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Charfi Triki C, Zouari Mallouli S, Ben Jdila M, Ben Said M, Kamoun Feki F, Weckhuysen S, Masmoudi S, Fakhfakh F. First report of Tunisian patients with CDKL5-related encephalopathy. Epilepsia Open 2024; 9:906-917. [PMID: 37701975 PMCID: PMC11145601 DOI: 10.1002/epi4.12824] [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: 02/06/2023] [Accepted: 09/09/2023] [Indexed: 09/14/2023] Open
Abstract
OBJECTIVE Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) are associated with a wide spectrum of clinical presentations. Early-onset epileptic encephalopathy (EOEE) is the most recognized phenotype. Here we describe phenotypic features in eight Tunisian patients with CDKL5-related encephalopathy. METHODS We included all cases with clinical features consistent with CDKL5-related encephalopathy: infantile epileptic spasm, acquired microcephaly, movement disorders and visual impairment. We collected data about seizure types, electroencephalogram, magnetic resonance imaging, and metabolic analysis. The diagnosis of CDKL5 mutation was made thanks to Sanger sequencing with an ABI PRISM 3100-Avant automated DNA sequencer using a Big Dye Terminator Cycle Sequencing Reaction Kit v1.1. and Next Generation Sequencing (NGS) since the development of a gene panel responsible for DEE within the framework of "Strengthening the Sfax University Expertise for diagnosis and management of epileptic encephalopathies". RESULTS We collected four boys and four girls aged meanly 6 years old with confirmed mutation on CDKL5 gene. Overall, we identified five de novo CDKL5 mutations including three Frame-shift mutations, one missense mutation, and a splicing variant. The mean age at first seizure onset was 4 months. The first seizure type was infantile epileptic spasm (4/8) followed by tonic (2/8) and myoclonic seizures (2/8). Out of eight cases, four exhibited two stages epileptic course while epilepsy in three other patients progressed on three stages. Regarding development, most cases (6/8) had psychomotor retardation from the start whilst the two others showed psychomotor regression with the onset of seizures. Additional clinical features included visual impairment (7/8), tone abnormalities (7/8), stereotypies (7/8), and acquired microcephaly (6/8). SIGNIFICANCE Our present report delineates an unusual phenotype of CDKL5-related encephalopathy with male gender predominance and delayed onset epilepsy. It interestingly described new phenotypic features and uncommon benign developmental profiles in boys, different patterns of CDKL5-epilepsy, neuroimaging findings, and CDKL5 mutational spectrum.
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Affiliation(s)
- Chahnez Charfi Triki
- Child Neurology Department, Hedi Chaker Sfax University Hospital, and Research Laboratory LR19ES15University of SfaxSfaxTunisia
| | - Salma Zouari Mallouli
- Child Neurology Department, Hedi Chaker Sfax University Hospital, and Research Laboratory LR19ES15University of SfaxSfaxTunisia
| | - Marwa Ben Jdila
- Laboratory of Molecular and Functional Genetics, Faculty of Science of SfaxUniversity of SfaxSfaxTunisia
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of SfaxUniversity of SfaxSfaxTunisia
| | - Fatma Kamoun Feki
- Child Neurology Department, Hedi Chaker Sfax University Hospital, and Research Laboratory LR19ES15University of SfaxSfaxTunisia
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIBUniversity of AntwerpAntwerpBelgium
- Department of NeurologyAntwerp University HospitalAntwerpBelgium
- Translational Neurosciences, Faculty of Medicine and Health ScienceUniversity of AntwerpAntwerpBelgium
| | - Sabeur Masmoudi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of SfaxUniversity of SfaxSfaxTunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of SfaxUniversity of SfaxSfaxTunisia
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Bernardo P, Cuccurullo C, Rubino M, De Vita G, Terrone G, Bilo L, Coppola A. X-Linked Epilepsies: A Narrative Review. Int J Mol Sci 2024; 25:4110. [PMID: 38612920 PMCID: PMC11012983 DOI: 10.3390/ijms25074110] [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: 03/11/2024] [Revised: 04/03/2024] [Accepted: 04/06/2024] [Indexed: 04/14/2024] Open
Abstract
X-linked epilepsies are a heterogeneous group of epileptic conditions, which often overlap with X-linked intellectual disability. To date, various X-linked genes responsible for epilepsy syndromes and/or developmental and epileptic encephalopathies have been recognized. The electro-clinical phenotype is well described for some genes in which epilepsy represents the core symptom, while less phenotypic details have been reported for other recently identified genes. In this review, we comprehensively describe the main features of both X-linked epileptic syndromes thoroughly characterized to date (PCDH19-related DEE, CDKL5-related DEE, MECP2-related disorders), forms of epilepsy related to X-linked neuronal migration disorders (e.g., ARX, DCX, FLNA) and DEEs associated with recently recognized genes (e.g., SLC9A6, SLC35A2, SYN1, ARHGEF9, ATP6AP2, IQSEC2, NEXMIF, PIGA, ALG13, FGF13, GRIA3, SMC1A). It is often difficult to suspect an X-linked mode of transmission in an epilepsy syndrome. Indeed, different models of X-linked inheritance and modifying factors, including epigenetic regulation and X-chromosome inactivation in females, may further complicate genotype-phenotype correlations. The purpose of this work is to provide an extensive and updated narrative review of X-linked epilepsies. This review could support clinicians in the genetic diagnosis and treatment of patients with epilepsy featuring X-linked inheritance.
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Affiliation(s)
- Pia Bernardo
- Pediatric Psychiatry and Neurology Unit, Department of Neurosciences, Santobono-Pausilipon Children’s Hospital, 80129 Naples, Italy
| | - Claudia Cuccurullo
- Neurology and Stroke Unit, Ospedale del Mare Hospital, ASL Napoli 1 Centro, 80147 Naples, Italy;
| | - Marica Rubino
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
| | - Gabriella De Vita
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy;
| | - Gaetano Terrone
- Child Neuropsychiatry Units, Department of Translational Medical Sciences, University Federico II of Naples, 80131 Naples, Italy;
| | - Leonilda Bilo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
| | - Antonietta Coppola
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
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Brito F, Lagos C, Cubillos J, Orellana J, Gajardo M, Böhme D, Encina G, Repetto GM. Genomic analysis in Chilean patients with suspected Rett syndrome: keep a broad differential diagnosis. Front Genet 2024; 15:1278198. [PMID: 38566815 PMCID: PMC10986174 DOI: 10.3389/fgene.2024.1278198] [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: 08/15/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction: Rett syndrome (RTT, MIM #312750) is a rare genetic disorder that leads to developmental regression and severe disability and is caused by pathogenic variants in the MECP2 gene. The diagnosis of RTT is based on clinical features and, depending on resources and access, on molecular confirmation. There is scarce information on molecular diagnosis from patients in Latin America, mostly due to limited availability and coverage of genomic testing. This pilot study aimed to implement genomic testing and characterize clinical and molecular findings in a group of Chilean patients with a clinical diagnosis of RTT. Methods: Twenty-eight patients with suspected RTT underwent characterization of phenotypic manifestations and molecular testing using Clinical Exome SolutionTM CES_V2 by SOPHiA Genetics. Data was analyzed using the commercial bioinformatics platform, SOPHiA DDMTM. A virtual panel of 34 genes, including MECP2 and other genes that are in the differential diagnosis of RTT, was used to prioritize initial analyses, followed by evaluation of the complete exome sequence data. Results: Twelve patients (42.8% of participants) had variants in MECP2, of which 11 (39.2%) were interpreted as pathogenic/likely pathogenic (P/LP), thus confirming the diagnosis of RTT in them. Eight additional patients (28.5%) harbored ten variants in nine other genes. Four of these variants were interpreted as P/LP (14.2%) (GRIN2B, MADD, TRPM3 and ZEB2) resulting in alternative neurodevelopmental diagnoses, and six were considered of uncertain significance. No evident candidate variant was found for eight patients. Discussion: This study allowed to reach a diagnosis in half of the participants. The diagnosis of RTT was confirmed in over a third of them, while others were found to have alternative neurodevelopmental disorders. Further evaluation is needed to identify the cause in those with negative or uncertain results. This information is useful for the patients, families, and clinicians to guide clinical management, even more so since the development of novel therapies for RTT. We also show the feasibility of implementing a step-wide approach to genomic testing in a setting with limited resources.
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Affiliation(s)
- Florencia Brito
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Catalina Lagos
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | | | - Joan Orellana
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Mallen Gajardo
- Escuela de Ingeniería, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
| | - Daniela Böhme
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Biosoluciones-UDD, Santiago, Chile
| | | | - Gabriela M. Repetto
- Rare Diseases Program, Center for Genetics and Genomics, Institute of Sciences and Innovation in Medicine, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
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Vorsanova SG, Demidova IA, Kolotii AD, Kurinnaia OS, Kravets VS, Soloviev IV, Yurov YB, Iourov IY. Klinefelter syndrome mosaicism in boys with neurodevelopmental disorders: a cohort study and an extension of the hypothesis. Mol Cytogenet 2022; 15:8. [PMID: 35248137 PMCID: PMC8897849 DOI: 10.1186/s13039-022-00588-z] [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: 02/02/2022] [Accepted: 02/21/2022] [Indexed: 01/14/2023] Open
Abstract
Abstract
Background
Klinefelter syndrome is a common chromosomal (aneuploidy) disorder associated with an extra X chromosome in males. Regardless of numerous studies dedicated to somatic gonosomal mosaicism, Klinefelter syndrome mosaicism (KSM) has not been systematically addressed in clinical cohorts. Here, we report on the evaluation of KSM in a large cohort of boys with neurodevelopmental disorders. Furthermore, these data have been used for an extension of the hypothesis, which we have recently proposed in a report on Turner’s syndrome mosaicism in girls with neurodevelopmental disorders.
Results
Klinefelter syndrome-associated karyotypes were revealed in 49 (1.1%) of 4535 boys. Twenty one boys (0.5%) were non-mosaic 47,XXY individuals. KSM was found in 28 cases (0.6%) and manifested as mosaic aneuploidy (50,XXXXXY; 49,XXXXY; 48,XXXY; 48,XXYY; 47,XXY; and 45,X were detected in addition to 47,XXY/46,XY) and mosaic supernumerary marker chromosomes derived from chromosome X (ring chromosomes X and rearranged chromosomes X). It is noteworthy that KSM was concomitant with Rett-syndrome-like phenotypes caused by MECP2 mutations in 5 boys (0.1%).
Conclusion
Our study provides data on the occurrence of KSM in neurodevelopmental disorders among males. Accordingly, it is proposed that KSM may be a possible element of pathogenic cascades in psychiatric and neurodegenerative diseases. These observations allowed us to extend the hypothesis proposed in our previous report on the contribution of somatic gonosomal mosaicism (Turner’s syndrome mosaicism) to the etiology of neurodevelopmental disorders. Thus, it seems to be important to monitor KSM (a possible risk factor or a biomarker for adult-onset multifactorial brain diseases) and analysis of neuromarkers for aging in individuals with Klinefelter syndrome. Cases of two or more supernumerary chromosomes X were all associated with KSM. Finally, Rett syndrome-like phenotypes associated with KSM appear to be more common in males with neurodevelopmental disorders than previously recognized.
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Siri B, Varesio C, Freri E, Darra F, Gana S, Mei D, Porta F, Fontana E, Galati G, Solazzi R, Niceta M, Veggiotti P, Alfei E. CDKL5 deficiency disorder in males: Five new variants and review of the literature. Eur J Paediatr Neurol 2021; 33:9-20. [PMID: 33989939 DOI: 10.1016/j.ejpn.2021.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 04/18/2021] [Accepted: 04/24/2021] [Indexed: 11/30/2022]
Abstract
The X-linked Cyclin-Dependent Kinase-Like 5 (CDKL5) gene encodes a serine-threonine kinase highly expressed in the developing brain. Loss of function of CDKL5 is pointed out to underlie the CDKL5 Deficiency Disorder (CDD), an X-linked dominant disease characterized by early-onset epileptic encephalopathy and developmental delay, usually affecting females more than males. To the best to our knowledge, only 45 males with CDD have been reported so far. Type and position of CDKL5 variants with different impact on the protein are reported to influence the clinical presentation. X-chromosome inactivation occurring in females and post-zygotic mosaicism in males are also believed to contribute to this variability. Based on these issues, genotype-phenotype correlations are still challenging. Here, we describe clinical features of five additional affected males with unreported CDKL5 variants, expanding the molecular spectrum of the disorder. We also reviewed the clinical profile of the previously reported 45 males with molecularly confirmed CDD. Severe developmental delay, cortical visual impairment, and early-onset refractory epilepsy characterize the CDD picture in males. By assessing the molecular spectrum, we confirm that germ-line truncating CDKL5 variants, equally distributed across the coding sequence, are the most recurrent mutations in CDD, and cause the worsen phenotype. While recurrence and relevance of missense substitutions within C-terminal remain still debated, disease-causing missense changes affecting the N-terminal catalytic domain correlate to a severe clinical phenotype. Finally, our data provide evidence that post-zygotic CDKL5 mosaicism may result in milder phenotypes and, at least in a subset of subjects, in variable response to antiepileptic treatments.
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Affiliation(s)
- Barbara Siri
- Department of Paediatrics, Ospedale Infantile Regina Margherita, University of Torino, Italy; Division of Metabolism, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Costanza Varesio
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Italy; Department of Brain and Behavioral Sciences, University of Pavia, Italy.
| | - Elena Freri
- Department of Paediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesca Darra
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, AOUI Verona, Verona, Italy
| | - Simone Gana
- Medical Genetics Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Davide Mei
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Italy
| | - Francesco Porta
- Department of Paediatrics, AOU Città della Salute e della Scienza di Torino, University of Torino, Italy
| | - Elena Fontana
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, AOUI Verona, Verona, Italy
| | - Giulia Galati
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, AOUI Verona, Verona, Italy
| | - Roberta Solazzi
- Department of Paediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marcello Niceta
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Pierangelo Veggiotti
- L. Sacco Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy; Paediatric Neurology Unit V. Buzzi Children's Hospital Milan, Italy
| | - Enrico Alfei
- Paediatric Neurology Unit V. Buzzi Children's Hospital Milan, Italy
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Ciccia LM, Scalia B, Venti V, Pizzo F, Pappalardo MG, La Mendola FMC, Falsaperla R, Praticò AD. CDKL5 Gene: Beyond Rett Syndrome. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
CDKL5 is a gene located in the X-chromosome (Xp22) encoding a serine/threonine kinase involved in various signaling pathways, implicated in cell proliferation, axon development, dendrite growth, synapse formation, and maintenance. Mutations occurring in this gene have been associated with drug-resistant early-onset epilepsy, with multiple seizures type, and deep cognitive and motor development delay with poor or absent speech, ataxic gait or inability to walk, hand stereotypies and in a few cases decrement of head growth. Many aspects remain unclear about the CDKL5 deficiency disorders, research will be fundamental to better understand the pathogenesis of neurological damage and consequently developed more targeted and profitable therapies, as there is not, at the present, a gene-based treatment and the seizures are in most of the cases drug resistant. In this article, we summarize the actual knowledge about CDKL5 gene function and mostly the consequence given by its dysfunction, also examining the possible therapeutic approaches.
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Affiliation(s)
- Lina Maria Ciccia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Bruna Scalia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Valeria Venti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Francesco Pizzo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Maria Grazia Pappalardo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | | | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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Terzic B, Cui Y, Edmondson AC, Tang S, Sarmiento N, Zaitseva D, Marsh ED, Coulter DA, Zhou Z. X-linked cellular mosaicism underlies age-dependent occurrence of seizure-like events in mouse models of CDKL5 deficiency disorder. Neurobiol Dis 2021; 148:105176. [PMID: 33197557 PMCID: PMC7856307 DOI: 10.1016/j.nbd.2020.105176] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/08/2020] [Indexed: 11/29/2022] Open
Abstract
CDKL5 deficiency disorder (CDD) is an infantile, epileptic encephalopathy presenting with early-onset seizures, intellectual disability, motor impairment, and autistic features. The disorder has been linked to mutations in the X-linked CDKL5, and mouse models of the disease recapitulate several aspects of CDD symptomology, including learning and memory impairments, motor deficits, and autistic-like features. Although early-onset epilepsy is one of the hallmark features of CDD, evidence of spontaneous seizure activity has only recently been described in Cdkl5-deficient heterozygous female mice, but the etiology, prevalence, and sex-specificity of this phenotype remain unknown. Here, we report the first observation of disturbance-associated seizure-like events in heterozygous female mice across two independent mouse models of CDD: Cdkl5 knockout mice and CDKL5 R59X knock-in mice. We find that both the prevalence and severity of this phenotype increase with aging, with a median onset around 28 weeks of age. Similar seizure-like events are not observed in hemizygous knockout male or homozygous knockout female littermates, suggesting that X-linked cellular mosaicism is a driving factor underlying these seizure-like events. Together, these findings not only contribute to our understanding of the effects of CDKL5 loss on seizure susceptibility, but also document a novel, pre-clinical phenotype for future therapeutic investigation.
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Affiliation(s)
- Barbara Terzic
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Yue Cui
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Andrew C Edmondson
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sheng Tang
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Child Neurology and CHOP Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicolas Sarmiento
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Daria Zaitseva
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric D Marsh
- Departments of Neuroscience, Neurology, and Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Child Neurology and CHOP Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Douglas A Coulter
- Departments of Neuroscience, Neurology, and Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Child Neurology and CHOP Research Institute, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Zhaolan Zhou
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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8
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CDKL5 Deficiency Disorder-A Complex Epileptic Encephalopathy. Brain Sci 2020; 10:brainsci10020107. [PMID: 32079229 PMCID: PMC7071516 DOI: 10.3390/brainsci10020107] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 12/31/2022] Open
Abstract
CDKL5 deficiency disorder (CDD) is a complex of clinical symptoms resulting from the presence of non-functional CDKL5 protein, i.e., serine-threonine kinase (previously referred to as STK9), or its complete absence. The clinical picture is characterized by epileptic seizures (that start within the first three months of life and most often do not respond to pharmacological treatment), epileptic encephalopathy secondary to seizures, and retardation of psychomotor development, which are often observed already in the first months of life. Due to the fact that CDKL5 is located on the X chromosome, the prevalence of CDD among women is four times higher than in men. However, the course is usually more severe among male patients. Recently, many clinical centers have analyzed this condition and provided knowledge on the function of CDKL5 protein, the natural history of the disease, therapeutic options, and their effectiveness and prognosis. The International CDKL5 Disorder Database was established in 2012, which focuses its activity on expanding knowledge related to this condition and disseminating such knowledge to the families of patients.
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9
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Liang JS, Huang H, Wang JS, Lu JF. Phenotypic manifestations between male and female children with CDKL5 mutations. Brain Dev 2019; 41:783-789. [PMID: 31122804 DOI: 10.1016/j.braindev.2019.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 04/17/2019] [Accepted: 05/07/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cyclin-dependent kinase-like 5 (CDKL5), which maps to chromosome Xp22.13 and contains 20 coding exons, has been recognized as the gene responsible for early-onset epileptic encephalopathy (EoEE). A retrospective study is carried out to analyze potential genotypic and phenotypic differences between male and female patients with CDKL5 mutations. MATERIALS AND METHODS Targeted next-generation DNA sequencing was employed to search for mutations in patients with cryptogenic EE. A total of 44 patients with EoEE/infantile spasms (ISs)/West syndrome were enrolled for pathogenic mutation screening. The clinical phenotypes of patients with CDKL5 mutations were analyzed and compared with those of 166 published cases. RESULTS One novel and three recurrent mutations were found in four enrolled patients (two boys and two girls). One female patient had partial seizures during the early infantile period and epileptic spasms and tonic seizures several weeks thereafter. The other female patient had IS with hypsarrhythmia. The two male patients had IS without typical hypsarrhythmia and were bedridden. Brain MRIs of the male patients revealed brain atrophy and white matter hyperintensity. The female patients exhibited autistic features with hand stereotypies. CONCLUSION Our study highlights that both girls and boys with IS harbor CDKL5 mutations. Male children with CDKL5 mutations demonstrate a higher frequency of infantile spasms and brain atrophy, whereas female children often exhibit atypical Rett syndrome with EoEE. In addition, male children have a more severe phenotype than female children.
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Affiliation(s)
- Jao-Shwann Liang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Nursing, Oriental Institute of Technology, New Taipei City, Taiwan
| | - Hsin Huang
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Jinn-Shyan Wang
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Jyh-Feng Lu
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.
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10
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Olson HE, Demarest ST, Pestana-Knight EM, Swanson LC, Iqbal S, Lal D, Leonard H, Cross JH, Devinsky O, Benke TA. Cyclin-Dependent Kinase-Like 5 Deficiency Disorder: Clinical Review. Pediatr Neurol 2019; 97:18-25. [PMID: 30928302 PMCID: PMC7120929 DOI: 10.1016/j.pediatrneurol.2019.02.015] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 01/21/2019] [Accepted: 02/16/2019] [Indexed: 01/08/2023]
Abstract
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a developmental encephalopathy caused by pathogenic variants in the gene CDKL5. This unique disorder includes early infantile onset refractory epilepsy, hypotonia, developmental intellectual and motor disabilities, and cortical visual impairment. We review the clinical presentations and genetic variations in CDD based on a systematic literature review and experience in the CDKL5 Centers of Excellence. We propose minimum diagnostic criteria. Pathogenic variants include deletions, truncations, splice variants, and missense variants. Pathogenic missense variants occur exclusively within the kinase domain or affect splice sites. The CDKL5 protein is widely expressed in the brain, predominantly in neurons, with roles in cell proliferation, neuronal migration, axonal outgrowth, dendritic morphogenesis, and synapse development. The molecular biology of CDD is revealing opportunities in precision therapy, with phase 2 and 3 clinical trials underway or planned to assess disease specific and disease modifying treatments.
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Affiliation(s)
- Heather E Olson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.
| | - Scott T Demarest
- Children's Hospital Colorado, University of Colorado, School of Medicine, Aurora, Colorado; Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Elia M Pestana-Knight
- Cleveland Clinic Neurological Institute Epilepsy Center, Cleveland Clinic Neurological Institute Pediatric Neurology Department, Neurogenetics, Cleveland Clinic Children's, Cleveland, Ohio
| | - Lindsay C Swanson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Sumaiya Iqbal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts
| | - Dennis Lal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts; Genomic Medicine Institute, Cleveland Clinic, Cleveland, Ohio; Neurological Institute, Cleveland Clinic, Cleveland, Ohio
| | - Helen Leonard
- Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
| | - J Helen Cross
- UCL Great Ormond Street NIHR BRC Institute of Child Health, London, UK
| | - Orrin Devinsky
- Department of Neurology, NYU Langone Health, New York, New York
| | - Tim A Benke
- Children's Hospital Colorado, University of Colorado, School of Medicine, Aurora, Colorado; Department of Pediatrics, University of Colorado, School of Medicine, Aurora, Colorado; Department of Pharmacology, University of Colorado, School of Medicine, Aurora, Colorado; Department of Neurology, University of Colorado, School of Medicine, Aurora, Colorado; Department of Otolaryngology, University of Colorado, School of Medicine, Aurora, Colorado
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11
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Bodian DL, Schreiber JM, Vilboux T, Khromykh A, Hauser NS. Mutation in an alternative transcript of CDKL5 in a boy with early-onset seizures. Cold Spring Harb Mol Case Stud 2018; 4:mcs.a002360. [PMID: 29444904 PMCID: PMC5983171 DOI: 10.1101/mcs.a002360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/02/2018] [Indexed: 01/05/2023] Open
Abstract
Infantile-onset epilepsies are a set of severe, heterogeneous disorders for which clinical genetic testing yields causative mutations in ∼20%–50% of affected individuals. We report the case of a boy presenting with intractable seizures at 2 wk of age, for whom gene panel testing was unrevealing. Research-based whole-genome sequencing of the proband and four unaffected family members identified a de novo mutation, NM_001323289.1:c.2828_2829delGA in CDKL5, a gene associated with X-linked early infantile epileptic encephalopathy 2. CDKL5 has multiple alternative transcripts, and the mutation lies in an exon in the brain-expressed forms. The mutation was undetected by gene panel sequencing because of its intronic location in the CDKL5 transcript typically used to define the exons of this gene for clinical exon-based tests (NM_003159). This is the first report of a patient with a mutation in an alternative transcript of CDKL5. This finding suggests that incorporating alternative transcripts into the design and variant interpretation of exon-based tests, including gene panel and exome sequencing, could improve the diagnostic yield.
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Affiliation(s)
- Dale L Bodian
- Inova Translational Medicine Institute, Inova Health System, Falls Church, Virginia 22042, USA
| | - John M Schreiber
- Pediatric Specialists of Virginia, Falls Church, Virginia 22042, USA
| | - Thierry Vilboux
- Inova Translational Medicine Institute, Inova Health System, Falls Church, Virginia 22042, USA
| | - Alina Khromykh
- Inova Translational Medicine Institute, Inova Health System, Falls Church, Virginia 22042, USA
| | - Natalie S Hauser
- Inova Translational Medicine Institute, Inova Health System, Falls Church, Virginia 22042, USA
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12
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Kyle SM, Vashi N, Justice MJ. Rett syndrome: a neurological disorder with metabolic components. Open Biol 2018; 8:170216. [PMID: 29445033 PMCID: PMC5830535 DOI: 10.1098/rsob.170216] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/18/2018] [Indexed: 02/06/2023] Open
Abstract
Rett syndrome (RTT) is a neurological disorder caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2), a ubiquitously expressed transcriptional regulator. Despite remarkable scientific progress since its discovery, the mechanism by which MECP2 mutations cause RTT symptoms is largely unknown. Consequently, treatment options for patients are currently limited and centred on symptom relief. Thought to be an entirely neurological disorder, RTT research has focused on the role of MECP2 in the central nervous system. However, the variety of phenotypes identified in Mecp2 mutant mouse models and RTT patients implicate important roles for MeCP2 in peripheral systems. Here, we review the history of RTT, highlighting breakthroughs in the field that have led us to present day. We explore the current evidence supporting metabolic dysfunction as a component of RTT, presenting recent studies that have revealed perturbed lipid metabolism in the brain and peripheral tissues of mouse models and patients. Such findings may have an impact on the quality of life of RTT patients as both dietary and drug intervention can alter lipid metabolism. Ultimately, we conclude that a thorough knowledge of MeCP2's varied functional targets in the brain and body will be required to treat this complex syndrome.
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Affiliation(s)
- Stephanie M Kyle
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Neeti Vashi
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A1
| | - Monica J Justice
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A1
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13
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Neupauerová J, Štěrbová K, Vlčková M, Sebroňová V, Maříková T, Krůtová M, David S, Kršek P, Žaliová M, Seeman P, Laššuthová P. Two Novel Variants Affecting CDKL5 Transcript Associated with Epileptic Encephalopathy. Genet Test Mol Biomarkers 2017; 21:613-618. [DOI: 10.1089/gtmb.2017.0110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Jana Neupauerová
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Katalin Štěrbová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Markéta Vlčková
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Věra Sebroňová
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Tat'ána Maříková
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Marcela Krůtová
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Staněk David
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Pavel Kršek
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Markéta Žaliová
- CLIP–Childhood Leukaemia Investigation Prague, Department of Paediatric Haematology and Oncology, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Petra Laššuthová
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
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14
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Reichow B, George-Puskar A, Lutz T, Smith IC, Volkmar FR. Brief report: systematic review of Rett syndrome in males. J Autism Dev Disord 2016; 45:3377-83. [PMID: 26254891 DOI: 10.1007/s10803-015-2519-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Rett syndrome (RTT) is a neurogenetic disorder in which a period of typical development is followed by loss of previously acquired skills. Once thought to occur exclusively in females, increasing numbers of male cases of RTT have been reported. This systematic review included 36 articles describing 57 cases of RTT in males. Mutations of the MECP2 gene were present in 56 % of cases, and 68 % of cases reported other genetic abnormalities. This is the first review of published reports of RTT in male patients.
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Affiliation(s)
- Brian Reichow
- AJ Pappanikou Center for Excellence in Developmental Disabilities, University of Connecticut Health Center, Farmington, CT, USA.
- University of Florida, 1345Q Norman Hall, PO Box 117050, Gainesville, FL, 32661-7050, USA.
| | | | - Tara Lutz
- University of Connecticut, Storrs, CT, USA
| | - Isaac C Smith
- AJ Pappanikou Center for Excellence in Developmental Disabilities, University of Connecticut Health Center, Farmington, CT, USA
- Yale Child Study Center, New Haven, CT, USA
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15
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Recurrent occurrences of CDKL5 mutations in patients with epileptic encephalopathy. Hum Genome Var 2015; 2:15042. [PMID: 27081548 PMCID: PMC4785533 DOI: 10.1038/hgv.2015.42] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/02/2015] [Accepted: 09/23/2015] [Indexed: 11/08/2022] Open
Abstract
The cyclin-dependent kinase-like 5 gene (CDKL5) is recognized as one of the genes responsible for epileptic encephalopathy. We identified CDKL5 mutations in five Japanese patients (one male and four female) with epileptic encephalopathy. Although all mutations were of de novo origin, they were located in the same positions as previously reported pathogenic mutations. These recurrent occurrences of de novo mutations in the same loci may indicate hot spots of nucleotide alteration.
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16
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Wong VCN, Kwong AKY. CDKL5 variant in a boy with infantile epileptic encephalopathy: case report. Brain Dev 2015; 37:446-8. [PMID: 25085838 DOI: 10.1016/j.braindev.2014.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/02/2014] [Accepted: 07/06/2014] [Indexed: 01/05/2023]
Abstract
UNLABELLED A Chinese boy presented at 18 months with intractable epilepsy, developmental delay and autistic features. He had multiple seizure types, including absence, myoclonic seizures, limb spasm and tonic seizures. His seizures were finally controlled at 3 years of age with clonazepam and a short course of chloral hydrate incidentally given for his insomnia. Subsequently, he had improvement in his communication skills. RESULT A novel hemizygous missense variant (c.1649G>A; p.R550Q) in exon 12 of CDKL5 gene was detected for him, his asymptomatic mother and elder sister. His phenotype is less severe than other male cases. CONCLUSION We recommend screening CDKL5 for boys with pharmarco-resistant epilepsy and a trial of benzodiazepines for Infantile Epileptic Encephalopathy (IEE).
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Affiliation(s)
- Virginia Chun-Nei Wong
- Division of Paediatric Neurology/Developmental Behavioural Paediatrics/NeuroHabilitation, Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region.
| | - Anna Ka-Yee Kwong
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
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Fehr S, Leonard H, Ho G, Williams S, de Klerk N, Forbes D, Christodoulou J, Downs J. There is variability in the attainment of developmental milestones in the CDKL5 disorder. J Neurodev Disord 2015; 7:2. [PMID: 25657822 PMCID: PMC4318547 DOI: 10.1186/1866-1955-7-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/16/2014] [Indexed: 11/29/2022] Open
Abstract
Background Individuals with the CDKL5 disorder have been described as having severely impaired development. A few individuals have been reported having attained more milestones including walking and running. Our aim was to investigate variation in attainment of developmental milestones and associations with underlying genotype. Methods Data was sourced from the International CDKL5 Disorder Database, and individuals were included if they had a pathogenic or probably pathogenic CDKL5 mutation and information on early development. Kaplan-Meier time-to-event analyses investigated the occurrence of developmental milestones. Mutations were grouped by their structural/functional consequence, and Cox regression was used to investigate the relationship between genotype and milestone attainment. Results The study included 109 females and 18 males. By 5 years of age, only 75% of the females had attained independent sitting and 25% independent walking whilst a quarter of the males could sit independently by 1 year 3 months. Only one boy could walk independently. No clear relationship between mutation group and milestone attainment was present, although females with a late truncating mutation attained the most milestones. Conclusion Attainment of developmental milestones is severely impaired in the CDKL5 disorder, with the majority who did attain skills attaining them at a late age. It appears as though males are more severely impaired than the females. Larger studies are needed to further investigate the role of genotype on clinical variability.
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Affiliation(s)
- Stephanie Fehr
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia Australia
| | - Helen Leonard
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia Australia
| | - Gladys Ho
- Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW Australia
| | - Simon Williams
- Department of Neurology and Rehabilitation, Princess Margaret Hospital, Perth, Western Australia Australia
| | - Nick de Klerk
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia Australia
| | - David Forbes
- School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia Australia
| | - John Christodoulou
- Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW Australia ; Disciplines of Paediatrics & Child Health and Genetic Medicine, University of Sydney, Sydney, NSW Australia
| | - Jenny Downs
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia Australia ; School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia Australia
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18
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Szafranski P, Golla S, Jin W, Fang P, Hixson P, Matalon R, Kinney D, Bock HG, Craigen W, Smith JL, Bi W, Patel A, Wai Cheung S, Bacino CA, Stankiewicz P. Neurodevelopmental and neurobehavioral characteristics in males and females with CDKL5 duplications. Eur J Hum Genet 2014; 23:915-21. [PMID: 25315662 DOI: 10.1038/ejhg.2014.217] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/21/2014] [Accepted: 09/05/2014] [Indexed: 12/21/2022] Open
Abstract
Point mutations and genomic deletions of the CDKL5 (STK9) gene on chromosome Xp22 have been reported in patients with severe neurodevelopmental abnormalities, including Rett-like disorders. To date, only larger-sized (8-21 Mb) duplications harboring CDKL5 have been described. We report seven females and four males from seven unrelated families with CDKL5 duplications 540-935 kb in size. Three families of different ethnicities had identical 667kb duplications containing only the shorter CDKL5 isoform. Four affected boys, 8-14 years of age, and three affected girls, 6-8 years of age, manifested autistic behavior, developmental delay, language impairment, and hyperactivity. Of note, two boys and one girl had macrocephaly. Two carrier mothers of the affected boys reported a history of problems with learning and mathematics while at school. None of the patients had epilepsy. Similarly to CDKL5 mutations and deletions, the X-inactivation pattern in all six studied females was random. We hypothesize that the increased dosage of CDKL5 might have affected interactions of this kinase with its substrates, leading to perturbation of synaptic plasticity and learning, and resulting in autistic behavior, developmental and speech delay, hyperactivity, and macrocephaly.
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Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sailaja Golla
- Departments of Pediatrics and Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Weihong Jin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ping Fang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Patricia Hixson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Reuben Matalon
- Division of General Academic Pediatrics, Department of Pediatrics, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Daniel Kinney
- Memorial Children's Hospital Navarre Pediatrics South Bend, South Bend, IN, USA
| | - Hans-Georg Bock
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS, USA
| | - William Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Janice L Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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19
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Zhao Y, Zhang X, Bao X, Zhang Q, Zhang J, Cao G, Zhang J, Li J, Wei L, Pan H, Wu X. Clinical features and gene mutational spectrum of CDKL5-related diseases in a cohort of Chinese patients. BMC MEDICAL GENETICS 2014; 15:24. [PMID: 24564546 PMCID: PMC3938974 DOI: 10.1186/1471-2350-15-24] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/12/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Mutations in the cyclin-dependent kinase-like 5 (CDKL5) (NM_003159.2) gene have been associated with early-onset epileptic encephalopathies or Hanefeld variants of RTT(Rett syndrome). In order to clarify the CDKL5 genotype-phenotype correlations in Chinese patients, CDKL5 mutational screening in cases with early-onset epileptic encephalopathies and RTT without MECP2 mutation were performed. METHODS The detailed clinical information including clinical manifestation, electroencephalogram (EEG), magnetic resonance imaging (MRI), blood, urine amino acid and organic acid screening of 102 Chinese patients with early-onset epileptic encephalopathies and RTT were collected. CDKL5 gene mutations were analyzed by PCR, direct sequencing and multiplex ligation-dependent probe amplification (MLPA). The patterns of X-chromosome inactivation (XCI) were studied in the female patients with CDKL5 gene mutation. RESULTS De novo CDKL5 gene mutations were found in ten patients including one missense mutation (c.533G > A, p.R178Q) which had been reported, two splicing mutations (ISV6 + 1A > G, ISV13 + 1A > G), three micro-deletions (c.1111delC, c.2360delA, c.234delA), two insertions (c.1791 ins G, c.891_892 ins TT in a pair of twins) and one nonsense mutation (c.1375C > T, p.Q459X). Out of ten patients, 7 of 9 females with Hanefeld variants of RTT and the remaining 2 females with early onset epileptic encephalopathy, were detected while only one male with infantile spasms was detected. The common features of all female patients with CDKL5 gene mutations included refractory seizures starting before 4 months of age, severe psychomotor retardation, Rett-like features such as hand stereotypies, deceleration of head growth after birth and poor prognosis. In contrast, the only one male patient with CDKL5 mutation showed no obvious Rett-like features as females in our cohort. The X-chromosome inactivation patterns of all the female patients were random. CONCLUSIONS Mutations in CDKL5 gene are responsible for 7 with Hanefeld variants of RTT and 2 with early-onset epileptic encephalopathy in 71 girls as well as for 1 infantile spasms in 31 males. There are some differences in the phenotypes among genders with CDKL5 gene mutations and CDKL5 gene mutation analysis should be considered in both genders.
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Affiliation(s)
| | | | - Xinhua Bao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
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20
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Deng H, Zheng W, Song Z. Genetics, Molecular Biology, and Phenotypes of X-Linked Epilepsy. Mol Neurobiol 2013; 49:1166-80. [DOI: 10.1007/s12035-013-8589-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 11/05/2013] [Indexed: 11/25/2022]
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Abstract
Mutations in CDKL5 and ARX are known causes of early-onset epilepsy and severe developmental delay in males and females. Although numerous males with ARX mutations associated with various phenotypes have been reported in the literature, the majority of CDKL5 mutations have been identified in females with a phenotype characterized by early-onset epilepsy, severe global developmental delay, absent speech, and stereotypic hand movements. To date, only 10 males with CDKL5 mutations have been reported. Our retrospective study reports on the clinical, neuroimaging, and molecular findings of 18 males with early-onset epilepsy caused by either CDKL5 or ARX mutations. These 18 patients include eight new males with CDKL5 mutations and 10 with ARX mutations identified through sequence analysis of 266 and 346 males, respectively, at our molecular diagnostic laboratory. Our large dataset therefore expands on the number of reported males with CDKL5 mutations and highlights that aberrations of CDKL5 and ARX combined are an important consideration in the genetic forms of early-onset epilepsy in boys.
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22
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Guerrini R, Parrini E. Epilepsy in Rett syndrome, and CDKL5- and FOXG1-gene-related encephalopathies. Epilepsia 2012; 53:2067-78. [PMID: 22998673 DOI: 10.1111/j.1528-1167.2012.03656.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Rett syndrome is an X-linked neurodevelopmental disorder that manifests in early childhood with developmental stagnation, and loss of spoken language and hand use, with the development of distinctive hand stereotypies, severe cognitive impairment, and autistic features. About 60% of patients have epilepsy. Seizure onset before the age of 3 years is unlikely, and onset after age 20 is rare. Diagnosis of Rett syndrome is based on key clinical elements that identify "typical" Rett syndrome but also "variant" or "atypical" forms. Diagnostic criteria have been modified only slightly over time, even after discovering that MECP2 gene alterations are present in >90% of patients with typical Rett syndrome but only in 50-70% of atypical cases. Over the last several years, intragenic or genomic alterations of the CDKL5 and FOXG1 genes have been associated with severe cognitive impairment, early onset epilepsy and, often, dyskinetic movement disorders, which have variably been defined as Rett variants. It is now clearly emerging that epilepsy has distinctive characteristics in typical Rett syndrome and in the different syndromes caused by CDKL5 and FOXG1 gene alterations. The progressive parting of CDKL5- and FOXG1-gene-related encephalopathies from the core Rett syndrome is reflected by the effort to produce clearer diagnostic criteria for typical and atypical Rett syndrome. Efforts to characterize the molecular pathology underlying these developmental encephalopathies are pointing to abnormalities of telencephalic development, neuronal morphogenesis, maturation and maintenance, and dendritic arborization.
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Affiliation(s)
- Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy.
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23
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What we know and would like to know about CDKL5 and its involvement in epileptic encephalopathy. Neural Plast 2012; 2012:728267. [PMID: 22779007 PMCID: PMC3385648 DOI: 10.1155/2012/728267] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 04/06/2012] [Indexed: 12/11/2022] Open
Abstract
In the last few years, the X-linked serine/threonine kinase cyclin-dependent kinase-like 5 (CDKL5) has been associated with early-onset epileptic encephalopathies characterized by the manifestation of intractable epilepsy within the first weeks of life, severe developmental delay, profound hypotonia, and often the presence of some Rett-syndrome-like features. The association of CDKL5 with neurodevelopmental disorders and its high expression levels in the maturing brain underscore the importance of this kinase for proper brain development. However, our present knowledge of CDKL5 functions is still rather limited. The picture that emerges from the molecular and cellular studies suggests that CDKL5 functions are important for regulating both neuronal morphology through cytoplasmic signaling pathways and activity-dependent gene expression in the nuclear compartment. This paper surveys the current state of CDKL5 research with emphasis on the clinical symptoms associated with mutations in CDKL5, the different mechanisms regulating its functions, and the connected molecular pathways. Finally, based on the available data we speculate that CDKL5 might play a role in neuronal plasticity and we adduce and discuss some possible arguments supporting this hypothesis.
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24
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Moseley BD, Dhamija R, Wirrell EC, Nickels KC. Historic, clinical, and prognostic features of epileptic encephalopathies caused by CDKL5 mutations. Pediatr Neurol 2012; 46:101-5. [PMID: 22264704 DOI: 10.1016/j.pediatrneurol.2011.11.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 11/14/2011] [Indexed: 01/11/2023]
Abstract
Mutations within the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene are important causes of early-onset epileptic encephalopathies. We sought to determine the historic, clinical, and prognostic features of epilepsy secondary to CDKL5 mutations. We performed retrospective chart reviews of children at our institution with epilepsy and CDKL5 mutations. Six children were identified. One manifested a deletion in exons 10-15 of the CDKL5 gene, another manifested a single base-pair duplication in exon 3, and the rest manifested base-pair exchanges. The mean age of seizure onset was 1.8 months (range, 1-3 months). Although the majority (4/6, 67%) presented with partial-onset seizures, all children developed infantile spasms. All children demonstrated developmental delay and visual impairment. Although such mutations are X-linked, two children were boys. They did not present with more severe phenotypes than their female counterparts. Despite trials of antiepileptic drugs (mean, 5; range, 3-7), steroids/adrenocorticotropic hormone (4/6; 67%), and the ketogenic diet (6/6; 100%), all children manifested refractory seizures at last follow-up. Although no treatment eliminated seizures, topiramate, vigabatrin, and the ketogenic diet were most helpful at reducing seizure frequency.
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Affiliation(s)
- Brian D Moseley
- Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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25
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Bahi-Buisson N, Bienvenu T. CDKL5-Related Disorders: From Clinical Description to Molecular Genetics. Mol Syndromol 2011; 2:137-152. [PMID: 22670135 DOI: 10.1159/000331333] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) have been described in girls with Rett-like features and early-onset epileptic encephalopathy including infantile spasms. To date, with more than 80 reported cases, the phenotype of CDKL5-related encephalopathy is better defined. The main features consist of early-onset seizures starting before 5 months of age, severe mental retardation with absent speech and Rett-like features such as hand stereotypies and deceleration of head growth. On the other hand, neuro-vegetative signs and developmental regression are rare in CDKL5 mutation patients. The CDKL5 gene encodes a serine threonine kinase protein which is characterized by a catalytic domain and a long C-terminal extension involved in the regulation of the catalytic activity of CDKL5 and in the sub-nuclear localization of the protein. To our knowledge, more than 70 different point mutations have been described including missense mutations within the catalytic domain, nonsense mutations causing the premature termination of the protein distributed in the entire open reading frame, splice variants, and frameshift mutations. Additionally, CDKL5 mutations have recently been described in 7 males with a more severe epileptic encephalopathy and a worse outcome compared to female patients. Finally, about 23 male and female patients have been identified with gross rearrangements encompassing all or part of the CDKL5 gene, with a phenotype reminiscent of CDKL5-related encephalopathy combined with dysmorphic features. Even if recent data clearly indicate that CDKL5 plays an important role in brain function, the protein remains largely uncharacterized. Phenotype-genotype correlation is additionally hampered by the relatively small number of patients described.
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Liang JS, Shimojima K, Takayama R, Natsume J, Shichiji M, Hirasawa K, Imai K, Okanishi T, Mizuno S, Okumura A, Sugawara M, Ito T, Ikeda H, Takahashi Y, Oguni H, Imai K, Osawa M, Yamamoto T. CDKL5 alterations lead to early epileptic encephalopathy in both genders. Epilepsia 2011; 52:1835-42. [DOI: 10.1111/j.1528-1167.2011.03174.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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A novel transcript of cyclin-dependent kinase-like 5 (CDKL5) has an alternative C-terminus and is the predominant transcript in brain. Hum Genet 2011; 131:187-200. [PMID: 21748340 DOI: 10.1007/s00439-011-1058-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 06/28/2011] [Indexed: 12/21/2022]
Abstract
The X-linked cyclin-dependent kinase-like 5 (CDKL5) gene is an important molecular determinant of early-onset intractable seizures with infantile spasms and Rett syndrome-like phenotype. The gene encodes a kinase that may influence components of molecular pathways associated with MeCP2. In humans there are two previously reported splice variants that differ in the 5' untranslated exons and produce the same 115 kDa protein. Furthermore, very recently, a novel transcript including a novel exon (16b) has been described. By aligning both the human and mouse CDKL5 proteins to the orthologs of other species, we identified a theoretical 107 kDa isoform with an alternative C-terminus that terminates in intron 18. In human brain and all other tissues investigated except the testis, this novel isoform is the major CDKL5 transcript. The detailed characterisation of this novel isoform of CDKL5 reveals functional and subcellular localisation attributes that overlap greatly, but not completely, with that of the previously studied human CDKL5 protein. Considering its predominant expression in the human and mouse brain, we believe that this novel isoform is likely to be of primary pathogenic importance in human diseases associated with CDKL5 deficiency, and suggest that screening of the related intronic sequence should be included in the molecular genetic analyses of patients with a suggestive clinical phenotype.
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Abstract
PURPOSE OF REVIEW Although the association between learning disability and epilepsy is well known, until relatively recently specific processes underlying this association were relatively poorly understood. However, scientific advances in molecular biology are starting to guide researchers towards descriptions of genetic and pathophysiological processes that may explain why syndromes of epilepsy and learning disability often co-exist. RECENT FINDINGS This article will focus largely on three areas of advancing knowledge: insights gained from wider use of genome-wide array comparative genomic hybridization (aCGH), specific insights gained from detailed study of Rett syndrome and the role of abnormalities of astrocytic function in predisposing to both epilepsy and learning disability. SUMMARY The enormous complexity of the biological underpinnings of the co-occurrence of epilepsy and learning disability are becoming apparent. In the future it is likely that research into therapeutic approaches will include, amongst other approaches, investigations of gene structure and expression, the role of astrocytes and the stability of dendritic spines.
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Melani F, Mei D, Pisano T, Savasta S, Franzoni E, Ferrari AR, Marini C, Guerrini R. CDKL5 gene-related epileptic encephalopathy: electroclinical findings in the first year of life. Dev Med Child Neurol 2011; 53:354-60. [PMID: 21309761 DOI: 10.1111/j.1469-8749.2010.03889.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM Cyclin-dependent kinase-like 5 (CDKL5) gene abnormalities cause an early-onset epileptic encephalopathy. We performed video-electroencephalography (video-EEG) monitoring early in the course of CDKL5-related epileptic encephalopathy in order to examine the early electroclinical characteristics of the condition. METHOD We used video-EEG to monitor six infants (five females, one male) with CDKL5-related epileptic encephalopathy (five mutations; one deletion), at ages 45 days to 12 months and followed them up to the ages of 14 months to 5 years (mean age 23 mo). We focused our analysis on the first year of life. The results were evaluated against those of a comparison group of nine infants (aged below 1y) with epileptic encephalography who had tested negative for CDKL5 mutations and deletions. RESULTS One infant exhibited normal background activity, three exhibited moderate slowing, and two exhibited a suppression burst pattern. Two participants had epileptic spasms and four had a stereotyped complex seizure pattern, which we defined as a 'prolonged' generalized tonic-clonic event consisting of a tonic-tonic/vibratory contraction, followed by a clonic phase with series of spasms, gradually translating into repetitive distal myoclonic jerks. Seizure duration ranged from 2 to 4 minutes. The EEG correlate of each clinical phase included an initial electrodecremental event (tonic vibratory phase), irregular series of sharp waves and spike slow waves (clonic phase with series of spasms), and bilateral rhythmic sharp waves (time locked with myoclonus). INTERPRETATION Infants with CDKL5-related early epileptic encephalopathy can present in the first year of life with an unusual electroclinical pattern of 'prolonged' generalized tonic-clonic seizures.
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Affiliation(s)
- Federico Melani
- Paediatric Neurology Unit and Laboratories, A. Meyer Children's Hospital, University of Florence, Florence, Italy.
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Early-onset seizures due to mosaic exonic deletions of CDKL5 in a male and two females. Genet Med 2011; 13:447-52. [DOI: 10.1097/gim.0b013e31820605f5] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Castrén M, Gaily E, Tengström C, Lähdetie J, Archer H, Ala-Mello S. Epilepsy caused by CDKL5 mutations. Eur J Paediatr Neurol 2011; 15:65-9. [PMID: 20493745 DOI: 10.1016/j.ejpn.2010.04.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 03/24/2010] [Accepted: 04/07/2010] [Indexed: 12/28/2022]
Abstract
Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) have been identified in female patients with early onset epileptic encephalopathy and severe mental retardation with a Rett-like phenotype. Subsequently CDKL5 mutations were shown to be associated with more diverse phenotypes including mild epilepsy and autism without epilepsy. Furthermore, CDKL5 mutations were found in patients with Angelman-like phenotype. The severity of epilepsy associated with CDKL5 mutations was recently shown to correlate with the type of CDKL5 mutations and epilepsy was identified to involve three distinct sequential stages. Here, we describe the phenotype of a severe form of neurodevelopmental disease in a female patient with a de novo nonsense mutation of the CDKL5 gene c.175C > T (p.R59X) affecting the catalytic domain of CDKL5 protein. Mutations in the CDKL5 gene are less common in males and can be associated with a genomic deletion as found in our male patient with a deletion of 0.3 Mb at Xp22.13 including the CDKL5 gene. We review phenotypes associated with CDKL5 mutations and examine putative relationships between the clinical epilepsy phenotype and the type of the mutation in the CDKL5 gene.
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Affiliation(s)
- Maija Castrén
- Rinnekoti Foundation, Rinnekodintie 10, FIN-02980 Espoo, Finland.
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An isoform of the severe encephalopathy-related CDKL5 gene, including a novel exon with extremely high sequence conservation, is specifically expressed in brain. J Hum Genet 2010; 56:52-7. [PMID: 21124335 DOI: 10.1038/jhg.2010.143] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We report the identification of a novel exon, which is referred to as exon 16b, within the cyclin-dependent kinase (CDK)-like 5 (CDKL5) gene that is implicated in the X-linked infantile spasm syndrome and the early-onset seizure variant of Rett syndrome. Interestingly, it is highly conserved in species through evolution, suggesting a potential functional role, but does not display any homology with other referenced sequences. Most importantly, the transcript including this exon is specifically expressed in brain. We suggest that CDKL5 exon 16b should now be considered in the genetic screening of patients presenting with a CDKL5-related disease profile.
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Mei D, Marini C, Novara F, Bernardina BD, Granata T, Fontana E, Parrini E, Ferrari AR, Murgia A, Zuffardi O, Guerrini R. Xp22.3 genomic deletions involving theCDKL5gene in girls with early onset epileptic encephalopathy. Epilepsia 2010; 51:647-54. [DOI: 10.1111/j.1528-1167.2009.02308.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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