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Lou Y, Shi X, Su G, Guo Y, Gao L, Wang Y, Miao P, Feng J. Hemizygous splicing variant in CNKSR2 results in X-linked intellectual developmental disorder. Mol Genet Genomic Med 2024; 12:e2389. [PMID: 38337158 PMCID: PMC10858311 DOI: 10.1002/mgg3.2389] [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: 10/29/2023] [Revised: 01/08/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Intellectual disability (ID) refers to a childhood-onset neurodevelopmental disorder with a prevalence of approximately 1%-3%. METHODS We performed whole exome sequencing for the patient with ID. And the splicing variant we found was validated by minigene assay. RESULTS Here, we report a boy with ID caused by a variant of CNKSR2. His neurological examination revealed hypsarrhythmia via electroencephalography and a right temporal polar arachnoid cyst via brain magnetic resonance imaging. A novel splicing variant in the CNKSR2 gene (NM_014927.5, c.1657+1G>A) was discovered by exome sequencing. The variant caused a 166 bp intron retention between exons 14 and 15, which was validated by a minigene assay. The variant was not reported in public databases such as gnomAD and the Exome Aggregation Consortium. CONCLUSIONS The variant was predicted to be damaging to correct the translation of the CNKRS2 protein and was classified as likely pathogenic according to the ACMG guidelines.
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Affiliation(s)
- Yuting Lou
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
| | - Xinglei Shi
- Department of PediatricsSuichang Branch of the Second Affiliated Hospital School of Medicine, Zhejiang UniversityHangzhouChina
| | - Guofa Su
- Department of PediatricsSongyang Branch of the Second Affiliated Hospital School of Medicine, Zhejiang UniversityHangzhouChina
| | - Yufan Guo
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
| | - Liuyan Gao
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
| | - Ye Wang
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
| | - Pu Miao
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
| | - Jianhua Feng
- Department of PediatricsThe Second Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouChina
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Posar A, Visconti P. Continuous Spike-Waves during Slow Sleep Today: An Update. CHILDREN (BASEL, SWITZERLAND) 2024; 11:169. [PMID: 38397281 PMCID: PMC10887038 DOI: 10.3390/children11020169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/19/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
In the context of childhood epilepsy, the concept of continuous spike-waves during slow sleep (CSWS) includes several childhood-onset heterogeneous conditions that share electroencephalograms (EEGs) characterized by a high frequency of paroxysmal abnormalities during sleep, which have negative effects on the cognitive development and behavior of the child. These negative effects may have the characteristics of a clear regression or of a slowdown in development. Seizures are very often present, but not constantly. The above makes it clear why CSWS have been included in epileptic encephalopathies, in which, by definition, frequent EEG paroxysmal abnormalities have an unfavorable impact on cognitive functions, including socio-communicative skills, causing autistic features, even regardless of the presence of clinically overt seizures. Although several decades have passed since the original descriptions of the electroclinical condition of CSWS, there are still many areas that are little-known and deserve to be further studied, including the EEG diagnostic criteria, the most effective electrophysiological parameter for monitoring the role of the thalamus in CSWS pathogenesis, its long-term evolution, the nosographic location of Landau-Kleffner syndrome, standardized neuropsychological and behavioral assessments, and pharmacological and non-pharmacological therapies.
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Affiliation(s)
- Annio Posar
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Disturbi dello Spettro Autistico, 40139 Bologna, Italy;
- Department of Biomedical and Neuromotor Sciences, Bologna University, 40139 Bologna, Italy
| | - Paola Visconti
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Disturbi dello Spettro Autistico, 40139 Bologna, Italy;
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Whitney R, Go C, Abushama A, Jain P. CNKSR2-Related Developmental and Epileptic Encephalopathy with Spike-Wave Activation in Sleep: A Report of Two Additional Cases and Review of the Literature. Neurol India 2024; 72:129-137. [PMID: 38443014 DOI: 10.4103/ni.ni_1191_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/14/2022] [Indexed: 03/07/2024]
Abstract
CNKSR2 variants have been associated with X linked intellectual disability and epilepsy including developmental and epileptic encephalopathy with spike wave activation in sleep (D/EE SWAS) in males. We aimed to describe a sibling pair with a novel pathogenic variant in CNKSR2 with D/EE SWAS and review published cases of D/EE SWAS. A retrospective chart review and a comprehensive review of the literature were conducted. Two brothers with a novel pathogenic variant in the CNKSR2 gene (c. 114delG, p.Ile39SerfsX14) were identified. The epilepsy phenotype was similar to previous cases and was characterized by early onset seizures, nocturnal seizures (focal motor with/without impaired awareness), global developmental delay and language impairment, frontal central temporal predominant epileptiform discharges with a spike wave index >95%, and treatment resistance. However, phenotypic variability was observed and the younger brother had milder neuro developmental impairment, and the diagnosis of D/EE SWAS was made by surveillance electro encephalogram (EEG). Literature search yielded 23 cases, and their clinical/neuro physiological features are discussed. To conclude, CNKSR2 related D/EE SWAS may be early onset and occur before the age of 5 years in some. Early surveillance EEG may aid in diagnosis. Phenotypic variability was observed in our cases as well as sibling pairs in the literature, which may impact genetic counseling.
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Affiliation(s)
- Robyn Whitney
- Department of Paediatrics, Division of Neurology, McMaster University, Hamilton, ON, Canada
| | - Cristina Go
- Department of Paediatrics, Division of Neurology, Hospital for Sick Children (HSC), University of Toronto, Toronto, ON, Canada
| | - Ahmed Abushama
- Department of Paediatrics, Division of Neurology, Hospital for Sick Children (HSC), University of Toronto, Toronto, ON, Canada
| | - Puneet Jain
- Department of Paediatrics, Division of Neurology, Hospital for Sick Children (HSC), University of Toronto, Toronto, ON, Canada
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Brechtmann F, Bechtler T, Londhe S, Mertes C, Gagneur J. Evaluation of input data modality choices on functional gene embeddings. NAR Genom Bioinform 2023; 5:lqad095. [PMID: 37942285 PMCID: PMC10629286 DOI: 10.1093/nargab/lqad095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/07/2023] [Accepted: 09/28/2023] [Indexed: 11/10/2023] Open
Abstract
Functional gene embeddings, numerical vectors capturing gene function, provide a promising way to integrate functional gene information into machine learning models. These embeddings are learnt by applying self-supervised machine-learning algorithms on various data types including quantitative omics measurements, protein-protein interaction networks and literature. However, downstream evaluations comparing alternative data modalities used to construct functional gene embeddings have been lacking. Here we benchmarked functional gene embeddings obtained from various data modalities for predicting disease-gene lists, cancer drivers, phenotype-gene associations and scores from genome-wide association studies. Off-the-shelf predictors trained on precomputed embeddings matched or outperformed dedicated state-of-the-art predictors, demonstrating their high utility. Embeddings based on literature and protein-protein interactions inferred from low-throughput experiments outperformed embeddings derived from genome-wide experimental data (transcriptomics, deletion screens and protein sequence) when predicting curated gene lists. In contrast, they did not perform better when predicting genome-wide association signals and were biased towards highly-studied genes. These results indicate that embeddings derived from literature and low-throughput experiments appear favourable in many existing benchmarks because they are biased towards well-studied genes and should therefore be considered with caution. Altogether, our study and precomputed embeddings will facilitate the development of machine-learning models in genetics and related fields.
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Affiliation(s)
- Felix Brechtmann
- TUM School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
- Munich Center for Machine Learning, Munich, Germany
| | - Thibault Bechtler
- TUM School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
| | - Shubhankar Londhe
- TUM School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
| | - Christian Mertes
- TUM School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
- Munich Data Science Institute, Technical University of Munich, Garching, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Julien Gagneur
- TUM School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
- Computational Health Center, Helmholtz Center Munich, Neuherberg, Germany
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5
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Freibauer AE, RamachandranNair R, Jain P, Jones KC, Whitney R. The genetic landscape of developmental and epileptic encephalopathy with spike-and-wave activation in sleep. Seizure 2023; 110:119-125. [PMID: 37352690 DOI: 10.1016/j.seizure.2023.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/13/2023] [Accepted: 06/19/2023] [Indexed: 06/25/2023] Open
Abstract
OBJECTIVE Epileptic Encephalopathy / Developmental Epileptic Encephalopathy with spike-and-wave activation in sleep (EE/DEE-SWAS) is defined as an epilepsy syndrome characterized by neurodevelopmental regression temporally related to the emergence of significant activation of spike-wave discharges in EEG during sleep. The availability of genetic testing has made it evident that monogenic and chromosomal abnormalities play an aetiological role in the development of EE/DEE-SWAS. We sought to review the literature to better understand the genetic landscape of EE/DEE-SWAS. METHODS In this systematic review, we reviewed cases of EE/DEE-SWAS associated with a genetic aetiology, collecting information related to the underlying aetiology, onset, management, and EEG patterns. RESULTS One hundred and seventy-two cases of EE/DEE-SWAS were identified. Genetic causes of note included pathogenic variants in GRIN2A, ZEB2, CNKSR2 and chromosome 17q21.31 deletions, each of which demonstrated unique clinical characteristics, EEG patterns, and age of onset. Factors identified to raise suspicion of a potential genetic aetiology included the presentation of DEE-SWAS and onset of SWAS under the age of five years. Treatment of EE/DEE-SWAS due to genetic causes was diverse, including a combination of anti-seizure medications, steroids, and other clinical strategies, with no clear consensus on a preferred or superior treatment. Data collected was significantly heterogeneous, with a lack of consistent use of neuropsychology testing, EEG patterns, or use of established clinical definitions. CONCLUSIONS Uniformity concerning the new definition of EE/DEE-SWAS, guidelines for management and more frequent genetic screening will be needed to guide best practices for the treatment of patients with EE/DEE-SWAS.
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Affiliation(s)
- Alexander E Freibauer
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON, Canada
| | | | - Puneet Jain
- Epilepsy Program, Division of Neurology, Department of Paediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Kevin C Jones
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON, Canada.
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Serwe G, Kachaner D, Gagnon J, Plutoni C, Lajoie D, Duramé E, Sahmi M, Garrido D, Lefrançois M, Arseneault G, Saba-El-Leil MK, Meloche S, Emery G, Therrien M. CNK2 promotes cancer cell motility by mediating ARF6 activation downstream of AXL signalling. Nat Commun 2023; 14:3560. [PMID: 37322019 PMCID: PMC10272126 DOI: 10.1038/s41467-023-39281-z] [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: 10/20/2022] [Accepted: 05/31/2023] [Indexed: 06/17/2023] Open
Abstract
Cell motility is a critical feature of invasive tumour cells that is governed by complex signal transduction events. Particularly, the underlying mechanisms that bridge extracellular stimuli to the molecular machinery driving motility remain partially understood. Here, we show that the scaffold protein CNK2 promotes cancer cell migration by coupling the pro-metastatic receptor tyrosine kinase AXL to downstream activation of ARF6 GTPase. Mechanistically, AXL signalling induces PI3K-dependent recruitment of CNK2 to the plasma membrane. In turn, CNK2 stimulates ARF6 by associating with cytohesin ARF GEFs and with a novel adaptor protein called SAMD12. ARF6-GTP then controls motile forces by coordinating the respective activation and inhibition of RAC1 and RHOA GTPases. Significantly, genetic ablation of CNK2 or SAMD12 reduces metastasis in a mouse xenograft model. Together, this work identifies CNK2 and its partner SAMD12 as key components of a novel pro-motility pathway in cancer cells, which could be targeted in metastasis.
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Affiliation(s)
- Guillaume Serwe
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - David Kachaner
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Jessica Gagnon
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Cédric Plutoni
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Driss Lajoie
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Eloïse Duramé
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Malha Sahmi
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Damien Garrido
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Martin Lefrançois
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Geneviève Arseneault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Marc K Saba-El-Leil
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Sylvain Meloche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Gregory Emery
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada.
- Molecular Biology Program, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.
- Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.
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Maruo T, Mizutani K, Miyata M, Kuriu T, Sakakibara S, Takahashi H, Kida D, Maesaka K, Sugaya T, Sakane A, Sasaki T, Takai Y, Mandai K. s-Afadin binds to MAGUIN/Cnksr2 and regulates the localization of the AMPA receptor and glutamatergic synaptic response in hippocampal neurons. J Biol Chem 2023; 299:103040. [PMID: 36803960 PMCID: PMC10040811 DOI: 10.1016/j.jbc.2023.103040] [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: 03/22/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/19/2023] Open
Abstract
A hippocampal mossy fiber synapse implicated in learning and memory is a complex structure in which a presynaptic bouton attaches to the dendritic trunk by puncta adherentia junctions (PAJs) and wraps multiply branched spines. The postsynaptic densities (PSDs) are localized at the heads of each of these spines and faces to the presynaptic active zones. We previously showed that the scaffolding protein afadin regulates the formation of the PAJs, PSDs, and active zones in the mossy fiber synapse. Afadin has two splice variants: l-afadin and s-afadin. l-Afadin, but not s-afadin, regulates the formation of the PAJs but the roles of s-afadin in synaptogenesis remain unknown. We found here that s-afadin more preferentially bound to MAGUIN (a product of the Cnksr2 gene) than l-afadin in vivo and in vitro. MAGUIN/CNKSR2 is one of the causative genes for nonsyndromic X-linked intellectual disability accompanied by epilepsy and aphasia. Genetic ablation of MAGUIN impaired PSD-95 localization and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor surface accumulation in cultured hippocampal neurons. Our electrophysiological analysis revealed that the postsynaptic response to glutamate, but not its release from the presynapse, was impaired in the MAGUIN-deficient cultured hippocampal neurons. Furthermore, disruption of MAGUIN did not increase the seizure susceptibility to flurothyl, a GABAA receptor antagonist. These results indicate that s-afadin binds to MAGUIN and regulates the PSD-95-dependent cell surface localization of the AMPA receptor and glutamatergic synaptic responses in the hippocampal neurons and that MAGUIN is not involved in the induction of epileptic seizure by flurothyl in our mouse model.
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Affiliation(s)
- Tomohiko Maruo
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan; Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan; Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; Department of Biochemistry, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
| | - Kiyohito Mizutani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Toshihiko Kuriu
- Research and Development Center, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, Japan
| | - Shotaro Sakakibara
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; Department of Biochemistry, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
| | - Hatena Takahashi
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan
| | - Daichi Kida
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan
| | - Kouki Maesaka
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan
| | - Tsukiko Sugaya
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Ayuko Sakane
- Department of Biochemistry, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan; Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, Tokushima University, Tokushima, Japan
| | - Takuya Sasaki
- Department of Biochemistry, Tokushima University Graduate School of Medical Sciences, Tokushima, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
| | - Kenji Mandai
- Department of Molecular and Cellular Neurobiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan; Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
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Udaykumar N, Zaidi MAA, Rai A, Sen J. CNKSR2, a downstream mediator of retinoic acid signaling, modulates the Ras/Raf/MEK pathway to regulate patterning and invagination of the chick forebrain roof plate. Development 2023; 150:286897. [PMID: 36734326 DOI: 10.1242/dev.200857] [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: 04/13/2022] [Accepted: 01/03/2023] [Indexed: 02/04/2023]
Abstract
During embryonic development, the forebrain roof plate undergoes invagination, leading to separation of the cerebral hemispheres. Any defects in this process, in humans, lead to middle interhemispheric holoprosencephaly (MIH-HPE). In this study, we have identified a previously unreported downstream mediator of retinoic acid (RA) signaling, CNKSR2, which is expressed in the forebrain roof plate in the chick embryo. Knockdown of CNKSR2 affects invagination, cell proliferation and patterning of the roof plate, similar to the phenotypes observed upon inhibition of RA signaling. We further demonstrate that CNKSR2 functions by modulating the Ras/Raf/MEK signaling. This appears to be crucial for patterning of the forebrain roof plate and its subsequent invagination, leading to the formation of the cerebral hemispheres. Thus, a set of novel molecular players have been identified that regulate the morphogenesis of the avian forebrain.
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Affiliation(s)
- Niveda Udaykumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Mohd Ali Abbas Zaidi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Aishwarya Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Jonaki Sen
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
- Mehta Family Center for Engineering in Medicine (MFCEM), Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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Liu Y, Liang Z, Cai W, Shao Q, Pan Q. Case report: Phenotype expansion and analysis of TRIO and CNKSR2 variations. Front Neurol 2022; 13:948877. [PMID: 36105777 PMCID: PMC9465251 DOI: 10.3389/fneur.2022.948877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/05/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction TRIO and CNKSR2 have been demonstrated as the important regulators of RAC1. TRIO is a guanine exchange factor (GEF) and promotes RAC1 activity by accelerating the GDP to GTP exchange. CNKSR2 is a scaffold and adaptor protein and helps to maintain Rac1 GTP/GDP levels at a concentration conducive for dendritic spines formation. Dysregulated RAC1 activity causes synaptic function defects leading to neurodevelopmental disorders (NDDs), which manifest as intellectual disability, learning difficulties, and language disorders. Case presentation Here, we reported two cases with TRIO variation from one family and three cases with CNKSR2 variation from another family. The family with TRIO variation carries a novel heterozygous frameshift variant c.3506delG (p. Gly1169AlafsTer11), where a prenatal case and an apparently asymptomatic carrier mother with only enlarged left lateral ventricles were firstly reported. On the other hand, the CNKSR2 family carries a novel hemizygous non-sense variant c.1282C>T (p. Arg428*). Concurrently, we identified a novel phenotype never reported in known pathogenic CNKSR2 variants, that hydrocephalus and widening lateral ventricle in a 6-year-old male of this family. Furthermore, the genotype–phenotype relationship for TRIO, CNKSR2, and RAC1 was explored through a literature review. Conclusion The novel variants and unique clinical features of these two pedigrees will help expand our understanding of the genetic and phenotypic profile of TRIO- and CNKSR2-related diseases.
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Affiliation(s)
- Yuefang Liu
- Department of Clinical Genetics, Huai'an Maternity and Child Clinical College of Xuzhou Medical University, Huai'an, China
| | - Zhe Liang
- Department of Clinical Genetics, Huai'an Maternity and Child Clinical College of Xuzhou Medical University, Huai'an, China
| | - Weili Cai
- School of Medical Science and Laboratory Medicine, Jiangsu College of Nursing, Institute of Medical Genetics and Reproductive Immunity, Huai'an, China
- *Correspondence: Weili Cai
| | - Qixiang Shao
- School of Medical Science and Laboratory Medicine, Jiangsu College of Nursing, Institute of Medical Genetics and Reproductive Immunity, Huai'an, China
- Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Reproductive Sciences Institute, Jiangsu University, Zhenjiang, China
- Qixiang Shao
| | - Qiong Pan
- Department of Clinical Genetics, Huai'an Maternity and Child Clinical College of Xuzhou Medical University, Huai'an, China
- Qiong Pan
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10
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Functions of CNKSR2 and Its Association with Neurodevelopmental Disorders. Cells 2022; 11:cells11020303. [PMID: 35053419 PMCID: PMC8774548 DOI: 10.3390/cells11020303] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/05/2022] [Accepted: 01/13/2022] [Indexed: 02/04/2023] Open
Abstract
The Connector Enhancer of Kinase Suppressor of Ras-2 (CNKSR2), also known as CNK2 or MAGUIN, is a scaffolding molecule that contains functional protein binding domains: Sterile Alpha Motif (SAM) domain, Conserved Region in CNK (CRIC) domain, PSD-95/Dlg-A/ZO-1 (PDZ) domain, Pleckstrin Homology (PH) domain, and C-terminal PDZ binding motif. CNKSR2 interacts with different molecules, including RAF1, ARHGAP39, and CYTH2, and regulates the Mitogen-Activated Protein Kinase (MAPK) cascade and small GTPase signaling. CNKSR2 has been reported to control the development of dendrite and dendritic spines in primary neurons. CNKSR2 is encoded by the CNKSR2 gene located in the X chromosome. CNKSR2 is now considered as a causative gene of the Houge type of X-linked syndromic mental retardation (MRXHG), an X-linked Intellectual Disability (XLID) that exhibits delayed development, intellectual disability, early-onset seizures, language delay, attention deficit, and hyperactivity. In this review, we summarized molecular features, neuronal function, and neurodevelopmental disorder-related variations of CNKSR2.
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