Vizarra
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
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2
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Xuan X, Ruan J, Wu C, Gao Y, Li L, Lei X. A TTC19 mutation associated with progressive movement disorders and peripheral neuropathy: Case report and systematic review. CNS Neurosci Ther 2024; 30:e14425. [PMID: 37927170 PMCID: PMC10948947 DOI: 10.1111/cns.14425] [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: 04/28/2023] [Revised: 06/30/2023] [Accepted: 08/14/2023] [Indexed: 11/07/2023] Open
Abstract
BACKGROUND Mitochondrial complex III (CIII) deficiency is an autosomal recessive disease characterized by symptoms such as ataxia, cognitive dysfunction, and spastic paraplegia. Multiple genes are associated with complex III defects. Among them, the mutation of TTC19 is a rare subtype. METHODS We screened a Chinese boy with weakness of limbs and his non-consanguineous parents by whole exome sequencing and targeted sequencing. RESULTS We report a Chinese boy diagnosed with mitochondrial complex III defect type 2 carrying a homozygous variant (c.719-732del, p.Leu240Serfs*17) of the TTC19 gene. According to the genotype analysis of his family members, this is an autosomal recessive inheritance. We provide his clinical manifestation. CONCLUSIONS A new type of TTC19 mutation (c.719-732del, p.Leu240Serfs*17) was found, which enriched the TTC19 gene mutation spectrum and provided new data for elucidating the pathogenesis of CIII-deficient diseases.
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Affiliation(s)
- Xianjun Xuan
- Department of NeurologyHangzhou Ninth People's HospitalHangzhouChina
| | - Jie Ruan
- Zhejiang Provincial Key Laboratory for Drug Evaluation and Clinical Research, Department of Clinical Pharmacy, the First Affiliated HospitalZhejiang University School of MedicineHangzhouChina
| | - Chunhong Wu
- Department of NeurologyHangzhou Ninth People's HospitalHangzhouChina
| | - Yiyi Gao
- Ningbo Medical Center Lihuili HospitalNingboChina
| | - Lingfei Li
- Department of Neurology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
| | - Xiaoguang Lei
- First Department of Neurology, First Affiliated Hospital of Kunming Medical UniversityKunming Medical UniversityKunmingChina
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3
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Wang L, Yang Z, He X, Pu S, Yang C, Wu Q, Zhou Z, Cen X, Zhao H. Mitochondrial protein dysfunction in pathogenesis of neurological diseases. Front Mol Neurosci 2022; 15:974480. [PMID: 36157077 PMCID: PMC9489860 DOI: 10.3389/fnmol.2022.974480] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
Mitochondria are essential organelles for neuronal function and cell survival. Besides the well-known bioenergetics, additional mitochondrial roles in calcium signaling, lipid biogenesis, regulation of reactive oxygen species, and apoptosis are pivotal in diverse cellular processes. The mitochondrial proteome encompasses about 1,500 proteins encoded by both the nuclear DNA and the maternally inherited mitochondrial DNA. Mutations in the nuclear or mitochondrial genome, or combinations of both, can result in mitochondrial protein deficiencies and mitochondrial malfunction. Therefore, mitochondrial quality control by proteins involved in various surveillance mechanisms is critical for neuronal integrity and viability. Abnormal proteins involved in mitochondrial bioenergetics, dynamics, mitophagy, import machinery, ion channels, and mitochondrial DNA maintenance have been linked to the pathogenesis of a number of neurological diseases. The goal of this review is to give an overview of these pathways and to summarize the interconnections between mitochondrial protein dysfunction and neurological diseases.
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Affiliation(s)
- Liang Wang
- National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital of Sichuan University, Chengdu, China
| | - Ziyun Yang
- National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital of Sichuan University, Chengdu, China
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Xiumei He
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Shiming Pu
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Cheng Yang
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Qiong Wu
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Zuping Zhou
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Xiaobo Cen
- National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital of Sichuan University, Chengdu, China
| | - Hongxia Zhao
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China
- Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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4
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Mitochondrial Neurodegeneration. Cells 2022; 11:cells11040637. [PMID: 35203288 PMCID: PMC8870525 DOI: 10.3390/cells11040637] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/28/2022] [Accepted: 02/06/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are cytoplasmic organelles, which generate energy as heat and ATP, the universal energy currency of the cell. This process is carried out by coupling electron stripping through oxidation of nutrient substrates with the formation of a proton-based electrochemical gradient across the inner mitochondrial membrane. Controlled dissipation of the gradient can lead to production of heat as well as ATP, via ADP phosphorylation. This process is known as oxidative phosphorylation, and is carried out by four multiheteromeric complexes (from I to IV) of the mitochondrial respiratory chain, carrying out the electron flow whose energy is stored as a proton-based electrochemical gradient. This gradient sustains a second reaction, operated by the mitochondrial ATP synthase, or complex V, which condensates ADP and Pi into ATP. Four complexes (CI, CIII, CIV, and CV) are composed of proteins encoded by genes present in two separate compartments: the nuclear genome and a small circular DNA found in mitochondria themselves, and are termed mitochondrial DNA (mtDNA). Mutations striking either genome can lead to mitochondrial impairment, determining infantile, childhood or adult neurodegeneration. Mitochondrial disorders are complex neurological syndromes, and are often part of a multisystem disorder. In this paper, we divide the diseases into those caused by mtDNA defects and those that are due to mutations involving nuclear genes; from a clinical point of view, we discuss pediatric disorders in comparison to juvenile or adult-onset conditions. The complementary genetic contributions controlling organellar function and the complexity of the biochemical pathways present in the mitochondria justify the extreme genetic and phenotypic heterogeneity of this new area of inborn errors of metabolism known as ‘mitochondrial medicine’.
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5
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Organization of the Respiratory Supercomplexes in Cells with Defective Complex III: Structural Features and Metabolic Consequences. Life (Basel) 2021; 11:life11040351. [PMID: 33920624 PMCID: PMC8074069 DOI: 10.3390/life11040351] [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: 03/18/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial respiratory chain encompasses four oligomeric enzymatic complexes (complex I, II, III and IV) which, together with the redox carrier ubiquinone and cytochrome c, catalyze electron transport coupled to proton extrusion from the inner membrane. The protonmotive force is utilized by complex V for ATP synthesis in the process of oxidative phosphorylation. Respiratory complexes are known to coexist in the membrane as single functional entities and as supramolecular aggregates or supercomplexes (SCs). Understanding the assembly features of SCs has relevant biomedical implications because defects in a single protein can derange the overall SC organization and compromise the energetic function, causing severe mitochondrial disorders. Here we describe in detail the main types of SCs, all characterized by the presence of complex III. We show that the genetic alterations that hinder the assembly of Complex III, not just the activity, cause a rearrangement of the architecture of the SC that can help to preserve a minimal energetic function. Finally, the major metabolic disturbances associated with severe SCs perturbation due to defective complex III are discussed along with interventions that may circumvent these deficiencies.
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6
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Exploiting pyocyanin to treat mitochondrial disease due to respiratory complex III dysfunction. Nat Commun 2021; 12:2103. [PMID: 33833234 PMCID: PMC8032734 DOI: 10.1038/s41467-021-22062-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/25/2021] [Indexed: 01/13/2023] Open
Abstract
Mitochondrial diseases impair oxidative phosphorylation and ATP production, while effective treatment is still lacking. Defective complex III is associated with a highly variable clinical spectrum. We show that pyocyanin, a bacterial redox cycler, can replace the redox functions of complex III, acting as an electron shunt. Sub-μM pyocyanin was harmless, restored respiration and increased ATP production in fibroblasts from five patients harboring pathogenic mutations in TTC19, BCS1L or LYRM7, involved in assembly/stabilization of complex III. Pyocyanin normalized the mitochondrial membrane potential, and mildly increased ROS production and biogenesis. These in vitro effects were confirmed in both DrosophilaTTC19KO and in Danio rerioTTC19KD, as administration of low concentrations of pyocyanin significantly ameliorated movement proficiency. Importantly, daily administration of pyocyanin for two months was not toxic in control mice. Our results point to utilization of redox cyclers for therapy of complex III disorders.
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7
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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8
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Habibzadeh P, Inaloo S, Silawi M, Dastsooz H, Farazi Fard MA, Sadeghipour F, Faghihi Z, Rezaeian M, Yavarian M, Böhm J, Faghihi MA. A Novel TTC19 Mutation in a Patient With Neurological, Psychological, and Gastrointestinal Impairment. Front Neurol 2019; 10:944. [PMID: 31551910 PMCID: PMC6737916 DOI: 10.3389/fneur.2019.00944] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/15/2019] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial complex III deficiency nuclear type 2 is an autosomal-recessive disorder caused by mutations in TTC19 gene. TTC19 is involved in the preservation of mitochondrial complex III, which is responsible for transfer of electrons from reduced coenzyme Q to cytochrome C and thus, contributes to the formation of electrochemical potential and subsequent ATP generation. Mutations in TTC19 have been found to be associated with a wide range of neurological and psychological manifestations. Herein, we report on a 15-year-old boy born from first-degree cousin parents, who initially presented with psychiatric symptoms. He subsequently developed progressive ataxia, spastic paraparesis with involvement of caudate bodies and lentiform nuclei with cerebellar atrophy. Eventually, the patient developed gastrointestinal involvement. Using whole-exome sequencing (WES), we identified a novel homozygous frameshift mutation in the TTC19 gene in the patient (NM_017775.3, c.581delG: p.Arg194Asnfs*16). Advanced genetic sequencing technologies developed in recent years have not only facilitated identification of novel disease genes, but also allowed revelations about novel phenotypes associated with mutations in the genes already linked with other clinical features. Our findings expanded the clinical features of TTC19 mutation to potentially include gastrointestinal involvement. Further functional studies are needed to elucidate the underlying pathophysiological mechanisms.
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Affiliation(s)
- Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Soroor Inaloo
- Neonatal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Silawi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Dastsooz
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Italian Institute for Genomic Medicine (IIGM), University of Turin, Turin, Italy
| | - Mohammad Ali Farazi Fard
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forough Sadeghipour
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohaddeseh Rezaeian
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Yavarian
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm, CNRS, Université de Strasbourg, Illkirch, France
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States
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9
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Novel Homozygous Variant in TTC19 Causing Mitochondrial Complex III Deficiency with Recurrent Stroke-Like Episodes: Expanding the Phenotype. Semin Pediatr Neurol 2018; 26:16-20. [PMID: 29961508 DOI: 10.1016/j.spen.2018.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A 7-year-old boy with family history of consanguinity presented with developmental delay and recurrent hemiplegia involving both sides of the body, with variable facial and ocular involvement. Brain MRI showed bilateral striatal necrosis with cystic degeneration and lactate peaks on spectroscopy. Biochemical testing demonstrated mildly elevated lactate and pyruvate. Whole-exome sequencing revealed a novel homozygous pathogenic frameshift mutation in gene TTC19, diagnostic of mitochondrial complex III deficiency.
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10
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Bottani E, Cerutti R, Harbour ME, Ravaglia S, Dogan SA, Giordano C, Fearnley IM, D'Amati G, Viscomi C, Fernandez-Vizarra E, Zeviani M. TTC19 Plays a Husbandry Role on UQCRFS1 Turnover in the Biogenesis of Mitochondrial Respiratory Complex III. Mol Cell 2017; 67:96-105.e4. [PMID: 28673544 DOI: 10.1016/j.molcel.2017.06.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/03/2017] [Accepted: 06/01/2017] [Indexed: 12/29/2022]
Abstract
Loss-of-function mutations in TTC19 (tetra-tricopeptide repeat domain 19) have been associated with severe neurological phenotypes and mitochondrial respiratory chain complex III deficiency. We previously demonstrated the mitochondrial localization of TTC19 and its link with complex III biogenesis. Here we provide detailed insight into the mechanistic role of TTC19, by investigating a Ttc19?/? mouse model that shows progressive neurological and metabolic decline, decreased complex III activity, and increased production of reactive oxygen species. By using both the Ttc19?/? mouse model and a range of human cell lines, we demonstrate that TTC19 binds to the fully assembled complex III dimer, i.e., after the incorporation of the iron-sulfur Rieske protein (UQCRFS1). The in situ maturation of UQCRFS1 produces N-terminal polypeptides, which remain bound to holocomplex III. We show that, in normal conditions, these UQCRFS1 fragments are rapidly removed, but when TTC19 is absent they accumulate within complex III, causing its structural and functional impairment.
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Affiliation(s)
- Emanuela Bottani
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Raffaele Cerutti
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Michael E Harbour
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Sabrina Ravaglia
- Istituto Neurologico "Casimiro Mondino," via Mondino 2, Pavia 27100, Italy
| | - Sukru Anil Dogan
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Carla Giordano
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Ian M Fearnley
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Giulia D'Amati
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Carlo Viscomi
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK
| | - Erika Fernandez-Vizarra
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK.
| | - Massimo Zeviani
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building Hills Road, Cambridge CB2 0XY, UK.
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11
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Tanaka F, Doi H, Kunii M. Autosomal recessive spinocerebellar ataxias in Japan. Rinsho Shinkeigaku 2016; 56:395-9. [PMID: 27181749 DOI: 10.5692/clinicalneurol.cn-000879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Recent new sequencing techniques allow the identification of novel responsible genes for autosomal recessive spinocerebellar ataxias (ARCAs). However, the same phenotypes are sometimes attributed to the different responsible genes in ARCAs. On the contrary, the same responsible genes may cause heterogeneous phenotypes with respect to the age at onset, symptoms, and the severity of the disease progression. In addition, it is an important issue to clarify whether the gene mutations identified in Caucasian patients with infantile-onset ARCAs are also observed in Japanese patients with adult-onset ARCAs. In this article we review the characteristics of several ARCAs, the existence of which has been recently identified or confirmed in Japan.
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Affiliation(s)
- Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine
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12
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Fernández-Vizarra E, Zeviani M. Nuclear gene mutations as the cause of mitochondrial complex III deficiency. Front Genet 2015; 6:134. [PMID: 25914718 PMCID: PMC4391031 DOI: 10.3389/fgene.2015.00134] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/20/2015] [Indexed: 11/13/2022] Open
Abstract
Complex III (CIII) deficiency is one of the least common oxidative phosphorylation defects associated to mitochondrial disease. CIII constitutes the center of the mitochondrial respiratory chain, as well as a crossroad for several other metabolic pathways. For more than 10 years, of all the potential candidate genes encoding structural subunits and assembly factors, only three were known to be associated to CIII defects in human pathology. Thus, leaving many of these cases unresolved. These first identified genes were MT-CYB, the only CIII subunit encoded in the mitochondrial DNA; BCS1L, encoding an assembly factor, and UQCRB, a nuclear-encoded structural subunit. Nowadays, thanks to the fast progress that has taken place in the last 3-4 years, pathological changes in seven more genes are known to be associated to these conditions. This review will focus on the strategies that have permitted the latest discovery of mutations in factors that are necessary for a correct CIII assembly and activity, in relation with their function. In addition, new data further establishing the molecular role of LYRM7/MZM1L as a chaperone involved in CIII biogenesis are provided.
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Affiliation(s)
| | - Massimo Zeviani
- Mitochondrial Biology Unit, Medical Research Council Cambridge, UK
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13
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Koch J, Freisinger P, Feichtinger RG, Zimmermann FA, Rauscher C, Wagentristl HP, Konstantopoulou V, Seidl R, Haack TB, Prokisch H, Ahting U, Sperl W, Mayr JA, Maier EM. Mutations in TTC19: expanding the molecular, clinical and biochemical phenotype. Orphanet J Rare Dis 2015; 10:40. [PMID: 25887401 PMCID: PMC4422538 DOI: 10.1186/s13023-015-0254-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/15/2015] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND TTC19 deficiency is a progressive neurodegenerative disease associated with isolated mitochondrial respiratory chain (MRC) complex III deficiency and loss-of-function mutations in the TT19 gene in the few patients reported so far. METHODS We performed exome sequencing and selective mutational analysis of TTC19, respectively, in patients from three unrelated families presenting with initially unspecific clinical signs of muscular hypotonia and global developmental delay followed by regression, ataxia, loss of speech, and rapid neurological deterioration. One patient showed severe lactic acidosis at the neonatal age and during intercurrent illness. RESULTS We identified homozygous mutations in all three index cases, in two families novel missense mutations (c.544 T > C/p.Leu185Pro; c.917 T > C/p.Leu324Pro). The younger sister of the severely affected patient 3 showed only mild delay of motor skills and muscular hypotonia so far but is also homozygous for the same mutation. Notably, one patient revealed normal activities of MRC complex III in two independent muscle biopsies. Neuroimaging of the severely affected patients demonstrated lesions in putamen and caudate nuclei, cerebellar atrophy, and the unusual finding of hypertrophic olivary nuclei degeneration. Reviewing the literature revealed striking similarities regarding neuroimaging and clinical course in pediatric patients with TTC19 deficiency: patterns consistent with Leigh or Leigh-like syndrome were found in almost all, hypertrophic olivary nucleus degeneration in all patients reported so far. The clinical course in pediatric patients is characterized by an initially unspecific developmental delay, followed by regression, progressive signs and symptoms of cerebellar, basal ganglia and brainstem affection, especially loss of speech and ataxia. Subsequently, neurological deterioration leading to a vegetative state occurs. CONCLUSIONS Our findings add to the phenotypic, genetic, and biochemical spectrum of TTC19 deficiency. However, TTC19 deficient patients do show characteristic clinical and neuroimaging features, which may facilitate diagnosis of this yet rare disorder. Normal MRC complex III activity does not exclude the diagnosis.
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Affiliation(s)
- Johannes Koch
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Peter Freisinger
- Department of Pediatrics Kreisklinken Reutlingen, Steinenbergstr. 31, 72764, Reutlingen, Germany.
| | - René G Feichtinger
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Franz A Zimmermann
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Christian Rauscher
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Hans P Wagentristl
- Department of Pediatrics, Krankenhaus der Barmherzigen Brueder, Esterhazystr. 26, 7000, Eisenstadt, Austria.
| | - Vassiliki Konstantopoulou
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Rainer Seidl
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Tobias B Haack
- Institute of Human Genetics, Helmholtz Zentrum München, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. .,Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Trogerstr. 32/3, 81675, Munich, Germany.
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. .,Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Trogerstr. 32/3, 81675, Munich, Germany.
| | - Uwe Ahting
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Trogerstr. 32/3, 81675, Munich, Germany.
| | - Wolfgang Sperl
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Johannes A Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
| | - Esther M Maier
- Department of Pediatrics, Paracelsus Medical University Salzburg, Muellner Hauptstr. 48, 5020, Salzburg, Austria. .,Present affiliation: Dr. von Hauner Children's Hospital, University of Munich, Lindwurmstr. 4, 80337, Munich, Germany.
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