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Daniels C, Greene C, Smith L, Pestana-Knight E, Demarest S, Zhang B, Benke TA, Poduri A, Olson H. CDKL5 deficiency disorder and other infantile-onset genetic epilepsies. Dev Med Child Neurol 2024; 66:456-468. [PMID: 37771170 PMCID: PMC10922313 DOI: 10.1111/dmcn.15747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 07/25/2023] [Accepted: 08/02/2023] [Indexed: 09/30/2023]
Abstract
AIM To differentiate phenotypic features of individuals with CDKL5 deficiency disorder (CDD) from those of individuals with other infantile-onset epilepsies. METHOD We performed a retrospective cohort study and ascertained individuals with CDD and comparison individuals with infantile-onset epilepsy who had epilepsy gene panel testing. We reviewed records, updated variant classifications, and compared phenotypic features. Wilcoxon rank-sum tests and χ2 or Fisher's exact tests were performed for between-cohort comparisons. RESULTS We identified 137 individuals with CDD (110 females, 80.3%; median age at last follow-up 3 year 11 months) and 313 individuals with infantile-onset epilepsies (156 females, 49.8%; median age at last follow-up 5 years 2 months; 35% with genetic diagnosis). Features reported significantly more frequently in the CDD group than in the comparison cohort included developmental and epileptic encephalopathy (81% vs 66%), treatment-resistant epilepsy (95% vs 71%), sequential seizures (46% vs 6%), epileptic spasms (66% vs 42%, with hypsarrhythmia in 30% vs 48%), regression (52% vs 29%), evolution to Lennox-Gastaut syndrome (23% vs 5%), diffuse hypotonia (72% vs 36%), stereotypies (69% vs 11%), paroxysmal movement disorders (29% vs 17%), cerebral visual impairment (94% vs 28%), and failure to thrive (38% vs 22%). INTERPRETATION CDD, compared with other suspected or confirmed genetic epilepsies presenting in the first year of life, is more often characterized by a combination of treatment-resistant epilepsy, developmental and epileptic encephalopathy, sequential seizures, spasms without hypsarrhythmia, diffuse hypotonia, paroxysmal movement disorders, cerebral visual impairment, and failure to thrive. Defining core phenotypic characteristics will improve precision diagnosis and treatment.
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Affiliation(s)
- Carolyn Daniels
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Caitlin Greene
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Lacey Smith
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Elia Pestana-Knight
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Scott Demarest
- Children’s Hospital Colorado, Aurora, CO, USA
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Bo Zhang
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Timothy A Benke
- Children’s Hospital Colorado, Aurora, CO, USA
- Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO, USA
- Department of Pharmacology, University of Colorado, School of Medicine, Aurora, CO, USA
- Department of Neurology, University of Colorado, School of Medicine, Aurora, CO, USA
- Department of Otolaryngology, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Annapurna Poduri
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Heather Olson
- Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
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Raspa M, Gwaltney A, Bann C, von Hehn J, Benke TA, Marsh ED, Peters SU, Ananth A, Percy AK, Neul JL. Psychometric Assessment of the Rett Syndrome Caregiver Assessment of Symptom Severity (RCASS). J Autism Dev Disord 2024:10.1007/s10803-024-06238-0. [PMID: 38438817 DOI: 10.1007/s10803-024-06238-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2024] [Indexed: 03/06/2024]
Abstract
Rett syndrome is a severe neurodevelopmental disorder that affects about 1 in 10,000 females. Clinical trials of disease modifying therapies are on the rise, but there are few psychometrically sound caregiver-reported outcome measures available to assess treatment benefit. We report on a new caregiver-reported outcome measure, the Rett Caregiver Assessment of Symptom Severity (RCASS). Using data from the Rett Natural History Study (n = 649), we examined the factor structure, using both exploratory and confirmatory factor analysis, and the reliability and validity of the RCASS. The four-factor model had the best overall fit, which covered movement, communication, behavior, and Rett-specific symptoms. The RCASS had moderate internal consistency. Strong face validity was found with age and mutation type, and convergent validity was established with other similar measures, including the Revised Motor-Behavior Assessment Scale, Clinical Severity Scale, Clinical Global Impression Scale, and the Child Health Questionnaire. These data provide initial evidence that the RCASS is a viable caregiver-outcome measure for use in clinical trials in Rett syndrome. Future work to assess sensitivity to change and other measures of reliability, such as test-retest and inter-rater agreement, are needed.
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Affiliation(s)
- Melissa Raspa
- RTI International, 3040 East Cornwallis Road, Research Triangle Park, NC, 27708, USA.
| | - Angela Gwaltney
- RTI International, 3040 East Cornwallis Road, Research Triangle Park, NC, 27708, USA
| | - Carla Bann
- RTI International, 3040 East Cornwallis Road, Research Triangle Park, NC, 27708, USA
| | | | - Timothy A Benke
- Children's Hospital Colorado and University of Colorado School of Medicine, Aurora, USA
| | - Eric D Marsh
- Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Sarika U Peters
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, USA
| | - Amitha Ananth
- University of Alabama at Birmingham, Birmingham, USA
| | - Alan K Percy
- University of Alabama at Birmingham, Birmingham, USA
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, USA.
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Neul JL, Percy AK, Benke TA, Berry-Kravis EM, Glaze DG, Peters SU, Marsh ED, An D, Bishop KM, Youakim JM. Trofinetide Treatment Demonstrates a Benefit Over Placebo for the Ability to Communicate in Rett Syndrome. Pediatr Neurol 2024; 152:63-72. [PMID: 38232652 DOI: 10.1016/j.pediatrneurol.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/27/2023] [Accepted: 11/18/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND Trofinetide was approved by the US Food and Drug Administration for the treatment of Rett syndrome (RTT) in March 2023. Benefiting the ability to communicate in RTT is often identified as the most important caregiver goal for new therapies. This analysis reports the communication-related end points from the phase 3 LAVENDER study of trofinetide in RTT. METHODS Females with RTT, aged five to 20 years, were randomized 1:1 to trofinetide or placebo for 12 weeks. Secondary efficacy end points related to communication were based on change from baseline to week 12 and included the caregiver-rated Communication and Symbolic Behavior Scales Developmental Profile™ Infant-Toddler Checklist (CSBS-DP-IT) Social Composite score (key secondary end point; scores ranged from 0 to 26 [higher scores indicated better communication]) and novel clinician rating scales (0 [normal] to 7 [severe impairment]) measuring the ability to communicate choices nonverbally (RTT-COMC) and verbally (RTT-VCOM). RESULTS Trofinetide demonstrated a statistically significant difference versus placebo for the CSBS-DP-IT Social Composite score (least squares mean [LSM] difference = 1.0; 95% confidence interval [CI], 0.3 to 1.7; P = 0.0064; Cohen's d effect size = 0.43) and a nominally significant difference for the RTT-COMC (LSM difference: -0.3; 95% CI, -0.6 to -0.0; P = 0.0257; Cohen's d effect size = 0.36). As expected, there was no difference for the RTT-VCOM. CONCLUSIONS Significant treatment benefit for trofinetide versus placebo was observed in scales measuring the ability to communicate. These scales may be appropriate for future clinical studies in RTT and other neurodevelopmental disorders.
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Affiliation(s)
- Jeffrey L Neul
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alan K Percy
- University of Alabama at Birmingham, Birmingham, Alabama
| | - Timothy A Benke
- Children's Hospital of Colorado, University of Colorado School of Medicine, Aurora, Colorado
| | | | - Daniel G Glaze
- Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - Sarika U Peters
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eric D Marsh
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Di An
- Acadia Pharmaceuticals Inc, San Diego, California
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Saldaris JM, Jacoby P, Marsh ED, Suter B, Leonard H, Olson HE, Rajaraman R, Pestana-Knight E, Weisenberg J, Price D, Drummond C, Benke TA, Demarest S, Downs J. Adapting a measure of gross motor skills for individuals with CDKL5 deficiency disorder: A psychometric study. Epilepsy Res 2024; 200:107287. [PMID: 38237219 DOI: 10.1016/j.eplepsyres.2024.107287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 02/23/2024]
Abstract
PURPOSE Validated measures capable of demonstrating meaningful interventional change in the CDKL5 deficiency disorder (CDD) are lacking. The study objective was to modify the Rett Syndrome Gross Motor Scale (RSGMS) and evaluate its psychometric properties for individuals with CDD. METHODS Item and scoring categories of the RSGMS were modified. Caregivers registered with the International CDKL5 Clinical Research Network uploaded motor videos filmed at home to a protected server and completed a feedback questionnaire (n = 70). Rasch (n = 137), known groups (n = 109), and intra- and inter-rater reliability analyses (n = 50) were conducted. RESULTS The age of individuals with CDD ranged from 1.5 to 34.1 years. The modified scale, Gross Motor-Complex Disability (GM-CD), comprised 17 items. There were no floor or ceiling effects and inter- and intra-rater reliability were good. Rasch analysis demonstrated that the items encompassed a large range of performance difficulty, although there was some item redundancy and some disordered categories. One item, Prone Head Position, was a poor fit. Caregiver-reported acceptability was positive. Scores differed by age and functional abilities. SUMMARY GM-CD appears to be a suitable remotely administered measure and psychometrically sound for individuals with CDD. This study provides the foundation to propose the use of GM-CD in CDD clinical trials. Longitudinal evaluation is planned.
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Affiliation(s)
- J M Saldaris
- Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia
| | - P Jacoby
- Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia
| | - E D Marsh
- Division of Child Neurology, Children's Hospital of Philadelphia and Departments of Neurology and Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - B Suter
- Department of Pediatrics & Neurology, Baylor College of Medicine, Houston, TX, USA
| | - H Leonard
- Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia
| | - H E Olson
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - R Rajaraman
- UCLA Mattel Children's Hospital, Los Angeles, CA, USA
| | | | - J Weisenberg
- St. Louis Children's Hospital and Washington University School of Medicine, St Louis, MO, USA
| | - D Price
- NYU Langone Health and Department of Neurology, New York University, New York, NY, USA
| | - C Drummond
- Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia
| | - T A Benke
- University of Colorado, School of Medicine, Depts Pediatrics, Neurology and Pharmacology and Children's Hospital Colorado, Aurora, CO, USA
| | - S Demarest
- University of Colorado, School of Medicine, Depts Pediatrics, Neurology and Pharmacology and Children's Hospital Colorado, Aurora, CO, USA.
| | - J Downs
- Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia; Curtin School of Allied Health, Curtin University, Perth, WA, Australia.
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XiangWei W, Perszyk RE, Liu N, Xu Y, Bhattacharya S, Shaulsky GH, Smith-Hicks C, Fatemi A, Fry AE, Chandler K, Wang T, Vogt J, Cohen JS, Paciorkowski AR, Poduri A, Zhang Y, Wang S, Wang Y, Zhai Q, Fang F, Leng J, Garber K, Myers SJ, Jauss RT, Park KL, Benke TA, Lemke JR, Yuan H, Jiang Y, Traynelis SF. Clinical and functional consequences of GRIA variants in patients with neurological diseases. Cell Mol Life Sci 2023; 80:345. [PMID: 37921875 PMCID: PMC10754216 DOI: 10.1007/s00018-023-04991-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 11/05/2023]
Abstract
AMPA receptors are members of the glutamate receptor family and mediate a fast component of excitatory synaptic transmission at virtually all central synapses. Thus, their functional characteristics are a critical determinant of brain function. We evaluate intolerance of each GRIA gene to genetic variation using 3DMTR and report here the functional consequences of 52 missense variants in GRIA1-4 identified in patients with various neurological disorders. These variants produce changes in agonist EC50, response time course, desensitization, and/or receptor surface expression. We predict that these functional and localization changes will have important consequences for circuit function, and therefore likely contribute to the patients' clinical phenotype. We evaluated the sensitivity of variant receptors to AMPAR-selective modulators including FDA-approved drugs to explore potential targeted therapeutic options.
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Affiliation(s)
- Wenshu XiangWei
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Nana Liu
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Yuchen Xu
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Neurology, The First Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, China
| | - Subhrajit Bhattacharya
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- School of Pharmaceutical and Health Sciences, Keck Graduate Institute, Claremont Colleges, Claremont, CA, 91711, USA
| | - Gil H Shaulsky
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Center for Functional Evaluation of Rare Variants, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Constance Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Ali Fatemi
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Andrew E Fry
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, CF14 4XW, UK
- Division of Cancer and Genetics, Cardiff University, Cardiff, CF14 4XN, UK
| | - Kate Chandler
- Manchester Centre for Genomic Medicine (MCGM), Manchester University NHS Foundation Trust, Saint Mary's Hospital, Oxford Road, Manchester, M13 9WL, UK
| | - Tao Wang
- Department of Pediatrics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, B4 6NH, UK
| | - Julie S Cohen
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Alex R Paciorkowski
- University of Rochester Medical Center, Child Neurology, 601 Elmwood Ave., Rochester, NY, 14642, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
| | - Yuehua Zhang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
| | - Shuang Wang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
| | - Yuping Wang
- Department of Neurology, Center of Epilepsy, Beijing Key Laboratory of Neuromodulation, Institute of Sleep and Consciousness Disorders, Beijing Institute for Brain Disorders, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Qiongxiang Zhai
- Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Fang Fang
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, 100069, China
| | - Jie Leng
- Department Neurology, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Zhengzhou, 450066, Henan, China
- Department of Endocrinology, Genetics and Metabolism, School of Medicine, Chengdu Women's and Children's Central Hospital, University of Electronic Science and Technology of China, Sichuan, 611731, China
| | - Kathryn Garber
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Scott J Myers
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Center for Functional Evaluation of Rare Variants, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Robin-Tobias Jauss
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Kristen L Park
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Timothy A Benke
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Hongjie Yuan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Center for Functional Evaluation of Rare Variants, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Yuwu Jiang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China.
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Center for Functional Evaluation of Rare Variants, Emory University School of Medicine, Atlanta, GA, 30322, USA.
- Emory Neurodegenerative Disease Center, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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Neul JL, Benke TA, Marsh ED, Suter B, Silveira L, Fu C, Peters SU, Percy AK. Top caregiver concerns in Rett syndrome and related disorders: data from the US natural history study. J Neurodev Disord 2023; 15:33. [PMID: 37833681 PMCID: PMC10571464 DOI: 10.1186/s11689-023-09502-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023] Open
Abstract
OBJECTIVE Recent advances in the understanding of neurodevelopmental disorders such as Rett syndrome (RTT) have enabled the discovery of novel therapeutic approaches that require formal clinical evaluation of efficacy. Clinical trial success depends on outcome measures that assess clinical features that are most impactful for affected individuals. To determine the top concerns in RTT and RTT-related disorders we asked caregivers to list the top caregiver concerns to guide the development and selection of appropriate clinical trial outcome measures for these disorders. METHODS Caregivers of participants enrolled in the US Natural History Study of RTT and RTT-related disorders (n = 925) were asked to identify the top 3 concerning problems impacting the affected participant. We generated a weighted list of top caregiver concerns for each of the diagnostic categories and compared results between the disorders. Further, for classic RTT, caregiver concerns were analyzed by age, clinical severity, and common RTT-causing mutations in MECP2. RESULTS The top caregiver concerns for classic RTT were effective communication, seizures, walking/balance issues, lack of hand use, and constipation. The frequency of the top caregiver concerns for classic RTT varied by age, clinical severity, and specific mutations, consistent with known variation in the frequency of clinical features across these domains. Caregivers of participants with increased seizure severity often ranked seizures as the first concern, whereas caregivers of participants without active seizures often ranked hand use or communication as the top concern. Comparison across disorders found commonalities in the top caregiver concerns between classic RTT, atypical RTT, MECP2 duplication syndrome, CDKL5 deficiency disorder, and FOXG1 syndrome; however, distinct differences in caregiver concerns between these disorders are consistent with the relative prevalence and impact of specific clinical features. CONCLUSION The top caregiver concerns for individuals with RTT and RTT-related disorders reflect the impact of the primary clinical symptoms of these disorders. This work is critical in the development of meaningful therapies, as optimal therapy should address these concerns. Further, outcome measures to be utilized in clinical trials should assess these clinical issues identified as most concerning by caregivers.
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Affiliation(s)
- Jeffrey L Neul
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Timothy A Benke
- University of Colorado School of Medicine/Children's Hospital Colorado, Aurora, CO, USA
| | - Eric D Marsh
- Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | | | - Lori Silveira
- University of Colorado School of Medicine/Children's Hospital Colorado, Aurora, CO, USA
| | - Cary Fu
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sarika U Peters
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan K Percy
- University of Alabama at Birmingham, Birmingham, AL, USA
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Myers SJ, Yuan H, Perszyk RE, Zhang J, Kim S, Nocilla KA, Allen JP, Bain JM, Lemke JR, Lal D, Benke TA, Traynelis SF. Classification of missense variants in the N-methyl-d-aspartate receptor GRIN gene family as gain- or loss-of-function. Hum Mol Genet 2023; 32:2857-2871. [PMID: 37369021 PMCID: PMC10508039 DOI: 10.1093/hmg/ddad104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Advances in sequencing technology have generated a large amount of genetic data from patients with neurological conditions. These data have provided diagnosis of many rare diseases, including a number of pathogenic de novo missense variants in GRIN genes encoding N-methyl-d-aspartate receptors (NMDARs). To understand the ramifications for neurons and brain circuits affected by rare patient variants, functional analysis of the variant receptor is necessary in model systems. For NMDARs, this functional analysis needs to assess multiple properties in order to understand how variants could impact receptor function in neurons. One can then use these data to determine whether the overall actions will increase or decrease NMDAR-mediated charge transfer. Here, we describe an analytical and comprehensive framework by which to categorize GRIN variants as either gain-of-function (GoF) or loss-of-function (LoF) and apply this approach to GRIN2B variants identified in patients and the general population. This framework draws on results from six different assays that assess the impact of the variant on NMDAR sensitivity to agonists and endogenous modulators, trafficking to the plasma membrane, response time course and channel open probability. We propose to integrate data from multiple in vitro assays to arrive at a variant classification, and suggest threshold levels that guide confidence. The data supporting GoF and LoF determination are essential to assessing pathogenicity and patient stratification for clinical trials as personalized pharmacological and genetic agents that can enhance or reduce receptor function are advanced. This approach to functional variant classification can generalize to other disorders associated with missense variants.
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Affiliation(s)
- Scott J Myers
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- The Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hongjie Yuan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- The Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jing Zhang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Sukhan Kim
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Kelsey A Nocilla
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - James P Allen
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- The Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jennifer M Bain
- Department of Neurology, Division of Child Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig 04103, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig 04103, Germany
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44106, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics (CCG), Medical Faculty of the University of Cologne, Köln 50923, Germany
| | - Timothy A Benke
- Department of Pediatrics, Pharmacology and Neurology, University of Colorado School of Medicine, and Children’s Hospital Colorado, Aurora, CO 80045, USA
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- The Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA
- Emory Neurodegenerative Disease Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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Percy AK, Neul JL, Benke TA, Marsh ED, Glaze DG. A review of the Rett Syndrome Behaviour Questionnaire and its utilization in the assessment of symptoms associated with Rett syndrome. Front Pediatr 2023; 11:1229553. [PMID: 37635789 PMCID: PMC10450502 DOI: 10.3389/fped.2023.1229553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/03/2023] [Indexed: 08/29/2023] Open
Abstract
The Rett Syndrome Behaviour Questionnaire (RSBQ), which is completed by the caregiver, is one of the most widely used efficacy measures in clinical studies of Rett syndrome (RTT) due to its specificity to the core features of RTT. As healthcare providers participate in routine healthcare assessments of individuals with RTT in clinical practice, there is a need for these providers to understand the psychometric properties of the RSBQ and how it relates to the core clinical features of RTT. Here, we describe the characteristics of the RSBQ, review the literature on its validity and reliability as well as its performance in a phase 2 study and the recent phase 3 LAVENDER study. The RSBQ was first shown to discriminate RTT from other intellectual disorders with good inter-rater and test-retest reliability scores. It was subsequently validated as an appropriate instrument for measuring behavior in females with RTT and adopted as a clinical trial outcome. In LAVENDER, the FDA-approved drug trofinetide significantly improved the RSBQ total score over placebo in girls and women with RTT and change from baseline for all RSBQ subscores were directionally in favor of trofinetide. The change in RSBQ was aligned with the Clinical Global Impression-Improvement scale, suggesting that improvement in behavioral components may be related to overall clinical status. Given its validity and ubiquity in RTT clinical studies, it is important that the interplay of the domains and the psychometric profile of the RSBQ are understood.
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Affiliation(s)
- Alan K. Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jeffrey L. Neul
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Timothy A. Benke
- Children’s Hospital of Colorado/University of Colorado School of Medicine, Aurora, CO, United States
| | - Eric D. Marsh
- Department of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Daniel G. Glaze
- Texas Children’s Hospital/Baylor College of Medicine, Houston, TX, United States
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9
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Meredith FL, Vu TA, Gehrke B, Benke TA, Dondzillo A, Rennie KJ. Expression of hyperpolarization-activated current ( Ih) in zonally defined vestibular calyx terminals of the crista. J Neurophysiol 2023; 129:1468-1481. [PMID: 37198134 PMCID: PMC10259860 DOI: 10.1152/jn.00135.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/19/2023] Open
Abstract
Calyx terminals make afferent synapses with type I hair cells in vestibular epithelia and express diverse ionic conductances that influence action potential generation and discharge regularity in vestibular afferent neurons. Here we investigated the expression of hyperpolarization-activated current (Ih) in calyx terminals in central and peripheral zones of mature gerbil crista slices, using whole cell patch-clamp recordings. Slowly activating Ih was present in >80% calyces tested in both zones. Peak Ih and half-activation voltages were not significantly different; however, Ih activated with a faster time course in peripheral compared with central zone calyces. Calyx Ih in both zones was blocked by 4-(N-ethyl-N-phenylamino)-1,2-dimethyl-6-(methylamino) pyrimidinium chloride (ZD7288; 100 µM), and the resting membrane potential became more hyperpolarized. In the presence of dibutyryl-cAMP (dB-cAMP), peak Ih was increased, activation kinetics became faster, and the voltage of half-activation was more depolarized compared with control calyces. In current clamp, calyces from both zones showed three different categories of firing: spontaneous firing, phasic firing where a single action potential was evoked after a hyperpolarizing pulse, or a single evoked action potential followed by membrane potential oscillations. In the absence of Ih, the latency to peak of the action potential increased; Ih produces a small depolarizing current that facilitates firing by driving the membrane potential closer to threshold. Immunostaining showed the expression of HCN2 subunits in calyx terminals. We conclude that Ih is found in calyx terminals across the crista and could influence conventional and novel forms of synaptic transmission at the type I hair cell-calyx synapse.NEW & NOTEWORTHY Calyx afferent terminals make synapses with vestibular hair cells and express diverse conductances that impact action potential firing in vestibular primary afferents. Conventional and nonconventional synaptic transmission modes are influenced by hyperpolarization-activated current (Ih), but regional differences were previously unexplored. We show that Ih is present in both central and peripheral calyces of the mammalian crista. Ih produces a small depolarizing resting current that facilitates firing by driving the membrane potential closer to threshold.
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Affiliation(s)
- Frances L Meredith
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Tiffany A Vu
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Brandon Gehrke
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Timothy A Benke
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, United States
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, Colorado, United States
- Department of Neurology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Anna Dondzillo
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
| | - Katherine J Rennie
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado, United States
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10
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Neul JL, Percy AK, Benke TA, Berry-Kravis EM, Glaze DG, Marsh ED, Lin T, Stankovic S, Bishop KM, Youakim JM. Trofinetide for the treatment of Rett syndrome: a randomized phase 3 study. Nat Med 2023; 29:1468-1475. [PMID: 37291210 PMCID: PMC10287558 DOI: 10.1038/s41591-023-02398-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 05/12/2023] [Indexed: 06/10/2023]
Abstract
Rett syndrome is a rare, genetic neurodevelopmental disorder. Trofinetide is a synthetic analog of glycine-proline-glutamate, the N-terminal tripeptide of the insulin-like growth factor 1 protein, and has demonstrated clinical benefit in phase 2 studies in Rett syndrome. In this phase 3 study ( https://clinicaltrials.gov identifier NCT04181723 ), females with Rett syndrome received twice-daily oral trofinetide (n = 93) or placebo (n = 94) for 12 weeks. For the coprimary efficacy endpoints, least squares mean (LSM) change from baseline to week 12 in the Rett Syndrome Behaviour Questionnaire for trofinetide versus placebo was -4.9 versus -1.7 (P = 0.0175; Cohen's d effect size, 0.37), and LSM Clinical Global Impression-Improvement at week 12 was 3.5 versus 3.8 (P = 0.0030; effect size, 0.47). For the key secondary efficacy endpoint, LSM change from baseline to week 12 in the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist Social Composite score was -0.1 versus -1.1 (P = 0.0064; effect size, 0.43). Common treatment-emergent adverse events included diarrhea (80.6% for trofinetide versus 19.1% for placebo), which was mostly mild to moderate in severity. Significant improvement for trofinetide compared with placebo was observed for the coprimary efficacy endpoints, suggesting that trofinetide provides benefit in treating the core symptoms of Rett syndrome.
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Affiliation(s)
- Jeffrey L Neul
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan K Percy
- University of Alabama at Birmingham, Birmingham, AL, USA
| | - Timothy A Benke
- Children's Hospital of Colorado and University of Colorado School of Medicine, Aurora, CO, USA
| | | | - Daniel G Glaze
- Texas Children's Hospital and Baylor College of Medicine, Houston, TX, USA
| | - Eric D Marsh
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Tim Lin
- Acadia Pharmaceuticals Inc., San Diego, CA, USA
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11
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Neul JL, Benke TA, Marsh ED, Suter B, Silveira L, Fu C, Peters SU, Percy AK. Top Caregiver Concerns in Rett syndrome and related disorders: data from the US Natural History Study. Res Sq 2023:rs.3.rs-2566253. [PMID: 36993737 PMCID: PMC10055548 DOI: 10.21203/rs.3.rs-2566253/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Objective Recent advances in the understanding of neurodevelopmental disorders such as Rett syndrome (RTT) has enabled development of novel therapeutic approaches that are currently undergoing clinical evaluation or are proposed to move into clinical development. Clinical trial success depends on outcome measures that assess clinical features that are most impactful for affected individuals. To determine the top concerns in RTT and RTT-related disorders we asked caregivers to list the top clinical concerns in order to gain information to guide the development and selection of outcome measures for future clinical trials. Methods Caregivers of participants enrolled in the US Natural History Study of RTT and related disorders were asked to identify the top 3 concerning problems impacting the affected participant. We generated a weighted list of top caregiver concerns for each of the diagnostic categories and compared results between the disorders. Further, for Classic RTT, caregiver concerns were analyzed by age, clinical severity, and common RTT-causing mutations in MECP2. Results The top caregiver concerns for Classic RTT were effective communication, seizures, walking/balance issues, lack of hand use, and constipation. The rank order of the frequency of the top caregiver concerns for Classic RTT varied by age, clinical severity, and specific mutations, consistent with known variation in the frequency of clinical features across these domains. The frequency of caregiver concern for seizures, hand use, and spoken language increased in relation to clinician assessed severity in these clinical domains, showing consistency between clinician assessments and caregiver concerns. Comparison across disorders found commonalities in the top caregiver concerns between Classic RTT, Atypical RTT, MECP2 Duplication Syndrome, CDKL5 Deficiency Disorder, and FOXG1 Syndrome; however, distinct differences in caregiver concerns between these disorders are consistent with the relative prevalence and impact of specific clinical features. Conclusion The top caregiver concerns for individuals with RTT and the RTT-related disorders reflect the impact of the primary clinical symptoms of these disorders. This work is critical in the development of meaningful therapies, as optimal therapy should address these concerns. Further, outcome measures to be utilized in clinical trials should assess these clinical issues identified as most concerning by caregivers.
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Affiliation(s)
| | - Timothy A Benke
- University of Colorado School of Medicine: University of Colorado Anschutz Medical Campus School of Medicine
| | | | | | - Lori Silveira
- University of Colorado School of Medicine: University of Colorado Anschutz Medical Campus School of Medicine
| | - Cary Fu
- Vanderbilt University Medical Center
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12
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Saby JN, Peters SU, Benke TA, Standridge SM, Swanson LC, Lieberman DN, Olson HE, Key AP, Percy AK, Neul JL, Nelson CA, Roberts TPL, Marsh ED. Comparison of evoked potentials across four related developmental encephalopathies. J Neurodev Disord 2023; 15:10. [PMID: 36870948 PMCID: PMC9985257 DOI: 10.1186/s11689-023-09479-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/23/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Developing biomarkers is a priority for drug development for all conditions, but vital in the rare neurodevelopmental disorders where sensitive outcome measures are lacking. We have previously demonstrated the feasibility and tracking of evoked potentials to disease severity in Rett syndrome and CDKL5 deficiency disorder. The aim of the current study is to characterize evoked potentials in two related developmental encephalopathies, MECP2 duplication syndrome and FOXG1 syndrome, and compare across all four groups to better understand the potential of these measures to serve as biomarkers of clinical severity for the developmental encephalopathies. METHODS Visual and auditory evoked potentials were acquired from participants with MECP2 duplication syndrome and FOXG1 syndrome across five sites of the Rett Syndrome and Rett-Related Disorders Natural History Study. A group of age-matched individuals (mean = 7.8 years; range = 1-17) with Rett syndrome, CDKL5 deficiency disorder, and typically-developing participants served as a comparison group. The analysis focused on group-level differences as well as associations between the evoked potentials and measures of clinical severity from the Natural History Study. RESULTS As reported previously, group-level comparisons revealed attenuated visual evoked potentials (VEPs) in participants with Rett syndrome (n = 43) and CDKL5 deficiency disorder (n = 16) compared to typically-developing participants. VEP amplitude was also attenuated in participants with MECP2 duplication syndrome (n = 15) compared to the typically-developing group. VEP amplitude correlated with clinical severity for Rett syndrome and FOXG1 syndrome (n = 5). Auditory evoked potential (AEP) amplitude did not differ between groups, but AEP latency was prolonged in individuals with MECP2 duplication syndrome (n = 14) and FOXG1 syndrome (n = 6) compared to individuals with Rett syndrome (n = 51) and CDKL5 deficiency disorder (n = 14). AEP amplitude correlated with severity in Rett syndrome and CDKL5 deficiency disorder. AEP latency correlated with severity in CDKL5 deficiency disorder, MECP2 duplication syndrome, and FOXG1 syndrome. CONCLUSIONS There are consistent abnormalities in the evoked potentials in four developmental encephalopathies some of which correlate with clinical severity. While there are consistent changes amongst these four disorders, there are also condition specific findings that need to be further refined and validated. Overall, these results provide a foundation for further refinement of these measures for use in future clinical trials for these conditions.
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Affiliation(s)
- Joni N Saby
- Division of Radiology Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Sarika U Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA
| | - Timothy A Benke
- Department of Pediatrics, Neurology,, Pharmacology and Otolaryngology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | - Shannon M Standridge
- Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, , USA
| | - Lindsay C Swanson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - David N Lieberman
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Heather E Olson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Alexandra P Key
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA
| | - Alan K Percy
- Department of Pediatrics (Neurology), University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA
| | - Charles A Nelson
- Laboratories of Cognitive Neuroscience, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Graduate School of Education, Harvard University, Cambridge, MA, USA
| | - Timothy P L Roberts
- Division of Radiology Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eric D Marsh
- Division of Child Neurology, Children's Hospital of Philadelphia, Abramson Research Building- Room 502E, 3615 Civic Center Boulevard, Philadelphia, PA, 19104, USA.
- Orphan Disease Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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13
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Sanderson JL, Freund RK, Castano AM, Benke TA, Dell'Acqua ML. The Ca V1.2 G406R mutation decreases synaptic inhibition and alters L-type Ca 2+ channel-dependent LTP at hippocampal synapses in a mouse model of Timothy Syndrome. Neuropharmacology 2022; 220:109271. [PMID: 36162529 PMCID: PMC9644825 DOI: 10.1016/j.neuropharm.2022.109271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022]
Abstract
Genetic alterations in autism spectrum disorders (ASD) frequently disrupt balance between synaptic excitation and inhibition and alter plasticity in the hippocampal CA1 region. Individuals with Timothy Syndrome (TS), a genetic disorder caused by CaV1.2 L-type Ca2+ channel (LTCC) gain-of function mutations, such as G406R, exhibit social deficits, repetitive behaviors, and cognitive impairments characteristic of ASD that are phenocopied in TS2-neo mice expressing G406R. Here, we characterized hippocampal CA1 synaptic function in male TS2-neo mice and found basal excitatory transmission was slightly increased and inhibitory transmission strongly decreased. We also found distinct impacts on two LTCC-dependent forms of long-term potentiation (LTP) synaptic plasticity that were not readily consistent with LTCC gain-of-function. LTP induced by high-frequency stimulation (HFS) was strongly impaired in TS2-neo mice, suggesting decreased LTCC function. Yet, CaV1.2 expression, basal phosphorylation, and current density were similar for WT and TS2-neo. However, this HFS-LTP also required GABAA receptor activity, and thus may be impaired in TS2-neo due to decreased inhibitory transmission. In contrast, LTP induced in WT mice by prolonged theta-train (PTT) stimulation in the presence of a β-adrenergic receptor agonist to increase CaV1.2 phosphorylation was partially induced in TS2-neo mice by PTT stimulation alone, consistent with increased LTCC function. Overall, our findings provide insights regarding how altered CaV1.2 channel function disrupts basal transmission and plasticity that could be relevant for neurobehavioral alterations in ASD.
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Affiliation(s)
- Jennifer L Sanderson
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA
| | - Ronald K Freund
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA
| | - Anna M Castano
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA
| | - Timothy A Benke
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA; Departments of Pediatrics, Neurology, and Otolaryngology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 E. 19th Ave, Mail Stop 8303, Aurora, CO, 80045, USA.
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14
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Buchanan CB, Stallworth JL, Joy AE, Dixon RE, Scott AE, Beisang AA, Benke TA, Glaze DG, Haas RH, Heydemann PT, Jones MD, Lane JB, Lieberman DN, Marsh ED, Neul JL, Peters SU, Ryther RC, Skinner SA, Standridge SM, Kaufmann WE, Percy AK. Anxiety-like behavior and anxiolytic treatment in the Rett syndrome natural history study. J Neurodev Disord 2022; 14:31. [PMID: 35568815 PMCID: PMC9107202 DOI: 10.1186/s11689-022-09432-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 02/28/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a neurodevelopmental disorder most often related to a pathogenic variant in the X-linked MECP2 gene. Internalizing behaviors appear to be common, but standard methods of diagnosing anxiety are not readily applied in this population which typically has cognitive impairment and limited expressive language. This study aims to describe the frequency of anxiety-like behavior and anxiolytic treatments along with associated clinical features in individuals with RTT. METHODS Parental reports and medication logs provided data from 1380 females with RTT participating in two iterations of the multicenter U.S. RTT Natural History Study (RNHS) from 2006 to 2019. RESULTS Most participants with RTT (77.5%) had at least occasional anxious or nervous behavior. Anxiety was reported to be the most troublesome concern for 2.6%, and within the top 3 concerns for 10.0%, of participants in the second iteration. Parents directly reported treatment for anxious or nervous behavior in 16.6% of participants in the second iteration with most reporting good control of the behavior (71.6%). In the medication logs of both RNHS iterations, the indication of anxiety was listed for a similar number of participants (15% and 14.5%, respectively). Increased use of anxiolytics and selective serotonin reuptake inhibitors (SSRIs) was related to more frequent anxiety-like behaviors (P < 0.001), older age (P < 0.001), and mild MECP2 variants (P = 0.002). CONCLUSION Anxiety-like behavior is frequent at all ages and is a significant parental concern in RTT. Older individuals and those with mild MECP2 variants are more likely to be treated with medications. Better diagnosis and treatment of anxiety in RTT should be a goal of both future studies and clinical care. TRIAL REGISTRATION NCT00299312 and NCT02738281.
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Affiliation(s)
- Caroline B. Buchanan
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Jennifer L. Stallworth
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Aubin E. Joy
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Rebekah E. Dixon
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Alexandra E. Scott
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Arthur A. Beisang
- grid.429065.c0000 0000 9002 4129Gillette Children’s Hospital, St. Paul, MN USA
| | - Timothy A. Benke
- grid.241116.10000000107903411Children’s Hospital Colorado, University of Colorado at Denver, Denver, CO USA
| | - Daniel G. Glaze
- grid.39382.330000 0001 2160 926XBaylor College of Medicine, Houston, TX USA
| | - Richard H. Haas
- grid.266100.30000 0001 2107 4242Rady Children’s Hospital-San Diego, University of California, San Diego, CA USA
| | - Peter T. Heydemann
- grid.240684.c0000 0001 0705 3621Rush University Medical Center, Chicago, IL USA
| | - Mary D. Jones
- grid.414016.60000 0004 0433 7727UCSF Benioff Children’s Hospital of Oakland, Oakland, CA USA
| | - Jane B. Lane
- grid.265892.20000000106344187Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL USA
| | - David N. Lieberman
- grid.38142.3c000000041936754XBoston Children’s Hospital, Harvard Medical School, Boston, MA USA
| | - Eric D. Marsh
- grid.25879.310000 0004 1936 8972Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
| | - Jeffrey L. Neul
- grid.412807.80000 0004 1936 9916Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN USA
| | - Sarika U. Peters
- grid.412807.80000 0004 1936 9916Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN USA
| | - Robin C. Ryther
- grid.4367.60000 0001 2355 7002Washington University School of Medicine in St. Louis, St. Louis, MO USA
| | - Steve A. Skinner
- grid.418307.90000 0000 8571 0933Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29649 USA
| | - Shannon M. Standridge
- grid.239573.90000 0000 9025 8099Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USA ,grid.24827.3b0000 0001 2179 9593Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH USA
| | - Walter E. Kaufmann
- grid.254567.70000 0000 9075 106XUniversity of South Carolina School of Medicine, Columbia, SC USA ,grid.189967.80000 0001 0941 6502Emory University School of Medicine, Atlanta, GA USA
| | - Alan K. Percy
- grid.265892.20000000106344187Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL USA
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15
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Saby JN, Mulcahey PJ, Zavez AE, Peters SU, Standridge SM, Swanson LC, Lieberman DN, Olson HE, Key AP, Percy AK, Neul JL, Nelson CA, Roberts TPL, Benke TA, Marsh ED. Electrophysiological biomarkers of brain function in CDKL5 deficiency disorder. Brain Commun 2022; 4:fcac197. [PMID: 35974796 PMCID: PMC9374482 DOI: 10.1093/braincomms/fcac197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 05/05/2022] [Accepted: 08/02/2022] [Indexed: 11/14/2022] Open
Abstract
CDKL5 deficiency disorder is a debilitating developmental and epileptic encephalopathy for which no targeted treatment exists. A number of promising therapeutics are under development for CDKL5 deficiency disorder but a lack of validated biomarkers of brain function and clinical severity may limit the ability to objectively assess the efficacy of new treatments as they become available. To address this need, the current study quantified electrophysiological measures in individuals with CDKL5 deficiency disorder and the association between these parameters and clinical severity. Visual and auditory evoked potentials, as well as resting EEG, were acquired across 5 clinical sites from 26 individuals with CDKL5 deficiency disorder. Evoked potential and quantitative EEG features were calculated and compared with typically developing individuals in an age- and sex-matched cohort. Baseline and Year 1 data, when available, were analysed and the repeatability of the results was tested. Two clinician-completed severity scales were used for evaluating the clinical relevance of the electrophysiological parameters. Group-level comparisons revealed reduced visual evoked potential amplitude in CDKL5 deficiency disorder individuals versus typically developing individuals. There were no group differences in the latency of the visual evoked potentials or in the latency or amplitude of the auditory evoked potentials. Within the CDKL5 deficiency disorder group, auditory evoked potential amplitude correlated with disease severity at baseline as well as Year 1. Multiple quantitative EEG features differed between CDKL5 deficiency disorder and typically developing participants, including amplitude standard deviation, 1/f slope and global delta, theta, alpha and beta power. Several quantitative EEG features correlated with clinical severity, including amplitude skewness, theta/delta ratio and alpha/delta ratio. The theta/delta ratio was the overall strongest predictor of severity and also among the most repeatable qEEG measures from baseline to Year 1. Together, the present findings point to the utility of evoked potentials and quantitative EEG parameters as objective measures of brain function and disease severity in future clinical trials for CDKL5 deficiency disorder. The results also underscore the utility of the current methods, which could be similarly applied to the identification and validation of electrophysiological biomarkers of brain function for other developmental encephalopathies.
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Affiliation(s)
| | | | - Alexis E Zavez
- Orphan Disease Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarika U Peters
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shannon M Standridge
- Cincinnati Children’s Hospital Medical Center, Division of Neurology and University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Lindsay C Swanson
- Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - David N Lieberman
- Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Heather E Olson
- Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Alexandra P Key
- Department of Hearing and Speech Sciences, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alan K Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Charles A Nelson
- Laboratories of Cognitive Neuroscience, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Cambridge, MA 02115, USA
- Graduate School of Education, Harvard University, Cambridge, MA 02115, USA
| | - Timothy P L Roberts
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Timothy A Benke
- Department of Pediatrics, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO 80045, USA
- Department of Neurology, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO 80045, USA
- Department of Pharmacology, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO 80045, USA
- Department of Otolaryngology, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO 80045, USA
| | - Eric D Marsh
- Correspondence to: Eric D. Marsh, MD Division of Child Neurology Abramson Research Building, Room 502E 3615 Civic Center Boulevard Philadelphia, PA 19104, USA E-mail:
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16
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Olson HE, Costantini JA, Swanson LC, Kaufmann WE, Benke TA, Fulton AB, Hansen R, Poduri A, Heidary G. Cerebral visual impairment in CDKL5 deficiency disorder: vision as an outcome measure. Dev Med Child Neurol 2021; 63:1308-1315. [PMID: 34028805 PMCID: PMC8782241 DOI: 10.1111/dmcn.14908] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
AIM To characterize the neuro-ophthalmological phenotype of cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) and assess visual acuity as a reproducible, quantitative outcome measure. METHOD We retrospectively analyzed clinical data from patients with CDD. Complete neuro-ophthalmological assessments, including visual acuity, were evaluated. RESULTS Of 26 patients (22 females, four males; median age 4y, interquartile range 2y 1mo-7y 10mo), cerebral visual impairment (CVI), defined as visual dysfunction in the absence of ocular or anterior visual pathway abnormalities, was diagnosed in all those over 2 years of age. Ophthalmological examinations revealed nystagmus in 10 patients and strabismus in 24 patients. Visual acuity was measured in 24 patients, by preferential looking in all and by sweep visual evoked potential in 13. Visual acuities were lower than age expectations and demonstrated improvement in the first 3 years. Adjusting for age and sex, average preferential looking visual acuity after 2 years of age was higher in patients with intact mobility than in those who were non-mobile. INTERPRETATION CVI was observed in patients with CDD. Visual acuity improved over time and correlated with mobility. Visual acuity, as a quantifiable measure of visual function, should be considered as an outcome measure in pre-clinical and clinical studies for CDD. What this paper adds Cerebral visual impairment is highly prevalent in cyclin-dependent kinase-like 5 deficiency disorder (CDD). Visual acuity is a measurable quantitative outcome measure in CDD. Visual acuity in CDD correlates with gross motor ability.
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Affiliation(s)
- Heather E. Olson
- Division of Epilepsy and Clinical Neurophysiology and
Epilepsy Genetics Program, Department of Neurology, Boston Children’s
Hospital and Harvard Medical School, Boston, MA, USA,CDKL5 Center of Excellence, Department of Neurology, Boston
Children’s Hospital, Boston, MA, USA
| | - Julia A. Costantini
- CDKL5 Center of Excellence, Department of Neurology, Boston
Children’s Hospital, Boston, MA, USA
| | - Lindsay C. Swanson
- CDKL5 Center of Excellence, Department of Neurology, Boston
Children’s Hospital, Boston, MA, USA
| | - Walter E. Kaufmann
- Department of Human Genetics, Emory University School of
Medicine, Atlanta, GA, USA
| | - Timothy A. Benke
- Children’s Hospital Colorado, University of Colorado
School of Medicine Departments of Pediatrics, Neurology, Pharmacology and
Otolaryngology, Aurora, Colorado, USA
| | - Anne B. Fulton
- Department of Ophthalmology, Boston Children’s
Hospital and Harvard Medical School, Boston, MA, USA
| | - Ronald Hansen
- Department of Ophthalmology, Boston Children’s
Hospital and Harvard Medical School, Boston, MA, USA
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology and
Epilepsy Genetics Program, Department of Neurology, Boston Children’s
Hospital and Harvard Medical School, Boston, MA, USA
| | - Gena Heidary
- CDKL5 Center of Excellence, Department of Neurology, Boston
Children’s Hospital, Boston, MA, USA,Department of Ophthalmology, Boston Children’s
Hospital and Harvard Medical School, Boston, MA, USA
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17
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Olson HE, Daniels CI, Haviland I, Swanson LC, Greene CA, Denny AMM, Demarest ST, Pestana-Knight E, Zhang X, Moosa AN, Fidell A, Weisenberg JL, Suter B, Fu C, Neul JL, Percy AK, Marsh ED, Benke TA, Poduri A. Current neurologic treatment and emerging therapies in CDKL5 deficiency disorder. J Neurodev Disord 2021; 13:40. [PMID: 34530725 PMCID: PMC8447578 DOI: 10.1186/s11689-021-09384-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 08/16/2021] [Indexed: 12/05/2022] Open
Abstract
Background CDKL5 deficiency disorder (CDD) is associated with refractory infantile onset epilepsy, global developmental delay, and variable features that include sleep, behavioral disturbances, and movement disorders. Current treatment is primarily symptom-based and informed by experience in caring for this population. Methods We describe medication and non-medication approaches to treatment of epilepsy and additional key neurologic symptoms (sleep disturbances, behavioral issues, movement disorders, and swallowing dysfunction) in a cohort of 177 individuals meeting criteria for CDD, 154 evaluated at 4 CDKL5 Centers of Excellence in the USA and 40 identified through the NIH Natural History Study of Rett and Related Disorders. Results The four most frequently prescribed anti-seizure medications were broad spectrum, prescribed in over 50% of individuals. While the goal was not to ascertain efficacy, we obtained data from 86 individuals regarding response to treatment, with 2-week response achieved in 14–48% and sustained 3-month response in 5–36%, of those with known response. Additional treatments for seizures included cannabis derivatives, tried in over one-third of individuals, and clinical trial medications. In combination with pharmacological treatment, 50% of individuals were treated with ketogenic diet for attempted seizure control. Surgical approaches included vagus nerve stimulators, functional hemispherectomy, and corpus callosotomy, but numbers were too limited to assess response. Nearly one-third of individuals received pharmacologic treatment for sleep disturbances, 13% for behavioral dysregulation and movement disorders, and 43% had gastrostomy tubes. Conclusions Treatment for neurologic features of CDD is currently symptom-based and empiric rather than CDD-specific, though clinical trials for CDD are emerging. Epilepsy in this population is highly refractory, and no specific anti-seizure medication was associated with improved seizure control. Ketogenic diet is commonly used in patients with CDD. While behavioral interventions are commonly instituted, information on the use of medications for sleep, behavioral management, and movement disorders is sparse and would benefit from further characterization and optimization of treatment approaches. The heterogeneity in treatment approaches highlights the need for systematic review and guidelines for CDD. Additional disease-specific and disease-modifying treatments are in development. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-021-09384-z.
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Affiliation(s)
- Heather E Olson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA.
| | - Carolyn I Daniels
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA
| | - Isabel Haviland
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA
| | - Lindsay C Swanson
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA
| | - Caitlin A Greene
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA
| | - Anne Marie M Denny
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA.,Division of Pediatric Neurology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Scott T Demarest
- Children's Hospital Colorado, University of Colorado, School of Medicine, Aurora, CO, USA.,Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Elia Pestana-Knight
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaoming Zhang
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ahsan N Moosa
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Andrea Fidell
- Children's Hospital Colorado, University of Colorado, School of Medicine, Aurora, CO, USA.,Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Judith L Weisenberg
- Department of Pediatric Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bernhard Suter
- Division of Child Neurology, Texas Children's Hospital, Departments of Neurology and Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan K Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Eric D Marsh
- Division of Child Neurology, Children's Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy A Benke
- Children's Hospital Colorado, University of Colorado, School of Medicine, Aurora, CO, USA.,Department of Pediatrics, School of Medicine, University of Colorado, Aurora, CO, USA.,Departments of Pharmacology, Neurology, and Otolaryngology, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Mailstop 3063, Boston, MA, 02115, USA
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18
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Aledo-Serrano Á, Gómez-Iglesias P, Toledano R, Garcia-Peñas JJ, Garcia-Morales I, Anciones C, Soto-Insuga V, Benke TA, Del Pino I, Gil-Nagel A. Sodium channel blockers for the treatment of epilepsy in CDKL5 deficiency disorder: Findings from a multicenter cohort. Epilepsy Behav 2021; 118:107946. [PMID: 33848848 DOI: 10.1016/j.yebeh.2021.107946] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/21/2021] [Accepted: 03/21/2021] [Indexed: 12/15/2022]
Abstract
OBJECTIVE This study was aimed to analyze the effectiveness of sodium channel blockers (SCBs) in CDKL5 deficiency disorder (CDD)-related epilepsy. METHODS A retrospective, observational study was performed, including patients with CDD diagnosis evaluated between 2016 and 2019 at three tertiary Epilepsy Centers. Demographic, electroclinical and genetic features, as well as ASM treatments and their outcomes were analyzed, with special focus on SCBs. RESULTS Twenty-one patients evaluated at three tertiary Epilepsy Centers were included, of which 19 presented with epilepsy (90.5%); all had pathogenic mutations of CDKL5. Six patients (31.6%) were classified as SCB responders (more than 50% reduction), four being currently seizure free (mean seizure-free period of 8 years). Most frequent SCB drugs were oxcarbazepine (OXC), carbamazepine (CBZ), and lacosamide (LCM). None of them presented relevant adverse events. In contrast, three patients showed seizure aggravation in the non-responder group. When comparing both groups, responders had statistically significant younger age at SCB treatment and epilepsy onset, higher proportion of focal epileptiform activity and less frequent history of West syndrome. CONCLUSIONS The results of this study indicate that treatment with SCBs might be effective and safe in a subset of patients with CDD-related epilepsy.
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Affiliation(s)
- Ángel Aledo-Serrano
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit. Neuroscience Department, Corachan Clinic, Barcelona, Spain.
| | | | - Rafael Toledano
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit, Neurology Department, Ramon y Cajal University Hospital, Madrid, Spain
| | - Juan Jose Garcia-Peñas
- Department of Pediatric Neurology, Niño Jesus University Children's Hospital, Madrid, Spain
| | - Irene Garcia-Morales
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit. Neurology Department, Clínico San Carlos University Hospital, Madrid, Spain
| | - Carla Anciones
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain
| | - Victor Soto-Insuga
- Department of Pediatric Neurology, Niño Jesus University Children's Hospital, Madrid, Spain
| | - Timothy A Benke
- Departments of Pediatrics, Neurology, and Pharmacology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, United States
| | - Isabel Del Pino
- Principe Felipe Research Center (Centro de Investigación Principe Felipe, CIPF), Valencia, Spain
| | - Antonio Gil-Nagel
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain
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19
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Saby JN, Benke TA, Peters SU, Standridge SM, Matsuzaki J, Cutri-French C, Swanson LC, Lieberman DN, Key AP, Percy AK, Neul JL, Nelson CA, Roberts TP, Marsh ED. Multisite Study of Evoked Potentials in Rett Syndrome. Ann Neurol 2021; 89:790-802. [PMID: 33480039 PMCID: PMC8882338 DOI: 10.1002/ana.26029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The aim of the current study was to evaluate the utility of evoked potentials as a biomarker of cortical function in Rett syndrome (RTT). As a number of disease-modifying therapeutics are currently under development, there is a pressing need for biomarkers to objectively and precisely assess the effectiveness of these treatments. METHOD Yearly visual evoked potentials (VEPs) and auditory evoked potentials (AEPs) were acquired from individuals with RTT, aged 2 to 37 years, and control participants across 5 sites as part of the Rett Syndrome and Related Disorders Natural History Study. Baseline and year 1 data, when available, were analyzed and the repeatability of the results was tested. Two syndrome-specific measures from the Natural History Study were used for evaluating the clinical relevance of the VEP and AEP parameters. RESULTS At the baseline study, group level comparisons revealed reduced VEP and AEP amplitude in RTT compared to control participants. Further analyses within the RTT group indicated that this reduction was associated with RTT-related symptoms, with greater severity associated with lower VEP and AEP amplitude. In participants with RTT, VEP and AEP amplitude was also negatively associated with age. Year 1 follow-up data analyses yielded similar findings and evidence of repeatability of EPs at the individual level. INTERPRETATION The present findings indicate the promise of evoked potentials (EPs) as an objective measure of disease severity in individuals with RTT. Our multisite approach demonstrates potential research and clinical applications to provide unbiased assessment of disease staging, prognosis, and response to therapy. ANN NEUROL 2021;89:790-802.
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Affiliation(s)
- Joni N. Saby
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy A. Benke
- Department of Pediatrics, Neurology, Pharmacology and Otolaryngology, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, Colorado
| | - Sarika U. Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Shannon M. Standridge
- Cincinnati Children’s Hospital Medical Center, Division of Neurology and University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Junko Matsuzaki
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Clare Cutri-French
- Division of Child Neurology, Children’s Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Lindsay C. Swanson
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts
| | - David N. Lieberman
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts
| | - Alexandra P. Key
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Alan K. Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jeffrey L. Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Charles A. Nelson
- Laboratories of Cognitive Neuroscience, Boston Children’s Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School
| | - Timothy P.L. Roberts
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eric D. Marsh
- Division of Child Neurology, Children’s Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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20
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Raspa M, Bann CM, Gwaltney A, Benke TA, Fu C, Glaze DG, Haas R, Heydemann P, Jones M, Kaufmann WE, Lieberman D, Marsh E, Peters S, Ryther R, Standridge S, Skinner SA, Percy AK, Neul JL. A Psychometric Evaluation of the Motor-Behavioral Assessment Scale for Use as an Outcome Measure in Rett Syndrome Clinical Trials. Am J Intellect Dev Disabil 2020; 125:493-509. [PMID: 33211820 PMCID: PMC7778880 DOI: 10.1352/1944-7558-125.6.493] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 07/23/2020] [Indexed: 05/13/2023]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder that primarily affects females. Recent work indicates the potential for disease modifying therapies. However, there remains a need to develop outcome measures for use in clinical trials. Using data from a natural history study (n = 1,075), we examined the factor structure, internal consistency, and validity of the clinician-reported Motor Behavior Assessment scale (MBA). The analysis resulted in a five-factor model: (1) motor dysfunction, (2) functional skills, (3) social skills, (4) aberrant behavior, and (5) respiratory behaviors. Item Response Theory (IRT) analyses demonstrated that all items had acceptable discrimination. The revised MBA subscales showed a positive relationship with parent reported items, age, and a commonly used measure of clinical severity in RTT, and mutation type. Further work is needed to evaluate this measure longitudinally and to add items related to the RTT phenotype.
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Affiliation(s)
- Melissa Raspa
- Melissa Raspa, Carla M. Bann, and Angela Gwaltney, RTI International
| | - Carla M Bann
- Melissa Raspa, Carla M. Bann, and Angela Gwaltney, RTI International
| | - Angela Gwaltney
- Melissa Raspa, Carla M. Bann, and Angela Gwaltney, RTI International
| | | | - Cary Fu
- Cary Fu, Vanderbilt Kennedy Center
| | | | - Richard Haas
- Richard Haas, University of California San Diego
| | | | | | | | | | - Eric Marsh
- David Lieberman and Eric Marsh, Children's Hospital Boston
| | | | - Robin Ryther
- Robin Ryther, Washington University School of Medicine
| | | | | | - Alan K Percy
- Alan K. Percy, University of Alabama at Birmingham
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21
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Hallgrímsson B, Aponte JD, Katz DC, Bannister JJ, Riccardi SL, Mahasuwan N, McInnes BL, Ferrara TM, Lipman DM, Neves AB, Spitzmacher JAJ, Larson JR, Bellus GA, Pham AM, Aboujaoude E, Benke TA, Chatfield KC, Davis SM, Elias ER, Enzenauer RW, French BM, Pickler LL, Shieh JTC, Slavotinek A, Harrop AR, Innes AM, McCandless SE, McCourt EA, Meeks NJL, Tartaglia NR, Tsai ACH, Wyse JPH, Bernstein JA, Sanchez-Lara PA, Forkert ND, Bernier FP, Spritz RA, Klein OD. Automated syndrome diagnosis by three-dimensional facial imaging. Genet Med 2020; 22:1682-1693. [PMID: 32475986 PMCID: PMC7521994 DOI: 10.1038/s41436-020-0845-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/27/2022] Open
Abstract
Purpose Deep phenotyping is an emerging trend in precision medicine for genetic disease. The shape of the face is affected in 30–40% of known genetic syndromes. Here, we determine whether syndromes can be diagnosed from 3D images of human faces. Methods We analyzed variation in three-dimensional (3D) facial images of 7057 subjects: 3327 with 396 different syndromes, 727 of their relatives, and 3003 unrelated, unaffected subjects. We developed and tested machine learning and parametric approaches to automated syndrome diagnosis using 3D facial images. Results Unrelated, unaffected subjects were correctly classified with 96% accuracy. Considering both syndromic and unrelated, unaffected subjects together, balanced accuracy was 73% and mean sensitivity 49%. Excluding unrelated, unaffected subjects substantially improved both balanced accuracy (78.1%) and sensitivity (56.9%) of syndrome diagnosis. The best predictors of classification accuracy were phenotypic severity and facial distinctiveness of syndromes. Surprisingly, unaffected relatives of syndromic subjects were frequently classified as syndromic, often to the syndrome of their affected relative. Conclusion Deep phenotyping by quantitative 3D facial imaging has considerable potential to facilitate syndrome diagnosis. Furthermore, 3D facial imaging of “unaffected” relatives may identify unrecognized cases or may reveal novel examples of semidominant inheritance.
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Affiliation(s)
- Benedikt Hallgrímsson
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - J David Aponte
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - David C Katz
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jordan J Bannister
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB, Canada
| | - Sheri L Riccardi
- Human Medical Genetics and Genomics Program and Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Nick Mahasuwan
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - Brenda L McInnes
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Tracey M Ferrara
- Human Medical Genetics and Genomics Program and Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Danika M Lipman
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Amanda B Neves
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jared A J Spitzmacher
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jacinda R Larson
- Department of Cell Biology & Anatomy, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Gary A Bellus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Pediatrics, Geisinger Medical Center, Danville, PA, USA
| | - Anh M Pham
- Department of Pediatrics, Cedars Sinai Medical Center & David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Elias Aboujaoude
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Timothy A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kathryn C Chatfield
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Shanlee M Davis
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ellen R Elias
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Robert W Enzenauer
- Department of Pediatric Ophthalmology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Brooke M French
- Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Laura L Pickler
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Joseph T C Shieh
- Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - Anne Slavotinek
- Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - A Robertson Harrop
- Department of Surgery, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - A Micheil Innes
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Shawn E McCandless
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Emily A McCourt
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Naomi J L Meeks
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Nicole R Tartaglia
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Anne C-H Tsai
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - J Patrick H Wyse
- Division of Ophthalmology, Department of Surgery & Department of Medical Genetics, Cummings School of Medicine, University of Calgary, Calgary, AB, Canada
| | | | - Pedro A Sanchez-Lara
- Department of Pediatrics, Cedars Sinai Medical Center & David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Nils D Forkert
- Department of Radiology, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Francois P Bernier
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Richard A Spritz
- Human Medical Genetics and Genomics Program and Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
| | - Ophir D Klein
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA. .,Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, CA, USA.
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22
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Peters SU, Fu C, Suter B, Marsh E, Benke TA, Skinner SA, Lieberman DN, Standridge S, Jones M, Beisang A, Feyma T, Heydeman P, Ryther R, Kaufmann WE, Glaze DG, Neul JL, Percy AK. Characterizing the phenotypic effect of Xq28 duplication size in MECP2 duplication syndrome. Clin Genet 2019; 95:575-581. [PMID: 30788845 DOI: 10.1111/cge.13521] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022]
Abstract
Individuals with methyl CpG binding protein 2 (MECP2) duplication syndrome (MDS) have varying degrees of severity in their mobility, hand use, developmental skills, and susceptibility to infections. In the present study, we examine the relationship between duplication size, gene content, and overall phenotype in MDS using a clinical severity scale. Other genes typically duplicated within Xq28 (eg, GDI1, RAB39B, FLNA) are associated with distinct clinical features independent of MECP2. We additionally compare the phenotype of this cohort (n = 48) to other reported cohorts with MDS. Utilizing existing indices of clinical severity in Rett syndrome, we found that larger duplication size correlates with higher severity in total clinical severity scores (r = 0.36; P = 0.02), and in total motor behavioral assessment inventory scores (r = 0.31; P = 0.05). Greater severity was associated with having the RAB39B gene duplicated, although most of these participants also had large duplications. Results suggest that developmental delays in the first 6 months of life, hypotonia, vasomotor disturbances, constipation, drooling, and bruxism are common in MDS. This is the first study to show that duplication size is related to clinical severity. Future studies should examine whether large duplications which do not encompass RAB39B also contribute to clinical severity. Results also suggest the need for creating an MDS specific severity scale.
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Affiliation(s)
- Sarika U Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Bernhard Suter
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Eric Marsh
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | | | - David N Lieberman
- Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts
| | - Shannon Standridge
- Department of Pediatrics, Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Mary Jones
- Department of Pediatrics, UCSF Benioff Children's Hospital, Oakland, California
| | - Arthur Beisang
- Department of Pediatrics, Gilette Children's Specialty Healthcare, Saint Paul, Minnesota
| | - Timothy Feyma
- Department of Pediatrics, Gilette Children's Specialty Healthcare, Saint Paul, Minnesota
| | - Peter Heydeman
- Department of Pediatrics, Rush University Medical Center, Chicago, Illinois
| | - Robin Ryther
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Daniel G Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Jeffrey L Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alan K Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
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23
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Neul JL, Benke TA, Marsh ED, Skinner SA, Merritt J, Lieberman DN, Standridge S, Feyma T, Heydemann P, Peters S, Ryther R, Jones M, Suter B, Kaufmann WE, Glaze DG, Percy AK. The array of clinical phenotypes of males with mutations in Methyl-CpG binding protein 2. Am J Med Genet B Neuropsychiatr Genet 2019; 180:55-67. [PMID: 30536762 PMCID: PMC6488031 DOI: 10.1002/ajmg.b.32707] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 11/19/2018] [Indexed: 01/09/2023]
Abstract
Mutations in the X-linked gene MECP2 are associated with a severe neurodevelopmental disorder, Rett syndrome (RTT), primarily in girls. It had been suspected that mutations in Methyl-CpG-binding protein 2 (MECP2) led to embryonic lethality in males, however such males have been reported. To enhance understanding of the phenotypic spectrum present in these individuals, we identified 30 males with MECP2 mutations in the RTT Natural History Study databases. A wide phenotypic spectrum was observed, ranging from severe neonatal encephalopathy to cognitive impairment. Two males with a somatic mutation in MECP2 had classic RTT. Of the remaining 28 subjects, 16 had RTT-causing MECP2 mutations, 9 with mutations that are not seen in females with RTT but are likely pathogenic, and 3 with uncertain variants. Two subjects with RTT-causing mutations were previously diagnosed as having atypical RTT; however, careful review of the clinical history determined that an additional 12/28 subjects met criteria for atypical RTT, but with more severe clinical presentation and course, and less distinctive RTT features, than females with RTT, leading to the designation of a new diagnostic entity, male RTT encephalopathy. Increased awareness of the clinical spectrum and widespread comprehensive genomic testing in boys with neurodevelopmental problems will lead to improved identification.
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Affiliation(s)
- Jeffrey L. Neul
- Vanderbilt University Medical Center,University of California, San Diego,Co-corresponding authors: Jeffrey Neul, PMB 40, 230 Appleton Place, Vanderbilt University Medical Center, Nashville, TN 37203-5721, Telephone: 615-322-8242, Facsimile: , Alan Percy, 1720 2 Avenue South, CIRC 320E, University of Alabama at Birmingham, Birmingham, AL 35294-0021, Telephone: 205-996-4927, Facsimile: 205-975-6330,
| | | | - Eric D. Marsh
- Children’s Hospital of Philadelphia, University of Pennsylvania
| | | | - Jonathan Merritt
- Vanderbilt University Medical Center,University of California, San Diego
| | | | | | | | | | | | | | - Mary Jones
- University of California, San Francisco Benioff Children’s Hospital Oakland
| | | | | | - Daniel G. Glaze
- Vanderbilt University Medical Center,University of California, San Diego
| | - Alan K. Percy
- University of Alabama at Birmingham,Co-corresponding authors: Jeffrey Neul, PMB 40, 230 Appleton Place, Vanderbilt University Medical Center, Nashville, TN 37203-5721, Telephone: 615-322-8242, Facsimile: , Alan Percy, 1720 2 Avenue South, CIRC 320E, University of Alabama at Birmingham, Birmingham, AL 35294-0021, Telephone: 205-996-4927, Facsimile: 205-975-6330,
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Kirk ME, Meredith FL, Benke TA, Rennie KJ. AMPA receptor-mediated rapid EPSCs in vestibular calyx afferents. J Neurophysiol 2017; 117:2312-2323. [PMID: 28298303 DOI: 10.1152/jn.00394.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 03/10/2017] [Accepted: 03/10/2017] [Indexed: 01/21/2023] Open
Abstract
In the vestibular periphery neurotransmission between hair cells and primary afferent nerves occurs via specialized ribbon synapses. Type I vestibular hair cells (HCIs) make synaptic contacts with calyx terminals, which enclose most of the HCI basolateral surface. To probe synaptic transmission, whole cell patch-clamp recordings were made from calyx afferent terminals isolated together with their mature HCIs from gerbil crista. Neurotransmitter release was measured as excitatory postsynaptic currents (EPSCs) in voltage clamp. Spontaneous EPSCs were classified as simple or complex. Simple events exhibited a rapid rise time and a fast monoexponential decay (time constant < 1 ms). The remaining events, constituting ~40% of EPSCs, showed more complex characteristics. Extracellular Sr2+ greatly increased EPSC frequency, and EPSCs were blocked by the AMPA receptor blocker NBQX. The role of presynaptic Ca2+ channels was assessed by application of the L-type Ca2+ channel blocker nifedipine (20 µM), which reduced EPSC frequency. In contrast, the L-type Ca2+ channel opener BAY K 8644 increased EPSC frequency. Cyclothiazide increased the decay time constant of averaged simple EPSCs by approximately twofold. The low-affinity AMPA receptor antagonist γ-d-glutamylglycine (2 mM) reduced the proportion of simple EPSCs relative to complex events, indicating glutamate accumulation in the restricted cleft between HCI and calyx. In crista slices EPSC frequency was greater in central compared with peripheral calyces, which may be due to greater numbers of presynaptic ribbons in central hair cells. Our data support a role for L-type Ca2+ channels in spontaneous release and demonstrate regional variations in AMPA-mediated quantal transmission at the calyx synapse.NEW & NOTEWORTHY In vestibular calyx terminals of mature cristae we find that the majority of excitatory postsynaptic currents (EPSCs) are rapid monophasic events mediated by AMPA receptors. Spontaneous EPSCs are reduced by an L-type Ca2+ channel blocker and notably enhanced in extracellular Sr2+ EPSC frequency is greater in central areas of the crista compared with peripheral areas and may be associated with more numerous presynaptic ribbons in central hair cells.
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Affiliation(s)
- Matthew E Kirk
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado
| | - Frances L Meredith
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado
| | - Timothy A Benke
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado.,Departments of Pediatrics, Neurology, and Pharmacology, University of Colorado School of Medicine, Aurora, Colorado
| | - Katherine J Rennie
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado; .,Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado; and
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25
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Barcomb K, Buard I, Coultrap SJ, Kulbe JR, O'Leary H, Benke TA, Bayer KU. Autonomous CaMKII requires further stimulation by Ca2+/calmodulin for enhancing synaptic strength. FASEB J 2014; 28:3810-9. [PMID: 24843070 DOI: 10.1096/fj.14-250407] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A hallmark feature of Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) is generation of autonomous (Ca(2+)-independent) activity by T286 autophosphorylation. Biochemical studies have shown that "autonomous" CaMKII is ∼5-fold further stimulated by Ca(2+)/CaM, but demonstration of a physiological function for such regulation within cells has remained elusive. In this study, CaMKII-induced enhancement of synaptic strength in rat hippocampal neurons required both autonomous activity and further stimulation. Synaptic strength was decreased by CaMKIIα knockdown and rescued by reexpression, but not by mutants impaired for autonomy (T286A) or binding to NMDA-type glutamate receptor subunit 2B (GluN2B; formerly NR2B; I205K). Full rescue was seen with constitutively autonomous mutants (T286D), but only if they could be further stimulated (additional T305/306A mutation), and not with two other mutations that additionally impair Ca(2+)/CaM binding. Compared to rescue with wild-type CaMKII, the CaM-binding-impaired mutants even had reduced synaptic strength. One of these mutants (T305/306D) mimicked an inhibitory autophosphorylation of CaMKII, whereas the other one (Δstim) abolished CaM binding without introducing charged residues. Inhibitory T305/306 autophosphorylation also reduced GluN2B binding, but this effect was independent of reduced Ca(2+)/CaM binding and was not mimicked by T305/306D mutation. Thus, even autonomous CaMKII activity must be further stimulated by Ca(2+)/CaM for enhancement of synaptic strength.
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Affiliation(s)
| | | | | | | | - Heather O'Leary
- Department of Pharmacology and Department of Pediatrics, Section of Neurology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Timothy A Benke
- Department of Pharmacology and Department of Pediatrics, Section of Neurology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
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Boada R, Hutaff-Lee C, Schrader A, Weitzenkamp D, Benke TA, Goldson EJ, Costa ACS. Antagonism of NMDA receptors as a potential treatment for Down syndrome: a pilot randomized controlled trial. Transl Psychiatry 2012; 2:e141. [PMID: 22806212 PMCID: PMC3410988 DOI: 10.1038/tp.2012.66] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Down syndrome (DS) is the most common genetic cause of intellectual disability. The N-methyl-D-aspartate (NMDA) receptor uncompetitive antagonist, memantine hydrochloride (memantine), has been shown to improve learning/memory and rescue one form of hippocampus synaptic plasticity dysfunction in the best-studied mouse model of DS available, the Ts65Dn mouse. Given the status of memantine as a treatment for Alzheimer's disease (AD) approved by the Food and Drug Administration, the preclinical evidence of potential efficacy in Ts65Dn mice, and the favorable safety profile of memantine, we designed a study to investigate whether the findings in the mouse model could be translated to individuals with DS. In this pilot, proof-of-principle study we hypothesized that memantine therapy would improve test scores of young adults with DS on measures of episodic and spatial memory, which are generally considered to be hippocampus dependent. Accordingly, in this randomized, double-blind, placebo-controlled trial, we compared the effect of 16-week treatment with either memantine or placebo on cognitive and adaptive functions of 40 young adults with DS using a carefully selected set of neuropsychological outcome measures. Safety and tolerability were also monitored. Although no significant differences were observed between the memantine and placebo groups on the two primary outcome measures, we found a significant improvement in the memantine group in one of the secondary measures associated with the primary hypothesis. Only infrequent and mild adverse events were noted.
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Affiliation(s)
- R Boada
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA,The Children's Hospital Colorado, Aurora, CO, USA
| | - C Hutaff-Lee
- The Children's Hospital Colorado, Aurora, CO, USA
| | - A Schrader
- The Children's Hospital Colorado, Aurora, CO, USA
| | - D Weitzenkamp
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver, Aurora, CO, USA
| | - T A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA,The Children's Hospital Colorado, Aurora, CO, USA,Department of Neurology, University of Colorado School of Medicine, Aurora, CO, USA,Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA,Neuroscience Training Program, University of Colorado Denver, Aurora, CO, USA,Colorado Intellectual and Developmental Disability Research Center, University of Colorado Denver, Aurora, CO, USA
| | - E J Goldson
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA,The Children's Hospital Colorado, Aurora, CO, USA
| | - A C S Costa
- Neuroscience Training Program, University of Colorado Denver, Aurora, CO, USA,Colorado Intellectual and Developmental Disability Research Center, University of Colorado Denver, Aurora, CO, USA,Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA,Department of Medicine, Division of Clinical Pharmacology and Toxicology, University of Colorado School of Medicine, 12700 East 19th Avenue, MS C-237, Aurora, CO 80045, USA. E-mail:
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27
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Liu X, Li F, Stubblefield EA, Blanchard B, Richards TL, Larson GA, He Y, Huang Q, Tan AC, Zhang D, Benke TA, Sladek JR, Zahniser NR, Li CY. Direct reprogramming of human fibroblasts into dopaminergic neuron-like cells. Cell Res 2011; 22:321-32. [PMID: 22105488 PMCID: PMC3271588 DOI: 10.1038/cr.2011.181] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Transplantation of exogenous dopaminergic neuron (DA neurons) is a promising approach for treating Parkinson's disease (PD). However, a major stumbling block has been the lack of a reliable source of donor DA neurons. Here we show that a combination of five transcriptional factors Mash1, Ngn2, Sox2, Nurr1, and Pitx3 can directly and effectively reprogram human fibroblasts into DA neuron-like cells. The reprogrammed cells stained positive for various markers for DA neurons. They also showed characteristic DA uptake and production properties. Moreover, they exhibited DA neuron-specific electrophysiological profiles. Finally, they provided symptomatic relief in a rat PD model. Therefore, our directly reprogrammed DA neuron-like cells are a promising source of cell-replacement therapy for PD.
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Affiliation(s)
- Xinjian Liu
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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Wray CD, Benke TA. Effect of price increase of adrenocorticotropic hormone on treatment practices of infantile spasms. Pediatr Neurol 2010; 43:163-6. [PMID: 20691936 PMCID: PMC3197710 DOI: 10.1016/j.pediatrneurol.2010.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 02/25/2010] [Accepted: 04/12/2010] [Indexed: 11/17/2022]
Abstract
Intramuscular adrenocorticotropic hormone putatively constitutes the most efficacious treatment for infantile spasms. Adrenocorticotropic hormone in the United States is an "orphan drug," made by a single manufacturer. The price of adrenocorticotropic hormone increased almost 14-fold on August 27, 2007. We sought to evaluate the impact of this price increase on treatment practices at our institution, using a retrospective chart review of all children with infantile spasms treated during 2007-2009. We identified 97 patients whose spasms were treated using antiepileptic drugs, and we determined the length of stay for those hospitalized to initiate adrenocorticotropic hormone. Patients before the price increase were more likely to have been treated with adrenocorticotropic hormone as first medication, and were hospitalized 2.2 +/- 0.5 S.D. days for initiation. Patients after the price increase were more likely to have been treated initially with oral antiepileptic drugs rather than adrenocorticotropic hormone (P < 0.002). Those commencing adrenocorticotropic hormone after the price increase were hospitalized significantly longer (5.1 +/- 0.6 days S.D., P < 0.001). Treatment choices need to be evidence-based, but other factors often influence them.
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Affiliation(s)
- Carter D. Wray
- Department of Pediatrics, School of Medicine, University of Colorado at Denver, Aurora, Colorado
| | - Timothy A. Benke
- Department of Pediatrics, School of Medicine, University of Colorado at Denver, Aurora, Colorado
,Department of Neurology and Department of Pharmacology, School of Medicine, University of Colorado at Denver, Aurora, Colorado
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29
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Bernard TJ, Fenton LZ, Apkon SD, Boada R, Wilkening GN, Wilkinson CC, Soep JB, Miyamoto SD, Tripputi M, Armstrong-Wells J, Benke TA, Manco-Johnson MJ, Goldenberg NA. Biomarkers of hypercoagulability and inflammation in childhood-onset arterial ischemic stroke. J Pediatr 2010; 156:651-6. [PMID: 20022340 DOI: 10.1016/j.jpeds.2009.10.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 10/05/2009] [Accepted: 10/27/2009] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To test the hypothesis that acute elevations of biomarkers of hypercoagulability and inflammation are common in children with arterial ischemic stroke (AIS), particularly among etiologic subtypes that carry an increased risk of recurrent stroke. STUDY DESIGN In this prospective/retrospective institutional-based cohort study of acute childhood-onset AIS (n = 50) conducted between 2005 and 2009, D-dimer, factor VIII (FVIII) activity, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were serially evaluated at the time of clinical blood sampling. Patients were classified by stroke subtype as cardioembolic, moyamoya, non-moyamoya arteriopathy, or other. RESULTS Both D-dimer and CRP were frequently elevated in acute childhood-onset AIS and exhibited a decreasing trend with time. Acute D-dimer levels were significantly higher in cardioembolic AIS compared with noncardioembolic AIS (median, 2.04 microg/mL [range 0.54-4.54 microg/mL] vs 0.32 microg/mL [0.22-3.18 microg/mL]; P = .002). At an optimal threshold of > or = 0.50 microg/mL, the sensitivity and specificity of D-dimer for cardioembolic subtype were 78% and 79%, respectively. CONCLUSIONS Our findings identify D-dimer and CRP as candidate biomarkers for etiology and prognosis in childhood-onset AIS. Further studies should investigate the role of these and other biomarkers of hypercoagulability and inflammation in childhood-onset AIS.
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Affiliation(s)
- Timothy J Bernard
- Department of Pediatrics, Section of Child Neurology, Mountain States Regional Hemophilia and Thrombosis Center, University of Colorado Denver and The Children's Hospital, Aurora, CO 80045-0507, USA.
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Cornejo BJ, Mesches MH, Benke TA. A single early-life seizure impairs short-term memory but does not alter spatial learning, recognition memory, or anxiety. Epilepsy Behav 2008; 13:585-92. [PMID: 18678283 PMCID: PMC2586615 DOI: 10.1016/j.yebeh.2008.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 07/06/2008] [Accepted: 07/07/2008] [Indexed: 11/19/2022]
Abstract
The impact of a single seizure on cognition remains controversial. We hypothesized that a single early-life seizure (sELS) on rat Postnatal Day (P) 7 would alter only hippocampus-dependent learning and memory in mature (P60) rats. The Morris water maze, the novel object and novel place recognition tasks, and contextual fear conditioning were used to assess learning and memory associated with hippocampus/prefrontal cortex, perirhinal/hippocampal cortex, and amygdala function, respectively. The elevated plus maze and open-field test were used to assess anxiety associated with the septum. We report that sELS impaired hippocampus-dependent short-term memory, but not spatial learning or recall. sELS did not disrupt performance in the novel object and novel place recognition tasks. Contextual fear conditioning performance suggested intact amydgala function. sELS did not change anxiety levels as measured by the elevated plus maze or open-field test. Our data suggest that the long-term cognitive impact of sELS is limited largely to the hippocampus/prefrontal cortex.
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Affiliation(s)
- Brandon J. Cornejo
- Department of Pharmacology, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Medical Scientist Training Program, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
| | - Michael H. Mesches
- Department of Pharmacology, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Department of Pediatrics, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Department of Veterans Affairs Hospital, Denver, Colorado, 80220
| | - Timothy A. Benke
- Department of Pharmacology, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Department of Pediatrics, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Department of Neurology, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
- Neuroscience Program, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado, 80045
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Stafstrom CE, Benke TA. Early-life seizures and cognitive impairment: a spiny problem? Epilepsy Curr 2008; 8:27-8. [PMID: 18265887 DOI: 10.1111/j.1535-7511.2007.00225.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Recurrent Seizures and the Molecular Maturation of Hippocampal and Neocortical Glutamatergic Synapses. Swann JW, Le JT, Lee CL. Dev Neurosci 2007;29( 1 – 2 ):168–178. Recurrent seizures in animal models of early-onset epilepsy have been shown to produce deficits in spatial learning and memory. While neuronal loss does not appear to underlie these effects, dendritic spine loss has been shown to occur. In experiments reported here, seizures induced either by tetanus toxin or flurothyl during the second postnatal week were found to reduce the expression of NMDA receptor subunits in both the hippocampus and neocortex. Most experiments focused on alterations in the expression of the NR2A subunit and its associated scaffolding protein, PSD95, since their expression is developmentally regulated. Results suggest that the depression in expression can be delayed by at least 5 days but persists for at least 3–4 weeks. These effects were dependent on the number of seizures experienced, and were not observed when seizures were induced in adult mice. Taken together, the results suggest that recurrent seizures in infancy may interrupt synapse maturation and produce persistent decreases in molecular markers for glutamatergic synapses - particularly components of the NMDA receptor complex implicated in learning and memory.
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Abstract
Minimal evidence exists about the risk of recurrent childhood acute ischemic stroke in patients subjected to a subsequent head or neck injury. Recurrent or multiple dissections have been demonstrated in select cases. Minor head trauma has also been associated with acute ischemic stroke. The objective of this study was to survey pediatric stroke experts about participation of patients following acute ischemic stroke in high impact, medium impact, and low impact exercise. International Pediatric Stroke Study members were surveyed about athletic participation after stroke. Participants were asked about 2 scenarios: acute ischemic stroke with dissection, and acute ischemic stroke with a negative coagulation work-up and a negative angiogram. In these scenarios, most experts would eventually allow moderate impact sports, with some restrictions. Many experts would not allow high impact sports after a dissection, but disagree about recommendations after idiopathic acute ischemic stroke.
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Affiliation(s)
- Timothy J Bernard
- Department of Pediatrics, Child Neurology Training Program, University of Colorado at Denver and Health Sciences Center, Denver, Colorado, USA.
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Abstract
OBJECTIVE The contribution of seizures to cognitive changes remains controversial. We tested the hypothesis that a single episode of neonatal seizures (sNS) on rat postnatal day (P) 7 permanently impairs hippocampal-dependent function in mature (P60) rats because of long-lasting changes at the synaptic level. METHODS sNS was induced with subcutaneously injected kainate on P7. Learning, memory, mossy fiber sprouting, spine density, hippocampal synaptic plasticity, and glutamate receptor expression and subcellular distribution were measured at P60. RESULTS sNS selectively impaired working memory in a hippocampal-dependent radial arm water-maze task without inducing mossy fiber sprouting or altering spine density. sNS impaired CA1 hippocampal long-term potentiation and enhanced long-term depression. Subcellular fractionation and cross-linking, used to determine whether glutamate receptor trafficking underlies the alterations of memory and synaptic plasticity, demonstrated that sNS induced a selective reduction in the membrane pool of glutamate receptor 1 subunits. sNS induced a decrease in the total amount of N-methyl-D-aspartate receptor 2A and an increase in the primary subsynaptic scaffold, PSD-95. INTERPRETATION These molecular consequences are consistent with the alterations in plasticity and memory caused by sNS at the synaptic level. Our data demonstrate the cognitive impact of sNS and associate memory deficits with specific alterations in glutamatergic synaptic function.
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Affiliation(s)
- Brandon J Cornejo
- Department of Pharmacology, University of Colorado, School of Medicine, Denver, CO 80262, USA
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Abstract
Periodic bursts of activity in the disinhibited in vitro hippocampal CA3 network spread through the neural population by the glutamatergic recurrent collateral axons that link CA3 pyramidal cells. It was previously proposed that these bursts of activity are terminated by exhaustion of releasable glutamate at the recurrent collateral synapses so that the next periodic burst of network activity cannot occur until the supply of glutamate has been replenished. As a test of this hypothesis, the rate of glutamate release at CA3 axon terminals was reduced by substitution of extracellular Ca2+ with Sr2+. Reduction of the rate of glutamate release reduces the rate of depletion and should thereby prolong bursts. Here we demonstrate that Sr2+ substitution prolongs spontaneous bursts in the disinhibited adult CA3 hippocampal slices to 37.2 ± 7.6 (SE) times the duration in control conditions. Sr2+ also decreased the probability of burst initiation and the rate of burst onset, consistent with reduced synchrony of glutamate release and a consequent reduced rate of spread of excitation through the slice. These findings support the supply of releasable glutamate as an important determinant of the probability and duration of synchronous CA3 network activity.
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Affiliation(s)
- Jethro Jones
- Department of Pediatrics, University of Colorado Health Science Center, Denver, USA
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Bannister NJ, Benke TA, Mellor J, Scott H, Gürdal E, Crabtree JW, Isaac JTR. Developmental changes in AMPA and kainate receptor-mediated quantal transmission at thalamocortical synapses in the barrel cortex. J Neurosci 2006; 25:5259-71. [PMID: 15917466 PMCID: PMC6724821 DOI: 10.1523/jneurosci.0827-05.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During the first week of life, there is a shift from kainate to AMPA receptor-mediated thalamocortical transmission in layer IV barrel cortex. However, the mechanisms underlying this change and the differential properties of AMPA and kainate receptor-mediated transmission remain essentially unexplored. To investigate this, we studied the quantal properties of AMPA and kainate receptor-mediated transmission using strontium-evoked miniature EPSCs. AMPA and kainate receptor-mediated transmission exhibited very different quantal properties but were never coactivated by a single quantum of transmitter, indicating complete segregation to different synapses within the thalamocortical input. Nonstationary fluctuation analysis showed that synaptic AMPA receptors exhibited a range of single-channel conductance (gamma) and a strong negative correlation between gamma and functional channel number, indicating that these two parameters are reciprocally regulated at thalamocortical synapses. We obtained the first estimate of gamma for synaptic kainate receptors (<2 pS), and this primarily accounted for the small quantal size of kainate receptor-mediated transmission. Developmentally, the quantal contribution to transmission of AMPA receptors increased and that of kainate receptors decreased. No changes in AMPA or kainate quantal amplitude or in AMPA receptor gamma were observed, demonstrating that the developmental change was attributable to a decrease in the number of kainate synapses and an increase in the number of AMPA synapses contributing to transmission. Therefore, we demonstrate fundamental differences in the quantal properties for these two types of synapse. Thus, the developmental switch in transmission will dramatically alter information transfer at thalamocortical inputs to layer IV.
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Affiliation(s)
- Neil J Bannister
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, Bristol BS8 1TD, United Kingdom
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Schnee ME, Lawton DM, Furness DN, Benke TA, Ricci AJ. Auditory hair cell-afferent fiber synapses are specialized to operate at their best frequencies. Neuron 2005; 47:243-54. [PMID: 16039566 DOI: 10.1016/j.neuron.2005.06.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 05/05/2005] [Accepted: 06/01/2005] [Indexed: 11/21/2022]
Abstract
Auditory afferent fiber activity is driven by high-fidelity information transfer from the sensory hair cell. Presynaptic specializations, posited to maintain fidelity, are investigated at synapses with characteristic frequencies of 120 Hz and 320 Hz. Morphological data indicate that high-frequency cells have more synapses and higher vesicle density near dense bodies (DBs). Tracking vesicular release via capacitance changes identified three overlapping kinetic components of release corresponding to morphologically identified vesicle pools. High-frequency cells released faster; however, when normalized to release site number, low-frequency cells released faster, likely due to a greater Ca2+ load per synapse. The Ca(2+)-dependence of release was nonsaturating and independent of frequency, suggesting that release, not refilling, was rate limiting. A model of release derived from vesicle equilibration between morphologically defined pools reproduced the capacitance data, supporting a critical role in vesicle trafficking for DBs. The model suggests that presynaptic specializations enable synapses to operate most efficiently at their characteristic frequencies.
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Affiliation(s)
- M E Schnee
- Neuroscience Center and Kresge Hearing Labs, Louisiana State University, New Orleans, LA 70112, USA
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Dzhala VI, Talos DM, Sdrulla DA, Brumback AC, Mathews GC, Benke TA, Delpire E, Jensen FE, Staley KJ. NKCC1 transporter facilitates seizures in the developing brain. Nat Med 2005; 11:1205-13. [PMID: 16227993 DOI: 10.1038/nm1301] [Citation(s) in RCA: 682] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 08/24/2005] [Indexed: 12/21/2022]
Abstract
During development, activation of Cl(-)-permeable GABA(A) receptors (GABA(A)-R) excites neurons as a result of elevated intracellular Cl(-) levels and a depolarized Cl(-) equilibrium potential (E(Cl)). GABA becomes inhibitory as net outward neuronal transport of Cl(-) develops in a caudal-rostral progression. In line with this caudal-rostral developmental pattern, GABAergic anticonvulsant compounds inhibit motor manifestations of neonatal seizures but not cortical seizure activity. The Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) facilitates the accumulation of Cl(-) in neurons. The NKCC1 blocker bumetanide shifted E(Cl) negative in immature neurons, suppressed epileptiform activity in hippocampal slices in vitro and attenuated electrographic seizures in neonatal rats in vivo. Bumetanide had no effect in the presence of the GABA(A)-R antagonist bicuculline, nor in brain slices from NKCC1-knockout mice. NKCC1 expression level versus expression of the Cl(-)-extruding transporter (KCC2) in human and rat cortex showed that Cl(-) transport in perinatal human cortex is as immature as in the rat. Our results provide evidence that NKCC1 facilitates seizures in the developing brain and indicate that bumetanide should be useful in the treatment of neonatal seizures.
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Affiliation(s)
- Volodymyr I Dzhala
- Department of Neurology, School of Medicine, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, Colorado 80262, USA
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Rennie KJ, Streeter MA, Benke TA, Moritz AT. Modeling channel properties in vestibular calyx terminals. Biomed Sci Instrum 2005; 41:358-63. [PMID: 15850132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Two types of hair cell have been described in the vestibular end organs of amniotes, but the coding of sensory signals by different hair cell types is not well understood. Type I hair cells are contacted by cup-shaped afferent calyx terminals, whereas type II hair cells are contacted by bouton terminals. The whole cell patch-clamp technique has been used to record voltage-dependent ionic currents from calyx terminals. Type I hair cells along with their calyces were non-enzymatically dissociated from the semicircular canals and utricles of Mongolian gerbils. Voltage-dependent currents identified in whole cell voltage-clamp included transient inward sodium currents and outward potassium currents. Potassium currents were pharmacologically blocked by cesium in the patch electrode solution. The NEURON simulation environment was used to model the properties of the calyx terminal. A series of interconnected cylindrical compartments was designed to represent the inner and outer calyx membrane, the base of the calyx and a short axon segment. Kinetic parameters for the Na+ current were optimized with a genetic algorithm to match kinetic data from the whole cell recordings.
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Affiliation(s)
- K J Rennie
- Department of Otolaryngology, University of Colorado Health Sciences Center, 4200 E. Ninth Ave., Denver, CO 80262, USA
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Abstract
In experimental models of epilepsy, single and recurrent seizures are often used in an attempt to determine the effects of the seizures themselves on mammalian brain function. These models attempt to emulate as many features as possible of their human disease counterparts without many of the confounding factors such as underlying disease processes and medication effects. Numerous models have been used in the past to address different questions. Nevertheless, the basic questions are often the same: 1. Do seizures cause long-term damage? 2. Do seizures predispose to chronic epilepsy (epileptogenesis), that is long-term spontaneous repetitive seizures? 3. Are these results developmentally regulated? 4. Are the underlying mechanisms of epileptogenesis and brain damage related? In pursuing these questions, the goal is to determine how seizures exert their effects and to minimize any side effects from the methods employed to induce the seizures themselves. This requires a detailed characterization of the methods used to induce seizures. In this chapter, we will review the literature regarding the tetanus toxin model of chronic epilepsy with regard to its mechanisms of action, clinical comparisons, how it is experimentally implemented and the results obtained thus far. These results will be compared to other models of chronic epilepsy in order to make generalizations about the effects of repetitive seizures in adult and early life. At this time, it appears that repetitive seizures cause long-term changes in learning ability and may cause a predisposition to chronic seizures at all ages. In younger animals, both features of learning impairment and epilepsy are not typically associated with cell loss as they are in adult animals. At all ages, some form of synaptic reorganization has been demonstrated to occur.
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Affiliation(s)
- Timothy A Benke
- Cain Foundation Labouratories, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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Benke TA, Lüthi A, Palmer MJ, Wikström MA, Anderson WW, Isaac JT, Collingridge GL. Mathematical modelling of non-stationary fluctuation analysis for studying channel properties of synaptic AMPA receptors. J Physiol 2001; 537:407-20. [PMID: 11731574 PMCID: PMC2278972 DOI: 10.1111/j.1469-7793.2001.00407.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
1. The molecular properties of synaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors are an important factor determining excitatory synaptic transmission in the brain. Changes in the number (N) or single-channel conductance (gamma) of functional AMPA receptors may underlie synaptic plasticity, such as long-term potentiation (LTP) and long-term depression (LTD). These parameters have been estimated using non-stationary fluctuation analysis (NSFA). 2. The validity of NSFA for studying the channel properties of synaptic AMPA receptors was assessed using a cable model with dendritic spines and a microscopic kinetic description of AMPA receptors. Electrotonic, geometric and kinetic parameters were altered in order to determine their effects on estimates of the underlying gamma. 3. Estimates of gamma were very sensitive to the access resistance of the recording (R(A)) and the mean open time of AMPA channels. Estimates of gamma were less sensitive to the distance between the electrode and the synaptic site, the electrotonic properties of dendritic structures, recording electrode capacitance and background noise. Estimates of gamma were insensitive to changes in spine morphology, synaptic glutamate concentration and the peak open probability (P(o)) of AMPA receptors. 4. The results obtained using the model agree with biological data, obtained from 91 dendritic recordings from rat CA1 pyramidal cells. A correlation analysis showed that R(A) resulted in a slowing of the decay time constant of excitatory postsynaptic currents (EPSCs) by approximately 150 %, from an estimated value of 3.1 ms. R(A) also greatly attenuated the absolute estimate of gamma by approximately 50-70 %. 5. When other parameters remain constant, the model demonstrates that NSFA of dendritic recordings can readily discriminate between changes in gamma vs. changes in N or P(o). Neither background noise nor asynchronous activation of multiple synapses prevented reliable discrimination between changes in gamma and changes in either N or P(o). 6. The model (available online) can be used to predict how changes in the different properties of AMPA receptors may influence synaptic transmission and plasticity.
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Affiliation(s)
- T A Benke
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, University Walk, Bristol BS8 1TD, UK.
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Lüthi A, Chittajallu R, Duprat F, Palmer MJ, Benke TA, Kidd FL, Henley JM, Isaac JT, Collingridge GL. Hippocampal LTD expression involves a pool of AMPARs regulated by the NSF-GluR2 interaction. Neuron 1999; 24:389-99. [PMID: 10571232 DOI: 10.1016/s0896-6273(00)80852-1] [Citation(s) in RCA: 239] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated whether the interaction between the N-ethyl-maleimide-sensitive fusion protein (NSF) and the AMPA receptor (AMPAR) subunit GluR2 is involved in synaptic plasticity in the CA1 region of the hippocampus. Blockade of the NSF-GluR2 interaction by a specific peptide (pep2m) introduced into neurons prevented homosynaptic, de novo long-term depression (LTD). Moreover, saturation of LTD prevented the pep2m-induced reduction in AMPAR-mediated excitatory postsynaptic currents (EPSCs). Minimal stimulation experiments indicated that both pep2m action and LTD were due to changes in quantal size and quantal content but were not associated with changes in AMPAR single-channel conductance or EPSC kinetics. These results suggest that there is a pool of AMPARs dependent on the NSF-GluR2 interaction and that LTD expression involves the removal of these receptors from synapses.
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Affiliation(s)
- A Lüthi
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, United Kingdom
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Isaac JT, Lüthi A, Palmer MJ, Anderson WW, Benke TA, Collingridge GL. An investigation of the expression mechanism of LTP of AMPA receptor-mediated synaptic transmission at hippocampal CA1 synapses using failures analysis and dendritic recordings. Neuropharmacology 1998; 37:1399-410. [PMID: 9849675 DOI: 10.1016/s0028-3908(98)00140-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
There is considerable controversy surrounding the mechanism of expression of long-term potentiation of AMPA receptor-mediated synaptic transmission in the CA1 region of the hippocampus, a process thought to be important for learning and memory in the mammalian CNS. We have re-examined the expression mechanism of this form of synaptic plasticity using whole-cell dendritic recordings, minimal stimulation to activate one or a few synapses, and failures analysis. Dendritic recordings provide improved resolution of small synaptic events, as compared to previous studies using somatic recordings, because there is less dendritic filtering of signals. We find that long-term potentiation (LTP) is associated with changes in the size of synaptic responses when they occur (potency) in all cells and this is accompanied by significant decreases in failure rate in approximately 60% of the experiments. This suggests that in some cells an increase in quantal amplitude is the sole expression mechanism for LTP and, in the cells where failure rate decreased, there is an additional mechanism causing a change in quantal content.
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Affiliation(s)
- J T Isaac
- Department of Anatomy, University of Bristol, UK
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Abstract
Activity-dependent alteration in synaptic strength is a fundamental property of the vertebrate central nervous system and is thought to underlie learning and memory. The most extensively studied model of activity-dependent synaptic plasticity is long-term potentiation (LTP) of glutamate-responsive (glutamatergic) synapses, a widespread phenomenon involving multiple mechanisms. The best characterized form of LTP occurs in the CA1 region of the hippocampus, in which LTP is initiated by transient activation of NMDA (N-methyl-D-aspartate) receptors and is expressed as a persistent increase in synaptic transmission through AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate) receptors. This increase is due, at least in part, to a postsynaptic modification of AMPA-receptor function; this modification could be caused by an increase in the number of receptors, their open probability, their kinetics or their single-channel conductance. Here we show that the induction of LTP in the CA1 region of the hippocampus is often associated with an increase in single-channel conductance of AMPA receptors. This shows that elementary channel properties can be rapidly modified by synaptic activity and provides an insight into one molecular mechanism by which glutamatergic synapses can alter their strength.
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Affiliation(s)
- T A Benke
- Department of Anatomy, University of Bristol, UK
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Bresink I, Benke TA, Collett VJ, Seal AJ, Parsons CG, Henley JM, Collingridge GL. Effects of memantine on recombinant rat NMDA receptors expressed in HEK 293 cells. Br J Pharmacol 1996; 119:195-204. [PMID: 8886398 PMCID: PMC1915856 DOI: 10.1111/j.1476-5381.1996.tb15971.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The actions of the uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonists, memantine (1-amino-3,5-dimethyladamantane) and (+)-MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate, dizocilpine), on recombinant NMDA receptors has been studied by use of the whole-cell patch clamp technique. 2. Human embryonic kidney (HEK) 293 cells were transiently transfected with different NMDA receptor subunit combinations (NR1a/NR2A, NR1a/NR2B and NR1a/NR2D). A mutant form of the green fluorescent protein (GFP) cotransfected with the NMDA receptor subunits to enable the visualization of transfected cells. 3. Memantine (0.3-30 microM) blocked L-glutamate (100 microM)-mediated currents in a concentration-dependent manner in NR1a/NR2A, NR1a/NR2B and NR1a/NR2D transfected cells with IC50 values (at -70 mV) of 0.93 +/- 0.15 microM, 0.82 +/- 0.12 microM and 0.47 +/- 0.06 microM (mean +/- s.c. mean), respectively. 4. The memantine-induced block was strongly voltage-dependent. Alteration of the holding potential from -70 mV to +60 mV resulted in an e-fold increase in the IC50 values per 30-33 mV change in membrane potential, for all 3 subunit combinations investigated. 5. The kinetics of the actions of memantine (30 microM) were investigated for the NR1a/2A combination, in 6 cells (13-15 determinations). At -70 mV, the block and recovery from block were both best described by two exponentials with time-constants of 201 +/- 23 ms (81 +/- 2%) and 3.9 +/- 0.6 s and 597 +/- 94 ms (18 +/- 1%) and 18.6 +/- 2.4 s, respectively. The predominant effect of depolarization was to increase the weight of the faster recovery time-constant. Kinetic analysis suggests that these results are consistent with previously proposed Markov models. 6. (+)-MK-801 was studied briefly for comparative purposes. (+)-MK-801 (200 nM) preferentially blocked NMDA receptor currents (at -70 mV) in NR1a/NR2A and NR1a/NR2B (82 +/- 10% and 93 +/- 2% depressions) compared to NR1a/NR2D (38 +/- 7%) transfected cells. (+)-MK-801 appeared to be less voltage-dependent than memantine on all three receptor combinations. 7. In conclusion, memantine was a voltage-dependent antagonist of recombinant rat NMDA receptors expressed in HEK 293 cells but showed little selectivity between the subunits investigated. Its actions on these recombinant receptor combinations are similar to its actions on native NMDA receptors.
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Affiliation(s)
- I Bresink
- Dept. of Anatomy, Medical School, University of Bristol, England
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Abstract
Genetic manipulation offers great potential for studying the molecular and cellular processes which control or regulate the complex developmental properties of neurons. Gene transfer into neurons, however, is notoriously difficult. In this study we have used a replication-defective adenovirus (Adv/RSV beta gal), expressing beta-galactosidase (beta-gal) as a reporter gene, to infect dissociated cultures of rat hippocampal neurons and hippocampal slice cultures. Because future studies will require either long-term (e.g., developmental) or short-term (e.g., electrophysiological) expression of recombinant genes in neuronal cultures, we have optimized infection conditions for each situation. The Adv/RSV beta gal construct infects neurons and glial cells equally well, with no apparent alterations in cellular morphology. In slice cultures, the same efficiency and temporal control of beta-gal expression following Adv/RSV beta gal infection was achieved. Focal application of the adenoviruses, by microinjection, permitted infection of discrete subregions within the hippocampal explants. Whole cell recordings of dissociated hippocampal neurons and field recordings from the explant cultures, infected with Adv/RSV beta gal at low multiplicities of infection, indicated no significant alteration in the electrophysiological profiles of neurons in these cultures. The results demonstrate the utility of adenoviruses as gene transfer vectors for primary cultures of neurons. Adenovirus-mediated gene transfer into slice cultures also provides an opportunity to study development or plasticity in an environment where the circuitry and cytoarchitecture of the tissue are preserved and the areas of genetic manipulation can be spatially isolated.
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Affiliation(s)
- M F Wilkemeyer
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas, USA
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Benke TA, Jones OT, Collingridge GL, Angelides KJ. N-Methyl-D-aspartate receptors are clustered and immobilized on dendrites of living cortical neurons. Proc Natl Acad Sci U S A 1993; 90:7819-23. [PMID: 7689230 PMCID: PMC47234 DOI: 10.1073/pnas.90.16.7819] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The response of nerve cells to synaptic inputs and the propagation of this activation is critically dependent on the cell-surface distribution of ion channels. In the hippocampus, Ca2+ influx through N-methyl-D-aspartate receptors (NMDAR) and/or voltage-dependent calcium channels on dendrites is thought to be critically involved in long-term potentiation, neurite outgrowth, epileptogenesis, synaptogenesis, and cell death. We report that conantokin-G (CntxG), a peptide from Conus geographus venom, competitively blocked with high affinity and specificity NMDAR-mediated currents in hippocampal neurons and is a reliable probe for exploring NMDAR distribution. Fluorescent derivatives of CntxG were prepared and used to directly determine NMDAR distribution on living hippocampal neurons by digital imaging and confocal fluorescence microscopy. In hippocampal slices, the CA1 dendritic subfield was strongly labeled by CntxG, whereas the CA3 mossy fiber region was not. On CA1 hippocampal neurons in culture, dendritic CntkG-sensitive NMDAR were clustered at sites of synaptic contacts, whereas somatic NMDAR were distributed diffusely and in patches. NMDAR distribution differed from the distribution of voltage-dependent calcium channels. A significant fraction of labeled NMDAR on somata and dendrites was found to be highly mobile: rates were consistent with the possible rapid recruitment of NMDAR to specific synaptic locations. The localization of NMDAR and modulation of this distribution demonstrated here may have important implications for the events that underlie neuronal processing and synaptic remodeling during associative synaptic modification.
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Affiliation(s)
- T A Benke
- Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030
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Benke TA, Clark JW, Wisoff PJ, Schneider S, Balasubramaniam C, Hawkins HK, Laurent J, Perling L, Shehab A. Comparative study of suture and laser-assisted anastomoses in rat sciatic nerves. Lasers Surg Med 1989; 9:602-15. [PMID: 2557502 DOI: 10.1002/lsm.1900090611] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Conventional suture repair of peripheral nerves results in a fibrotic reaction that is detrimental to nerve regeneration. As an alternative procedure known as "laser-assisted" repair, a laser can be used, along with a reduced number of sutures, to reanastomose served peripheral nerves. To explore the long-term implications of this technique, the right sciatic nerves of Sprague-Dawley rats were surgically cut and reanastomosed either by means of four epineurial sutures or two epineurial sutures and CO2 laser welds. Tensile strength, electrophysiology, histology, and functional studies were performed up to 11 months postoperatively. Tensile strength measurements indicate no long-term disadvantage with the laser-assisted technique, although the short-term tensile strength is lower than with conventional suture repair. The conduction velocities of the repaired nerves were similar for both techniques; however, laser-assisted repaired nerves were found to have lower stimulation thresholds and reduced branching compared to the suture repaired nerves. The measured functional recovery was similar for both repair techniques.
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Affiliation(s)
- T A Benke
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251
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