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Zhang X, Han Y, Yang L, Xu N, Zhu L, Qiu S, Li Y, Xu L, Yu X. Clinical phenotype and genetic characteristics of SZT2 related diseases: A case report and literature review. Seizure 2024; 114:111-120. [PMID: 38134649 DOI: 10.1016/j.seizure.2023.12.008] [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: 05/30/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023] Open
Abstract
PURPOSE Seizure threshold 2 protein homolog gene (SZT2, MIM: 615463) related diseases are extremely rare autosomal recessive disorders with a wide spectrum of clinical phenotypes ranging from mild intellectual impairment to severe developmental epileptic encephalopathy (DEE). Most SZT2 related diseases are accompanied by craniofacial malformation and corpus callosum malformation. This study attempts to analyze and summarize the clinical phenotype and genetic characteristics of SZT2 related diseases, providing a basis for early diagnosis, treatment, and prognosis. METHOD We analyzed the clinical characteristics of a Chinese child with pathogenic variants of SZT2. We also performed whole-exome sequencing (WES) on the patient. In addition, we conducted a literature review of previously reported patients with pathogenic mutations in the SZT2 gene. RESULT The proband was a boy aged 1 year and 9 months with severe global developmental delay, transient drug-controlled focal epilepsy, cluster epilepsy, autism spectrum disorder, craniofacial deformity, hypotonia, focal EEG discharge, corpus callosum malformation, and persistent cavum septum pellucidum. WES revealed that the patient carried the SZT2 gene c.7584dupA and c.6302A>C complex heterozygous variants; the former being Likely Pathogenic (LP) and the latter Uncertain Significance (VUS) according to ACMG classification guidelines. According to our literature review, 43 cases of SZT2 related diseases have been reported so far; these include 15 cases with homozygous variations and 28 cases with complex heterozygous variations. A total of 57 types of variation were found, including 47 genetic variants, 2 de novo variants, and 8 unknown genetic modes. In addition, 2 high-frequency variants were found (c.5949_5951delTGT and c.6553C>T). The main clinical manifestations of the 40 patients were global developmental delay (GDD) of varying degrees (38/40, 95.00 %), seizures (36/40, 90.00 %), cranial deformity (27/40, 67.50 %), facial deformity (22/40, 55.00 %), hypotonia (22/40, 55.00 %), abnormal interseizure EEG discharge (26/40, 65.00 %), slow background activity (20/40, 50.00 %), corpus callosum deformity (18/40, 45.00 %). There was also one case of sudden unexpected death in epilepsy (SUDEP) and 3 cases of death from infection. In addition, three fetuses with the same variant had hydrocephalus and encephalocele. CONCLUSION The compound heterozygous mutation of c.7584dupA and c.6302A>C in the SZT2 gene is the genetic etiology of this patient, expanding the mutation spectrum of SZT2 related diseases. Early genetic testing is the best choice for clear diagnosis, treatment, and prognosis.
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Affiliation(s)
- Xin Zhang
- Postgrad Training Base Jinzhou Med Univ, Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China; Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Yuzeng Han
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Li Yang
- Postgrad Training Base Jinzhou Med Univ, Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China; Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China.
| | - Na Xu
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Liping Zhu
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Shiyan Qiu
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Yufen Li
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Liyun Xu
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
| | - Xixi Yu
- Department of Pediatrics, Linyi People's Hospital, Linyi, Shandong 276003, PR China
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2
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Muthaffar OY, Jan MMS, Alyazidi AS, Alotibi TK, Alsulami EA. Insight into Genetic Mutations of SZT2: Is It a Syndrome? Biomedicines 2023; 11:2402. [PMID: 37760843 PMCID: PMC10525120 DOI: 10.3390/biomedicines11092402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The seizure threshold 2 (SZT2) gene encodes a protein of unknown function, which is widely expressed, confers a low seizure threshold, and enhances epileptogenesis. It also comprises the KICSTOR protein complex, which inhibits the mTORC1 pathway. A pathogenic variant in the SZT2 gene could result in hyperactive mTORC1 signaling, which can lead to several neurological disorders. AIM OF THE STUDY To review every reported case and present two novel cases to expand the current knowledge and understanding of the mutation. METHODS Whole exome sequencing (WES) was used to identify the novel cases and present their clinical and radiological findings. A detailed revision of the literature was conducted to illustrate and compare findings. The clinical, genetical, neuroimaging, and electrophysiological data were extracted. RESULTS The study included 16 female patients and 13 male patients in addition to the 2 novel male cases. Eighteen patients had heterozygous mutations; others were homozygous. The majority presented with facial dysmorphism (n = 22). Seizures were noted as the predominant hallmark (n = 26). Developmental delay and hypotonia were reported in 27 and 15 patients, respectively. The majority of patients had multifocal epileptiform discharges on the electroencephalogram (EEG) and short and thick corpus callosum on the magnetic resonance imaging (MRI). CONCLUSION Several promising features are becoming strongly linked to patients with SZT2 mutations. High variability among the cases was observed. Developmental delay and facial dysmorphism can be investigated as potential hallmarks; aiding clinicians in diagnosing the condition and optimizing management plans.
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Affiliation(s)
- Osama Y. Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (O.Y.M.); (M.M.S.J.)
| | - Mohammed M. S. Jan
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (O.Y.M.); (M.M.S.J.)
| | - Anas S. Alyazidi
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
| | - Taif K. Alotibi
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
| | - Eman A. Alsulami
- Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.K.A.); (E.A.A.)
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3
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Figlia G, Müller S, Hagenston AM, Kleber S, Roiuk M, Quast JP, Ten Bosch N, Carvajal Ibañez D, Mauceri D, Martin-Villalba A, Teleman AA. Brain-enriched RagB isoforms regulate the dynamics of mTORC1 activity through GATOR1 inhibition. Nat Cell Biol 2022; 24:1407-1421. [PMID: 36097071 PMCID: PMC9481464 DOI: 10.1038/s41556-022-00977-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 07/13/2022] [Indexed: 12/26/2022]
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) senses nutrient availability to appropriately regulate cellular anabolism and catabolism. During nutrient restriction, different organs in an animal do not respond equally, with vital organs being relatively spared. This raises the possibility that mTORC1 is differentially regulated in different cell types, yet little is known about this mechanistically. The Rag GTPases, RagA or RagB bound to RagC or RagD, tether mTORC1 in a nutrient-dependent manner to lysosomes where mTORC1 becomes activated. Although the RagA and B paralogues were assumed to be functionally equivalent, we find here that the RagB isoforms, which are highly expressed in neurons, impart mTORC1 with resistance to nutrient starvation by inhibiting the RagA/B GTPase-activating protein GATOR1. We further show that high expression of RagB isoforms is observed in some tumours, revealing an alternative strategy by which cancer cells can retain elevated mTORC1 upon low nutrient availability.
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Affiliation(s)
- Gianluca Figlia
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Sandra Müller
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Anna M Hagenston
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, INF 366, Heidelberg, Germany
| | - Susanne Kleber
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mykola Roiuk
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Jan-Philipp Quast
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Nora Ten Bosch
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Damian Carvajal Ibañez
- Heidelberg University, Heidelberg, Germany.,Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniela Mauceri
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, INF 366, Heidelberg, Germany
| | - Ana Martin-Villalba
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Aurelio A Teleman
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,Heidelberg University, Heidelberg, Germany.
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Yang S, Yang LM, Liao HM, Fang HJ, Ning ZS, Liao CS, Wu LW. Genetic analysis of developmental and epileptic encephalopathy caused by novel biallelic SZT2 gene mutations in three Chinese Han infants: a case series and literature review. Neurol Sci 2022; 43:5039-5048. [DOI: 10.1007/s10072-022-06038-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/21/2022] [Indexed: 11/28/2022]
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Calhoun JD, Aziz MC, Happ HC, Gunti J, Gleason C, Mohamed N, Zeng K, Hiller M, Bryant E, Mithal DS, Bellinski I, Kinsley L, Grimmel M, Schwaibold EMC, Smith-Hicks C, Chassevent A, Scala M, Accogli A, Torella A, Striano P, Capra V, Bird LM, Ben-Sahra I, Ekhilevich N, Hershkovitz T, Weiss K, Millichap J, Gerard EE, Carvill GL. mTORC1 functional assay reveals SZT2 loss-of-function variants and a founder in-frame deletion. Brain 2022; 145:1939-1948. [PMID: 35773235 PMCID: PMC9630660 DOI: 10.1093/brain/awab451] [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: 04/08/2021] [Revised: 10/27/2021] [Accepted: 11/19/2021] [Indexed: 11/14/2022] Open
Abstract
Biallelic pathogenic variants in SZT2 result in a neurodevelopmental disorder with shared features, including early-onset epilepsy, developmental delay, macrocephaly, and corpus callosum abnormalities. SZT2 is as a critical scaffolding protein in the amino acid sensing arm of the mTORC1 signalling pathway. Due to its large size (3432 amino acids), lack of crystal structure, and absence of functional domains, it is difficult to determine the pathogenicity of SZT2 missense and in-frame deletions, but these variants are increasingly detected and reported by clinical genetic testing in individuals with epilepsy. To exemplify this latter point, here we describe a cohort of 12 individuals with biallelic SZT2 variants and phenotypic overlap with SZT2-related neurodevelopmental disorders. However, the majority of individuals carried one or more SZT2 variants of uncertain significance (VUS), highlighting the need for functional characterization to determine, which, if any, of these VUS were pathogenic. Thus, we developed a novel individualized platform to identify SZT2 loss-of-function variants in the context of mTORC1 signalling and reclassify VUS. Using this platform, we identified a recurrent in-frame deletion (SZT2 p.Val1984del) which was determined to be a loss-of-function variant and therefore likely pathogenic. Haplotype analysis revealed that this single in-frame deletion is a founder variant in those of Ashkenazi Jewish ancestry. Moreover, this approach allowed us to tentatively reclassify all of the VUS in our cohort of 12 individuals, identifying five individuals with biallelic pathogenic or likely pathogenic variants. Clinical features of these five individuals consisted of early-onset seizures (median 24 months), focal seizures, developmental delay and macrocephaly similar to previous reports. However, we also show a widening of the phenotypic spectrum, as none of the five individuals had corpus callosum abnormalities, in contrast to previous reports. Overall, we present a rapid assay to resolve VUS in SZT2, identify a founder variant in individuals of Ashkenazi Jewish ancestry, and demonstrate that corpus callosum abnormalities is not a hallmark feature of this condition. Our approach is widely applicable to other mTORopathies including the most common causes of the focal genetic epilepsies, DEPDC5, TSC1/2, MTOR and NPRL2/3.
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Affiliation(s)
- Jeffrey D Calhoun
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Miriam C Aziz
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Hannah C Happ
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Jonathan Gunti
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Colleen Gleason
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Najma Mohamed
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Kristy Zeng
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Meredith Hiller
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Emily Bryant
- Ann and Robert H. Lurie Children's Hospital of Chicago Epilepsy Center and Division of Neurology, Chicago, IL 60610, USA
| | - Divakar S Mithal
- Ann and Robert H. Lurie Children's Hospital of Chicago Epilepsy Center and Division of Neurology, Chicago, IL 60610, USA
| | - Irena Bellinski
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Lisa Kinsley
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Mona Grimmel
- Ann & Robert H. Lurie Children's Hospital of Chicago, Department of Pediatrics, Epilepsy Center and Division of Neurology, Chicago, IL 60610, USA
| | - Eva M C Schwaibold
- Institute of Human Genetics, Heidelberg University, Heidelberg 69120, Germany
| | - Constance Smith-Hicks
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Anna Chassevent
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Marcello Scala
- Giannina Gaslini Children's Hospital, Genova, GE 16147, Italy.,Medical Genetic Unit, IRCCS Istituto G.Gaslini, 16147 Genoa, Italy
| | - Andrea Accogli
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montreal, QC, H4A 3J1, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Annalaura Torella
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre (MUHC), Montreal, QC, H4A 3J1, Canada
| | - Pasquale Striano
- Giannina Gaslini Children's Hospital, Genova, GE 16147, Italy.,Medical Genetic Unit, IRCCS Istituto G.Gaslini, 16147 Genoa, Italy
| | - Valeria Capra
- Giannina Gaslini Children's Hospital, Genova, GE 16147, Italy.,Medical Genetic Unit, IRCCS Istituto G.Gaslini, 16147 Genoa, Italy
| | - Lynne M Bird
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Issam Ben-Sahra
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, NA 80078, Italy
| | - Nina Ekhilevich
- San Diego Department of Pediatrics and Rady Children's Hospital Division of Dysmorphology/Genetics, University of California, San Diego, CA 92161, USA
| | - Tova Hershkovitz
- San Diego Department of Pediatrics and Rady Children's Hospital Division of Dysmorphology/Genetics, University of California, San Diego, CA 92161, USA.,Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Karin Weiss
- San Diego Department of Pediatrics and Rady Children's Hospital Division of Dysmorphology/Genetics, University of California, San Diego, CA 92161, USA.,Department of Biochemistry and Molecular Genetics, Northwestern Feinberg School of Medicine, Chicago, IL 60610, USA
| | - John Millichap
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA.,Ann and Robert H. Lurie Children's Hospital of Chicago Epilepsy Center and Division of Neurology, Chicago, IL 60610, USA
| | - Elizabeth E Gerard
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA
| | - Gemma L Carvill
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60610, USA.,Genetics Institute, Rambam Medical Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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Cherian A, Divya KP, Pavuluri H, Thomas B. The Dysfunctional Gangway: SZT2-associated Epilepsy with Thick Corpus Callosum. J Pediatr Neurosci 2021; 16:289-292. [PMID: 36531768 PMCID: PMC9757505 DOI: 10.4103/jpn.jpn_128_20] [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: 05/22/2020] [Accepted: 07/04/2020] [Indexed: 06/17/2023] Open
Abstract
Mutations in seizure threshold 2 (SZT2) gene on chromosome 1p34.2 are an of late identified cause of epilepsy and epileptic encephalopathy. We report a 3-year-old girl who presented with developmental delay, dysmorphic facies, refractory seizures, and subsequent developmental regression. Despite significant multifocal epileptiform abnormalities on her electroencephalogram, she had a paucity of generalized discharges indicating a functional deficiency of corpus callosum inspite of its increased thickness seen on magnetic resonance imaging. Her clinical exome sequencing revealed a homozygous single base pair duplication in the SZT2 gene that resulted in a frameshift mutation and premature truncation of the protein. Our case emphasizes the role of SZT2 gene in the diagnostic algorithm of early childhood refractory epilepsy especially in the context of a thick yet dysfunctional corpus callosum.
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Affiliation(s)
- Ajith Cherian
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
| | - Kalikavil Puthanveedu Divya
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
| | - Harini Pavuluri
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
| | - Bejoy Thomas
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
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Trivisano M, Rivera M, Terracciano A, Ciolfi A, Napolitano A, Pepi C, Calabrese C, Digilio MC, Tartaglia M, Curatolo P, Vigevano F, Specchio N. Developmental and epileptic encephalopathy due to SZT2 genomic variants: Emerging features of a syndromic condition. Epilepsy Behav 2020; 108:107097. [PMID: 32402703 DOI: 10.1016/j.yebeh.2020.107097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
Abstract
Seizure threshold 2 (SZT2) gene mutations have been associated with developmental and epileptic encephalopathies (DEEs). Following a literature review, we collected 22 patients and identified the main clinical features related to SZT2 variants that are epilepsy with onset within the first years of life, intellectual disability (ID), macrocephaly with dysmorphic facial features, corpus callosum (CC) shape abnormalities, and cortical migration disorders. Moreover, we identified the c.7825T>G homozygous missense variant in SZT2 in two female siblings presenting with focal seizures, mild-moderate ID, behavioral disturbances, and facial dysmorphisms. Interictal Electroencephalogram (EEG) and ictal EEG were both informative and revealed, respectively, temporal bilateral asynchronous slow and epileptiform abnormalities and a focal onset in both of them. Neuroimaging study revealed a thick and abnormally shaped CC. Seizure threshold 2 has been identified as a component of the KICSTOR complex, a newly recognized protein complex involved in the mammalian target of rapamycin (mTOR) pathway. mTOR signaling dysregulation represents common pathogenetic mechanisms that can explain the presence of both epileptogenesis and ID. Even if few cases had been reported, a new clinical phenotype is emerging, and recent hypothesis of hyperactivation of mTORC1 signaling might also open to targeted treatments, challenging an early diagnosis as of paramount importance.
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Affiliation(s)
- Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Manuel Rivera
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Departamento de Neuropediatria, Fleni, Montañeses 2325, C1428AQK Ciudad de Buenos Aires, Argentina
| | | | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Antonio Napolitano
- Neuroradiology Unit, Department of Imaging, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Chiara Pepi
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Via Montpellier 1, 00133 Rome, Italy
| | - Costanza Calabrese
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Cristina Digilio
- Medical Genetics, Department of Pediatrics, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Via Montpellier 1, 00133 Rome, Italy
| | - Federico Vigevano
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome; Member of European Reference Network EpiCARE
| | - Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Member of European Reference Network EpiCARE.
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A framework for an evidence-based gene list relevant to autism spectrum disorder. Nat Rev Genet 2020; 21:367-376. [PMID: 32317787 DOI: 10.1038/s41576-020-0231-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) is often grouped with other brain-related phenotypes into a broader category of neurodevelopmental disorders (NDDs). In clinical practice, providers need to decide which genes to test in individuals with ASD phenotypes, which requires an understanding of the level of evidence for individual NDD genes that supports an association with ASD. Consensus is currently lacking about which NDD genes have sufficient evidence to support a relationship to ASD. Estimates of the number of genes relevant to ASD differ greatly among research groups and clinical sequencing panels, varying from a few to several hundred. This Roadmap discusses important considerations necessary to provide an evidence-based framework for the curation of NDD genes based on the level of information supporting a clinically relevant relationship between a given gene and ASD.
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Sun X, Zhong X, Li T. Novel SZT2 mutations in three patients with developmental and epileptic encephalopathies. Mol Genet Genomic Med 2019; 7:e926. [PMID: 31397114 PMCID: PMC6732301 DOI: 10.1002/mgg3.926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/15/2019] [Accepted: 07/26/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The seizure threshold 2 (SZT2) gene encodes a large, highly conserved protein that lowers seizure threshold and may also enhance epileptogenesis. In this study, three patients diagnosed with SZT2-related developmental and epileptic encephalopathies (DEEs) were reviewed aiming to expand knowledge of the genotype and phenotype of SZT2 mutations. METHODS Targeted next-generation sequencing was performed to identify pathogenic mutations in 205 cases with DEEs of unknown etiology. Detailed clinical and genetic data were collected from SZT2-associated patients. RESULTS Four novel mutations were found (c.1626 + 1G>A, c.5772dupA, c.4209C > A, c.7307_7308insG) in three patients. All the variants were inherited from their parents. Two patients were siblings and harbored the same mutations and presented developmental delay prior to the onset of seizures. All the individuals were diagnosed as DEEs, drug refractory epilepsy, and experienced status epilepticus (SE); one patient died of SE. One subject showed subependymal nodules as similar as those of tuberous sclerosis complex (TSC) in cranial magnetic resonance imaging (MRI). CONCLUSION Our results expand the genotype and phenotypes of SZT2-related DEEs, suggesting that SZT2 mutations play a role in developmental delay and epileptic encephalopathy, with high susceptibility to SE and relatively specific MRI findings.
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Affiliation(s)
- Xiaomin Sun
- Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Xuefei Zhong
- Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Tingsong Li
- Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Key Laboratory of Pediatrics in Chongqing, Chongqing, China.,Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
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