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Yang N, Chen L, Zhang Y, Wu X, Hao Y, Yang F, Yang Z, Liang J. Novel NARS2 variants in a patient with early-onset status epilepticus: case study and literature review. BMC Pediatr 2024; 24:96. [PMID: 38310242 PMCID: PMC10837881 DOI: 10.1186/s12887-024-04553-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/11/2024] [Indexed: 02/05/2024] Open
Abstract
BACKGROUND NARS2 as a member of aminoacyl-tRNA synthetases was necessary to covalently join a specific tRNA to its cognate amino acid. Biallelic variants in NARS2 were reported with disorders such as Leigh syndrome, deafness, epilepsy, and severe myopathy. CASE PRESENTATION Detailed clinical phenotypes were collected and the NARS2 variants were discovered by whole exome sequencing and verified by Sanger sequencing. Additionally, 3D protein structure visualization was performed by UCSF Chimera. The proband in our study had early-onset status epilepticus with abnormal EEG and MRI results. She also performed global developmental delay (GDD) and myocardial dysfunction. Next-generation sequencing (NGS) and Sanger sequencing revealed compound heterozygous missense variants [NM_024678.6:exon14: c.1352G > A(p.Arg451His); c.707T > C(p.Phe236Ser)] of the NARS2 gene. The proband develops refractory epilepsy with GDD and hyperlactatemia. Unfortunately, she finally died for status seizures two months later. CONCLUSION We discovered two novel missense variants of NARS2 in a patient with early-onset status epilepticus and myocardial dysfunction. The NGS enables the patient to be clearly diagnosed as combined oxidative phosphorylation deficiency 24 (COXPD24, OMIM:616,239), and our findings expands the spectrum of gene variants in COXPD24.
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Affiliation(s)
- Nuo Yang
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, 130021, China
| | - Limin Chen
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China
| | - Yanfeng Zhang
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, 130021, China
| | - Xuemei Wu
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, 130021, China
| | - Yunpeng Hao
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, 130021, China
| | - Fan Yang
- Cipher Gene LLC, Beijing, 100089, China
| | | | - Jianmin Liang
- Department of Pediatric Neurology, First hospital of Jilin University, Changchun, 130021, China.
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, 130021, China.
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Khodaeian M, Bitarafan F, Garrousi F, Sardehie EA, Pak N, Hosseinpour S, Shakiba M, Falah M, Garshasbi M, Tavasoli AR. Expanding phenotype heterogeneity of NARS2 by presenting subdural hematoma and parenchymal hemorrhage. J Clin Lab Anal 2023; 37:e24983. [PMID: 37950505 PMCID: PMC10749492 DOI: 10.1002/jcla.24983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 10/12/2023] [Accepted: 10/22/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND NARS2 encodes mitochondrial Asparaginyl-tRNA Synthetase 2, which catalyzes the aminoacylation of tRNA-Asn in the mitochondria. To date, 24 variants have been reported in NARS2 gene in 35 patients. The phenotypic variability of NARS2-associated disorder is broad, ranging from neurodevelopmental disorders to hearing loss. In this study, we report some novel imaging findings in an Iranian patient suffering from epileptic encephalopathy, caused by a previously reported variant, c.500A > G; p.(His167Arg), in NARS2. METHODS The spectrum of clinical manifestations of two Iranian patients was investigated and genetic analysis was performed by Whole-exome sequencing (WES). Additionally, we also reviewed the literature and summarized the phenotypes of previously reported patients with variants in the NARS2 gene. RESULTS Here, we present the phenotypic and genetic features of 2 unrelated Iranian infants presented with neurodevelopmental delay, seizures, hearing impairment, feeding problems, elevated serum lactate levels in addition to subdural hematoma and cerebral parenchymal hemorrhage in the brain magnetic resonance imaging (MRI) of one of the patients. Genetic analysis revealed a biallelic missense variant in NARS2: c.500A > G; p.(His167Arg). We described the subdural hematoma and cerebral parenchymal hemorrhage of the brain for the first time. CONCLUSIONS Our study provides new clinical findings, subdural hematoma, and parenchymal hemorrhage, in NARS2-related disorders. Our findings along with previous studies provide more evidence of the clinical presentation of the disease caused by pathogenic variants in NARS2. Expanding the clinical spectrum increases the diagnostic rate of molecular testing and improves the quality of counseling for at-risk couples.
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Affiliation(s)
| | - Fatemeh Bitarafan
- Department of Medical GeneticsOslo University Hospital and University of Oslo0450OsloNorway
| | | | | | - Neda Pak
- Pediatric Radiology Division, Children's Medical Center, Pediatrics Center of ExcellenceTehran University of Medical SciencesTehranIran
| | - Sareh Hosseinpour
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of ExcellenceTehran University of Medical SciencesTehranIran
| | - Marjan Shakiba
- Department of Pediatric Endocrinology and Metabolism, Mofid Children's HospitalShahid Beheshti University of Medical SciencesTehranIran
| | - Masoumeh Falah
- ENT and Head and Neck Research Center and Department, The Five Senses Health Institute, School of Medicine, Hazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical SciencesTarbiat Modares UniversityTeheranIran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of ExcellenceTehran University of Medical SciencesTehranIran
- Department of Neurology, Barrow Neurological InstitutePhoenix Children's HospitalPhoenixArizonaUSA
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Kong LY, Wu YZ, Cheng RQ, Wang PH, Peng BW. Role of Mutations of Mitochondrial Aminoacyl-tRNA Synthetases Genes on Epileptogenesis. Mol Neurobiol 2023; 60:5482-5492. [PMID: 37316759 DOI: 10.1007/s12035-023-03429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Mitochondria are the structures in cells that are responsible for producing energy. They contain a specific translation unit for synthesizing mitochondria-encoded respiratory chain components: the mitochondrial DNA (mt DNA). Recently, a growing number of syndromes associated with the dysfunction of mt DNA translation have been reported. However, the functions of these diseases still need to be precise and thus attract much attention. Mitochondrial tRNAs (mt tRNAs) are encoded by mt DNA; they are the primary cause of mitochondrial dysfunction and are associated with a wide range of pathologies. Previous research has shown the role of mt tRNAs in the epileptic mechanism. This review will focus on the function of mt tRNA and the role of mitochondrial aminoacyl-tRNA synthetase (mt aaRS) in order to summarize some common relevant mutant genes of mt aaRS that cause epilepsy and the specific symptoms of the disease they cause.
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Affiliation(s)
- Ling-Yue Kong
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yi-Ze Wu
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Run-Qi Cheng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Pei-Han Wang
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Bi-Wen Peng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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Finsterer J, Mehri S. Progressive Mitochondrial Encephalopathy Due to the Novel Compound Heterozygous Variants c.182C>T and c.446A>AG in NARS2: A Case Report. Cureus 2023; 15:e43969. [PMID: 37746452 PMCID: PMC10515475 DOI: 10.7759/cureus.43969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2023] [Indexed: 09/26/2023] Open
Abstract
Progressive mitochondrial encephalopathy manifesting as developmental delay, regression, epilepsy, myoclonus, dystonia, and spasticity due to a novel compound heterozygous variant in NARS2 has not been reported. The patient is a 3.5-year-old female with normal psychomotor development until she experienced her first generalized status epilepticus at 4.5 months of age. After seizure control, generalized myoclonus and psychomotor regression became evident. She suffered from two other epileptic states and seizure control remained inadequate despite the use of multiple anti-seizure drugs. Neurologic examination revealed generalized hypotonia, discoordination, unstable eye contact, drooling, open mouth, myoclonus, periodic torticollis, and ankle contractions. Cerebral MRI revealed hydrocephalus ex vacuo due to diffuse cortical and subcortical atrophy bilaterally and incomplete myelination. Genetic testing at 12 months of age revealed the compound heterozygous variants chr11: 78204182C>T and chr11: 78282446A>AG in NARS2. Despite anti-seizure drugs, mitochondrial cocktail, and cannabidiol, the disease progressed to intractable seizures and severe tetraspasticity. In summary, this case demonstrates that compound heterozygous variants in NARS2 can phenotypically manifest exclusively in the brain with intractable epilepsy, myoclonus, developmental delay, regression, hypotonia, cerebral atrophy, and hypomyelination, followed by tetraspasticity and dystonia.
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Affiliation(s)
- Josef Finsterer
- Neurology, Neurology and Neurophysiology Center, Vienna, AUT
| | - Sounira Mehri
- Nutrition-Functional Foods and Vascular Health, Biochemistry Laboratory, Faculty of Medicine of Monastir, Monastir, TUN
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Hu W, Fang H, Peng Y, Li L, Guo D, Tang J, Yi J, Liu Q, Qin W, Wu L, Ning Z. Clinical and genetic analyses of premature mitochondrial encephalopathy with epilepsia partialis continua caused by novel biallelic NARS2 mutations. Front Neurosci 2022; 16:1076183. [PMID: 36620461 PMCID: PMC9811187 DOI: 10.3389/fnins.2022.1076183] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Biallelic NARS2 mutations can cause various neurodegenerative diseases, leading to growth retardation, intractable epilepsy, and hearing loss in early infancy and further progressing to spastic paraplegia, neurodegeneration, and even death. NARS2 mutations are associated with mitochondrial dysfunction and cause combined oxidative phosphorylation deficiency 24 (COXPD24). Relatively few cases have been reported worldwide; therefore, the pathogenesis of COXPD24 is poorly understood. We studied two unrelated patients with COXPD24 with similar phenotypes who presented with intractable refractory epilepsia partialis continua, hearing loss, and growth retardation. One patient died from epilepsy. Three novel NARS2 variants (case 1: c.185T > C and c.251 + 2T > G; case 2: c.185T > C and c.509T > G) were detected with whole-exome sequencing. c.251 + 2T > G is located at the donor splicing site in the non-coding sequence of the gene. The minigene experiment further verified that c.251 + 2T > G caused variable splicing abnormalities and produced truncated proteins. Molecular dynamics studies showed that c.185T > C and c.509T > G reduced the binding free energy of the NARS2 protein dimer. The literature review revealed fewer than 30 NARS2 variants. These findings improved our understanding of the disease phenotype and the variation spectrum and revealed the potential pathogenic mechanism of non-coding sequence mutations in COXPD24.
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Affiliation(s)
- Wenjing Hu
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Hongjun Fang
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Yu Peng
- Pediatrics Research Institute of Hunan Province, Hunan Children’s Hospital, Changsha, China
| | - Li Li
- Department of Radiology, Hunan Children’s Hospital, Changsha, China
| | - Danni Guo
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Jingwen Tang
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Jurong Yi
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Qingqing Liu
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Wei Qin
- Department of Neurology, Hunan Children’s Hospital, Changsha, China
| | - Liwen Wu
- Department of Neurology, Hunan Children’s Hospital, Changsha, China,*Correspondence: Liwen Wu,
| | - Zeshu Ning
- Department of Neurology, Hunan Children’s Hospital, Changsha, China,Zeshu Ning,
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