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Papadopoulos T, Gaignard P, Schiff M, Rio M, Karall D, Legendre A, Verloes A, Ruaud L. New description of an MRPS2 homozygous patient: Further features to help expend the phenotype. Eur J Med Genet 2024; 67:104889. [PMID: 38029925 DOI: 10.1016/j.ejmg.2023.104889] [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: 05/26/2023] [Revised: 09/04/2023] [Accepted: 10/29/2023] [Indexed: 12/01/2023]
Abstract
Mutated mito-ribosomal protein S2 (MRPS2) was already described in only three subjects, two with sensorineural hearing impairment, mild developmental delay, hypoglycemia, lactic acidemia and combined oxidative phosphorylation system deficiency and another, recently, presenting with a less severe phenotype. In order to expand the phenotype, we describe a new MRPS2 homozygous subject who shows particular features which have not yet been reported: initial microcephaly, joint hypermobility and autistic features.
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Affiliation(s)
- Thalia Papadopoulos
- APHP.Nord, Robert-Debré University Hospital, Department of Genetics, F-75019, Paris, France
| | - Pauline Gaignard
- Laboratoire de Biochimie Site Bicêtre, Faculté de Pharmacie, Hôpitaux Universitaires Paris-Saclay, Centre de référence des Maladies Mitochondriales, Filière Filnemus, France; Laboratoire de biologie médicale multisites Seqoia - FMG2025, Paris, France
| | - Manuel Schiff
- Necker Hospital, APHP, Reference Center for Inborn Error of Metabolism and Filière G2M, Pediatrics Department, University of Paris, Paris, France; Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Marlène Rio
- Departments of Pediatrics, Neurology and Genetics, Hopital Necker Enfants-Malades, 75015, Paris, France
| | - Daniela Karall
- Clinic for Pediatrics, Inherited Metabolic Disorders, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Adrien Legendre
- Laboratoire de biologie médicale multisites Seqoia - FMG2025, Paris, France
| | - Alain Verloes
- APHP.Nord, Robert-Debré University Hospital, Department of Genetics, F-75019, Paris, France; INSERM UMR 1141, Neurodiderot, University of Paris, F-75019, Paris, France
| | - Lyse Ruaud
- APHP.Nord, Robert-Debré University Hospital, Department of Genetics, F-75019, Paris, France; INSERM UMR 1141, Neurodiderot, University of Paris, F-75019, Paris, France.
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Chevrollier A, Bonnard AA, Ruaud L, Gueguen N, Perrin L, Desquiret-Dumas V, Guimiot F, Becker PH, Levy J, Reynier P, Gaignard P. Homozygous MFN2 variants causing severe antenatal encephalopathy with clumped mitochondria. Brain 2024; 147:91-99. [PMID: 37804319 DOI: 10.1093/brain/awad347] [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: 07/03/2023] [Revised: 08/30/2023] [Accepted: 09/25/2023] [Indexed: 10/09/2023] Open
Abstract
Pathogenic variants in the MFN2 gene are commonly associated with autosomal dominant (CMT2A2A) or recessive (CMT2A2B) Charcot-Marie-Tooth disease, with possible involvement of the CNS. Here, we present a case of severe antenatal encephalopathy with lissencephaly, polymicrogyria and cerebellar atrophy. Whole genome analysis revealed a homozygous deletion c.1717-274_1734 del (NM_014874.4) in the MFN2 gene, leading to exon 16 skipping and in-frame loss of 50 amino acids (p.Gln574_Val624del), removing the proline-rich domain and the transmembrane domain 1 (TM1). MFN2 is a transmembrane GTPase located on the mitochondrial outer membrane that contributes to mitochondrial fusion, shaping large mitochondrial networks within cells. In silico modelling showed that the loss of the TM1 domain resulted in a drastically altered topological insertion of the protein in the mitochondrial outer membrane. Fetus fibroblasts, investigated by fluorescent cell imaging, electron microscopy and time-lapse recording, showed a sharp alteration of the mitochondrial network, with clumped mitochondria and clusters of tethered mitochondria unable to fuse. Multiple deficiencies of respiratory chain complexes with severe impairment of complex I were also evidenced in patient fibroblasts, without involvement of mitochondrial DNA instability. This is the first reported case of a severe developmental defect due to MFN2 deficiency with clumped mitochondria.
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Affiliation(s)
- Arnaud Chevrollier
- MitoVasc Unit, INSERM U1083, CNRS 6015, SFR-ICAT, Angers University, MitoLab Team, 49000 Angers, France
| | - Adeline Alice Bonnard
- Department of Genetics, APHP Nord, Robert Debré University Hospital, 75019 Paris, France
- INSERM UMR 1131, Saint-Louis Research Institute, Paris University, 75010 Paris, France
| | - Lyse Ruaud
- Department of Genetics, APHP Nord, Robert Debré University Hospital, 75019 Paris, France
- INSERM UMR 1141, Paris-Cité University, NeuroDiderot, 75019 Paris, France
| | - Naïg Gueguen
- MitoVasc Unit, INSERM U1083, CNRS 6015, SFR-ICAT, Angers University, MitoLab Team, 49000 Angers, France
- Department of Biochemistry and Molecular biology, Angers University Hospital, 49000 Angers, France
| | - Laurence Perrin
- Department of Genetics, APHP Nord, Robert Debré University Hospital, 75019 Paris, France
| | - Valérie Desquiret-Dumas
- MitoVasc Unit, INSERM U1083, CNRS 6015, SFR-ICAT, Angers University, MitoLab Team, 49000 Angers, France
- Department of Biochemistry and Molecular biology, Angers University Hospital, 49000 Angers, France
| | - Fabien Guimiot
- INSERM UMR 1141, Paris-Cité University, NeuroDiderot, 75019 Paris, France
- Genetic department, CHU Robert Debre, Fetal Pathology Unit, 75019 Paris, France
| | - Pierre-Hadrien Becker
- Multi-site medical biology laboratory SeqOIA-FMG2025, 75014 Paris, France
- APHP Paris-Saclay, Department of Biochemistry, Reference Center for Mitochondrial Disease, FILNEMUS, Bicêtre University Hospital, 94275 Le Kremlin-Bicêtre, France
| | - Jonathan Levy
- Department of Genetics, APHP Nord, Robert Debré University Hospital, 75019 Paris, France
- Multi-site medical biology laboratory SeqOIA-FMG2025, 75014 Paris, France
| | - Pascal Reynier
- MitoVasc Unit, INSERM U1083, CNRS 6015, SFR-ICAT, Angers University, MitoLab Team, 49000 Angers, France
- Department of Biochemistry and Molecular biology, Angers University Hospital, 49000 Angers, France
| | - Pauline Gaignard
- Multi-site medical biology laboratory SeqOIA-FMG2025, 75014 Paris, France
- APHP Paris-Saclay, Department of Biochemistry, Reference Center for Mitochondrial Disease, FILNEMUS, Bicêtre University Hospital, 94275 Le Kremlin-Bicêtre, France
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Huang C, Luo H, Zeng B, Feng C, Chen J, Yuan H, Huang S, Yang B, Zou Y, Liu Y. Identification of two novel and one rare mutation in DYRK1A and prenatal diagnoses in three Chinese families with intellectual Disability-7. Front Genet 2023; 14:1290949. [PMID: 38179410 PMCID: PMC10765505 DOI: 10.3389/fgene.2023.1290949] [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] [Received: 09/08/2023] [Accepted: 12/07/2023] [Indexed: 01/06/2024] Open
Abstract
Background and purpose: Intellectual disability-7 (MRD7) is a subtype disorder of intellectual disability (MRD) involving feeding difficulties, hypoactivity, and febrile seizures at an age of early onset, then progressive intellectual and physical development deterioration. We purposed to identify the underlying causative genetic factors of three individuals in each Chinese family who presented with symptoms of intellectual disability and facial dysmorphic features. We provided prenatal diagnosis for the three families and genetic counseling for the prevention of this disease. Methods: We collected retrospective clinical diagnostic evidence for the three probands in our study, which included magnetic resonance imaging (MRI), computerized tomography (CT), electroencephalogram (EEG), and intelligence tests for the three probands in our study. Genetic investigation of the probands and their next of kin was performed by Trio-whole exome sequencing (WES). Sanger sequencing or quantitative PCR technologies were then used as the next step to verify the variants confirmed with Trio-WES for the three families. Moreover, we performed amniocentesis to explore the state of the three pathogenic variants in the fetuses by prenatal molecular genetic diagnosis at an appropriate gestational period for the three families. Results: The three probands and one fetus were clinically diagnosed with microcephaly and exhibited intellectual developmental disability, postnatal feeding difficulties, and facial dysmorphic features. Combining probands' clinical manifestations, Trio-WES uncovered the three heterozygous variants in DYRK1A: a novel variant exon3_exon4del p.(Gly4_Asn109del), a novel variant c.1159C>T p.(Gln387*), and a previously presented but rare pathogenic variant c.1309C>T p.(Arg437*) (NM_001396.5) in three families, respectively. In light of the updated American College of Medical Genetic and Genomics (ACMG) criterion, the variant of exon3_exon4del and c.1159C>T were both classified as likely pathogenic (PSV1+PM6), while c1309C>T was identified as pathogenic (PVS1+PS2_Moderate+PM2). Considering clinical features and molecular testimony, the three probands were confirmed diagnosed with MRD7. These three discovered variants were considered as the three causal mutations for MRD7. Prenatal diagnosis detected the heterozygous dominant variant of c.1159C>T p.(Gln387*) in one of the fetuses, indicating a significant probability of MRD7, subsequently the gestation was intervened by the parents' determination and professional obstetrical operation. On the other side, prenatal molecular genetic testing revealed wild-type alleles in the other two fetuses, and their parents both decided to sustain the gestation. Conclusion: We identified two novel and one rare mutation in DYRK1A which has broadened the spectrum of DYRK1A and provided evidence for the diagnosis of MRD7 at the molecular level. Besides, this study has supported the three families with MRD7 to determine the causative genetic factors efficiently and provide concise genetic counseling for the three families by using Trio-WES technology.
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Affiliation(s)
| | | | | | | | | | | | | | - Bicheng Yang
- Department of Medical Genetics, Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Yongyi Zou
- Department of Medical Genetics, Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Yanqiu Liu
- Department of Medical Genetics, Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
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Abou Haidar L, Harris RC, Pachnis P, Chen H, Gotway GK, Ni M, DeBerardinis RJ. Novel pathogenic UQCRC2 variants in a female with normal neurodevelopment. Cold Spring Harb Mol Case Stud 2023; 9:a006295. [PMID: 37709555 PMCID: PMC10815277 DOI: 10.1101/mcs.a006295] [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: 06/08/2023] [Accepted: 08/25/2023] [Indexed: 09/16/2023] Open
Abstract
Electron transport chain (ETC) disorders are a group of rare, multisystem diseases caused by impaired oxidative phosphorylation and energy production. Deficiencies in complex III (CIII), also known as ubiquinol-cytochrome c reductase, are particularly rare in humans. Ubiquinol-cytochrome c reductase core protein 2 (UQCRC2) encodes a subunit of CIII that plays a crucial role in dimerization. Several pathogenic UQCRC2 variants have been identified in patients presenting with metabolic abnormalities that include lactic acidosis, hyperammonemia, hypoglycemia, and organic aciduria. Almost all previously reported UQCRC2-deficient patients exhibited neurodevelopmental involvement, including developmental delays and structural brain anomalies. Here, we describe a girl who presented at 3 yr of age with lactic acidosis, hyperammonemia, and hypoglycemia but has not shown any evidence of neurodevelopmental dysfunction by age 15. Whole-exome sequencing revealed compound heterozygosity for two novel variants in UQCRC2: c.1189G>A; p.Gly397Arg and c.437T>C; p.Phe146Ser. Here, we discuss the patient's clinical presentation and the likely pathogenicity of these two missense variants.
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Affiliation(s)
- Lea Abou Haidar
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Robert C Harris
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Panayotis Pachnis
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Hongli Chen
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Garrett K Gotway
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Min Ni
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Ralph J DeBerardinis
- Children's Medical Center Research Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA;
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas 75390, USA
- Eugene McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas 75390, USA
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