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Simões de Oliveira L, O'Leary HE, Nawaz S, Loureiro R, Davenport EC, Baxter P, Louros SR, Dando O, Perkins E, Peltier J, Trost M, Osterweil EK, Hardingham GE, Cousin MA, Chattarji S, Booker SA, Benke TA, Wyllie DJA, Kind PC. Enhanced hippocampal LTP but normal NMDA receptor and AMPA receptor function in a rat model of CDKL5 deficiency disorder. Mol Autism 2024; 15:28. [PMID: 38877552 PMCID: PMC11177379 DOI: 10.1186/s13229-024-00601-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 05/07/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Mutations in the X-linked gene cyclin-dependent kinase-like 5 (CDKL5) cause a severe neurological disorder characterised by early-onset epileptic seizures, autism and intellectual disability (ID). Impaired hippocampal function has been implicated in other models of monogenic forms of autism spectrum disorders and ID and is often linked to epilepsy and behavioural abnormalities. Many individuals with CDKL5 deficiency disorder (CDD) have null mutations and complete loss of CDKL5 protein, therefore in the current study we used a Cdkl5-/y rat model to elucidate the impact of CDKL5 loss on cellular excitability and synaptic function of CA1 pyramidal cells (PCs). We hypothesised abnormal pre and/or post synaptic function and plasticity would be observed in the hippocampus of Cdkl5-/y rats. METHODS To allow cross-species comparisons of phenotypes associated with the loss of CDKL5, we generated a loss of function mutation in exon 8 of the rat Cdkl5 gene and assessed the impact of the loss of CDLK5 using a combination of extracellular and whole-cell electrophysiological recordings, biochemistry, and histology. RESULTS Our results indicate that CA1 hippocampal long-term potentiation (LTP) is enhanced in slices prepared from juvenile, but not adult, Cdkl5-/y rats. Enhanced LTP does not result from changes in NMDA receptor function or subunit expression as these remain unaltered throughout development. Furthermore, Ca2+ permeable AMPA receptor mediated currents are unchanged in Cdkl5-/y rats. We observe reduced mEPSC frequency accompanied by increased spine density in basal dendrites of CA1 PCs, however we find no evidence supporting an increase in silent synapses when assessed using a minimal stimulation protocol in slices. Additionally, we found no change in paired-pulse ratio, consistent with normal release probability at Schaffer collateral to CA1 PC synapses. CONCLUSIONS Our data indicate a role for CDKL5 in hippocampal synaptic function and raise the possibility that altered intracellular signalling rather than synaptic deficits contribute to the altered plasticity. LIMITATIONS This study has focussed on the electrophysiological and anatomical properties of hippocampal CA1 PCs across early postnatal development. Studies involving other brain regions, older animals and behavioural phenotypes associated with the loss of CDKL5 are needed to understand the pathophysiology of CDD.
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MESH Headings
- Animals
- Long-Term Potentiation
- Receptors, N-Methyl-D-Aspartate/metabolism
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, AMPA/metabolism
- Receptors, AMPA/genetics
- Spasms, Infantile/genetics
- Spasms, Infantile/metabolism
- Disease Models, Animal
- Rats
- Protein Serine-Threonine Kinases/metabolism
- Protein Serine-Threonine Kinases/genetics
- Hippocampus/metabolism
- Pyramidal Cells/metabolism
- Pyramidal Cells/pathology
- Male
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/pathology
- CA1 Region, Hippocampal/physiopathology
- Epileptic Syndromes/genetics
- Epileptic Syndromes/metabolism
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Genetic Diseases, X-Linked/physiopathology
- Synapses/metabolism
- Excitatory Postsynaptic Potentials
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Affiliation(s)
- Laura Simões de Oliveira
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Heather E O'Leary
- School of Medicine, University of Colorado, Denver, CO, USA
- Department of Pharmacology, University of Colorado Denver, 12800 East 19th Ave, Aurora, CO, 80045, USA
| | - Sarfaraz Nawaz
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, 560065, India
- Centre for Brain Development and Repair, Instem, Bangalore, India
| | - Rita Loureiro
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | | | - Paul Baxter
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Susana R Louros
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Owen Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Emma Perkins
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Julien Peltier
- Faculty of Medical Sciences, Newcastle University Biosciences Institute, Newcastle upon Tyne, NE2 4HH, UK
| | - Matthias Trost
- Faculty of Medical Sciences, Newcastle University Biosciences Institute, Newcastle upon Tyne, NE2 4HH, UK
| | - Emily K Osterweil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Giles E Hardingham
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Centre for Brain Development and Repair, Instem, Bangalore, India
| | - Sumantra Chattarji
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, 560065, India
- Centre for Brain Development and Repair, Instem, Bangalore, India
| | - Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
| | - Tim A Benke
- School of Medicine, University of Colorado, Denver, CO, USA.
- Department of Pharmacology, University of Colorado Denver, 12800 East 19th Ave, Aurora, CO, 80045, USA.
| | - David J A Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK.
- Centre for Brain Development and Repair, Instem, Bangalore, India.
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, UK.
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
- Simons Initiative for the Developing Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK.
- Centre for Brain Development and Repair, Instem, Bangalore, India.
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, UK.
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Wong K, Davies G, Leonard H, Downs J, Junaid M, Amin S. Growth patterns in individuals with CDKL5 deficiency disorder. Dev Med Child Neurol 2024; 66:469-482. [PMID: 37804112 DOI: 10.1111/dmcn.15777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/03/2023] [Accepted: 09/07/2023] [Indexed: 10/08/2023]
Abstract
AIM To compare growth in individuals with cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder with population norms and to investigate the effect of gastrostomy on growth. METHOD The longitudinal study included 353 individuals from the International CDKL5 Disorder Database with any anthropometric measurement in baseline and/or follow-up questionnaires. The British 1990 growth reference was used to determine the age- and sex-standardized z-score. Repeated cross-sectional data were fitted using a Gaussian linear regression model with generalized estimating equations. RESULTS All growth parameters were below the general population norm (mean z-scores: weight -0.97, height -0.65, body mass index [BMI] -0.81, head circumference -2.12). The disparity was particularly pronounced for all anthropometric measurements after 4 years of age except for BMI. Moreover, individuals with gastrostomy placement were shown to have a larger decrease than those without. INTERPRETATION In addition to weight, height, and BMI, head circumference was also compromised in this disorder. Microcephaly could be considered a helpful diagnostic feature, especially in adults. Any benefit of gastrostomy on weight and BMI was mainly seen in the early years.
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Affiliation(s)
- Kingsley Wong
- Telethon Kids Institute, Perth, Western Australia, Australia
| | - George Davies
- Department of Paediatric Neurology, University Hospitals Bristol and Weston, Bristol, UK
| | - Helen Leonard
- Telethon Kids Institute, Perth, Western Australia, Australia
| | - Jenny Downs
- Telethon Kids Institute, Perth, Western Australia, Australia
| | - Mohammed Junaid
- Telethon Kids Institute, Perth, Western Australia, Australia
| | - Sam Amin
- Department of Paediatric Neurology, University Hospitals Bristol and Weston, Bristol, UK
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Martinez D, Jiang E, Zhou Z. Overcoming genetic and cellular complexity to study the pathophysiology of X-linked intellectual disabilities. J Neurodev Disord 2024; 16:5. [PMID: 38424476 PMCID: PMC10902969 DOI: 10.1186/s11689-024-09517-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 02/04/2024] [Indexed: 03/02/2024] Open
Abstract
X-linked genetic causes of intellectual disability (ID) account for a substantial proportion of cases and remain poorly understood, in part due to the heterogeneous expression of X-linked genes in females. This is because most genes on the X chromosome are subject to random X chromosome inactivation (XCI) during early embryonic development, which results in a mosaic pattern of gene expression for a given X-linked mutant allele. This mosaic expression produces substantial complexity, especially when attempting to study the already complicated neural circuits that underly behavior, thus impeding the understanding of disease-related pathophysiology and the development of therapeutics. Here, we review a few selected X-linked forms of ID that predominantly affect heterozygous females and the current obstacles for developing effective therapies for such disorders. We also propose a genetic strategy to overcome the complexity presented by mosaicism in heterozygous females and highlight specific tools for studying synaptic and circuit mechanisms, many of which could be shared across multiple forms of intellectual disability.
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Affiliation(s)
- Dayne Martinez
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA
- Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA
| | - Evan Jiang
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA
- Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA
| | - Zhaolan Zhou
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA.
- Medical Scientist Training Program, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA.
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19102, USA.
- Intellectual and Developmental Disabilities Research Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
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4
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Aznar-Laín G, Fernández-Mayoralas DM, Caicoya AG, Rocamora R, Pérez-Jurado LA. CDKL5 Deficiency Disorder Without Epilepsy. Pediatr Neurol 2023; 144:84-89. [PMID: 37201242 DOI: 10.1016/j.pediatrneurol.2023.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/14/2023] [Accepted: 04/19/2023] [Indexed: 05/20/2023]
Abstract
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) has epilepsy as a cardinal feature. Here we report two new female patients and review six previously published patients, one male and five females, with features of CDD but who never developed epilepsy. In contrast with the classical and severe CDD phenotype, they presented with milder gross motor delays, autism spectrum disorder, and no visual cortical impairment. Prolonged video electroencephalography was normal in adult cases but showed interictal frontal-temporal bilateral spikes and sharp waves in sleep in the three-year-old girl. Causative CDKL5 variants included two likely gene damaging (nonsense and frameshift) and six missense variants, being de novo or maternally inherited from asymptomatic females with skewed X-chromosome inactivation (two missense variants). Our data indicate that a milder form of CDD without epilepsy can occur in some cases without clear correlation with specific variants in the CDKL5 gene.
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Affiliation(s)
- Gemma Aznar-Laín
- Paediatric Neurology, Hospital del Mar, Barcelona, Spain; Program in Neurosciences, Hospital del Mar Research Institute (IMIM), Barcelona, Spain; Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
| | | | - Anne G Caicoya
- Epilepsy Monitoring Unit, Quironsalud Hospital, Madrid, Spain
| | - Rodrigo Rocamora
- Program in Neurosciences, Hospital del Mar Research Institute (IMIM), Barcelona, Spain; Epilepsy Monitoring Unit, Department of Neurology, Hospital del Mar, Barcelona, Spain
| | - Luis A Pérez-Jurado
- Program in Neurosciences, Hospital del Mar Research Institute (IMIM), Barcelona, Spain; Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain; Genetics Service, Hospital del Mar, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
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Factors influencing the attainment of major motor milestones in CDKL5 deficiency disorder. Eur J Hum Genet 2023; 31:169-178. [PMID: 35978140 PMCID: PMC9905550 DOI: 10.1038/s41431-022-01163-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/22/2022] [Accepted: 07/21/2022] [Indexed: 11/09/2022] Open
Abstract
This study investigated the influence of factors at birth and in infancy on the likelihood of achieving major motor milestones in CDKL5 Deficiency Disorder (CDD). Data on 350 individuals with a pathogenic CDKL5 variant was sourced from the International CDKL5 Disorder Database. A first model included factors available at birth (e.g., sex, variant group and mosaicism) and the second additionally included factors available during infancy (e.g., age at seizure onset, number of anti-seizure medications used, experience of a honeymoon period and formal therapy). Cox regression was used to model the time to achieve the milestones. The probability of attaining the outcomes at specific ages was estimated by evaluating the time-to-event function at specific covariate values. Independent sitting and walking were achieved by 177/350 and 57/325 children respectively. By seven years of age, 67.1% of females but only 37.3% of males could sit independently. About a quarter each of females and males achieved independent walking by eight and six years, respectively. When observed from birth, female gender, a late truncating variant and mosaicism impacted most positively on the likelihood of independent sitting. When observed from one year, later seizure onset and experiencing a honeymoon period also improved the likelihood of independent sitting. Factors that favoured sitting (except gender) also improved walking. Having a truncating variant between aa178 and aa781 reduced the likelihood of achieving independent sitting and walking. It is possible to utilise factors occurring early in life to inform the likelihood of future motor development in CDD.
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6
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CDKL5 deficiency causes epileptic seizures independent of cellular mosaicism. J Neurol Sci 2022; 443:120498. [PMID: 36417806 DOI: 10.1016/j.jns.2022.120498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 10/06/2022] [Accepted: 11/12/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE In a study using a mouse model of CDKL5 deficiency disorder (CDD), seizures are specific to female mice heterozygous for Cdkl5 mutations and not observed in hemizygous knockout males or homozygous knockout females. The aim of this study was to examine whether the clinical phenotype of patients with CDD can be impacted by the type of genetic variant. METHODS Eleven CDD patients (six females and five males) were included in this study. The molecular diagnosis of hemizygous male patients was performed using digital PCR and their clinical phenotypes were compared with those of patients with mosaic or heterozygous CDKL5 variants. The severity of clinical phenotypes was graded by using CDKL5 Developmental Score and the adapted version of the CDKL5 Clinical Severity Assessment. The effect of cellular mosaicism on the severity of CDD was studied by comparing the clinical characteristics and comorbidities between individuals with hemizygous and mosaic or heterozygous CDKL5 variants. RESULTS One of the five male patients was mosaic for the CDKL5 variant. All patients developed seizures irrespective of their genetic status of the pathogenic variant. However, cellular mosaicism of CDKL5 deficiency was associated with lesser severity of other comorbidities such as feeding, respiratory, and visual functional impairments. SIGNIFICANCE This study provided evidence that cellular mosaicism of CDKL5 deficiency was not necessarily required for developing epilepsy. CDD patients not only exhibited clinical features of epilepsy but also exhibited the developmental consequences arising directly from the effect of the CDKL5 pathogenic variant.
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7
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Keehan L, Haviland I, Gofin Y, Swanson LC, El Achkar CM, Schreiber J, VanNoy GE, O’Heir E, O’Donnell-Luria A, Lewis RA, Magoulas P, Tran A, Azamian MS, Chao HT, Pham L, Samaco RC, Elsea S, Thorpe E, Kesari A, Perry D, Lee B, Lalani SR, Rosenfeld JA, Olson HE, Burrage LC. Wide range of phenotypic severity in individuals with late truncations unique to the predominant CDKL5 transcript in the brain. Am J Med Genet A 2022; 188:3516-3524. [PMID: 35934918 PMCID: PMC9669137 DOI: 10.1002/ajmg.a.62940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/10/2022] [Accepted: 06/19/2022] [Indexed: 01/31/2023]
Abstract
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is caused by heterozygous or hemizygous variants in CDKL5 and is characterized by refractory epilepsy, cognitive and motor impairments, and cerebral visual impairment. CDKL5 has multiple transcripts, of which the longest transcripts, NM_003159 and NM_001037343, have been used historically in clinical laboratory testing. However, the transcript NM_001323289 is the most highly expressed in brain and contains 170 nucleotides at the 3' end of its last exon that are noncoding in other transcripts. Two truncating variants in this region have been reported in association with a CDD phenotype. To clarify the significance and range of phenotypes associated with late truncating variants in this region of the predominant transcript in the brain, we report detailed information on two individuals, updated clinical information on a third individual, and a summary of published and unpublished individuals reported in ClinVar. The two new individuals (one male and one female) each had a relatively mild clinical presentation including periods of pharmaco-responsive epilepsy, independent walking and limited purposeful communication skills. A previously reported male continued to have a severe phenotype. Overall, variants in this region demonstrate a range of clinical severity consistent with reports in CDD but with the potential for milder presentation.
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Affiliation(s)
- Laura Keehan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Isabel Haviland
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Yoel Gofin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Lindsay C. Swanson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Christelle Moufawad El Achkar
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - John Schreiber
- Division of Epilepsy, Neurophysiology, and Critical Care Neurology, 8404 Children's National Hospital, Washington, DC, USA
| | - Grace E. VanNoy
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Emily O’Heir
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Anne O’Donnell-Luria
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Genetics and Genomics, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Richard A. Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| | - Pilar Magoulas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Alyssa Tran
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Mahshid S. Azamian
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Hsiao-Tuan Chao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
- Departments of Neuroscience and Pediatrics, Division of Neurology and Developmental Neuroscience, BCM, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- McNair Medical Institute at the Robert and Janice McNair Foundation, Houston, TX, USA
| | - Lisa Pham
- The Meyer Center for Developmental Pediatrics, Texas Children’s Hospital, Houston, TX, USA
| | - Rodney C. Samaco
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sarah Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | | | | | | | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Seema R. Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Heather E. Olson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Equal contributions
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
- Equal contributions
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CDKL5 deficiency disorder: molecular insights and mechanisms of pathogenicity to fast-track therapeutic development. Biochem Soc Trans 2022; 50:1207-1224. [PMID: 35997111 PMCID: PMC9444073 DOI: 10.1042/bst20220791] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/28/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022]
Abstract
CDKL5 deficiency disorder (CDD) is an X-linked brain disorder of young children and is caused by pathogenic variants in the cyclin-dependent kinase-like 5 (CDKL5) gene. Individuals with CDD suffer infantile onset, drug-resistant seizures, severe neurodevelopmental impairment and profound lifelong disability. The CDKL5 protein is a kinase that regulates key phosphorylation events vital to the development of the complex neuronal network of the brain. Pathogenic variants identified in patients may either result in loss of CDKL5 catalytic activity or are hypomorphic leading to partial loss of function. Whilst the progressive nature of CDD provides an excellent opportunity for disease intervention, we cannot develop effective therapeutics without in-depth knowledge of CDKL5 function in human neurons. In this mini review, we summarize new findings on the function of CDKL5. These include CDKL5 phosphorylation targets and the consequence of disruptions on signaling pathways in the human brain. This new knowledge of CDKL5 biology may be leveraged to advance targeted drug discovery and rapid development of treatments for CDD. Continued development of effective humanized models will further propel our understanding of CDD biology and may permit the development and testing of therapies that will significantly alter CDD disease trajectory in young children.
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Ta D, Downs J, Baynam G, Wilson A, Richmond P, Schmidt A, Decker A, Leonard H. Development of an International Database for a Rare Genetic Disorder: The MECP2 Duplication Database (MDBase). CHILDREN 2022; 9:children9081111. [PMID: 35892614 PMCID: PMC9332564 DOI: 10.3390/children9081111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 11/16/2022]
Abstract
The natural history of MECP2 duplication syndrome (MDS), a rare X-linked neurodevelopmental disorder with an estimated birth prevalence of 1/150,000 live births, is poorly understood due to a lack of clinical data collected for research. Such information is critical to the understanding of disease progression, therapeutic endpoints and outcome measures for clinical trials, as well as the development of therapies and orphan products. This clinical information can be systematically collected from caregivers through data collation efforts—yet, no such database has existed for MDS before now. Here, in this methodological study, we document the development, launch and management of the international MECP2 Duplication Database (MDBase). The MDBase consists of an extensive family questionnaire that collects information on general medical history, system-specific health problems, medication and hospitalisation records, developmental milestones and function, and quality of life (for individuals with MDS, and their caregivers). Launched in 2020, in its first two years of operation the MDBase has collected clinical data from 154 individuals from 26 countries—the largest sample size to date. The success of this methodology for the establishment and operation of the MDBase may provide insight and aid in the development of databases for other rare neurodevelopmental disorders.
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Affiliation(s)
- Daniel Ta
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
| | - Jenny Downs
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
- Curtin School of Allied Health, Curtin University, Bentley, WA 6102, Australia
| | - Gareth Baynam
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
- Rare Care Centre, Perth Children’s Hospital, Nedlands, WA 6009, Australia
- Western Australian Register of Developmental Anomalies, King Edward Memorial Hospital, Subiaco, WA 6904, Australia
| | - Andrew Wilson
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
- Curtin School of Allied Health, Curtin University, Bentley, WA 6102, Australia
- North Entrance, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, WA 6009, Australia
- Discipline of Paediatrics, School of Medicine, University of Western Australia, Perth, WA 6009, Australia
| | - Peter Richmond
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
- North Entrance, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, WA 6009, Australia
- Discipline of Paediatrics, School of Medicine, University of Western Australia, Perth, WA 6009, Australia
| | - Aron Schmidt
- MECP2 Duplication Foundation, Tuscon, AZ 85724, USA; (A.S.); (A.D.)
| | - Amelia Decker
- MECP2 Duplication Foundation, Tuscon, AZ 85724, USA; (A.S.); (A.D.)
- Department of Paediatrics, University of Arizona College of Medicine, Tuscon, AZ 85724, USA
| | - Helen Leonard
- Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia; (D.T.); (J.D.); (G.B.); (A.W.); (P.R.)
- Correspondence:
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10
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Leonard H, Downs J, Benke TA, Swanson L, Olson H, Demarest S. CDKL5 deficiency disorder: clinical features, diagnosis, and management. Lancet Neurol 2022; 21:563-576. [PMID: 35483386 PMCID: PMC9788833 DOI: 10.1016/s1474-4422(22)00035-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 12/19/2021] [Accepted: 01/18/2022] [Indexed: 12/25/2022]
Abstract
CDKL5 deficiency disorder (CDD) was first identified as a cause of human disease in 2004. Although initially considered a variant of Rett syndrome, CDD is now recognised as an independent disorder and classified as a developmental epileptic encephalopathy. It is characterised by early-onset (generally within the first 2 months of life) seizures that are usually refractory to polypharmacy. Development is severely impaired in patients with CDD, with only a quarter of girls and a smaller proportion of boys achieving independent walking; however, there is clinical variability, which is probably genetically determined. Gastrointestinal, sleep, and musculoskeletal problems are common in CDD, as in other developmental epileptic encephalopathies, but the prevalence of cerebral visual impairment appears higher in CDD. Clinicians diagnosing infants with CDD need to be familiar with the complexities of this disorder to provide appropriate counselling to the patients' families. Despite some benefit from ketogenic diets and vagal nerve stimulation, there has been little evidence that conventional antiseizure medications or their combinations are helpful in CDD, but further treatment trials are finally underway.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia.
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia; Curtin School of Allied Health, Curtin University, Perth, WA, Australia
| | - Tim A Benke
- Department of Neurology, Children's Hospital Colorado, Aurora, CO, USA; Department of Pediatrics, University of Colorado at Denver, Aurora, CO, USA; Department of Pharmacology, University of Colorado at Denver, Aurora, CO, USA; Department of Neurology, University of Colorado at Denver, Aurora, CO, USA; Department of Otolaryngology, University of Colorado at Denver, Aurora, CO, USA
| | - Lindsay Swanson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Heather Olson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Scott Demarest
- Department of Neurology, Children's Hospital Colorado, Aurora, CO, USA; Department of Pediatrics, University of Colorado at Denver, Aurora, CO, USA; Department of Neurology, University of Colorado at Denver, Aurora, CO, USA
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11
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Hieu NLT, Thu NTM, Ngan LTA, Van LTK, Huy DP, Linh PTT, Mai NTQ, Hien HTD, Hang DTT. Genetic analysis using targeted exome sequencing of 53 Vietnamese children with developmental and epileptic encephalopathies. Am J Med Genet A 2022; 188:2048-2060. [PMID: 35365919 DOI: 10.1002/ajmg.a.62741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 01/14/2022] [Accepted: 03/13/2022] [Indexed: 11/07/2022]
Abstract
Developmental and epileptic encephalopathies (DEE) refers to a group of rare and severe neurodevelopmental disorders where genetic etiologies can play a major role. This study aimed to elucidate the genetic etiologies of a cohort of 53 Vietnamese patients with DEE. All patients were classified into known electroclinical syndromes where possible. Exome sequencing (ES) followed by a targeted analysis on 294 DEE-related genes was then performed. Patients with identified causative variants were followed for 6 months to determine the impact of genetic testing on their treatment. The diagnostic yield was 38.0% (20/53), which was significantly higher in the earlier onset group (<12 months) than in the later onset group (≥12 months). The 19 identified variants belonged to 11 genes with various cellular functions. Genes encoding ion channels especially sodium voltage-gated channel were the most frequently involved. Most variants were missense variants and located in key protein functional domains. Four variants were novel and four had been reported previously but in different phenotypes. Within 6 months of further follow-up, treatment changes were applied for six patients based on the identified disease-causing variants, with five patients showing a positive impact. This is the first study in Vietnam to analyze the genetics of DEE. This study confirms the strong involvement of genetic etiologies in DEE, especially early onset DEE. The study also contributes to clarify the genotype-phenotype correlations of DEE and highlights the efficacy of targeted ES in the diagnosis and treatment of DEE.
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Affiliation(s)
- Nguyen Le Trung Hieu
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam.,University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | | | - Le Tran Anh Ngan
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Le Thi Khanh Van
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Do Phuoc Huy
- Medical Genetics Institute, Ho Chi Minh City, Vietnam
| | - Pham Thi Truc Linh
- Functional Genomic Unit, DNA Medical Technology Company, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Quynh Mai
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Huynh Thi Dieu Hien
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Do Thi Thu Hang
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
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12
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Fang X, Butler KM, Abidi F, Gass J, Beisang A, Feyma T, Ryther RC, Standridge S, Heydemann P, Jones M, Haas R, Lieberman DN, Marsh E, Benke TA, Skinner S, Neul JL, Percy AK, Friez MJ, Caylor RC. Analysis of X-inactivation status in a Rett syndrome natural history study cohort. Mol Genet Genomic Med 2022; 10:e1917. [PMID: 35318820 PMCID: PMC9034674 DOI: 10.1002/mgg3.1917] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a rare neurodevelopmental disorder associated with pathogenic MECP2 variants. Because the MECP2 gene is subject to X-chromosome inactivation (XCI), factors including MECP2 genotypic variation, tissue differences in XCI, and skewing of XCI all likely contribute to the clinical severity of individuals with RTT. METHODS We analyzed the XCI patterns from blood samples of 320 individuals and their mothers. It includes individuals with RTT (n = 287) and other syndromes sharing overlapping phenotypes with RTT (such as CDKL5 Deficiency Disorder [CDD, n = 16]). XCI status in each proband/mother duo and the parental origin of the preferentially inactivated X chromosome were analyzed. RESULTS The average XCI ratio in probands was slightly increased compared to their unaffected mothers (73% vs. 69%, p = .0006). Among the duos with informative XCI data, the majority of individuals with classic RTT had their paternal allele preferentially inactivated (n = 180/220, 82%). In sharp contrast, individuals with CDD had their maternal allele preferentially inactivated (n = 10/12, 83%). Our data indicate a weak positive correlation between XCI skewing ratio and clinical severity scale (CSS) scores in classic RTT patients with maternal allele preferentially inactivated XCI (rs = 0.35, n = 40), but not in those with paternal allele preferentially inactivated XCI (rs = -0.06, n = 180). The most frequent MECP2 pathogenic variants were enriched in individuals with highly/moderately skewed XCI patterns, suggesting an association with higher levels of XCI skewing. CONCLUSION These results extend our understanding of the pathogenesis of RTT and other syndromes with overlapping clinical features by providing insight into the both XCI and the preferential XCI of parental alleles.
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Affiliation(s)
- Xiaolan Fang
- Greenwood Genetic CenterGreenwoodSouth CarolinaUSA
| | | | - Fatima Abidi
- Greenwood Genetic CenterGreenwoodSouth CarolinaUSA
| | - Jennifer Gass
- Florida Cancer Specialists & Research InstituteFort MyersFLUSA,Present address:
Florida Cancer Specialists & Research InstituteFort MyersFloridaUSA
| | - Arthur Beisang
- Gillette Children’s Specialty HealthcareSt. PaulMinnesotaUSA
| | - Timothy Feyma
- Gillette Children’s Specialty HealthcareSt. PaulMinnesotaUSA
| | - Robin C. Ryther
- Department of NeurologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Shannon Standridge
- Division of NeurologyCincinnati Children’s Hospital Medical CenterCincinnatiOhioUSA,Department of Pediatrics, College of MedicineUniversity of CincinnatiCincinnatiOhioUSA
| | | | - Mary Jones
- Oakland Children’s Hospital, UCSFOaklandCaliforniaUSA
| | - Richard Haas
- University of California San DiegoSan DiegoCaliforniaUSA
| | - David N Lieberman
- Department of NeurologyBoston Children’s HospitalBostonMassachusettsUSA
| | - Eric D. Marsh
- Children’s Hospital of Philadelphia and University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Tim A. Benke
- University of Colorado School of Medicine, Children’s Hospital Colorado‐AuroraDenverColoradoUSA
| | | | - Jeffrey L. Neul
- Vanderbilt Kennedy CenterVanderbilt University Medical CenterNashville TN
| | - Alan K. Percy
- The University of Alabama at BirminghamBirminghamAlabamaUSA
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13
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Amin S, Monaghan M, Aledo-Serrano A, Bahi-Buisson N, Chin RF, Clarke AJ, Cross JH, Demarest S, Devinsky O, Downs J, Pestana Knight EM, Olson H, Partridge CA, Stuart G, Trivisano M, Zuberi S, Benke TA. International Consensus Recommendations for the Assessment and Management of Individuals With CDKL5 Deficiency Disorder. Front Neurol 2022; 13:874695. [PMID: 35795799 PMCID: PMC9251467 DOI: 10.3389/fneur.2022.874695] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
CDKL5 Deficiency Disorder (CDD) is a rare, X-linked dominant condition that causes a developmental and epileptic encephalopathy (DEE). The incidence is between ~ 1:40,000 and 1:60,000 live births. Pathogenic variants in CDKL5 lead to seizures from infancy and severe neurodevelopmental delay. During infancy and childhood, individuals with CDD suffer impairments affecting cognitive, motor, visual, sleep, gastrointestinal and other functions. Here we present the recommendations of international healthcare professionals, experienced in CDD management, to address the multisystem and holistic needs of these individuals. Using a Delphi method, an anonymous survey was administered electronically to an international and multidisciplinary panel of expert clinicians and researchers. To provide summary recommendations, consensus was set, a priori, as >70% agreement for responses. In the absence of large, population-based studies to provide definitive evidence for treatment, we propose recommendations for clinical management, influenced by this proposed threshold for consensus. We believe these recommendations will help standardize, guide and improve the medical care received by individuals with CDD.
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Affiliation(s)
- Sam Amin
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, United Kingdom
| | - Marie Monaghan
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, United Kingdom
| | - Angel Aledo-Serrano
- Epilepsy Program, Department of Neurology, Ruber Internacional Hospital, Madrid, Spain
| | - Nadia Bahi-Buisson
- Pediatric Neurology, Necker Enfants Malades, Université de Paris, Paris, France
| | - Richard F Chin
- Royal Hospital for Sick Children, University of Edinburgh, Edinburgh, United Kingdom
| | - Angus J Clarke
- University Hospital of Wales, Cardiff University, Cardiff, United Kingdom
| | - J Helen Cross
- Developmental Neurosciences, UCL NIHR BRC Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Scott Demarest
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine, Children's Hospital Colorado, Aurora, CO, United States
| | - Orrin Devinsky
- Department of Neurology, New York University, New York, NY, United States
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Perth, WA, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, WA, Australia
| | - Elia M Pestana Knight
- Cleveland Clinic Epilepsy Center, Cleveland Clinic Learner College of Medicine, Cleveland, OH, United States
| | - Heather Olson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA, United States
| | | | - Graham Stuart
- Bristol Heart Institute, Bristol Royal Hospital for Children, University of Bristol, Bristol, United Kingdom
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Sameer Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, United Kingdom.,College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Tim A Benke
- Department of Pediatrics, Pharmacology, Neurology, and Otolaryngology, University of Colorado School of Medicine, Children's Hospital Colorado, Aurora, CO, United States
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14
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Leonard H, Junaid M, Wong K, Aimetti AA, Pestana Knight E, Downs J. Influences on the trajectory and subsequent outcomes in CDKL5 deficiency disorder. Epilepsia 2021; 63:352-363. [PMID: 34837650 DOI: 10.1111/epi.17125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 10/28/2021] [Accepted: 11/02/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The study investigated the effect of seizure and medication burden at initial contact with the International CDKL5 Disorder Database on subsequent development and clinical severity and compared quality of life among those whose development progressed, remained stable, or regressed between baseline and follow-up. METHODS The effects of seizure and medication burden at baseline (high or low) on the CDKL5 Disorder Severity Scores and CDKL5 Developmental Score (CDS) at follow-up were assessed using linear and negative binomial regressions, respectively, with adjustment for age at baseline, gender, and follow-up duration with and without genotype. Seizure and medication burden were defined by average daily seizure count (high, ≥5/day; low, <5/day) and number of antiseizure medications (high, ≥3/day; low, <3/day), respectively. The effects of change in CDS over time (improved, stable, or deteriorated) on Quality of Life Inventory-Disability (QI-Disability) total and domain scores at follow-up were assessed in those aged at least 3 years at follow-up using linear regression models with adjustment for baseline CDS, gender, and follow-up duration. RESULTS The expected follow-up CDS was lower for individuals with high compared to low seizure burden at baseline (β = -.49, 95% confidence interval [CI] = -.84 to -.13). The average total QI-Disability score was 5.6 (95% CI = -.2 to 11.5) points higher among those with improved compared with stable or deteriorating CDS and 8.5 (95% CI = 3.1-13.8) points lower for those with deteriorating compared to stable or improved CDS. SIGNIFICANCE Our finding that later development showed slight improvement in those with better earlier seizure control even after adjustment for genotype suggests that the trajectory for an individual child is not necessarily predetermined and could possibly be influenced by optimal seizure management. This has implications for children's quality of life.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia.,Faculty of Health and Medical Sciences, Centre of Child Health Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Mohammed Junaid
- Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia
| | - Kingsley Wong
- Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia
| | | | - Elia Pestana Knight
- Pediatric Epilepsy Section, Epilepsy Center, Cleveland Clinic, Neurological Institute, Cleveland, Ohio, USA
| | - Jenny Downs
- Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia
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15
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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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16
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Brock DC, Demarest S, Benke TA. Clinical Trial Design for Disease-Modifying Therapies for Genetic Epilepsies. Neurotherapeutics 2021; 18:1445-1457. [PMID: 34595733 PMCID: PMC8609073 DOI: 10.1007/s13311-021-01123-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 02/04/2023] Open
Abstract
Although trials with anti-seizure medications (ASMs) have not shown clear anti-epileptogenic or disease-modifying activity in humans to date, rapid advancements in genomic technology and emerging gene-mediated and gene replacement options offer hope for the successful development of disease-modifying therapies (DMTs) for genetic epilepsies. In fact, more than 26 potential DMTs are in various stages of preclinical and/or clinical development for genetic syndromes associated with epilepsy. The scope of disease-modification includes but is not limited to effects on the underlying pathophysiology, the condition's natural history, epilepsy severity, developmental achievement, function, behavior, sleep, and quality of life. While conventional regulatory clinical trials for epilepsy therapeutics have historically focused on seizure reduction, similarly designed trials may prove ill-equipped to identify these broader disease-modifying benefits. As we look forward to this pipeline of DMTs, focused consideration should be given to the challenges they pose to conventional clinical trial designs for epilepsy therapeutics. Just as DMTs promise to fundamentally alter how we approach the care of patients with genetic epilepsy syndromes, DMTs likewise challenge how we traditionally construct and measure the success of clinical trials. In the following, we briefly review the historical and preclinical frameworks for DMT development for genetic epilepsies and explore the many novel challenges posed for such trials, including the choice of suitable outcome measures, trial structure, timing and duration of treatment, feasible follow-up period, varying safety profile, and ethical concerns.
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Affiliation(s)
- Dylan C Brock
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
- Children's Hospital Colorado, Aurora, CO, 80045, USA.
| | - Scott Demarest
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Children's Hospital Colorado, Aurora, CO, 80045, USA
| | - Tim A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Departments of Neurology, Pharmacology, and Otolaryngology, University of Colorado School of Medicine, CO, 80045, Aurora, USA
- Children's Hospital Colorado, Aurora, CO, 80045, USA
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17
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Patient-Derived Induced Pluripotent Stem Cells (iPSCs) and Cerebral Organoids for Drug Screening and Development in Autism Spectrum Disorder: Opportunities and Challenges. Pharmaceutics 2021; 13:pharmaceutics13020280. [PMID: 33669772 PMCID: PMC7922555 DOI: 10.3390/pharmaceutics13020280] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/23/2022] Open
Abstract
Autism spectrum disorder (ASD) represents a group of neurodevelopmental diseases characterized by persistent deficits in social communication, interaction, and repetitive patterns of behaviors, interests, and activities. The etiopathogenesis is multifactorial with complex interactions between genetic and environmental factors. The clinical heterogeneity and complex etiology of this pediatric disorder have limited the development of pharmacological therapies. The major limit to ASD research remains a lack of relevant human disease models which can faithfully recapitulate key features of the human pathology and represent its genetic heterogeneity. Recent advances in induced pluripotent stem cells (iPSCs), reprogrammed from somatic cells of patients into all types of patient-specific neural cells, have provided a promising cellular tool for disease modeling and development of novel drug treatments. The iPSCs technology allowed not only a better investigation of the disease etiopathogenesis but also opened up the potential for personalized therapies and offered new opportunities for drug discovery, pharmacological screening, and toxicity assessment. Moreover, iPSCs can be differentiated and organized into three-dimensional (3D) organoids, providing a model which mimics the complexity of the brain’s architecture and more accurately recapitulates tissue- and organ-level disease pathophysiology. The aims of this review were to describe the current state of the art of the use of human patient-derived iPSCs and brain organoids in modeling ASD and developing novel therapeutic strategies and to discuss the opportunities and major challenges in this rapidly moving field.
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