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Sabharwal A, Gupta V, Kv S, Kumar Manokaran R, Verma A, Mishra A, Bhoyar RC, Jain A, Sivadas A, Rawat S, Jolly B, Mohanty S, Gulati S, Gupta N, Kabra M, Scaria V, Sivasubbu S. Whole genome sequencing followed by functional analysis of genomic deletion encompassing ERCC8 and NDUFAF2 genes in a non-consanguineous Indian family reveals dysfunctional mitochondrial bioenergetics leading to infant mortality. Mitochondrion 2024; 75:101844. [PMID: 38237647 DOI: 10.1016/j.mito.2024.101844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 12/07/2023] [Accepted: 01/14/2024] [Indexed: 01/26/2024]
Abstract
Genomic investigations on an infant who presented with a putative mitochondrial disorder led to identification of compound heterozygous deletion with an overlapping region of ∼142 kb encompassing two nuclear encoded genes namely ERCC8 and NDUFAF2. Investigations on fetal-derived fibroblast culture demonstrated impaired bioenergetics and mitochondrial dysfunction, which explains the phenotype and observed infant mortality in the present study. The genetic findings from this study extended the utility of whole-genome sequencing as it led to development of a MLPA-based assay for carrier screening in the extended family and the prenatal testing aiding in the birth of two healthy children.
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Affiliation(s)
- Ankit Sabharwal
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, Texas, United States.
| | - Vishu Gupta
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shamsudheen Kv
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | | | - Ankit Verma
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India
| | - Anushree Mishra
- Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), Delhi, India
| | - Rahul C Bhoyar
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India
| | - Abhinav Jain
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ambily Sivadas
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sonali Rawat
- Stem Cell Facility, All India Institute of Medical Sciences (AIIMS), Delhi, India
| | - Bani Jolly
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sujata Mohanty
- Stem Cell Facility, All India Institute of Medical Sciences (AIIMS), Delhi, India
| | - Sheffali Gulati
- Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), Delhi, India
| | - Neerja Gupta
- Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), Delhi, India
| | - Madhulika Kabra
- Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), Delhi, India.
| | - Vinod Scaria
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
| | - Sridhar Sivasubbu
- CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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2
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Yip J, Thompson KS. T-cell Lymphoblastic Lymphoma in a Patient With Chromosome 8q21.11 Microdeletion. J Pediatr Hematol Oncol 2022; 44:e756-e759. [PMID: 34486555 DOI: 10.1097/mph.0000000000002309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/09/2021] [Indexed: 11/26/2022]
Abstract
The chromosome 8q21.11 deletion syndrome is an extremely rare genetic condition characterized by facial dysmorphic features, Peters anomaly and impaired intellectual development. We report a case of a 2-year-old female with chromosome 8q21.11-q21.2 microdeletion complicated by T-cell lymphoblastic lymphoma. Whole genome single-nucleotide polymorphism microarray detected an interstitial deletion of 8q21.11 to q.21.2, including 16 genes. Autopsy findings revealed a T-cell lymphoblastic lymphoma presenting as an anterior mediastinal mass, encroaching upon the aortic arch, left subclavian artery, left carotid bifurcation and trachea. The genes that may contribute to a neoplastic process are identified (PKIA, IL7, TPD52, PAG1, and FABP5) and discussed in this article.
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Affiliation(s)
- James Yip
- Department of Pathology, John A. Burns School of Medicine, University of Hawai'i
| | - Karen S Thompson
- Department of Pathology, John A. Burns School of Medicine, University of Hawai'i
- Clinical Laboratories of Hawaii, Honolulu, HI
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3
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Ben Ayed I, Bouzid A, Kammoun F, Souissi A, Jallouli O, Mallouli S, Guidara S, Loukil S, Aloulou H, Jbeli F, Aouichaoui S, Abid D, Abdelhedi F, Triki C, Kamoun H, Masmoudi S. 8q21.11 microdeletion syndrome: Delineation of HEY1 as a candidate gene in neurodevelopmental and cardiac defects. Mol Genet Genomic Med 2021; 9:e1811. [PMID: 34549899 PMCID: PMC8606210 DOI: 10.1002/mgg3.1811] [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: 06/13/2021] [Revised: 08/13/2021] [Accepted: 09/02/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND 8q21.11 microdeletion syndrome is a rare chromosomal disorder characterized by recurrent dysmorphic features, a variable degree of intellectual disability and ocular, cardiac and hand/feet abnormalities. To date, ZFHX4 is the only candidate gene implicated in the ocular findings. In this study, we evaluated a patient with a de novo 8q21.13-21.3 deletion to define a new small region of overlap (SRO) for this entity. METHODS We conducted a clinical evaluation and comparative genomic hybridization (CGH) 4x44K microarrays in a patient with de novo unbalanced translocation t(8;16)(q21; q11.2). RESULTS The case, a 6-year-old boy, presented dysmorphic features including an elongated face, brachycephaly with a high forehead, an underdeveloped ala, thin upper lip, micrognathia, low-set ears, hypotonia, mild intellectual disability, cortical atrophy with thin corpus callosum defect, and an atrial septal defect. No ocular abnormalities were found. Microarray analysis revealed a 9.6 Mb interstitial 8q21.11-21.3 deletion, not including the ZFHX4 gene. This microdeletion was confirmed in our patient through qPCR analysis, and both parents had a normal profile. Alignment analysis of our case defined a new SRO encompassing five genes. Among them, the HEY1 gene is involved in the embryonic development of the heart, central nervous system, and vascular system. Hrt1/Hey1 null mice show perinatal lethality due to congenital malformations of the aortic arch and its branch arteries. HEY1 has also been linked to the maintenance of neural stem cells, inhibition of oligodendrocyte differentiation, and myelin gene expression. CONCLUSION HEY1 is a candidate gene for both neurological and cardiac features of the 8q21.11 microdeletion syndrome and might, therefore, explain specific components of its pathophysiology.
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Affiliation(s)
- Ikhlas Ben Ayed
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.,Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
| | - Amal Bouzid
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.,Sharjah Institute for Medical Research, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Fatma Kammoun
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Research Laboratory, Sfax University, Sfax, Tunisia
| | - Amal Souissi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Olfa Jallouli
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Research Laboratory, Sfax University, Sfax, Tunisia
| | - Salma Mallouli
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Research Laboratory, Sfax University, Sfax, Tunisia
| | - Souhir Guidara
- Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Laboratory of Human Molecular Genetics, LR33ES99, Faculty of Medicine of Sfax, University of Sfax, Sfax, Tunisia
| | - Salma Loukil
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Hajer Aloulou
- Pediatric Department, Hedi Chaker University Hospital, University of Sfax, Sfax, Tunisia
| | - Fida Jbeli
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Sahar Aouichaoui
- Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
| | - Dorra Abid
- Cardiology Department, Hedi Chaker University Hospital, University of Sfax, Sfax, Tunisia
| | - Fatma Abdelhedi
- Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Laboratory of Human Molecular Genetics, LR33ES99, Faculty of Medicine of Sfax, University of Sfax, Sfax, Tunisia
| | - Chahnez Triki
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Research Laboratory, Sfax University, Sfax, Tunisia
| | - Hassen Kamoun
- Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia.,Laboratory of Human Molecular Genetics, LR33ES99, Faculty of Medicine of Sfax, University of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
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Mortreux J, Bacquet J, Boyer A, Alazard E, Bellance R, Giguet-Valard AG, Cerino M, Krahn M, Audic F, Chabrol B, Laugel V, Desvignes JP, Béroud C, Nguyen K, Verschueren A, Lévy N, Attarian S, Delague V, Missirian C, Bonello-Palot N. Identification of novel pathogenic copy number variations in Charcot-Marie-Tooth disease. J Hum Genet 2019; 65:313-323. [PMID: 31852984 DOI: 10.1038/s10038-019-0710-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/03/2019] [Accepted: 12/08/2019] [Indexed: 12/13/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a hereditary sensory-motor neuropathy characterized by a strong clinical and genetic heterogeneity. Over the past few years, with the occurrence of whole-exome sequencing (WES) or whole-genome sequencing (WGS), the molecular diagnosis rate has been improved by allowing the screening of more than 80 genes at one time. In CMT, except the recurrent PMP22 duplication accounting for about 60% of pathogenic variations, pathogenic copy number variations (CNVs) are rarely reported and only a few studies screening specifically CNVs have been performed. The aim of the present study was to screen for CNVs in the most prevalent genes associated with CMT in a cohort of 200 patients negative for the PMP22 duplication. CNVs were screened using the Exome Depth software on next generation sequencing (NGS) data obtained by targeted capture and sequencing of a panel of 81 CMT associated genes. Deleterious CNVs were identified in four patients (2%), in four genes: GDAP1, LRSAM1, GAN, and FGD4. All CNVs were confirmed by high-resolution oligonucleotide array Comparative Genomic Hybridization (aCGH) and/or quantitative PCR. By identifying four new CNVs in four different genes, we demonstrate that, although they are rare mutational events in CMT, CNVs might contribute significantly to mutational spectrum of Charcot-Marie-Tooth disease and should be searched in routine NGS diagnosis. This strategy increases the molecular diagnosis rate of patients with neuropathy.
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Affiliation(s)
- J Mortreux
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - J Bacquet
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - A Boyer
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - E Alazard
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - R Bellance
- Centre de référence Caribéen pour les maladies neuromusculaires, CeRCa, Hôpital Pierre-Zobda-Quitman, CHU de Martinique, France
| | - A G Giguet-Valard
- Centre de référence Caribéen pour les maladies neuromusculaires, CeRCa, Hôpital Pierre-Zobda-Quitman, CHU de Martinique, France
| | - M Cerino
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - M Krahn
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - F Audic
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone enfant, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - B Chabrol
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone enfant, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - V Laugel
- Centre de référence des maladies neuromusculaires, Service de pédiatrie, CHU Strasbourg, France
| | - J P Desvignes
- Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - C Béroud
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - K Nguyen
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - A Verschueren
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone Adulte, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - N Lévy
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - S Attarian
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone Adulte, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - V Delague
- Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - C Missirian
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - N Bonello-Palot
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France. .,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France.
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5
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Qin L, Yang C, Lü T, Li L, Zong D, Wu Y. [Analysis of GDAP1 gene mutation in a pedigree with autosomal dominant Charcot-Marie-Tooth disease]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2019; 39:63-68. [PMID: 30692068 DOI: 10.12122/j.issn.1673-4254.2019.01.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the molecular genetic mechanism of Charcot- Marie-Tooth (CMT) disease in a pedigree. METHODS Genomic DNA was extracted from the peripheral blood of the family members of a pedigree with autosomal dominant CMT disease, and 65 candidate genes of the proband were screened using target exon capture and the next generation sequencing, and the suspicious genes were verified using Sanger sequencing. PolyPhen-2, PROVEAN and SIFT software were used to predict the function of the mutant genes, and PyMOL-1 software was used to simulate the mutant protein structure. RESULTS A heterozygous missense mutation [c.371A>G (p.Y124C)] was detected in exon 3 of GDAP1 gene of the proband. This heterozygous mutation was also detected in both the proband's mother and her brother, but not in her father. Multiple sequence alignment analysis showed that tyrosine at codon 124 of GDAP1 protein was highly conserved. All the 3 prediction software predicted that the mutation was harmful. Molecular structure simulation showed a weakened interaction force between the amino acid residues at codon 124 and the surrounding amino acid residues to affect the overall stability of the protein. CONCLUSIONS The mutation of GDAP1 gene may be related to the pathogenesis of autosomal dominant AD-CMT in this pedigree. The newly discovered c.371A>G mutation (p.Y124C) expands the mutation spectrum of GDAP1 gene, but further study is needed to clarify the underlying pathogenesis.
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Affiliation(s)
- Li Qin
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Canhong Yang
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Tianming Lü
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Lanying Li
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Dandan Zong
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Yueying Wu
- Department of Neurology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
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6
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Yoshimura A, Yuan JH, Hashiguchi A, Hiramatsu Y, Ando M, Higuchi Y, Nakamura T, Okamoto Y, Matsumura K, Hamano T, Sawaura N, Shimatani Y, Kumada S, Okumura Y, Miyahara J, Yamaguchi Y, Kitamura S, Haginoya K, Mitsui J, Ishiura H, Tsuji S, Takashima H. Clinical and mutational spectrum of Japanese patients with Charcot-Marie-Tooth disease caused by GDAP1 variants. Clin Genet 2017; 92:274-280. [PMID: 28244113 DOI: 10.1111/cge.13002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 02/09/2017] [Accepted: 02/23/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Mutations in GDAP1 are responsible for heterogeneous clinical and electrophysiological phenotypes of Charcot-Marie-Tooth disease (CMT), with autosomal dominant or recessive inheritance pattern. The aim of this study is to identify the clinical and mutational spectrum of CMT patients with GDAP1 variants in Japan. MATERIALS AND METHODS From April 2007 to October 2014, using three state-of-art technologies, we conducted gene panel sequencing in a cohort of 1,030 patients with inherited peripheral neuropathies (IPNs), and 398 mutation-negative cases were further analyzed with whole-exome sequencing. RESULTS We identified GDAP1 variants from 10 patients clinically diagnosed with CMT. The most frequent recessive variant in our cohort (5/10), c.740C>T (p.A247V), was verified to be associated with a founder event. We also detected three novel likely pathogenic variants: c.928C>T (p.R310W) and c.546delA (p.E183Kfs*23) in Case 2 and c.376G>A (p.E126K) in Case 8. Nerve conduction study or sural nerve biopsy of all 10 patients indicated axonal type peripheral neuropathy. CONCLUSION We identified GDAP1 variants in approximately 1% of our cohort with IPNs, and established a founder mutation in half of these patients. Our study originally described the mutational spectrum and clinical features of GDAP1-related CMT patients in Japan.
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Affiliation(s)
- A Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - J-H Yuan
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - A Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Y Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - M Ando
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Y Higuchi
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - T Nakamura
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Y Okamoto
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - K Matsumura
- Department of Neurology, Teikyo University, Tokyo, Japan
| | - T Hamano
- Department of Neurology, Kansai Electric Power Hospital, Osaka, Japan
| | - N Sawaura
- Department of Pediatrics, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Y Shimatani
- Department of Clinical Neuroscience, Tokushima University Graduate School, Tokushima, Japan
| | - S Kumada
- Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan
| | - Y Okumura
- Department of Pediatric Neurology, Shizuoka Children's Hospital, Shizuoka, Japan
| | - J Miyahara
- Department of Neurology, Tominaga Hospital, Osaka, Japan
| | - Y Yamaguchi
- Department of Neurology, Hematology, Metabolism, Endocrinology and Diabetology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - S Kitamura
- Department of Neurology, Konan Hospital, Hyogo, Japan
| | - K Haginoya
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
| | - J Mitsui
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - H Ishiura
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - S Tsuji
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - H Takashima
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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7
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Niyazov DM, Kahler SG, Frye RE. Primary Mitochondrial Disease and Secondary Mitochondrial Dysfunction: Importance of Distinction for Diagnosis and Treatment. Mol Syndromol 2016; 7:122-37. [PMID: 27587988 DOI: 10.1159/000446586] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2016] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial disease refers to a heterogeneous group of disorders resulting in defective cellular energy production due to abnormal oxidative phosphorylation (oxphos). Primary mitochondrial disease (PMD) is diagnosed clinically and ideally, but not always, confirmed by a known or indisputably pathogenic mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) mutation. The PMD genes either encode oxphos proteins directly or they affect oxphos function by impacting production of the complex machinery needed to run the oxphos process. However, many disorders have the 'mitochondrial' phenotype without an identifiable mtDNA or nDNA mutation or they have a variant of unknown clinical significance. Secondary mitochondrial dysfunction (SMD) can be caused by genes encoding neither function nor production of the oxphos proteins and accompanies many hereditary non-mitochondrial diseases. SMD may also be due to nongenetic causes such as environmental factors. In our practice, we see many patients with clinical signs of mitochondrial dysfunction based on phenotype, biomarkers, imaging, muscle biopsy, or negative/equivocal mtDNA or nDNA test results. In these cases, it is often tempting to assign a patient's phenotype to 'mitochondrial disease', but SMD is often challenging to distinguish from PMD. Fortunately, rapid advances in molecular testing, made possible by next generation sequencing, have been effective at least in some cases in establishing accurate diagnoses to distinguish between PMD and SMD. This is important, since their treatments and prognoses can be quite different. However, even in the absence of the ability to distinguish between PMD and SMD, treating SMD with standard treatments for PMD can be effective. We review the latest findings regarding mitochondrial disease/dysfunction and give representative examples in which differentiation between PMD and SMD has been crucial for diagnosis and treatment.
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Affiliation(s)
- Dmitriy M Niyazov
- Department of Pediatrics, Ochsner Clinic Foundation, New Orleans, La, USA
| | - Stephan G Kahler
- Department of Pediatrics, Arkansas Children's Hospital and Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, Ark., USA
| | - Richard E Frye
- Department of Pediatrics, Arkansas Children's Hospital and Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, Ark., USA
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