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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.
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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
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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.
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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
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Pathophysiological Heterogeneity of the BBSOA Neurodevelopmental Syndrome. Cells 2022; 11:cells11081260. [PMID: 35455940 PMCID: PMC9024734 DOI: 10.3390/cells11081260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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.
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