1
|
Marino V, Phromkrasae W, Bertacchi M, Cassini P, Chakrabandhu K, Dell'Orco D, Studer M. Disrupted protein interaction dynamics in a genetic neurodevelopmental disorder revealed by structural bioinformatics and genetic code expansion. Protein Sci 2024; 33:e4953. [PMID: 38511490 PMCID: PMC10955615 DOI: 10.1002/pro.4953] [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: 10/11/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 03/22/2024]
Abstract
Deciphering the structural effects of gene variants is essential for understanding the pathophysiological mechanisms of genetic diseases. Using a neurodevelopmental disorder called Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS) as a genetic disease model, we applied structural bioinformatics and Genetic Code Expansion (GCE) strategies to assess the pathogenic impact of human NR2F1 variants and their binding with known and novel partners. While the computational analyses of the NR2F1 structure delineated the molecular basis of the impact of several variants on the isolated and complexed structures, the GCE enabled covalent and site-specific capture of transient supramolecular interactions in living cells. This revealed the variable quaternary conformations of NR2F1 variants and highlighted the disrupted interplay with dimeric partners and the newly identified co-factor, CRABP2. The disclosed consequence of the pathogenic mutations on the conformation, supramolecular interplay, and alterations in the cell cycle, viability, and sub-cellular localization of the different variants reflect the heterogeneous disease spectrum of BBSOAS and set up novel foundation for unveiling the complexity of neurodevelopmental diseases.
Collapse
Affiliation(s)
- Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological ChemistryUniversity of VeronaVeronaItaly
| | | | | | - Paul Cassini
- University Côte d'Azur, CNRS, Inserm, iBVNiceFrance
| | | | - Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological ChemistryUniversity of VeronaVeronaItaly
| | | |
Collapse
|
2
|
Deloulme JC, Leclercq M, Deschaux O, Flore G, Capellano L, Tocco C, Braz BY, Studer M, Lahrech H. Structural interhemispheric connectivity defects in mouse models of BBSOAS: Insights from high spatial resolution 3D white matter tractography. Neurobiol Dis 2024; 193:106455. [PMID: 38408685 DOI: 10.1016/j.nbd.2024.106455] [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: 11/10/2023] [Revised: 02/23/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024] Open
Abstract
White matter (WM) tract formation and axonal pathfinding are major processes in brain development allowing to establish precise connections between targeted structures. Disruptions in axon pathfinding and connectivity impairments will lead to neural circuitry abnormalities, often associated with various neurodevelopmental disorders (NDDs). Among several neuroimaging methodologies, Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) technique that has the advantage of visualizing in 3D the WM tractography of the whole brain non-invasively. DTI is particularly valuable in unpinning structural tract connectivity defects of neural networks in NDDs. In this study, we used 3D DTI to unveil brain-specific tract defects in two mouse models lacking the Nr2f1 gene, which mutations in patients have been proven to cause an emerging NDD, called Bosch-Boonstra-Schaaf Optic Atrophy (BBSOAS). We aimed to investigate the impact of the lack of cortical Nr2f1 function on WM morphometry and tract microstructure quantifications. We found in both mutant mice partial loss of fibers and severe misrouting of the two major cortical commissural tracts, the corpus callosum, and the anterior commissure, as well as the two major hippocampal efferent tracts, the post-commissural fornix, and the ventral hippocampal commissure. DTI tract malformations were supported by 2D histology, 3D fluorescent imaging, and behavioral analyses. We propose that these interhemispheric connectivity impairments are consistent in explaining some cognitive defects described in BBSOAS patients, particularly altered information processing between the two brain hemispheres. Finally, our results highlight 3DDTI as a relevant neuroimaging modality that can provide appropriate morphometric biomarkers for further diagnosis of BBSOAS patients.
Collapse
Affiliation(s)
| | | | - Olivier Deschaux
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France
| | - Gemma Flore
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso", CNR, Napoli, Italy
| | - Laetitia Capellano
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institute Neurosciences, 38000 Grenoble, France
| | - Chiara Tocco
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France
| | - Barbara Yael Braz
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institute Neurosciences, 38000 Grenoble, France
| | - Michèle Studer
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France.
| | | |
Collapse
|
3
|
Wang N, Wan R, Tang K. Transcriptional regulation in the development and dysfunction of neocortical projection neurons. Neural Regen Res 2024; 19:246-254. [PMID: 37488873 PMCID: PMC10503610 DOI: 10.4103/1673-5374.379039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 04/10/2023] [Accepted: 05/17/2023] [Indexed: 07/26/2023] Open
Abstract
Glutamatergic projection neurons generate sophisticated excitatory circuits to integrate and transmit information among different cortical areas, and between the neocortex and other regions of the brain and spinal cord. Appropriate development of cortical projection neurons is regulated by certain essential events such as neural fate determination, proliferation, specification, differentiation, migration, survival, axonogenesis, and synaptogenesis. These processes are precisely regulated in a tempo-spatial manner by intrinsic factors, extrinsic signals, and neural activities. The generation of correct subtypes and precise connections of projection neurons is imperative not only to support the basic cortical functions (such as sensory information integration, motor coordination, and cognition) but also to prevent the onset and progression of neurodevelopmental disorders (such as intellectual disability, autism spectrum disorders, anxiety, and depression). This review mainly focuses on the recent progress of transcriptional regulations on the development and diversity of neocortical projection neurons and the clinical relevance of the failure of transcriptional modulations.
Collapse
Affiliation(s)
- Ningxin Wang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, Guangdong Province, China
| | - Rong Wan
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, Guangdong Province, China
| | - Ke Tang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, Guangdong Province, China
| |
Collapse
|
4
|
Liang Y, Wan L, Liu X, Zhang J, Zhu G, Yang G. Infantile epileptic spasm syndrome as a new NR2F1 gene phenotype. Int J Dev Neurosci 2024; 84:75-83. [PMID: 38010976 DOI: 10.1002/jdn.10309] [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: 09/18/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
INTRODUCTION NR2F1 pathogenetic variants are associated with the Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS). Recent studies indicate that BBSOAS patients not only have visual impairments but may also have developmental delays, hypotonia, thin corpus callosum and epileptic seizures. However, reports of BBSOAS occurrence along with infantile epileptic spasm syndrome (IESS) are rare. METHODS Here, we report three cases involving children with IESS and BBSOAS caused by de novo NR2F1 pathogenetic variants and summarize the genotype, clinical characteristics, diagnosis and treatment of them. RESULTS All three children experienced epileptic spasms and global developmental delays, with brain Magnetic Resonance Imaging (MRI) suggesting abnormalities (thinning of the corpus callosum or widened extracerebral spaces) and two of the children exhibiting abnormal visual evoked potentials. CONCLUSIONS Our findings indicate that new missense NR2F1 pathogenetic variants may lead to IESS with abnormal visual evoked potentials. Thus, clinicians should be aware of the Bosch-Boonstra-Schaaf optic atrophy syndrome and regular monitoring of the fundus, and the optic nerve is necessary during follow-up.
Collapse
Affiliation(s)
- Yan Liang
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| | - Lin Wan
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| | - Xinting Liu
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| | - Jing Zhang
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| | - Gang Zhu
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| | - Guang Yang
- Senior Department of Pediatrics, Seventh Medical Center of PLA General Hospital, Beijing, China
- Department of Pediatrics, First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese People's Liberation Army, Beijing, China
| |
Collapse
|
5
|
Bonzano S, Dallorto E, Molineris I, Michelon F, Crisci I, Gambarotta G, Neri F, Oliviero S, Beckervordersandforth R, Lie DC, Peretto P, Bovetti S, Studer M, Marchis SD. NR2F1 shapes mitochondria in the mouse brain, providing new insights into Bosch-Boonstra-Schaaf optic atrophy syndrome. Dis Model Mech 2023; 16:dmm049854. [PMID: 37260288 PMCID: PMC10309583 DOI: 10.1242/dmm.049854] [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: 08/22/2022] [Accepted: 05/09/2023] [Indexed: 06/02/2023] Open
Abstract
The nuclear receptor NR2F1 acts as a strong transcriptional regulator in embryonic and postnatal neural cells. In humans, mutations in the NR2F1 gene cause Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS), a rare neurodevelopmental disorder characterized by multiple clinical features including vision impairment, intellectual disability and autistic traits. In this study, we identified, by genome-wide and in silico analyses, a set of nuclear-encoded mitochondrial genes as potential genomic targets under direct NR2F1 transcriptional control in neurons. By combining mouse genetic, neuroanatomical and imaging approaches, we demonstrated that conditional NR2F1 loss of function within the adult mouse hippocampal neurogenic niche results in a reduced mitochondrial mass associated with mitochondrial fragmentation and downregulation of key mitochondrial proteins in newborn neurons, the genesis, survival and functional integration of which are impaired. Importantly, we also found dysregulation of several nuclear-encoded mitochondrial genes and downregulation of key mitochondrial proteins in the brain of Nr2f1-heterozygous mice, a validated BBSOAS model. Our data point to an active role for NR2F1 in the mitochondrial gene expression regulatory network in neurons and support the involvement of mitochondrial dysfunction in BBSOAS pathogenesis.
Collapse
Affiliation(s)
- Sara Bonzano
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Eleonora Dallorto
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Ivan Molineris
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- IIGM Foundation-Italian Institute for Genomic Medicine, Sp142 Km 3.95, Candiolo 10060, Italy
| | - Filippo Michelon
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Isabella Crisci
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Giovanna Gambarotta
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
- Department of Clinical and Biological Sciences (DSCB), Regione Gonzole 10, Orbassano 10043, Italy
| | - Francesco Neri
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- IIGM Foundation-Italian Institute for Genomic Medicine, Sp142 Km 3.95, Candiolo 10060, Italy
| | - Salvatore Oliviero
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- IIGM Foundation-Italian Institute for Genomic Medicine, Sp142 Km 3.95, Candiolo 10060, Italy
| | - Ruth Beckervordersandforth
- Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Fahrstrasse 17, Erlangen 91054, Germany
| | - Dieter Chichung Lie
- Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Fahrstrasse 17, Erlangen 91054, Germany
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| | - Michèle Studer
- Institute de Biologie Valrose (iBV), Université Côte d'Azur (UCA), CNRS 7277, Inserm 1091, Avenue Valrose 28, Nice 06108, France
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology (DBIOS), University of Turin, Via Accademia Albertina 13, Turin 10123, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gonzole 10, Orbassano 10043, Italy
| |
Collapse
|
6
|
van Renterghem V, Vilain C, Devriendt K, Casteels I, Smits G, Soblet J, Balikova I. Two siblings with Bosch-Boonstra-Schaaf optic atrophy syndrome due to parental gonadal mosaicism. Eur J Med Genet 2023; 66:104729. [PMID: 36775012 DOI: 10.1016/j.ejmg.2023.104729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 10/01/2022] [Accepted: 02/10/2023] [Indexed: 02/12/2023]
Abstract
Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS, OMIM 615722) is a rare autosomal dominant disorder characterized by intellectual disability, optic atrophy, cortical visual impairment, mild facial dysmorphism, hypotonia, hearing problems, attention deficit and a thin corpus callosum. The gene underlying this disorder is NR2F1 located on chromosome 5q15 which encodes for a nuclear receptor protein. Mutations and deletions have been identified in patients. Here we report on a brother and a sister carrying a pathogenic nonsense NR2F1 variant. The patients have a mild phenotype showing optic atrophy, mild intellectual disability, dysmorphic features and thin corpus callosum. This correlates with previously described milder phenotypes in patients with mutations in this domain. The variant was not identified in the parental genome indicating most likely a gonadal mosaicism. Gonadal mosaicism has not yet been reported in Bosch-Boonstra-Schaaf Optic Atrophy Syndrome.
Collapse
Affiliation(s)
| | - Catheline Vilain
- Department of Genetics, University Hospital Erasme, Brussels, Belgium
| | | | - Ingele Casteels
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
| | - Guillaume Smits
- Department of Genetics, University Hospital Erasme, Brussels, Belgium
| | - Julie Soblet
- Department of Genetics, University Hospital Erasme, Brussels, Belgium
| | - Irina Balikova
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium.
| |
Collapse
|
7
|
Rocatcher A, Desquiret-Dumas V, Charif M, Ferré M, Gohier P, Mirebeau-Prunier D, Verny C, Milea D, Lenaers G, Bonneau D, Reynier P, Amati-Bonneau P. The top 10 most frequently involved genes in hereditary optic neuropathies in 2186 probands. Brain 2023; 146:455-460. [PMID: 36317462 DOI: 10.1093/brain/awac395] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/15/2022] [Accepted: 09/25/2022] [Indexed: 12/12/2022] Open
Abstract
Hereditary optic neuropathies are caused by the degeneration of retinal ganglion cells whose axons form the optic nerves, with a consistent genetic heterogeneity. As part of our diagnostic activity, we retrospectively evaluated the combination of Leber hereditary optic neuropathy mutations testing with the exon sequencing of 87 nuclear genes on 2186 patients referred for suspected hereditary optic neuropathies. The positive diagnosis rate in individuals referred for Leber hereditary optic neuropathy testing was 18% (199/1126 index cases), with 92% (184/199) carrying one of the three main pathogenic variants of mitochondrial DNA (m.11778G>A, 66.5%; m.3460G>A, 15% and m.14484T>C, 11%). The positive diagnosis rate in individuals referred for autosomal dominant or recessive optic neuropathies was 27% (451/1680 index cases), with 10 genes accounting together for 96% of this cohort. This represents an overall positive diagnostic rate of 30%. The identified top 10 nuclear genes included OPA1, WFS1, ACO2, SPG7, MFN2, AFG3L2, RTN4IP1, TMEM126A, NR2F1 and FDXR. Eleven additional genes, each accounting for less than 1% of cases, were identified in 17 individuals. Our results show that 10 major genes account for more than 96% of the cases diagnosed with our nuclear gene panel.
Collapse
Affiliation(s)
- Aude Rocatcher
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Valérie Desquiret-Dumas
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Majida Charif
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Genetics and Immuno-Cell Therapy Team, Mohammed First University, Oujda 60000, Morocco
| | - Marc Ferré
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Philippe Gohier
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Delphine Mirebeau-Prunier
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Christophe Verny
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Neurologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Dan Milea
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
- Singapore National Eye Centre, Singapore Eye Research Institute, Duke-NUS 169857, Singapore
| | - Guy Lenaers
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Neurologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Dominique Bonneau
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Génétique, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Pascal Reynier
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Patrizia Amati-Bonneau
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| |
Collapse
|
8
|
Kocaaga A, Yimenicioglu S, Gürsoy HH. Novel NR2F1 variant identified by whole-exome sequencing in a patient with Bosch-Boonstra-Schaaf optic atrophy syndrome. Indian J Ophthalmol 2022; 70:2762-2764. [PMID: 35791240 PMCID: PMC9426133 DOI: 10.4103/ijo.ijo_1061_22] [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] [Indexed: 11/25/2022] Open
Abstract
Bosch–Boonstra–Schaaf optic atrophy syndrome (BBSOAS) is an extremely rare autosomal dominant disorder characterized by intellectual disability, developmental delay, seizures, hypotonia, hearing loss, and optic nerve atrophy. This syndrome is caused by loss-of-function variants in the nuclear receptor subfamily 2 group F member 1 (NR2F1) gene. To date, approximately 80 patients have been reported with BBSOAS. Here, we describe a 3-year-old infant with delayed development, intellectual disability, strabismus, nystagmus, and optic atrophy with well-characterized features associated with BBSOAS. Whole-exome sequencing revealed a novel heterozygous missense mutation (NM_005654.6:c.437G>A, p.Cys146Tyr) in the NR2F1 gene. This missense variant is predicted to be deleterious by the protein prediction tools (SIFT, PolyPhen-2, and MutationTaster). To the best of our knowledge, this is the first patient with BBSOAS reported from Turkey.
Collapse
Affiliation(s)
- Ayca Kocaaga
- Department of Medical Genetics, Eskişehir City Hospital, Eskişehir, Turkey
| | - Sevgi Yimenicioglu
- Department of Pediatric Neurology, Eskişehir City Hospital, Eskişehir, Turkey
| | - Haluk Hüseyin Gürsoy
- Department of Ophtalmology, Eskisehir Osmangazi University Hospital, Eskişehir, Turkey
| |
Collapse
|
9
|
Pathophysiological Heterogeneity of the BBSOA Neurodevelopmental Syndrome. Cells 2022; 11:cells11081260. [PMID: 35455940 PMCID: PMC9024734 DOI: 10.3390/cells11081260] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/17/2022] [Accepted: 03/29/2022] [Indexed: 11/17/2022] Open
Abstract
The formation and maturation of the human brain is regulated by highly coordinated developmental events, such as neural cell proliferation, migration and differentiation. Any impairment of these interconnected multi-factorial processes can affect brain structure and function and lead to distinctive neurodevelopmental disorders. Here, we review the pathophysiology of the Bosch–Boonstra–Schaaf Optic Atrophy Syndrome (BBSOAS; OMIM 615722; ORPHA 401777), a recently described monogenic neurodevelopmental syndrome caused by the haploinsufficiency of NR2F1 gene, a key transcriptional regulator of brain development. Although intellectual disability, developmental delay and visual impairment are arguably the most common symptoms affecting BBSOAS patients, multiple additional features are often reported, including epilepsy, autistic traits and hypotonia. The presence of specific symptoms and their variable level of severity might depend on still poorly characterized genotype–phenotype correlations. We begin with an overview of the several mutations of NR2F1 identified to date, then further focuses on the main pathological features of BBSOAS patients, providing evidence—whenever possible—for the existing genotype–phenotype correlations. On the clinical side, we lay out an up-to-date list of clinical examinations and therapeutic interventions recommended for children with BBSOAS. On the experimental side, we describe state-of-the-art in vivo and in vitro studies aiming at deciphering the role of mouse Nr2f1, in physiological conditions and in pathological contexts, underlying the BBSOAS features. Furthermore, by modeling distinct NR2F1 genetic alterations in terms of dimer formation and nuclear receptor binding efficiencies, we attempt to estimate the total amounts of functional NR2F1 acting in developing brain cells in normal and pathological conditions. Finally, using the NR2F1 gene and BBSOAS as a paradigm of monogenic rare neurodevelopmental disorder, we aim to set the path for future explorations of causative links between impaired brain development and the appearance of symptoms in human neurological syndromes.
Collapse
|