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Mahesan A, Choudhary PK, Kamila G, Rohil A, Meena AK, Kumar A, Jauhari P, Chakrabarty B, Gulati S. NDUFV1-Related Mitochondrial Complex-1 Disorders: A Retrospective Case Series and Literature Review. Pediatr Neurol 2024; 155:91-103. [PMID: 38626668 DOI: 10.1016/j.pediatrneurol.2024.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/17/2024] [Accepted: 02/29/2024] [Indexed: 04/18/2024]
Abstract
BACKGROUND Pathogenic variants in the NDUFV1 gene disrupt mitochondrial complex I, leading to neuroregression with leukoencephalopathy and basal ganglia involvement on neuroimaging. This study aims to provide a concise review on NDUFV1-related disorders while adding the largest cohort from a single center to the existing literature. METHODS We retrospectively collected genetically proven cases of NDUFV1 pathogenic variants from our center over the last decade and explored reported instances in existing literature. Magnetic resonance imaging (MRI) patterns observed in these patients were split into three types-Leigh (putamen, basal ganglia, thalamus, and brainstem involvement), mitochondrial leukodystrophy (ML) (cerebral white matter involvement with cystic cavitations), and mixed (both). RESULTS Analysis included 44 children (seven from our center and 37 from literature). The most prevalent comorbidities were hypertonia, ocular abnormalities, feeding issues, and hypotonia at onset. Children with the Leigh-type MRI pattern exhibited significantly higher rates of breathing difficulties, whereas those with a mixed phenotype had a higher prevalence of dystonia. The c.1156C>T variant in exon 8 of the NDUFV1 gene was the most common variant among individuals of Asian ethnicity and is predominantly associated with irritability and dystonia. Seizures and Leigh pattern of MRI of the brain was found to be less commonly associated with this variant. Higher rate of mortality was observed in children with Leigh-type pattern on brain MRI and those who did not receive mitochondrial cocktail. CONCLUSIONS MRI phenotyping might help predict outcome. Appropriate and timely treatment with mitochondrial cocktail may reduce the probability of death and may positively impact the long-term outcomes, regardless of the genetic variant or age of onset.
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Affiliation(s)
- Aakash Mahesan
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Puneet Kumar Choudhary
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Gautam Kamila
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Aradhana Rohil
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Ankit Kumar Meena
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Atin Kumar
- Department of Radiodiagnosis and Interventional Radiology, AIIMS, New Delhi, India
| | - Prashant Jauhari
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Biswaroop Chakrabarty
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India
| | - Sheffali Gulati
- Child Neurology Division, Department of Pediatrics, Centre of Excellence & Advanced Research for Childhood Neurodevelopmental Disorders, All India Institute of Medical Sciences, New Delhi, India.
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Chapleau A, Boucher RM, Pastinen T, Thiffault I, Gould PV, Bernard G. Neuropathological characterization of the cavitating leukoencephalopathy caused by COA8 cytochrome c oxidase deficiency: a case report. Front Cell Neurosci 2023; 17:1216487. [PMID: 37601282 PMCID: PMC10436302 DOI: 10.3389/fncel.2023.1216487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
COA8-related leukoencephalopathy is a recently described rare cavitating leukoencephalopathy caused by biallelic variants in the COA8 gene. Clinically, it presents heterogeneously and usually follows a bi-phasic clinical course with a period of acute onset and regression, followed by stabilization, and in some cases, even subtle improvement. We present a 4-year-old boy with a homozygous 2.5 kilobase pair deletion in the COA8 gene following a severe neurological deterioration resulting in death weeks after onset. Brain MRI revealed a distinctive pattern of cavitating leukodystrophy predominantly involving the posterior cerebral white matter which improved upon a follow-up MRI a month later. Brain pathology displayed overall white matter destruction with gliosis and infiltration by macrophages. There was preservation of astrocytes around blood vessels and axons around the zones of demyelination. This study is the first neuropathological examination of COA8-related leukoencephalopathy and provides further characterization of the clinical and MRI phenotype.
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Affiliation(s)
- Alexandra Chapleau
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Renée-Myriam Boucher
- Centre Hospitalier Universitaire de Québec-Université Laval, Québec City, QC, Canada
| | - Tomi Pastinen
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, United States
- Kansas City School of Medicine, University of Missouri, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, United States
- Kansas City School of Medicine, University of Missouri, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital, Kansas City, MO, United States
| | - Peter V. Gould
- Service d’anatomopathologie Hôpital de l’Enfant-Jésus du CHU de Québec-Université Laval, Québec City, QC, Canada
| | - Geneviève Bernard
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada
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3
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Chin H, Cho J, Kim WJ, Kim SY, Lim BC, Kim KJ, Chae JH. A Case of Multiple Mitochondrial Dysfunctions Syndrome 4 with Novel ISCA2 Variants, Mimicking Post-Infectious Encephalitis. Child Neurol Open 2023; 10:2329048X231210421. [PMID: 37915614 PMCID: PMC10617010 DOI: 10.1177/2329048x231210421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/08/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023] Open
Abstract
ISCA2 loss of function leads to leukodystrophy and developmental regression (multiple mitochondrial dysfunctions syndrome 4 (MMDS4)). We present a first Korean case of MMDS4 presenting with rapid developmental regression and leukodystrophy after febrile episode, mimicking post-infectious encephalitis. The patient had displayed normal development until 12 months of age. At 13 months of age, one month after experiencing a post-vaccination fever, she quickly progressed to being unable to sit unassisted nor speak any words. Analysis of the cerebrospinal fluid (CSF) revealed lympho-dominant pleocytosis. Amino acid analysis of both the serum and CSF demonstrated elevated glycine exclusively in the CSF. Diffuse leukodystrophy was noted in the brain magnetic resonance image. Whole exome sequencing revealed compound heterozygous ISCA2 variants of c.166T>G, p.C56G and c.422A>C, p.Q141P. No evidence of mitochondrial disease other than bilateral optic atrophy was noted. In cases of early onset rapid developmental regression with leukodystrophy, MMDS4 should be considered.
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Affiliation(s)
- Hyungjin Chin
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Jaeso Cho
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
| | - Woo Joong Kim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Soo Yeon Kim
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Ki Joong Kim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Jong Hee Chae
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
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Lang SH, Camponeschi F, de Joya E, Borjas-Mendoza P, Tekin M, Thorson W. Multiple Mitochondrial Dysfunction Syndrome Type 3: A Likely Pathogenic Homozygous Variant Affecting a Patient of Cuban Descent and Literature Review. Genes (Basel) 2022; 13:2044. [PMID: 36360281 PMCID: PMC9690653 DOI: 10.3390/genes13112044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/31/2022] [Accepted: 11/04/2022] [Indexed: 11/01/2023] Open
Abstract
Multiple mitochondrial dysfunction syndrome type 3 (MMDS3) is a rare mitochondrial leukoencephalopathy caused by biallelic pathogenic variants in IBA57. Here, we describe a homozygous variant in IBA57, (NM_001010867.2): c.310G>T (p.Gly104Cys), in a 2-month-old infant of Cuban descent who presented with a one-month history of progressive hypotonia, weakness, and episodes of upgaze deviation. This is the first report of a patient homozygous for this variant and the first report of MMDS3 in a patient of Hispanic descent described to our knowledge. Using in silico tools, we found that the variant resides in a putative mutational hotspot located in the neighborhood of a key active ligand required for iron-sulfur cluster coordination. In addition, while previous case reports/series have reported the variable phenotypic features of the disease, the incidence of these features across the literature has not been well described. In order to construct a clearer global picture of the typical presentation of MMDS3, we reviewed 52 cases across the literature with respect to their clinical, biochemical, genotypic, and neuroradiographic features.
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Affiliation(s)
- Steven H. Lang
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | | | - Evan de Joya
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Paulo Borjas-Mendoza
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Mustafa Tekin
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Willa Thorson
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Becker N, Sharma A, Gosse M, Kubat B, Conway KS. The neuropathologic findings in a case of progressive cavitating leukoencephalopathy due to NDUFV1 pathogenic variants. Acta Neuropathol Commun 2022; 10:142. [PMID: 36163075 PMCID: PMC9511743 DOI: 10.1186/s40478-022-01445-1] [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] [Received: 07/19/2022] [Accepted: 09/07/2022] [Indexed: 11/10/2022] Open
Abstract
Pathogenic variants in the NDUFV1 gene, which codes for complex I of the mitochondrial respiratory chain, have been associated with a variety of clinical phenotypes, including a progressive cavitating leukoencephalopathy. The neuropathology of NDUFV1-associated leukoencephalopathy is not well-described. We present a report of a 24-year-old female with two pathogenic variants in the NDUFV1 gene, together with antemortem skeletal muscle biopsy and postmortem neuropathologic examination. Autopsy neuropathology showed a cavitating leukoencephalopathy with extensive white matter involvement, regions of active demyelination, and sparing of the subcortical U-fibers. Muscle biopsy showed subtle but distinct histologic abnormalities by light microscopy, and ultrastructural analysis demonstrated mitochondrial abnormalities including abnormal subsarcolemmal mitochondrial accumulation, electron-dense inclusions, and enlarged mitochondria with abnormal cristae. Our report is the first comprehensive description of the neuropathology in a patient with compound heterozygous variants in the NDUFV1 gene and progressive cavitating leukoencephalopathy. This case is evidence of pathogenicity of one NDUFV1 variant (c.565 T > C, p.S189P), which has not been previously described as pathogenic. These findings, in combination with the ultrastructural abnormalities in the mitochondria by electron microscopy, support the mitochondrial nature of the pathology. Together, this case highlights the link between mitochondrial abnormalities and demyelinating processes in the central nervous system (CNS).
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Affiliation(s)
- Nicole Becker
- Department of Pathology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Aditi Sharma
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Matthew Gosse
- Department of Pathology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Brooke Kubat
- Department of Neurology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, 52242, USA
| | - Kyle S Conway
- Department of Pathology, University of Michigan, 2800 Plymouth Rd., Building 35, Faculty Suite Room 36-1221-68, Ann Arbor, MI, 48109-2800, USA.
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Hanaford A, Johnson SC. The immune system as a driver of mitochondrial disease pathogenesis: a review of evidence. Orphanet J Rare Dis 2022; 17:335. [PMID: 36056365 PMCID: PMC9438277 DOI: 10.1186/s13023-022-02495-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/15/2022] [Indexed: 12/04/2022] Open
Abstract
Background Genetic mitochondrial diseases represent a significant challenge to human health. These diseases are extraordinarily heterogeneous in clinical presentation and genetic origin, and often involve multi-system disease with severe progressive symptoms. Mitochondrial diseases represent the most common cause of inherited metabolic disorders and one of the most common causes of inherited neurologic diseases, yet no proven therapeutic strategies yet exist. The basic cell and molecular mechanisms underlying the pathogenesis of mitochondrial diseases have not been resolved, hampering efforts to develop therapeutic agents. Main body In recent pre-clinical work, we have shown that pharmacologic agents targeting the immune system can prevent disease in the Ndufs4(KO) model of Leigh syndrome, indicating that the immune system plays a causal role in the pathogenesis of at least this form of mitochondrial disease. Intriguingly, a number of case reports have indicated that immune-targeting therapeutics may be beneficial in the setting of genetic mitochondrial disease. Here, we summarize clinical and pre-clinical evidence suggesting a key role for the immune system in mediating the pathogenesis of at least some forms of genetic mitochondrial disease. Conclusions Significant clinical and pre-clinical evidence indicates a key role for the immune system as a significant in the pathogenesis of at least some forms of genetic mitochondrial disease.
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Affiliation(s)
- Allison Hanaford
- Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Ave., JMB-925, Seattle, WA, 98101, USA
| | - Simon C Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Ave., JMB-925, Seattle, WA, 98101, USA. .,Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA. .,Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA. .,Department of Neurology, University of Washington, Seattle, WA, USA.
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7
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Camponeschi F, Ciofi-Baffoni S, Calderone V, Banci L. Molecular Basis of Rare Diseases Associated to the Maturation of Mitochondrial [4Fe-4S]-Containing Proteins. Biomolecules 2022; 12:biom12071009. [PMID: 35883565 PMCID: PMC9313013 DOI: 10.3390/biom12071009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 02/04/2023] Open
Abstract
The importance of mitochondria in mammalian cells is widely known. Several biochemical reactions and pathways take place within mitochondria: among them, there are those involving the biogenesis of the iron–sulfur (Fe-S) clusters. The latter are evolutionarily conserved, ubiquitous inorganic cofactors, performing a variety of functions, such as electron transport, enzymatic catalysis, DNA maintenance, and gene expression regulation. The synthesis and distribution of Fe-S clusters are strictly controlled cellular processes that involve several mitochondrial proteins that specifically interact each other to form a complex machinery (Iron Sulfur Cluster assembly machinery, ISC machinery hereafter). This machinery ensures the correct assembly of both [2Fe-2S] and [4Fe-4S] clusters and their insertion in the mitochondrial target proteins. The present review provides a structural and molecular overview of the rare diseases associated with the genes encoding for the accessory proteins of the ISC machinery (i.e., GLRX5, ISCA1, ISCA2, IBA57, FDX2, BOLA3, IND1 and NFU1) involved in the assembly and insertion of [4Fe-4S] clusters in mitochondrial proteins. The disease-related missense mutations were mapped on the 3D structures of these accessory proteins or of their protein complexes, and the possible impact that these mutations have on their specific activity/function in the frame of the mitochondrial [4Fe-4S] protein biogenesis is described.
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Affiliation(s)
- Francesca Camponeschi
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
- Correspondence: (S.C.-B.); (V.C.); Tel.: +39-055-4574192 (S.C.-B.); +39-055-4574276 (V.C.)
| | - Vito Calderone
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
- Correspondence: (S.C.-B.); (V.C.); Tel.: +39-055-4574192 (S.C.-B.); +39-055-4574276 (V.C.)
| | - Lucia Banci
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
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GLRX5-associated [Fe-S] cluster biogenesis disorder: further characterisation of the neurological phenotype and long-term outcome. Orphanet J Rare Dis 2021; 16:465. [PMID: 34732213 PMCID: PMC8565018 DOI: 10.1186/s13023-021-02073-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/10/2021] [Indexed: 11/11/2022] Open
Abstract
Background Identification and characterisation of monogenic causes of complex neurological phenotypes are important for genetic counselling and prognostication. Bi-allelic pathogenic variants in the gene encoding GLRX5, a protein involved in the early steps of Fe-S cluster biogenesis, are rare and cause two distinct phenotypes: isolated sideroblastic anemia and a neurological phenotype with variant non-ketotic hyperglycinemia. In this study, we analysed the evolution of clinical and MRI findings and long-term outcome of patients with GLRX5 mutations. Methods Four patients from three Australian families of Lebanese descent were identified. All patients presented in childhood and were followed up into adult life through multiple clinical assessments. All were prescribed sodium benzoate. Results All patients (all females, age range 18–56 years) showed a complex neurological phenotype characterised by varying combinations of spastic paraparesis, length-dependent motor/sensory-motor axonal polyneuropathy, and psychiatric disturbances with variable intellectual disability. All had non-ketotic hyperglycinemia and a homozygous pathogenic c.151_153delAAG (p.K51del) change in GLRX5. Motor disability gradually progressed reaching moderate disability during adolescence and moderately severe disability during adult life. The major MRI finding was the upper cervical spinal cord signal changes with contrast enhancement noted in all and additional leukoencephalopathy in one. On follow up MRI, the white matter lesions diminished on a subsequent scan and then remained static over time. The spinal cord showed gliotic changes. Two patients have previously demonstrated low pyruvate dehydrogenase complex deficiency but none had plasma lactate elevation, nor biochemical evidence of branch-chain keto-dehydrogenase deficiency. Glycine levels reduced in patients that tolerated sodium benzoate, possibly stabilising clinical manifestations. Conclusions This report demonstrates that the p.K51del GLRX5 variant causes a distinct and predictable neurological phenotype. The clinical assessments spanning from childhood to adult life enable physicians to infer the natural history of GLRX5 related neurological disorder. There may be widespread metabolic consequences, and optimal management is unknown.
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Selvanathan A, Parayil Sankaran B. Mitochondrial iron-sulfur cluster biogenesis and neurological disorders. Mitochondrion 2021; 62:41-49. [PMID: 34687937 DOI: 10.1016/j.mito.2021.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/26/2021] [Accepted: 10/18/2021] [Indexed: 12/20/2022]
Abstract
Iron-sulfur clusters (ISCs) are highly conserved moieties embedded into numerous crucial proteins in almost all bacteria, plants and mammals. As such, ISC biosynthesis is critical to cellular function. The pathway was first characterized in bacteria by the late 1990s, and over the subsequent 20 years there has been increasing understanding of its components in humans. Defects in the ISC pathway are now associated with many different human disease states, such as Friedreich ataxia and ISCU myopathy. Whilst the disorders have variable clinical features, most involve neurological phenotypes. There are common biochemical signatures in most of these conditions, as a lack of ISCs causes deficiencies of target proteins including Complex I, II and III, aconitase and lipoic acid. This review focuses on the disorders of ISC biogenesis that have been described in the literature to-date. Key clinical, biochemical and neuroradiological features will be discussed, providing a reference point for clinicians diagnosing and managing these patients. Therapies are mostly supportive at this stage. However, the improved understanding of the pathophysiology of these conditions could pave the way for disease-modifying therapies in the near future.
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Affiliation(s)
- Arthavan Selvanathan
- Genetic Metabolic Disorders Service, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, Australia
| | - Bindu Parayil Sankaran
- Genetic Metabolic Disorders Service, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW, Australia; Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Australia.
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10
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Fan HC, Lee HF, Yue CT, Chi CS. Clinical Characteristics of Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes. Life (Basel) 2021; 11:life11111111. [PMID: 34832987 PMCID: PMC8617702 DOI: 10.3390/life11111111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, a maternally inherited mitochondrial disorder, is characterized by its genetic, biochemical and clinical complexity. The most common mutation associated with MELAS syndrome is the mtDNA A3243G mutation in the MT-TL1 gene encoding the mitochondrial tRNA-leu(UUR), which results in impaired mitochondrial translation and protein synthesis involving the mitochondrial electron transport chain complex subunits, leading to impaired mitochondrial energy production. Angiopathy, either alone or in combination with nitric oxide (NO) deficiency, further contributes to multi-organ involvement in MELAS syndrome. Management for MELAS syndrome is amostly symptomatic multidisciplinary approach. In this article, we review the clinical presentations, pathogenic mechanisms and options for management of MELAS syndrome.
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Affiliation(s)
- Hueng-Chuen Fan
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
- Department of Medical Research, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan
- Department of Rehabilitation, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 356, Taiwan
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
| | - Hsiu-Fen Lee
- Department of Pediatrics, Taichung Veterans General Hospital, Taichung 407, Taiwan;
| | - Chen-Tang Yue
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
| | - Ching-Shiang Chi
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
- Correspondence: ; Tel.: +886-4-26581919-4301
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Gayathri N, Deepha S, Sharma S. Diagnosis of primary mitochondrial disorders -Emphasis on myopathological aspects. Mitochondrion 2021; 61:69-84. [PMID: 34592422 DOI: 10.1016/j.mito.2021.09.007] [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: 07/15/2021] [Revised: 09/03/2021] [Accepted: 09/22/2021] [Indexed: 12/29/2022]
Abstract
Mitochondrial disorders are one of the most common neurometabolic disorders affecting all age groups. The phenotype-genotype heterogeneity in these disorders can be attributed to the dual genetic control on mitochondrial functions, posing a challenge for diagnosis. Though the advancement in the high-throughput sequencing and other omics platforms resulted in a "genetics-first" approach, the muscle biopsy remains the benchmark in most of the mitochondrial disorders. This review focuses on the myopathological aspects of primary mitochondrial disorders. The utility of muscle biopsy is not limited to analyse the structural abnormalities; rather it also proves to be a potential tool to understand the deranged sub-cellular functions.
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Affiliation(s)
- Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India.
| | - Sekar Deepha
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
| | - Shivani Sharma
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
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A Review of Multiple Mitochondrial Dysfunction Syndromes, Syndromes Associated with Defective Fe-S Protein Maturation. Biomedicines 2021; 9:biomedicines9080989. [PMID: 34440194 PMCID: PMC8393393 DOI: 10.3390/biomedicines9080989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial proteins carrying iron-sulfur (Fe-S) clusters are involved in essential cellular pathways such as oxidative phosphorylation, lipoic acid synthesis, and iron metabolism. NFU1, BOLA3, IBA57, ISCA2, and ISCA1 are involved in the last steps of the maturation of mitochondrial [4Fe-4S]-containing proteins. Since 2011, mutations in their genes leading to five multiple mitochondrial dysfunction syndromes (MMDS types 1 to 5) were reported. The aim of this systematic review is to describe all reported MMDS-patients. Their clinical, biological, and radiological data and associated genotype will be compared to each other. Despite certain specific clinical elements such as pulmonary hypertension or dilated cardiomyopathy in MMDS type 1 or 2, respectively, nearly all of the patients with MMDS presented with severe and early onset leukoencephalopathy. Diagnosis could be suggested by high lactate, pyruvate, and glycine levels in body fluids. Genetic analysis including large gene panels (Next Generation Sequencing) or whole exome sequencing is needed to confirm diagnosis.
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Heidari E, Rasoulinezhad M, Pak N, Reza Ashrafi M, Heidari M, Banwell B, Garshasbi M, Reza Tavasoli A. Defective complex III mitochondrial respiratory chain due to a novel variant in CYC1 gene masquerades acute demyelinating syndrome or Leber hereditary optic neuropathy. Mitochondrion 2021; 60:12-20. [PMID: 34252606 DOI: 10.1016/j.mito.2021.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/03/2021] [Accepted: 07/07/2021] [Indexed: 11/15/2022]
Abstract
Complex III (CIII) is the third out of five mitochondrial respiratory chain complexes residing at the mitochondrial inner membrane. The assembly of 10 subunits encoded by nuclear DNA and one by mitochondrial DNA result in the functional CIII which transfers electrons from ubiquinol to cytochrome c. Deficiencies of CIII are among the least investigated mitochondrial disorders and thus clinical spectrum of patients with mutations in CIII is not well defined. We report on a 10-year-old girl born to consanguineous Iranian parents presenting with recurrent visual loss episodes and optic nerve contrast enhancement in brain imaging reminiscent of an acquired demyelination syndrome (i.e. optic neuritis or multiple sclerosis), who was ultimately confirmed to have a novel homozygous missense variant of unknown significance, c.949C > T; p.(Arg317Trp) in the CYC1 gene, a nuclear DNA subunit of complex III of the mitochondrial chain. Sanger sequencing confirmed the segregation of this variant with disease in the family. The effect of this variant on the protein structure was shown in-silico. Our findings, not only expand the clinical spectrum due to defects in CYC1 gene but also highlight that mitochondrial respiratory chain disorders could be considered as a potential differential diagnosis in children who present with unusual patterns of acquired demyelination syndromes (ADS). In addition, our results support the hypothesis that mitochondrial disorders might have an overlapping presentation with ADS.
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Affiliation(s)
- Erfan Heidari
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Rasoulinezhad
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Neda Pak
- Pediatric Radiology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Morteza Heidari
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Brenda Banwell
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.
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Feng WX, Zhuo XW, Liu ZM, Li JW, Zhang WH, Wu Y, Han TL, Fang F. Case Report: A Variant Non-ketotic Hyperglycinemia With GLRX5 Mutations: Manifestation of Deficiency of Activities of the Respiratory Chain Enzymes. Front Genet 2021; 12:605778. [PMID: 34054912 PMCID: PMC8155699 DOI: 10.3389/fgene.2021.605778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 04/08/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Variant non-ketotic hyperglycinaemia (NKH) is a rare disorder characterized by variable clinical, biochemical, and imaging features. The variant form of NKH is rare and characterized by variable clinical, biochemical and imaging features. Subjects: Herein, we report a girl with variant NKH with two mutations in glutaredoxin 5 (GLRX5), which has been described in only three patients. Results: The clinical and biochemical phenotypes of the patient are also described. She suffered from developmental regression associated with spasticity, developmental delay, anemia and optic atrophy. The mitochondrial leukoencephalopathy was used to designate these disorders. An increased T2 signal from the medulla oblongata to the C6 spinal region was also observed on spinal cord MRI. Tandem mass analysis of a dried blood sample revealed elevated levels of glycine. The patient has two compound heterozygous mutations (c.151_153 del AAG and c.196C>T) in the GLRX5 gene. The c.196C>T mutation led to a stop codon (p.Q66Ter). Activities of mitochondrial respiratory chain (MRC) complexes II+III in the patient's fibroblasts were abnormal. Conclusions: We present the case of a girl with variant NKH who manifested spasticity and bilateral cavitating leukoencephalopathy. The patient had a deficiency of a respiratory chain enzyme, and this is the first report. Genetic testing is important for physicians to evaluate suspected variant NKH patients and to provide proper genetic counseling.
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Affiliation(s)
- Wei-Xing Feng
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Xiu-Wei Zhuo
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Zhi-Mei Liu
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Jiu-Wei Li
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Wei-Hua Zhang
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Yun Wu
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Tong-Li Han
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
| | - Fang Fang
- Neurology Department, National Center for Children's Health China, Beijing Children Hospital Affiliated to Capital Medical University, Beijing, China
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Molecular Basis of Multiple Mitochondrial Dysfunctions Syndrome 2 Caused by CYS59TYR BOLA3 Mutation. Int J Mol Sci 2021; 22:ijms22094848. [PMID: 34063696 PMCID: PMC8125686 DOI: 10.3390/ijms22094848] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 11/16/2022] Open
Abstract
Multiple mitochondrial dysfunctions syndrome (MMDS) is a rare neurodegenerative disorder associated with mutations in genes with a vital role in the biogenesis of mitochondrial [4Fe-4S] proteins. Mutations in one of these genes encoding for BOLA3 protein lead to MMDS type 2 (MMDS2). Recently, a novel phenotype for MMDS2 with complete clinical recovery was observed in a patient containing a novel variant (c.176G > A, p.Cys59Tyr) in compound heterozygosity. In this work, we aimed to rationalize this unique phenotype observed in MMDS2. To do so, we first investigated the structural impact of the Cys59Tyr mutation on BOLA3 by NMR, and then we analyzed how the mutation affects both the formation of a hetero-complex between BOLA3 and its protein partner GLRX5 and the iron-sulfur cluster-binding properties of the hetero-complex by various spectroscopic techniques and by experimentally driven molecular docking. We show that (1) the mutation structurally perturbed the iron-sulfur cluster-binding region of BOLA3, but without abolishing [2Fe-2S]2+ cluster-binding on the hetero-complex; (2) tyrosine 59 did not replace cysteine 59 as iron-sulfur cluster ligand; and (3) the mutation promoted the formation of an aberrant apo C59Y BOLA3-GLRX5 complex. All these aspects allowed us to rationalize the unique phenotype observed in MMDS2 caused by Cys59Tyr mutation.
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Dang QCL, Phan DH, Johnson AN, Pasapuleti M, Alkhaldi HA, Zhang F, Vik SB. Analysis of Human Mutations in the Supernumerary Subunits of Complex I. Life (Basel) 2020; 10:life10110296. [PMID: 33233646 PMCID: PMC7699753 DOI: 10.3390/life10110296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 01/02/2023] Open
Abstract
Complex I is the largest member of the electron transport chain in human mitochondria. It comprises 45 subunits and requires at least 15 assembly factors. The subunits can be divided into 14 "core" subunits that carry out oxidation-reduction reactions and proton translocation, as well as 31 additional supernumerary (or accessory) subunits whose functions are less well known. Diminished levels of complex I activity are seen in many mitochondrial disease states. This review seeks to tabulate mutations in the supernumerary subunits of humans that appear to cause disease. Mutations in 20 of the supernumerary subunits have been identified. The mutations were analyzed in light of the tertiary and quaternary structure of human complex I (PDB id = 5xtd). Mutations were found that might disrupt the folding of that subunit or that would weaken binding to another subunit. In some cases, it appeared that no protein was made or, at least, could not be detected. A very common outcome is the lack of assembly of complex I when supernumerary subunits are mutated or missing. We suggest that poor assembly is the result of disrupting the large network of subunit interactions that the supernumerary subunits typically engage in.
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Cherian A, Divya KP, Jose J, Thomas B. Multifocal cavitating leukodystrophy-A distinct image in mitochondrial LYRM7 mutations. Mult Scler Relat Disord 2020; 47:102615. [PMID: 33189022 DOI: 10.1016/j.msard.2020.102615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 10/13/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
An adult woman presented with insidious onset slowly progressive symmetric spasticity and mild upper extremity dysmetria, with sparing of bowel and bladder functions. She had a distinct magnetic resonance imaging (MRI) pattern of bilateral symmetrical T2 hyperintensity involving periventricular especially parieto-occipital and deep cerebral white matter with multifocal small cavitations which were posterior predominant, sparing subcortical U fibres. Magnetic resonance spectroscopy (MRS) showed lactate peak. Her clinical exome sequencing revealed a pathogenic homozygous start-loss variation in exon 1 encoding the mitochondrial LYR motif-containing protein 7 (LYRM7 gene) which is an integral part of complex III of the mitochondrial respiratory chain. Our case was unique in the indolent adult onset leukodystrophy like presentation making her wheel chair bound by the fourth decade, while most reported patients to date had an early childhood presentation as repeated episodes of subacute leukoencephalopathy with motor regression or death by first decade. Myriad phenotypic presentation of the LYRM7 gene mutations reported till date is highlighted.
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Affiliation(s)
- Ajith Cherian
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
| | - K P Divya
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India.
| | - Jithu Jose
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
| | - Bejoy Thomas
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
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Parayil Sankaran B, Nagappa M, Chiplunkar S, Kothari S, Govindaraj P, Sinha S, Taly AB. Leukodystrophies and Genetic Leukoencephalopathies in Children Specified by Exome Sequencing in an Expanded Gene Panel. J Child Neurol 2020; 35:433-441. [PMID: 32180488 DOI: 10.1177/0883073820904294] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The overlapping clinical and neuroimaging phenotypes of leukodystrophies pose a diagnostic challenge to both clinicians and researchers alike. Studies on the application of exome sequencing in the diagnosis of leukodystrophies are emerging. We used targeted gene panel sequencing of 6440 genes to investigate the genetic etiology in a cohort of 50 children with neuroimaging diagnosis of leukodystrophy/genetic leukoencephalopathy of unknown etiology. These 50 patients without a definite biochemical or genetic diagnosis were derived from a cohort of 88 patients seen during a 2.5-year period (2015 January-2017 June). Patients who had diagnosis by biochemical or biopsy confirmation (n = 17) and patients with incomplete data or lack of follow-up (n = 21) were excluded. Exome sequencing identified variants in 30 (60%) patients, which included pathogenic or likely pathogenic variants in 28 and variants of unknown significance in 2. Among the patients with pathogenic or likely pathogenic variants, classic leukodystrophies constituted 13 (26%) and genetic leukoencephalopathies 15 (30%). The clinical and magnetic resonance imaging (MRI) findings and genetic features of the identified disorders are discussed.
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Affiliation(s)
- Bindu Parayil Sankaran
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Madhu Nagappa
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Shwetha Chiplunkar
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sonam Kothari
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Periyasamy Govindaraj
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Arun B Taly
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
- Neuromuscular Lab, National Institute of Mental Health and Neurosciences, Bangalore, India
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Friederich MW, Perez FA, Knight KM, Van Hove RA, Yang SP, Saneto RP, Van Hove JLK. Pathogenic variants in NUBPL result in failure to assemble the matrix arm of complex I and cause a complex leukoencephalopathy with thalamic involvement. Mol Genet Metab 2020; 129:236-242. [PMID: 31917109 PMCID: PMC8096346 DOI: 10.1016/j.ymgme.2019.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/27/2019] [Accepted: 12/29/2019] [Indexed: 01/16/2023]
Abstract
Disorders of the white matter are genetically very heterogeneous including several genes involved in mitochondrial bioenergetics. Diagnosis of the underlying cause is aided by pattern recognition on neuroimaging and by next-generation sequencing. Recently, genetic changes in the complex I assembly factor NUBPL have been characterized by a consistent recognizable pattern of leukoencephalopathy affecting deep white matter including the corpus callosum and cerebellum. Here, we report twin boys with biallelic variants in NUBPL, an unreported c.351 G > A; p.(Met117Ile) and a previously reported pathological variant c. 693 + 1 G > A. Brain magnetic resonance imaging showed abnormal T2 hyperintense signal involving the periventricular white matter, external capsule, corpus callosum, and, prominently, the bilateral thalami. The neuroimaging pattern evolved over 18 months with marked diffuse white matter signal abnormality, volume loss, and new areas of signal abnormality in the cerebellar folia and vermis. Magnetic resonance spectroscopy showed elevated lactate. Functional studies in cultured fibroblasts confirmed pathogenicity of the genetic variants. Complex I activity of the respiratory chain was deficient spectrophotometrically and on blue native gel with in-gel activity staining. There was absent assembly and loss of proteins of the matrix arm of complex I when traced with an antibody to NDUFS2, and incomplete assembly of the membrane arm when traced with an NDUFB6 antibody. There was decreased NUBPL protein on Western blot in patient fibroblasts compared to controls. Compromised NUBPL activity impairs assembly of the matrix arm of complex I and produces a severe, rapidly-progressive leukoencephalopathy with thalamic involvement on MRI, further expanding the neuroimaging phenotype.
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Affiliation(s)
- Marisa W Friederich
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado, RC1-N P18-4404K, 12800 East 19th Avenue, Aurora, CO 80045, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO 80045, USA
| | - Francisco A Perez
- Department of Radiology, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| | - Kaz M Knight
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado, RC1-N P18-4404K, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Roxanne A Van Hove
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado, RC1-N P18-4404K, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Samuel P Yang
- Clinical Genomics and Preventative Medicine, Providence Medical Group, 105 West 8th Street 454-E, Spokane, WA 99204, USA
| | - Russell P Saneto
- Mitochondrial Medicine and Metabolism, Department of Neurology, Division of Pediatric Neurology, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA; Center for Integrative Brain Research, Neuroscience Institute, 1900 Ninth Ave, Mailstop C9S-10, Seattle, WA 98101, USA
| | - Johan L K Van Hove
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado, RC1-N P18-4404K, 12800 East 19th Avenue, Aurora, CO 80045, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO 80045, USA.
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McAvoy K, Kawamata H. Glial mitochondrial function and dysfunction in health and neurodegeneration. Mol Cell Neurosci 2019; 101:103417. [PMID: 31678567 DOI: 10.1016/j.mcn.2019.103417] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/24/2019] [Accepted: 10/27/2019] [Indexed: 02/07/2023] Open
Abstract
Mitochondria play essential metabolic roles in neural cells. Mitochondrial dysfunction has profound effects on the brain. In primary mitochondrial diseases, mutations that impair specific oxidative phosphorylation (OXPHOS) proteins or OXPHOS assembly factors lead to isolated biochemical defects and a heterogeneous group of clinical phenotypes, including mitochondrial encephalopathies. A broader defect of OXPHOS function, due to mutations in proteins involved in mitochondrial DNA maintenance, mitochondrial biogenesis, or mitochondrial tRNAs can also underlie severe mitochondrial encephalopathies. While primary mitochondrial dysfunction causes rare genetic forms of neurological disorders, secondary mitochondrial dysfunction is involved in the pathophysiology of some of the most common neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Many studies have investigated mitochondrial function and dysfunction in bulk central nervous system (CNS) tissue. However, the interpretation of these studies has been often complicated by the extreme cellular heterogeneity of the CNS, which includes many different types of neurons and glial cells. Because neurons are especially dependent on OXPHOS for ATP generation, mitochondrial dysfunction is thought to be directly involved in cell autonomous neuronal demise. Despite being metabolically more flexible than neurons, glial mitochondria also play an essential role in the function of the CNS, and have adapted specific metabolic and mitochondrial features to support their diversity of functions. This review analyzes our current understanding and the gaps in knowledge of mitochondrial properties of glia and how they affect neuronal functions, in health and disease.
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Affiliation(s)
- Kevin McAvoy
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA.
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21
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Finsterer J. Mitochondrial metabolic stroke: Phenotype and genetics of stroke-like episodes. J Neurol Sci 2019; 400:135-141. [PMID: 30946993 DOI: 10.1016/j.jns.2019.03.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 02/07/2023]
Abstract
Stroke-like episodes (SLEs) are the hallmark of mitochondrial encephalopathy with lactic acidosis and stroke-like episode (MELAS) syndrome but rarely occur also in other specific or nonspecific mitochondrial disorders. Pathophysiologically, SLLs are most likely due to a regional disruption of the blood-brain barrier triggered by the underlying metabolic defect, epileptic activity, drugs, or other factors. SLEs manifest clinically with a plethora of cerebral manifestations, which not only include features typically seen in ischemic stroke, but also headache, epilepsy, ataxia, visual impairment, vomiting, and psychiatric abnormalities. The morphological correlate of a SLE is the stroke-like lesion (SLL), best visualised on multimodal MRI. In the acute stages, a SLL presents as vasogenic edema but may be mixed up with cytotoxic components. Additionally, SLLs are characterized by hyperperfusion on perfusion studies. In the chronic stage, SLLs present with a colorful picture before they completely disappear, or end up as white matter lesion, cyst, laminar cortical necrosis, focal atrophy, or as toenail sign. Treatment of SLLs is symptomatic and relies on recommendations by experts. Beneficial effects have been reported with nitric-oxide precursors, antiepileptic drugs, antioxidants, the ketogenic diet, and steroids. Lot of research is still needed to uncover the enigma SLE/SLL.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Vienna, Austria.
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22
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Marelli C, Salsano E, Politi LS, Labauge P. Spinal cord involvement in adult-onset metabolic and genetic diseases. J Neurol Neurosurg Psychiatry 2019; 90:211-218. [PMID: 30150321 DOI: 10.1136/jnnp-2018-318666] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 12/11/2022]
Abstract
In adulthood, spinal cord MRI abnormalities such as T2-weighted hyperintensities and atrophy are commonly associated with a large variety of causes (inflammation, infections, neoplasms, vascular and spondylotic diseases). Occasionally, they can be due to rare metabolic or genetic diseases, in which the spinal cord involvement can be a prominent or even predominant feature, or a secondary one. This review focuses on these rare diseases and associated spinal cord abnormalities, which can provide important but over-ridden clues for the diagnosis. The review was based on a PubMed search (search terms: 'spinal cord' AND 'leukoencephalopathy' OR 'leukodystrophy'; 'spinal cord' AND 'vitamin'), further integrated according to the authors' personal experience and knowledge. The genetic and metabolic diseases of adulthood causing spinal cord signal alterations were identified and classified into four groups: (1) leukodystrophies; (2) deficiency-related metabolic diseases; (3) genetic and acquired toxic/metabolic causes; and (4) mitochondrial diseases. A number of genetic and metabolic diseases of adulthood causing spinal cord atrophy without signal alterations were also identified. Finally, a classification based on spinal MRI findings is presented, as well as indications about the diagnostic work-up and differential diagnosis. Some of these diseases are potentially treatable (especially if promptly recognised), while others are inherited as autosomal dominant trait. Therefore, a timely diagnosis is needed for a timely therapy and genetic counselling. In addition, spinal cord may be the main site of pathology in many of these diseases, suggesting a tempting role for spinal cord abnormalities as surrogate MRI biomarkers.
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Affiliation(s)
- Cecilia Marelli
- Department of Neurology, Gui de Chauliac University Hospital, Montpellier, France .,Expert Center for Neurogenetic Diseases and Adult Mitochondrial and Metabolic Diseases, Gui de Chauliac University Hospital, Montpellier, France.,EA7402 Institut Universitaire de Recherche Clinique and Laboratoire de Genetique Moleculaire, Gui de Chauliac University Hospital, Montpellier, France.,MMDN, Université de Montpellier, EPHE, Inserm UMR-S1198, Montpellier, France
| | - Ettore Salsano
- Unit of Neurodegenerative and Neurometabolic Rare Diseases, RCCS Foundation 'Carlo Besta' Neurological Institute, Milan, Italy
| | - Letterio S Politi
- Advanced MRI Centre, University of Massachusetts Medical School, Worcester, USA.,Neuroimaging Research, Boston Children's Hospital, Boston, MA, USA
| | - Pierre Labauge
- Department of Neurology, Gui de Chauliac University Hospital, Montpellier, France.,Reference Centre for Adult Leukodystrophies, Gui de Chauliac University Hospital, Montpellier, France
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23
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Sivertseva SA, Bykova OV, Bakhtiyarova KZ, Prilenskaya AM, Sivertsev MY, Kandala NS, Bazhukhin DV, Smirnova NF, Guseva ME, Boyko AN. [Clinical cases of multiple sclerosis in children with cerebral palsy]. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:55-61. [PMID: 30160669 DOI: 10.17116/jnevro201811808255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The careful differential diagnosis is very important in pediatric cases of multiple sclerosis (MS). It has special difficulties, if MS started in patients with residual neurological pathology. Two cases of development of MS in children with cerebral palsy (CP) are presented. The clinical features and diagnostic difficulties in such comorbid situations are discussed .
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Affiliation(s)
- S A Sivertseva
- Tyumen Regional Center of Multiple Sclerosis, Tyumen, Russia
| | - O V Bykova
- Children's Hospital of the First Moscow State Medical University I.M. Sechenov, Moscow, Russia; Research and Clinical Centre of Pediatric Psychoneurology Moscow Department of Public Health, Moscow, Russia
| | | | - A M Prilenskaya
- Tyumen Regional Center of Multiple Sclerosis, Tyumen, Russia
| | | | - N S Kandala
- Tyumen Regional Center of Multiple Sclerosis, Tyumen, Russia
| | - D V Bazhukhin
- Tyumen Regional Center of Multiple Sclerosis, Tyumen, Russia
| | - N F Smirnova
- Pirogov Russian National Research Medical University, Department of Neurology, Neurosurgery and Medical Genetics, Moscow, Russia
| | - M E Guseva
- Pirogov Russian National Research Medical University, Department of Neurology, Neurosurgery and Medical Genetics, Moscow, Russia
| | - A N Boyko
- Pirogov Russian National Research Medical University, Department of Neurology, Neurosurgery and Medical Genetics, Moscow, Russia
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