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Yahya V, Dilena R, Del Bo R, Magni M, Biella F, Salani S, Fortunato F, Scola E, Di Fonzo A, Monfrini E. Soft cerebellar signs unveil RARS2-related epilepsy. Epileptic Disord 2024; 26:540-543. [PMID: 38733322 DOI: 10.1002/epd2.20237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/30/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024]
Affiliation(s)
- Vidal Yahya
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Robertino Dilena
- Neurophysiopathology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberto Del Bo
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Manuela Magni
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Fabio Biella
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Sabrina Salani
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesco Fortunato
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Elisa Scola
- Neuroradiology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessio Di Fonzo
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Edoardo Monfrini
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Neurology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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2
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Walimbe AS, Machol K, Kralik SF, Mizerik EA, Gofin Y, Bekheirnia MR, Gijavanekar C, Elsea SH, Emrick LT, Scaglia F. Expanded clinical phenotype and untargeted metabolomics analysis in RARS2-related mitochondrial disorder: a case report. BMC Neurol 2024; 24:87. [PMID: 38438854 PMCID: PMC10910770 DOI: 10.1186/s12883-024-03571-w] [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: 09/12/2023] [Accepted: 02/14/2024] [Indexed: 03/06/2024] Open
Abstract
BACKGROUND RARS2-related mitochondrial disorder is an autosomal recessive mitochondrial encephalopathy caused by biallelic pathogenic variants in the gene encoding the mitochondrial arginyl-transfer RNA synthetase 2 (RARS2, MIM *611524, NM_020320.5). RARS2 catalyzes the transfer of L-arginine to its cognate tRNA during the translation of mitochondrially-encoded proteins. The classical presentation of RARS2-related mitochondrial disorder includes pontocerebellar hypoplasia (PCH), progressive microcephaly, profound developmental delay, feeding difficulties, and hypotonia. Most patients also develop severe epilepsy by three months of age, which consists of focal or generalized seizures that frequently become pharmacoresistant and lead to developmental and epileptic encephalopathy (DEE). CASE PRESENTATION Here, we describe a six-year-old boy with developmental delay, hypotonia, and failure to thrive who developed an early-onset DEE consistent with Lennox-Gastaut Syndrome (LGS), which has not previously been observed in this disorder. He had dysmorphic features including bilateral macrotia, overriding second toes, a depressed nasal bridge, retrognathia, and downslanting palpebral fissures, and he did not demonstrate progressive microcephaly. Whole genome sequencing identified two variants in RARS2, c.36 + 1G > T, a previously unpublished variant that is predicted to affect splicing and is, therefore, likely pathogenic and c.419 T > G (p.Phe140Cys), a known pathogenic variant. He exhibited significant, progressive generalized brain atrophy and ex vacuo dilation of the supratentorial ventricular system on brain MRI and did not demonstrate PCH. Treatment with a ketogenic diet (KD) reduced seizure frequency and enabled him to make developmental progress. Plasma untargeted metabolomics analysis showed increased levels of lysophospholipid and sphingomyelin-related metabolites. CONCLUSIONS Our work expands the clinical spectrum of RARS2-related mitochondrial disorder, demonstrating that patients can present with dysmorphic features and an absence of progressive microcephaly, which can help guide the diagnosis of this condition. Our case highlights the importance of appropriate seizure phenotyping in this condition and indicates that patients can develop LGS, for which a KD may be a viable therapeutic option. Our work further suggests that analytes of phospholipid metabolism may serve as biomarkers of mitochondrial dysfunction.
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Affiliation(s)
- Ameya S Walimbe
- Division of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- Texas Children's Hospital, Houston, TX, 77030, USA
| | - Keren Machol
- Texas Children's Hospital, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Stephen F Kralik
- Department of Radiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Elizabeth A Mizerik
- Texas Children's Hospital, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yoel Gofin
- School of Medicine, Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel
- Genetics Institute, Meir Medical Center, Kfar Saba, Israel
| | - Mir Reza Bekheirnia
- Texas Children's Hospital, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Charul Gijavanekar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Lisa T Emrick
- Division of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- Texas Children's Hospital, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Fernando Scaglia
- Texas Children's Hospital, Houston, TX, 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
- BCM-CUHK Center of Medical Genetics, Prince of Wales Hospital, Hong Kong SAR, China.
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3
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Nicolle R, Altin N, Siquier-Pernet K, Salignac S, Blanc P, Munnich A, Bole-Feysot C, Malan V, Caron B, Nitschké P, Desguerre I, Boddaert N, Rio M, Rausell A, Cantagrel V. A non-coding variant in the Kozak sequence of RARS2 strongly decreases protein levels and causes pontocerebellar hypoplasia. BMC Med Genomics 2023; 16:143. [PMID: 37344844 DOI: 10.1186/s12920-023-01582-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
Bi-allelic variants in the mitochondrial arginyl-transfer RNA synthetase (RARS2) gene have been involved in early-onset encephalopathies classified as pontocerebellar hypoplasia (PCH) type 6 and in epileptic encephalopathy. A variant (NM_020320.3:c.-2A > G) in the promoter and 5'UTR of the RARS2 gene has been previously identified in a family with PCH. Only a mild impact of this variant on the mRNA level has been detected. As RARS2 is non-dosage-sensitive, this observation is not conclusive in regard of the pathogenicity of the variant.We report and describe here a new patient with the same variant in the RARS2 gene, at the homozygous state. This patient presents with a clinical phenotype consistent with PCH6 although in the absence of lactic acidosis. In agreement with the previous study, we measured RARS2 mRNA levels in patient's fibroblasts and detected a partially preserved gene expression compared to control. Importantly, this variant is located in the Kozak sequence that controls translation initiation. Therefore, we investigated the impact on protein translation using a bioinformatic approach and western blotting. We show here that this variant, additionally to its effect on the transcription, also disrupts the consensus Kozak sequence, and has a major impact on RARS2 protein translation. Through the identification of this additional case and the characterization of the molecular consequences, we clarified the involvement of this Kozak variant in PCH and on protein synthesis. This work also points to the current limitation in the pathogenicity prediction of variants located in the translation initiation region.
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Affiliation(s)
- Romain Nicolle
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
- Clinical Bioinformatics Laboratory, Université Paris Cité, INSERM UMR 1163, Imagine Institute, Paris, 75015, France
| | - Nami Altin
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
| | - Karine Siquier-Pernet
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
| | - Sherlina Salignac
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
| | - Pierre Blanc
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, AP-HP, Necker Hospital for Sick Children, Paris, 75015, France
| | - Arnold Munnich
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, AP-HP, Necker Hospital for Sick Children, Paris, 75015, France
| | - Christine Bole-Feysot
- Genomics Platform, Université Paris Cité, INSERM UMR 1163, Imagine Institute, Paris, 75015, France
| | - Valérie Malan
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, AP-HP, Necker Hospital for Sick Children, Paris, 75015, France
| | - Barthélémy Caron
- Clinical Bioinformatics Laboratory, Université Paris Cité, INSERM UMR 1163, Imagine Institute, Paris, 75015, France
| | - Patrick Nitschké
- Bioinformatics Core Facility, Université Paris Cité, INSERM UMR 1163, Imagine Institute, 75015, Paris, France
| | - Isabelle Desguerre
- Département de Neurologie Pédiatrique, AP-HP, Necker Hospital for Sick Children, 75015, Paris, France
| | - Nathalie Boddaert
- Département de Radiologie Pédiatrique, AP-HP, Necker Hospital for Sick Children and Université Paris Cité, INSERM UMR 1163 and INSERM U1299, Imagine Institute, Paris, 75015, France
| | - Marlène Rio
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, AP-HP, Necker Hospital for Sick Children, Paris, 75015, France
| | - Antonio Rausell
- Clinical Bioinformatics Laboratory, Université Paris Cité, INSERM UMR 1163, Imagine Institute, Paris, 75015, France
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, AP-HP, Necker Hospital for Sick Children, Paris, 75015, France
| | - Vincent Cantagrel
- Developmental Brain Disorders Laboratory, Université Paris Cité, INSERM UMR1163, Imagine Institute, 75015, Paris, France.
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Poquérusse J, Nolan M, Thorburn DR, Van Hove JLK, Friederich MW, Love DR, Taylor J, Powell CA, Minczuk M, Snell RG, Lehnert K, Glamuzina E, Jacobsen JC. Severe neonatal onset neuroregression with paroxysmal dystonia and apnoea: Expanding the phenotypic and genotypic spectrum of CARS2-related mitochondrial disease. JIMD Rep 2023; 64:223-232. [PMID: 37151360 PMCID: PMC10159863 DOI: 10.1002/jmd2.12360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/08/2023] [Accepted: 01/10/2023] [Indexed: 01/24/2023] Open
Abstract
Disorders of mitochondrial function are a collectively common group of genetic diseases in which deficits in core mitochondrial translation machinery, including aminoacyl tRNA synthetases, are key players. Biallelic variants in the CARS2 gene (NM_024537.4), which encodes the mitochondrial aminoacyl-tRNA synthetase for cysteine (CARS2, mt-aaRScys; MIM*612800), result in childhood onset epileptic encephalopathy and complex movement disorder with combined oxidative phosphorylation deficiency (MIM#616672). Prior to this report, eight unique pathogenic variants in the CARS2 gene had been reported in seven individuals. Here, we describe a male who presented in the third week of life with apnoea. He rapidly deteriorated with paroxysmal dystonic crises and apnoea resulting in death at 16 weeks. He had no evidence of seizure activity or multisystem disease and had normal brain imaging. Skeletal muscle biopsy revealed a combined disorder of oxidative phosphorylation. Whole-exome sequencing identified biallelic variants in the CARS2 gene: one novel (c.1478T>C, p.Phe493Ser), and one previously reported (c.655G>A, p.Ala219Thr; rs727505361). Northern blot analysis of RNA isolated from the patient's fibroblasts confirmed a clear defect in aminoacylation of the mitochondrial tRNA for cysteine (mt-tRNACys). To our knowledge, this is the earliest reported case of CARS2 deficiency with severe, early onset dystonia and apnoea, without epilepsy.
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Affiliation(s)
- Jessie Poquérusse
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
- Centre for Brain ResearchThe University of AucklandAucklandNew Zealand
| | - Melinda Nolan
- Department of NeurologyStarship Children's HealthAucklandNew Zealand
| | - David R. Thorburn
- Murdoch Children's Research InstituteMelbourneVictoriaAustralia
- Department of PaediatricsThe University of MelbourneMelbourneVictoriaAustralia
| | - Johan L. K. Van Hove
- Department of Pediatrics, School of MedicineUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
- Department of Pathology and Laboratory MedicineChildren's Hospital ColoradoAuroraColoradoUSA
| | - Marisa W. Friederich
- Department of Pediatrics, School of MedicineUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
- Department of Pathology and Laboratory MedicineChildren's Hospital ColoradoAuroraColoradoUSA
| | - Donald R. Love
- Diagnostic GeneticsLabPLUS, Auckland City HospitalAucklandNew Zealand
- Present address:
Division Chief, Pathology GeneticsSidra MedicineDohaQatar
| | - Juliet Taylor
- Genetic Health Service New ZealandAuckland City HospitalAucklandNew Zealand
| | | | - Michal Minczuk
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Russell G. Snell
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
- Centre for Brain ResearchThe University of AucklandAucklandNew Zealand
| | - Klaus Lehnert
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
- Centre for Brain ResearchThe University of AucklandAucklandNew Zealand
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic ServiceAuckland City HospitalAucklandNew Zealand
| | - Jessie C. Jacobsen
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
- Centre for Brain ResearchThe University of AucklandAucklandNew Zealand
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5
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Rosati A, L’Erario M, Bianchi R, Olivotto S, Battaglia DI, Darra F, Biban P, Biggeri A, Catelan D, Danieli G, Mondardini M, Cordelli DM, Amigoni A, Cesaroni E, Conio A, Costa P, Lombardini M, Meleleo R, Pugi A, Tornaboni E, Santarone ME, Vittorini R, Sartori S, Marini C, Vigevano F, Mastrangelo M, Pulitanò SM, Izzo F, Fusco L. KETASER01 protocol: What went right and what went wrong. Epilepsia Open 2022; 7:532-540. [PMID: 35833327 PMCID: PMC9436287 DOI: 10.1002/epi4.12627] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/12/2022] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To discuss the results of the KETASER01 trial and the reasons for its failure, particularly in view of future studies. METHODS KETASER01 is a multicenter, randomized, controlled, open-label, sequentially designed, non-profit Italian study that aimed to assess the efficacy of ketamine compared with conventional anesthetics in the treatment of refractory convulsive status epilepticus (RCSE) in children. RESULTS During the 5-year recruitment phase, a total of 76 RCSEs treated with third-line therapy were observed in five of the 10 participating Centers; only 10 individuals (five for each study arm; five females, mean age 6.5 ± 6.3 years) were enrolled in the KETASER01 study. Two of the five patients (40%) in the experimental arm were successfully treated with ketamine and two of the five (40%) children in the control arm, where successfully treated with thiopental. In the remaining six (60%) enrolled patients, RCSE was not controlled by the randomized anesthetic(s). SIGNIFICANCE The KETASER01 study was prematurely halted due to low eligibility of patients and no successful recruitment. No conclusions can be drawn regarding the objectives of the study. Here, we discuss the KETASER01 results and critically analyze the reasons for its failure in view of future trials.
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Affiliation(s)
- Anna Rosati
- Neuroscience DepartmentMeyer Children’s Hospital‐University of FlorenceFlorenceItaly
| | - Manuela L’Erario
- Intensive Care UnitMeyer Children’s Hospital‐University of FlorenceFlorenceItaly
| | - Roberto Bianchi
- Intensive Care UnitBambino Gesù Children’s Hospital, IRCCSRomeItaly
| | - Sara Olivotto
- Pediatric Neurology UnitChildren’s Hospital Vittore Buzzi, ASST Fatebenefratelli SaccoMilanItaly
| | | | - Francesca Darra
- Child Neuropsychiatry Department of Surgical Sciences, Dentistry, Gynecology and PediatricsUniversity of VeronaVeronaItaly
| | - Paolo Biban
- Department of Neonatal and Pediatric Intensive CareUniversity HospitalVeronaItaly
| | - Annibale Biggeri
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of PaduaPaduaItaly
| | - Dolores Catelan
- Department of Cardiac, Thoracic, Vascular Sciences and Public HealthUniversity of PaduaPaduaItaly
| | - Giacomo Danieli
- Department of Statistics, Computer Science, Applications G. ParentiUniversity of FlorenceFlorenceItaly
| | - Maria Cristina Mondardini
- Department of Pediatric Anesthesia and Intensive CareSant’Orsola‐Malpighi Hospital, University of BolognaBolognaItaly
| | - Duccio Maria Cordelli
- IRCCS Institute of Neurological Sciences of BolognaUOC Neuropsychiatry of the Pediatric AgeBolognaItaly
| | - Angela Amigoni
- Intensive Care Unit, Department of Woman’s and Child’s HealthUniversity Hospital of PaduaPaduaItaly
| | | | - Alessandra Conio
- Pediatric Intensive Care UnitHealth and Science City Hospital‐University of TurinTurinItaly
| | - Paola Costa
- Department of Neuropsychiatry WardInstitute for Maternal and Child Health, IRCCS “Burlo Garofolo”TriesteItaly
| | - Martina Lombardini
- Neuroscience DepartmentMeyer Children’s Hospital‐University of FlorenceFlorenceItaly
| | - Rosanna Meleleo
- Intensive Care UnitInstitute for Maternal and Child Health, IRCCS “Burlo Garofolo”TriesteItaly
| | - Alessandra Pugi
- Clinical Trial Office Meyer Children’s Hospital‐University of FlorenceFlorenceItaly
- Association La Nostra FamigliaIRCCS Eugenio MedeaLeccoItaly
| | - Elena Eve Tornaboni
- Clinical Trial Office Meyer Children’s Hospital‐University of FlorenceFlorenceItaly
- Association La Nostra FamigliaIRCCS Eugenio MedeaLeccoItaly
| | - Marta Elena Santarone
- Department of NeuroscienceBambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARERomeItaly
| | - Roberta Vittorini
- Child and Adolescence Neuropsychiatry UnitHealth and Science City Hospital‐University of TurinTurinItaly
| | - Stefano Sartori
- Pediatric Neurology Unit, Department of Woman’s and Child’s HealthUniversity Hospital of PaduaPaduaItaly
| | - Carla Marini
- Child Neuropsychiatry UnitPolytechnic University of the MarcheAnconaItaly
| | - Federico Vigevano
- Department of NeuroscienceBambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARERomeItaly
| | - Massimo Mastrangelo
- Pediatric Neurology UnitChildren’s Hospital Vittore Buzzi, ASST Fatebenefratelli SaccoMilanItaly
| | | | - Francesca Izzo
- Pediatric Intensive Care UnitChildren’s Hospital Vittore Buzzi, ASST Fatebenefratelli SaccoMilanItaly
| | - Lucia Fusco
- Department of NeuroscienceBambino Gesù Children’s Hospital, IRCCS, Full Member of European Reference Network EpiCARERomeItaly
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