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Suroliya V, Uppili B, Kumar M, Jha V, Srivastava AK, Faruq M. Identifying unstable CNG repeat loci in the human genome: a heuristic approach and implications for neurological disorders. Hum Genome Var 2024; 11:25. [PMID: 38871700 DOI: 10.1038/s41439-024-00281-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/08/2024] [Accepted: 05/14/2024] [Indexed: 06/15/2024] Open
Abstract
Tandem nucleotide repeat (TNR) expansions, particularly the CNG nucleotide configuration, are associated with a variety of neurodegenerative disorders. In this study, we aimed to identify novel unstable CNG repeat loci associated with the neurogenetic disorder spinocerebellar ataxia (SCA). Using a computational approach, 15,069 CNG repeat loci in the coding and noncoding regions of the human genome were identified. Based on the feature selection criteria (repeat length >10 and functional location of repeats), we selected 52 repeats for further analysis and evaluated the repeat length variability in 100 control subjects. A subset of 19 CNG loci observed to be highly variable in control subjects was selected for subsequent analysis in 100 individuals with SCA. The genes with these highly variable repeats also exhibited higher gene expression levels in the brain according to the tissue expression dataset (GTEx). No pathogenic expansion events were identified in patient samples, which is a limitation given the size of the patient group examined; however, these loci contain potential risk alleles for expandability. Recent studies have implicated GLS, RAI1, GIPC1, MED15, EP400, MEF2A, and CNKSR2 in neurological diseases, with GLS, GIPC1, MED15, RAI1, and MEF2A sharing the same repeat loci reported in this study. This finding validates the approach of evaluating repeat loci in different populations and their possible implications for human pathologies.
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Affiliation(s)
- Varun Suroliya
- Department of Neurology, All India Institute of Medical Sciences, Ansari Nagar, Delhi, 110020, India
| | - Bharathram Uppili
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy for Scientific and Innovative Research, Ghaziabad, 201002, India
| | - Manish Kumar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
- Academy for Scientific and Innovative Research, Ghaziabad, 201002, India
| | - Vineet Jha
- Persistent LABS, Persistent Systems Ltd., Pune, Maharashtra, India
| | - Achal K Srivastava
- Department of Neurology, All India Institute of Medical Sciences, Ansari Nagar, Delhi, 110020, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India.
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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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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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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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Ito H, Morishita R, Noda M, Ishiguro T, Nishikawa M, Nagata KI. The synaptic scaffolding protein CNKSR2 interacts with CYTH2 to mediate hippocampal granule cell development. J Biol Chem 2021; 297:101427. [PMID: 34800437 DOI: 10.1016/j.jbc.2021.101427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 11/25/2022] Open
Abstract
CNKSR2 is a synaptic scaffolding molecule that is encoded by the CNKSR2 gene located on the X chromosome. Heterozygous mutations to CNKSR2 in humans are associated with intellectual disability and epileptic seizures, yet the cellular and molecular roles for CNKSR2 in nervous system development and disease remain poorly characterized. Here, we identify a molecular complex comprising CNKSR2 and the guanine nucleotide exchange factor (GEF) for ARF small GTPases, CYTH2, that is necessary for the proper development of granule neurons in the mouse hippocampus. Notably, we show that CYTH2 binding prevents proteasomal degradation of CNKSR2. Furthermore, to explore the functional significance of coexpression of CNKSR2 and CYTH2 in the soma of granule cells within the hippocampal dentate gyrus, we transduced mouse granule cell precursors in vivo with small hairpin RNAs (shRNAs) to silence CNKSR2 or CYTH2 expression. We found that such manipulations resulted in the abnormal localization of transduced cells at the boundary between the granule cell layer and the hilus. In both cases, CNKSR2-knockdown and CYTH2-knockdown cells exhibited characteristics of immature granule cells, consistent with their putative roles in neuron differentiation. Taken together, our results demonstrate that CNKSR2 and its molecular interaction partner CYTH2 are necessary for the proper development of dentate granule cells within the hippocampus through a mechanism that involves the stabilization of a complex comprising these proteins.
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Affiliation(s)
- Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan.
| | - Rika Morishita
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan
| | - Mariko Noda
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan
| | - Tomoki Ishiguro
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan
| | - Masashi Nishikawa
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan; Department of Neurochemistry, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan.
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6
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Higa LA, Wardley J, Wardley C, Singh S, Foster T, Shen JJ. CNKSR2-related neurodevelopmental and epilepsy disorder: a cohort of 13 new families and literature review indicating a predominance of loss of function pathogenic variants. BMC Med Genomics 2021; 14:186. [PMID: 34266427 PMCID: PMC8281706 DOI: 10.1186/s12920-021-01033-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/01/2021] [Indexed: 11/25/2022] Open
Abstract
Background Pathogenic variants in connector enhancer of kinase suppressor of Ras-2 (CNKSR2) located on the X chromosome (Xp22.12) lead to a disorder characterized by developmental delay and a characteristic seizure phenotype. To date, 20 affected males representing 13 different pathogenic variants have been published. Case presentation We identified an 8-year-old male with seizures, abnormal electroencephalogram (EEG) with epileptiform abnormalities in the right hemisphere, and developmental delay with notable loss of speech following seizure onset. Additional concerns include multiple nighttime awakenings, hyperactivity, and autism spectrum disorder. Genetic testing identified a de novo pathogenic nonsense variant in CNKSR2. Through an active family support group, an additional 12 males are described, each harboring a different CNKSR2 variant. The clinical presentation and natural history consistently show early developmental delay, sleep disturbances, and seizure onset in childhood that is initially intractable but later becomes better controlled. Virtually all of the pathogenic variants are predicted to be loss of function, including genomic deletions, nonsense variants, splice site mutations, and small insertions or deletions. Conclusions This expanded knowledge, combined with functional studies and work with animal models currently underway, will enable a better understanding and improved ability to care for individuals with CNKSR2-related neurodevelopmental and epilepsy disorder. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-021-01033-7.
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Affiliation(s)
- Leigh Ann Higa
- Department of Pediatrics, Community Regional Medical Center, Fresno, CA, USA.,Division of Genomic Medicine, Department of Pediatrics, MIND Institute, University of California, Davis, 2825 50th Street, Sacramento, CA, 95817, USA
| | | | | | - Susan Singh
- CNKSR2 Family Support Group, Sanger, CA, USA
| | - Timothy Foster
- Division of Pediatric Neurology, Department of Pediatrics, UCSF Fresno, Fresno, CA, USA
| | - Joseph J Shen
- Division of Genetics, Department of Pediatrics, UCSF Fresno, Fresno, CA, USA. .,Division of Genomic Medicine, Department of Pediatrics, MIND Institute, University of California, Davis, 2825 50th Street, Sacramento, CA, 95817, USA.
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7
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Brand BA, Blesson AE, Smith-Hicks CL. The Impact of X-Chromosome Inactivation on Phenotypic Expression of X-Linked Neurodevelopmental Disorders. Brain Sci 2021; 11:brainsci11070904. [PMID: 34356138 PMCID: PMC8305405 DOI: 10.3390/brainsci11070904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 12/20/2022] Open
Abstract
Nearly 20% of genes located on the X chromosome are associated with neurodevelopmental disorders (NDD) due to their expression and role in brain functioning. Given their location, several of these genes are either subject to or can escape X-chromosome inactivation (XCI). The degree to which genes are subject to XCI can influence the NDD phenotype between males and females. We provide a general review of X-linked NDD genes in the context of XCI and detailed discussion of the sex-based differences related to MECP2 and FMR1, two common X-linked causes of NDD that are subject to XCI. Understanding the effects of XCI on phenotypic expression of NDD genes may guide the development of stratification biomarkers in X-linked disorders.
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Affiliation(s)
- Boudewien A Brand
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Alyssa E Blesson
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Constance L. Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Correspondence:
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8
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Kang Q, Yang L, Liao H, Wu L, Chen B, Yang S, Kuang X, Yang H, Liao C. CNKSR2 gene mutation leads to Houge type of X-linked syndromic mental retardation: A case report and review of literature. Medicine (Baltimore) 2021; 100:e26093. [PMID: 34114993 PMCID: PMC8202604 DOI: 10.1097/md.0000000000026093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/06/2021] [Indexed: 01/04/2023] Open
Abstract
RATIONALE Mutations of connector enhancer of kinase suppressor of Ras-2 (CNKSR2) gene were identified as the cause of Houge type of X-linked syndromic mental retardation. The mutations of CNKSR2 gene are rare, we reporta patient carrying a novel nonsense mutation of CNKSR2,c.625C > T(p.Gln209∗) and review the clinical features and mutations of CNKSR2 gene for this rare condition considering previous literature. PATIENT CONCERNS We report a case of a 7-year and 5-month-old Chinese patient with clinical symptoms of intellectual disability, language defect, epilepsy and hyperactivity. Genetic study revealed a novel nonsense variant of CNKSR2, which has not been reported yet. DIAGNOSIS According to clinical manifestations, genetic pattern and ACMG classification of mutation site as Class 1-cause disease, the patient was diagnosed as Houge type of X-linked syndromic mental retardation caused by CNKSR2 gene mutation. INTERVENTIONS The patient was administrated with a gradual titration of valproic acid (VPA). OUTCOMES On administration of valproic acid, he had no further seizures. LESSONS This is the first time to report a nonsense variant in CNKSR2, c.625C > T(p.Gln209∗), this finding could expand the spectrum of CNKSR2 mutations and might also support the further study of Houge type of X-linked syndromic mental retardation.
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9
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Wilkinson B, Coba MP. Molecular architecture of postsynaptic Interactomes. Cell Signal 2020; 76:109782. [PMID: 32941943 DOI: 10.1016/j.cellsig.2020.109782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 01/02/2023]
Abstract
The postsynaptic density (PSD) plays an essential role in the organization of the synaptic signaling machinery. It contains a set of core scaffolding proteins that provide the backbone to PSD protein-protein interaction networks (PINs). These core scaffolding proteins can be seen as three principal layers classified by protein family, with DLG proteins being at the top, SHANKs along the bottom, and DLGAPs connecting the two layers. Early studies utilizing yeast two hybrid enabled the identification of direct protein-protein interactions (PPIs) within the multiple layers of scaffolding proteins. More recently, mass-spectrometry has allowed the characterization of whole interactomes within the PSD. This expansion of knowledge has further solidified the centrality of core scaffolding family members within synaptic PINs and provided context for their role in neuronal development and synaptic function. Here, we discuss the scaffolding machinery of the PSD, their essential functions in the organization of synaptic PINs, along with their relationship to neuronal processes found to be impaired in complex brain disorders.
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Affiliation(s)
- Brent Wilkinson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Marcelo P Coba
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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Disease-associated synaptic scaffold protein CNK2 modulates PSD size and influences localisation of the regulatory kinase TNIK. Sci Rep 2020; 10:5709. [PMID: 32235845 PMCID: PMC7109135 DOI: 10.1038/s41598-020-62207-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/05/2020] [Indexed: 01/13/2023] Open
Abstract
Scaffold proteins are responsible for structural organisation within cells; they form complexes with other proteins to facilitate signalling pathways and catalytic reactions. The scaffold protein connector enhancer of kinase suppressor of Ras 2 (CNK2) is predominantly expressed in neural tissues and was recently implicated in X-linked intellectual disability (ID). We have investigated the role of CNK2 in neurons in order to contribute to our understanding of how CNK2 alterations might cause developmental defects, and we have elucidated a functional role for CNK2 in the molecular processes that govern morphology of the postsynaptic density (PSD). We have also identified novel CNK2 interaction partners and explored their functional interdependency with CNK2. We focussed on the novel interaction partner TRAF2- and NCK-interacting kinase TNIK, which is also associated with ID. Both CNK2 and TNIK are expressed in neuronal dendrites and concentrated in dendritic spines, and staining with synaptic markers indicates a clear postsynaptic localisation. Importantly, our data highlight that CNK2 plays a role in directing TNIK subcellular localisation, and in neurons, CNK2 participates in ensuring that this multifunctional kinase is present in the correct place at desirable levels. In summary, our data indicate that CNK2 expression is critical for modulating PSD morphology; moreover, our study highlights that CNK2 functions as a scaffold with the potential to direct the localisation of regulatory proteins within the cell. Importantly, we describe a novel link between CNK2 and the regulatory kinase TNIK, and provide evidence supporting the idea that alterations in CNK2 localisation and expression have the potential to influence the behaviour of TNIK and other important regulatory molecules in neurons.
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Bonardi CM, Mignot C, Serratosa JM, Giraldez BG, Moretti R, Rudolf G, Reale C, Gellert PM, Johannesen KM, Lesca G, Tassinari CA, Gardella E, Møller RS, Rubboli G. Expanding the clinical and EEG spectrum of CNKSR2-related encephalopathy with status epilepticus during slow sleep (ESES). Clin Neurophysiol 2020; 131:1030-1039. [PMID: 32197126 DOI: 10.1016/j.clinph.2020.01.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/11/2020] [Accepted: 01/13/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To investigate the clinical and EEG features of Encephalopathy with Status Epilepticus during slow Sleep (ESES) related to CNKSR2 pathogenic variants. METHODS Detailed clinical history, repeated wakefulness/overnight sleep EEGs, brain MRI were collected in five patients, including one female, with CNKSR2-related ESES. RESULTS Neurodevelopment in infancy was normal in two patients, delayed in three. Epilepsy onset (age range: 2-6 years) was associated with appearance or aggravation of cognitive impairment, language regression and/or behavioral disorders. Worsening of epilepsy and of cognitive/behavioral disturbances paralleled by enhancement of non-rapid eye movement (NREM) sleep-related, frontally predominant, EEG epileptic discharges [spike-wave-index (SWI): range 60-96%] was consistent with ESES. In three patients, episodes of absence status epilepticus or aggravation of atypical absences occurred, in this latter case associated with striking increment of awake SWI. Speech/oro-motor dyspraxia was diagnosed in four patients. In two patients, long-term follow-up showed epilepsy remission and persistence of mild/moderate cognitive disorders and behavioral disturbances into adulthood. CONCLUSIONS Novel findings of our study are occurrence also in females, normal neurodevelopment before epilepsy onset, epilepsy aggravation associated with enhanced awake SWI, mild/moderate evolution in adulthood and language disorder due to speech/oro-motor dyspraxia. SIGNIFICANCE Our findings expand the phenotypic spectrum of CNKSR2-related ESES.
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Affiliation(s)
- Claudia M Bonardi
- Danish Epilepsy Centre, Dianalund, Denmark; Department of Woman's and Child's Health, University Hospital of Padua, Italy.
| | - Cyril Mignot
- APHP, Groupe Hospitalier Pitié Salpêtrière, Unité Fonctionnelle de Génétique Médicale, Paris, France; Centre de Référence Déficiences Intellectuelles de Causes Rares, Paris, France; INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France.
| | - Jose M Serratosa
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
| | - Beatriz G Giraldez
- Neurology Laboratory and Epilepsy Unit, Department of Neurology, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
| | | | - Gabrielle Rudolf
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS U7104, INSERM U1258 Illkirch 67400, France; Department of Neurology, Strasbourg University Hospital, Université de Strasbourg Strasbourg, France.
| | - Chiara Reale
- Danish Epilepsy Centre, Dianalund, Denmark; Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.
| | | | | | - Gaetan Lesca
- Hospices Civils de Lyon, Service de Génétique, CHU de Lyon, Lyon, France.
| | | | - Elena Gardella
- Danish Epilepsy Centre, Dianalund, Denmark; Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark.
| | - Rikke S Møller
- Danish Epilepsy Centre, Dianalund, Denmark; Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark.
| | - Guido Rubboli
- Danish Epilepsy Centre, Dianalund, Denmark; University of Copenhagen, Copenhagen, Denmark.
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12
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Polla DL, Saunders HR, de Vries BBA, van Bokhoven H, de Brouwer APM. A de novo variant in the X-linked gene CNKSR2 is associated with seizures and mild intellectual disability in a female patient. Mol Genet Genomic Med 2019; 7:e00861. [PMID: 31414730 PMCID: PMC6785448 DOI: 10.1002/mgg3.861] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/03/2019] [Accepted: 07/05/2019] [Indexed: 01/18/2023] Open
Abstract
Background Eight different deletions and point variants of the X‐chromosomal gene CNKSR2 have been reported in families with males presenting intellectual disability (ID) and epilepsy. Obligate carrier females with a frameshift variant in the N‐terminal protein coding part of CNKSR2 or with a deletion of the complete gene are not affected. Only for one C‐terminal nonsense variant, two carrier females were mildly affected by seizures without or with mild motor and language delay. Methods Exome sequencing was performed in one female child of a Dutch family, presenting seizures, mild ID, facial dysmorphisms, and abnormalities of the extremities. Potential causative variants were validated by Sanger sequencing. X‐chromosome‐inactivation (XCI) analysis was performed by methylation‐sensitive PCR and fragment‐length analysis of the androgen‐receptor CAG repeat polymorphism. Results We identified a de novo variant, c.2304G>A (p.(Trp768*)), in the C‐terminal protein coding part of the X‐chromosomal gene CNKSR2 in a female patient with seizures and mild ID. Sanger sequencing confirmed the presence of this nonsense variant. XCI analysis showed a mild skewing of X inactivation (20:80) in the blood of our patient. Our variant is the second C‐terminal–affecting CNKSR2 variant described in neurologically affected females. Conclusion Our results indicate that CNKSR2 nonsense variants in the C‐terminal coding part can result in ID with seizures in female variant carriers.
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Affiliation(s)
- Daniel L Polla
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,CAPES Foundation, Ministry of Education of Brazil, Brasília, Brazil
| | - Harriet R Saunders
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bert B A de Vries
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arjan P M de Brouwer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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