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Saldaris JM, Ayalde J, Kankanange S, Keeley J, Leonard H, Jacoby P, Marsh ED, Benke TA, Demarest ST, Downs J. Parent-reported outcome measures evaluating communication in individuals with rare neurodevelopmental disorders: A systematic review. INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS 2024. [PMID: 39141588 DOI: 10.1111/1460-6984.13100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 07/25/2024] [Indexed: 08/16/2024]
Abstract
BACKGROUND Communication impairments are a leading concern for parent caregivers of individuals with rare neurodevelopmental disorders (RNDDs). Clinical trials of disease modifying therapies require valid and responsive outcome measures that are relevant to individuals with RNDDs. Identifying and evaluating current psychometric properties for communication measures is a critical step towards the selection and use of appropriate instruments. AIMS This systematic review offers (1) a description of parent-reported communication measures and (2) evidence for their psychometric properties, in RNDDs. METHODS The systematic review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022334649). MEDLINE (Ovid), Embase, PsychINFO, Web of Science, CINAHL Plus, Cochrane Library, ClinicalTrials.gov, the Australian New Zealand Clinical Trials Registry were searched from inception to August 2023. Methodological assessment of quality was completed using the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. Parent-reported measures used in observational studies and clinical trials were identified. Data on utility, reliability and validity for RNDDs were extracted. MAIN CONTRIBUTION Sixteen parent-reported communication measures were used in RNDD research, the Vineland Adaptive Behavior Scales being most commonly used. Validation data in RNDDs were identified for six of these measures. Limitations related to sample size or the scope of psychometric testing. CONCLUSIONS Many communication measures have been used for RNDDs but there are few data validating their use. Valid and reliable methods of measuring communication in persons with RNDDs is a priority for future high-quality clinical trials. WHAT THIS PAPER ADDS What is already known on the subject Communication is a critical domain for families with a child with a rare neurodevelopmental disorder (RNDD). Validated outcome measures are essential for accurate evaluation and interpretation of responses to treatments in clinical trials. What this paper adds to existing knowledge We identified 16 parent-reported communication measures that have been used with RNDDs, but only six measures had validation data for at least one RNDD. High quality evidence is accumulating, with all validation studies in this review published between 2020 to 2023. Modifications of existing measures may be required to assess communication for RNDDs. What are the clinical implications of this work? This systematic review catalogues the available psychometric data for communication measures and indicates an ongoing need for new validation studies to ensure they are fit-for-purpose for upcoming clinical trials in RNDDs. This review will inform the selection of communication measures for clinical trials and research studies.
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Affiliation(s)
- Jacinta M Saldaris
- Telethon Kids Institute, Nedlands, Western Australia, Australia
- The University of Western Australia, Centre for Child Health Research, Crawley, Western Australia, Australia
| | - Jeremiah Ayalde
- Telethon Kids Institute, Nedlands, Western Australia, Australia
| | | | - Jessica Keeley
- Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Helen Leonard
- Telethon Kids Institute, Nedlands, Western Australia, Australia
- The University of Western Australia, Centre for Child Health Research, Crawley, Western Australia, Australia
| | - Peter Jacoby
- Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Eric D Marsh
- Children's Hospital of Philadelphia, Division of Child Neurology, Philadelphia, Pennsylvania, USA
- Departments of Neurology and Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Tim A Benke
- Children's Hospital Colorado, Neurology and Pharmacology, Aurora, Colorado, USA
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Scott T Demarest
- Children's Hospital Colorado, Neurology and Pharmacology, Aurora, Colorado, USA
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Jenny Downs
- Telethon Kids Institute, Nedlands, Western Australia, Australia
- The University of Western Australia, Centre for Child Health Research, Crawley, Western Australia, Australia
- Curtin University, School of Allied Health, Bentley, Western Australia, Australia
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Mykins M, Bridges B, Jo A, Krishnan K. Multidimensional Analysis of a Social Behavior Identifies Regression and Phenotypic Heterogeneity in a Female Mouse Model for Rett Syndrome. J Neurosci 2024; 44:e1078232023. [PMID: 38199865 PMCID: PMC10957218 DOI: 10.1523/jneurosci.1078-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 11/01/2023] [Accepted: 11/17/2023] [Indexed: 01/12/2024] Open
Abstract
Regression is a key feature of neurodevelopmental disorders such as autism spectrum disorder, Fragile X syndrome, and Rett syndrome (RTT). RTT is caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). It is characterized by an early period of typical development with subsequent regression of previously acquired motor and speech skills in girls. The syndromic phenotypes are individualistic and dynamic over time. Thus far, it has been difficult to capture these dynamics and syndromic heterogeneity in the preclinical Mecp2-heterozygous female mouse model (Het). The emergence of computational neuroethology tools allows for robust analysis of complex and dynamic behaviors to model endophenotypes in preclinical models. Toward this first step, we utilized DeepLabCut, a marker-less pose estimation software to quantify trajectory kinematics and multidimensional analysis to characterize behavioral heterogeneity in Het in the previously benchmarked, ethologically relevant social cognition task of pup retrieval. We report the identification of two distinct phenotypes of adult Het: Het that display a delay in efficiency in early days and then improve over days like wild-type mice and Het that regress and perform worse in later days. Furthermore, regression is dependent on age and behavioral context and can be detected in the initial days of retrieval. Together, the novel identification of two populations of Het suggests differential effects on neural circuitry, opens new avenues to investigate the underlying molecular and cellular mechanisms of heterogeneity, and designs better studies for stratifying therapeutics.
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Affiliation(s)
- Michael Mykins
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Benjamin Bridges
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Angela Jo
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Keerthi Krishnan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
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Wong LC, Hsu CJ, Wu YT, Chu HF, Lin JH, Wang HP, Hu SC, Tsai YC, Tsai WC, Lee WT. Investigating the impact of probiotic on neurological outcomes in Rett syndrome: A randomized, double-blind, and placebo-controlled pilot study. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2024:13623613231225899. [PMID: 38361371 DOI: 10.1177/13623613231225899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
LAY ABSTRACT Rett syndrome often involves gastrointestinal symptoms and gut microbiota imbalances. We conducted a study to explore the feasibility of probiotic Lactobacillus plantarum PS128 and the impact on neurological functions in Rett syndrome. The results of our investigation demonstrated that the supplementation of probiotic L. plantarum PS128 was feasible and well tolerated, with 100% retention rate and 0% withdrawal rate. In addition, there was only one participant who had loose stool after taking L. plantarum PS128. Further, there was a tendency to enhance overall cognitive developmental level, as assessed using Mullen Scales of Early Learning. In addition, it significantly improved dystonia, as assessed using the Burke-Fahn-Marsden Movement Scale, in comparison with the placebo group. This study provides a strong foundation for future research and clinical trials exploring the potential of L. plantarum PS128 probiotics as a complementary therapy for individuals with Rett syndrome.
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Affiliation(s)
- Lee Chin Wong
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chia-Jui Hsu
- Department of Pediatrics, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan
| | - Yen-Tzu Wu
- School and Graduate Institute of Physical Therapy, National Taiwan University College of Medicine, Taiwan
- Department of Physical Medicine and Rehabilitation, National Taiwan University, Taipei, Taiwan
| | - Hsu-Feng Chu
- Biomedical Industry Ph.D. Program, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jui-Hsiang Lin
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
| | - Hsin-Pei Wang
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Pediatrics, National Taiwan University Hospital YunLin Branch, YunLin, Taiwan
| | - Su-Ching Hu
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Ying-Chieh Tsai
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Wen-Che Tsai
- Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
- Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan
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4
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Malar DS, Thitilertdecha P, Ruckvongacheep KS, Brimson S, Tencomnao T, Brimson JM. Targeting Sigma Receptors for the Treatment of Neurodegenerative and Neurodevelopmental Disorders. CNS Drugs 2023; 37:399-440. [PMID: 37166702 PMCID: PMC10173947 DOI: 10.1007/s40263-023-01007-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/18/2023] [Indexed: 05/12/2023]
Abstract
The sigma-1 receptor is a 223 amino acid-long protein with a recently identified structure. The sigma-2 receptor is a genetically unrelated protein with a similarly shaped binding pocket and acts to influence cellular activities similar to the sigma-1 receptor. Both proteins are highly expressed in neuronal tissues. As such, they have become targets for treating neurological diseases, including Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), multiple sclerosis (MS), Rett syndrome (RS), developmental and epileptic encephalopathies (DEE), and motor neuron disease/amyotrophic lateral sclerosis (MND/ALS). In recent years, there have been many pre-clinical and clinical studies of sigma receptor (1 and 2) ligands for treating neurological disease. Drugs such as blarcamesine, dextromethorphan and pridopidine, which have sigma-1 receptor activity as part of their pharmacological profile, are effective in treating multiple aspects of several neurological diseases. Furthermore, several sigma-2 receptor ligands are under investigation, including CT1812, rivastigmine and SAS0132. This review aims to provide a current and up-to-date analysis of the current clinical and pre-clinical data of drugs with sigma receptor activities for treating neurological disease.
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Affiliation(s)
- Dicson S Malar
- Natural Products for Neuroprotection and Anti-ageing Research Unit, Chulalongkorn University, Bangkok, Thailand
| | - Premrutai Thitilertdecha
- Siriraj Research Group in Immunobiology and Therapeutic Sciences, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kanokphorn S Ruckvongacheep
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Sirikalaya Brimson
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Tewin Tencomnao
- Natural Products for Neuroprotection and Anti-ageing Research Unit, Chulalongkorn University, Bangkok, Thailand
| | - James M Brimson
- Natural Products for Neuroprotection and Anti-ageing Research Unit, Chulalongkorn University, Bangkok, Thailand.
- Research, Innovation and International Affairs, Faculty of Allied Health Sciences, Chulalongkorn University, Room 409, ChulaPat-1 Building, 154 Rama 1 Road, Bangkok, 10330, Thailand.
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Goodspeed K, Armstrong D, Dolce A, Evans P, Said R, Tsai P, Sirsi D. Electroencephalographic (EEG) Biomarkers in Genetic Neurodevelopmental Disorders. J Child Neurol 2023; 38:466-477. [PMID: 37264615 PMCID: PMC10644693 DOI: 10.1177/08830738231177386] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/17/2022] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
Collectively, neurodevelopmental disorders are highly prevalent, but more than a third of neurodevelopmental disorders have an identifiable genetic etiology, each of which is individually rare. The genes associated with neurodevelopmental disorders are often involved in early brain development, neuronal signaling, or synaptic plasticity. Novel treatments for many genetic neurodevelopmental disorders are being developed, but disease-relevant clinical outcome assessments and biomarkers are limited. Electroencephalography (EEG) is a promising noninvasive potential biomarker of brain function. It has been used extensively in epileptic disorders, but its application in neurodevelopmental disorders needs further investigation. In this review, we explore the use of EEG in 3 of the most prevalent genetic neurodevelopmental disorders-Angelman syndrome, Rett syndrome, and fragile X syndrome. Quantitative analyses of EEGs, such as power spectral analysis or measures of connectivity, can quantify EEG signatures seen on qualitative review and potentially correlate with phenotypes. In both Angelman syndrome and Rett syndrome, increased delta power on spectral analysis has correlated with clinical markers of disease severity including developmental disability and seizure burden, whereas spectral power analysis on EEG in fragile X syndrome tends to demonstrate abnormalities in gamma power. Further studies are needed to establish reliable relationships between quantitative EEG biomarkers and clinical phenotypes in rare genetic neurodevelopmental disorders.
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Affiliation(s)
- Kimberly Goodspeed
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Dallas Armstrong
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Alison Dolce
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Patricia Evans
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rana Said
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Peter Tsai
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Deepa Sirsi
- Department of Pediatrics, Division of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Vavers E, Zvejniece L, Dambrova M. Sigma-1 receptor and seizures. Pharmacol Res 2023; 191:106771. [PMID: 37068533 PMCID: PMC10176040 DOI: 10.1016/j.phrs.2023.106771] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/03/2023] [Accepted: 04/13/2023] [Indexed: 04/19/2023]
Abstract
Over the last decade, sigma-1 receptor (Sig1R) has been recognized as a valid target for the treatment of seizure disorders and seizure-related comorbidities. Clinical trials with Sig1R ligands are underway testing therapies for the treatment of drug-resistant seizures, developmental and epileptic encephalopathies, and photosensitive epilepsy. However, the direct molecular mechanism by which Sig1R modulates seizures and the balance between excitatory and inhibitory pathways has not been fully elucidated. This review article aims to summarize existing knowledge of Sig1R and its involvement in seizures by focusing on the evidence obtained from Sig1R knockout animals and the anti-seizure effects of Sig1R ligands. In addition, this review article includes a discussion of the advantages and disadvantages of the use of existing compounds and describes the challenges and future perspectives on the use of Sig1R as a target for the treatment of seizure disorders.
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Affiliation(s)
- Edijs Vavers
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; University of Tartu, Faculty of Science and Technology, Institute of Chemistry, Ravila 14a, 50411, Tartu, Estonia.
| | - Liga Zvejniece
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Maija Dambrova
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; Riga Stradiņš University, Faculty of Pharmacy, Konsula 21, LV-1007, Riga, Latvia
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7
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Petriti U, Dudman DC, Scosyrev E, Lopez-Leon S. Global prevalence of Rett syndrome: systematic review and meta-analysis. Syst Rev 2023; 12:5. [PMID: 36642718 PMCID: PMC9841621 DOI: 10.1186/s13643-023-02169-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 12/29/2022] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Rett syndrome is a rare, severe neurodevelopmental disorder. Almost all cases occur in girls, in association with spontaneous (non-inherited) mutations involving the methyl-CpG-binding protein 2 gene located on the X chromosome. Diagnostic criteria for typical Rett syndrome require a period of regression, followed by recovery or stabilization, and fulfillment of all four main criteria (loss of purposeful hand skills, loss of spoken language, gait abnormalities, and stereotypic hand movements). Our objective was to estimate the prevalence of Rett syndrome in the general population, stratified by sex. METHODS We conducted a search of PubMed, Embase, Web of Science, Cochrane Library, LILACS, and LIVIVO to retrieve studies published in English between Jan. 1, 2000, and June 30, 2021. Pooled prevalence with a 95% confidence interval (CI) was estimated using a random-effects meta-analysis based on a generalized linear mixed model with a logit link. RESULTS Ten eligible studies were identified (all in females), with a combined sample size of 9.57 million women and 673 Rett syndrome cases. The pooled prevalence estimate (random effects) was 7.1 per 100,000 females (95% CI: 4.8, 10.5, heterogeneity p < 0.001). Despite greatly variable precision of estimation, all estimates were compatible with a prevalence range of approximately 5 to 10 cases per 100,000 females based on their respective 95% CIs. CONCLUSION These findings may facilitate planning of therapeutic trials in this indication in terms of target sample size and accrual times.
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Affiliation(s)
| | - Daniel C Dudman
- Former Rutgers University Ernest Mario School of Pharmacy, Piscataway, NJ, USA.,Former Quantitative Safety & Epidemiology, Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
| | - Emil Scosyrev
- Quantitative Safety & Epidemiology, Novartis Pharmaceuticals Corporation, One Health Plaza, Building 339-1131, East Hanover, NJ, 07936-1080, USA
| | - Sandra Lopez-Leon
- Quantitative Safety & Epidemiology, Novartis Pharmaceuticals Corporation, One Health Plaza, Building 339-1131, East Hanover, NJ, 07936-1080, USA. .,Rutgers Center for Pharmacoepidemiology and Treatment Science, Institute for Health, New Brunswick, NJ, USA.
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8
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Sivakumar S, Ghasemi M, Schachter SC. Targeting NMDA Receptor Complex in Management of Epilepsy. Pharmaceuticals (Basel) 2022; 15:ph15101297. [PMID: 36297409 PMCID: PMC9609646 DOI: 10.3390/ph15101297] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are widely distributed in the central nervous system (CNS) and play critical roles in neuronal excitability in the CNS. Both clinical and preclinical studies have revealed that the abnormal expression or function of these receptors can underlie the pathophysiology of seizure disorders and epilepsy. Accordingly, NMDAR modulators have been shown to exert anticonvulsive effects in various preclinical models of seizures, as well as in patients with epilepsy. In this review, we provide an update on the pathologic role of NMDARs in epilepsy and an overview of the NMDAR antagonists that have been evaluated as anticonvulsive agents in clinical studies, as well as in preclinical seizure models.
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Affiliation(s)
- Shravan Sivakumar
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
- Correspondence: (M.G.); (S.C.S.)
| | - Steven C. Schachter
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
- Harvard Medical School, Boston, MA 02114, USA
- Consortia for Improving Medicine with Innovation & Technology (CIMIT), Boston, MA 02114, USA
- Correspondence: (M.G.); (S.C.S.)
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9
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Grimm NB, Lee JT. Selective Xi reactivation and alternative methods to restore MECP2 function in Rett syndrome. Trends Genet 2022; 38:920-943. [PMID: 35248405 PMCID: PMC9915138 DOI: 10.1016/j.tig.2022.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
The human X-chromosome harbors only 4% of our genome but carries over 20% of genes associated with intellectual disability. Given that they inherit only one X-chromosome, males are more frequently affected by X-linked neurodevelopmental genetic disorders than females. However, despite inheriting two X-chromosomes, females can also be affected because X-chromosome inactivation enables only one of two X-chromosomes to be expressed per cell. For Rett syndrome and similar X-linked disorders affecting females, disease-specific treatments have remained elusive. However, a cure may be found within their own cells because every sick cell carries a healthy copy of the affected gene on the inactive X (Xi). Therefore, selective Xi reactivation may be a viable approach that would address the root cause of various X-linked disorders. Here, we discuss Rett syndrome and compare current approaches in the pharmaceutical pipeline to restore MECP2 function. We then focus on Xi reactivation and review available methods, lessons learned, and future directions.
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Affiliation(s)
- Niklas-Benedikt Grimm
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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10
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Morelli KH, Jin W, Shathe S, Madrigal AA, Jones KL, Schwartz JL, Bridges T, Mueller JR, Shankar A, Chaim IA, Day JW, Yeo GW. MECP2-related pathways are dysregulated in a cortical organoid model of myotonic dystrophy. Sci Transl Med 2022; 14:eabn2375. [PMID: 35767654 PMCID: PMC9645119 DOI: 10.1126/scitranslmed.abn2375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is a multisystem, autosomal-dominant inherited disorder caused by CTG microsatellite repeat expansions (MREs) in the 3' untranslated region of the dystrophia myotonica-protein kinase (DMPK) gene. Despite its prominence as the most common adult-onset muscular dystrophy, patients with congenital to juvenile-onset forms of DM1 can present with debilitating neurocognitive symptoms along the autism spectrum, characteristic of possible in utero cortical defects. However, the molecular mechanism by which CTG MREs lead to these developmental central nervous system (CNS) manifestations is unknown. Here, we showed that CUG foci found early in the maturation of three-dimensional (3D) cortical organoids from DM1 patient-derived induced pluripotent stem cells (iPSCs) cause hyperphosphorylation of CUGBP Elav-like family member 2 (CELF2) protein. Integrative single-cell RNA sequencing and enhanced cross-linking and immunoprecipitation (eCLIP) analysis revealed that reduced CELF2 protein-RNA substrate interactions results in misregulation of genes critical for excitatory synaptic signaling in glutamatergic neurons, including key components of the methyl-CpG binding protein 2 (MECP2) pathway. Comparisons to MECP2(y/-) cortical organoids revealed convergent molecular and cellular defects such as glutamate toxicity and neuronal loss. Our findings provide evidence suggesting that early-onset DM1 might involve neurodevelopmental disorder-associated pathways and identify N-methyl-d-aspartic acid (NMDA) antagonists as potential treatment avenues for neuronal defects in DM1.
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Affiliation(s)
- Kathryn H. Morelli
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Wenhao Jin
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Shashank Shathe
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Assael A. Madrigal
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Krysten L. Jones
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Joshua L. Schwartz
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Tristan Bridges
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Jasmine R. Mueller
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Archana Shankar
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - Isaac A. Chaim
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
| | - John W. Day
- Stanford University School of Medicine, Palo Alto, CA 94375, USA
| | - Gene W. Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA 92039, USA
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11
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Improving clinical trial readiness to accelerate development of new therapeutics for Rett syndrome. Orphanet J Rare Dis 2022; 17:108. [PMID: 35246185 PMCID: PMC8894842 DOI: 10.1186/s13023-022-02240-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 02/06/2022] [Indexed: 12/16/2022] Open
Abstract
Rett syndrome is associated with severe functional impairments and many comorbidities, each in urgent need of treatments. Mutations in the MECP2 gene were identified as causing Rett syndrome in 1999. Over the past 20 years there has been an abundance of preclinical research with some studies leading to human clinical trials. Despite this, few viable therapeutic options have emerged from this investment of effort. Reasons for this lack of success as they relate both to preclinical research and the clinical trial landscape are discussed. Considering what needs to be done to promote further success in the field, we take a positive and constructive approach and introduce the concept of clinical trial readiness and its necessary ingredients for Rett syndrome. These include: listening to the needs of families; support from advocacy groups; optimising use of existing clinic infrastructures and available natural history data; and, finally, the validation of existing outcome measures and/or the development and validation of new measures. We conclude by reiterating the need for a collaborative and coordinated approach amongst the many different stakeholder groups and the need to engage in new types of trial design which could be much more efficient, less costly and much less burdensome on families.
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12
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Ramirez JM, Karlen-Amarante M, Wang JDJ, Huff A, Burgraff N. Breathing disturbances in Rett syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:139-151. [PMID: 36031301 PMCID: PMC10029146 DOI: 10.1016/b978-0-323-91532-8.00018-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Rett Syndrome is an X-linked neurological disorder characterized by behavioral and neurological regression, seizures, motor deficits, and dysautonomia. A particularly prominent presentation includes breathing abnormalities characterized by breathing irregularities, hyperventilation, repetitive breathholding during wakefulness, obstructive and central apneas during sleep, and abnormal responses to hypoxia and hypercapnia. The condition and pathology of the respiratory system is further complicated by dysfunctions of breathing-motor coordination, which is reflected in dysphagia. The discovery of the X-linked mutations in the MECP2 gene has transformed our understanding of the cellular and molecular mechanisms that are at the root of various clinical phenotypes. However, the genotype-phenotype relationship is complicated by various factors which include not only X-inactivation but also consequences of the intermittent hypoxia and oxidative stress associated with the breathing abnormalities.
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Affiliation(s)
- Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States; Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA, United States.
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Jia-Der Ju Wang
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Nicholas Burgraff
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
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13
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Reviewing Evidence for the Relationship of EEG Abnormalities and RTT Phenotype Paralleled by Insights from Animal Studies. Int J Mol Sci 2021; 22:ijms22105308. [PMID: 34069993 PMCID: PMC8157853 DOI: 10.3390/ijms22105308] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 12/29/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder that is usually caused by mutations of the MECP2 gene. Patients with RTT suffer from severe deficits in motor, perceptual and cognitive domains. Electroencephalogram (EEG) has provided useful information to clinicians and scientists, from the very first descriptions of RTT, and yet no reliable neurophysiological biomarkers related to the pathophysiology of the disorder or symptom severity have been identified to date. To identify consistently observed and potentially informative EEG characteristics of RTT pathophysiology, and ascertain areas most worthy of further systematic investigation, here we review the literature for EEG abnormalities reported in patients with RTT and in its disease models. While pointing to some promising potential EEG biomarkers of RTT, our review identify areas of need to realize the potential of EEG including (1) quantitative investigation of promising clinical-EEG observations in RTT, e.g., shift of mu rhythm frequency and EEG during sleep; (2) closer alignment of approaches between patients with RTT and its animal models to strengthen the translational significance of the work (e.g., EEG measurements and behavioral states); (3) establishment of large-scale consortium research, to provide adequate Ns to investigate age and genotype effects.
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14
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Witkin JM, Cerne R, Newman AH, Izenwasser S, Smith JL, Tortella FC. N-Substituted-3-alkoxy-derivatives of dextromethorphan are functional NMDA receptor antagonists in vivo: Evidence from an NMDA-induced seizure model in rats. Pharmacol Biochem Behav 2021; 203:173154. [PMID: 33609599 PMCID: PMC9659398 DOI: 10.1016/j.pbb.2021.173154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 11/30/2022]
Abstract
Interest in developing NMDA receptor antagonists with reduced side-effects for neurological and psychiatric disorders has been re-energized by the recent introduction of esketamine into clinical practice for treatment-resistant depression. Structural analogs of dextromethorphan bind with low affinity to the NMDA receptor ion channel, have functional effects in vivo, and generally display a lower propensity for side-effects than that of ketamine and other higher affinity antagonists. As such, the aim of the present study was to determine whether a series of N-substituted-3-alkoxy-substituted dextromethorphan analogs produce their anticonvulsant effects through NMDA receptor blockade. Compounds were studied against NMDA-induced seizures in rats. Compounds were administered intracerebroventricularly in order to mitigate confounds of drug metabolism that arise from systemic administration. Comparison of the anticonvulsant potencies to their affinities for NMDA, σ1, and σ2 binding sites were made in order to evaluate the contribution of these receptors to anticonvulsant efficacy. The potencies to block convulsions were positively associated with their affinities to bind to the NMDA receptor ion channel ([3H]-TCP binding) (r = 0.71, p < 0.05) but not to σ1 receptors ([3H]-SKF 10047 binding) (r = -0.31, p = 0.46) or to σ2 receptors ([3H]-DTG binding) (p = -0.38, p = 0.36). This is the first report demonstrating that these dextromethorphan analogs are functional NMDA receptor antagonists in vivo. Given their potential therapeutic utility and favorable side-effect profiles, such low affinity NMDA receptor antagonists could be considered for further development in neurological (e.g., anticonvulsant) and psychiatric (e.g., antidepressant) disorders.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN, USA; Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
| | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN, USA; Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Amy H Newman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Sari Izenwasser
- Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent, Indianapolis, IN, USA
| | - Frank C Tortella
- Department of Neuropharmacology and Molecular Biology, Walter Reed Army Institute of Research, Silver Spring, MD, USA
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15
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Gomathi M, Padmapriya S, Balachandar V. Drug Studies on Rett Syndrome: From Bench to Bedside. J Autism Dev Disord 2020; 50:2740-2764. [PMID: 32016693 DOI: 10.1007/s10803-020-04381-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Drug studies on Rett syndrome (RTT) have drastically increased over the past few decades. This review aims to provide master data on bench-to-bedside drug studies involving RTT. A comprehensive literature review was performed by searching in PUBMED, MEDLINE and Google Scholar, international, national and regional clinical trial registries and pharmaceutical companies using the keywords "Rett syndrome treatment and/or drug or compound or molecule". Seventy drugs were investigated in non-clinical (N = 65 animal/cell line-based studies; N = 5 iPSC-based study) and clinical trials (N = 34) for ameliorating the symptoms of RTT. Though there is good progress in both clinical and non-clinical studies, none of these drugs entered phase III/IV for being launched as a therapeutic agent for RTT.
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Affiliation(s)
- Mohan Gomathi
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | | | - Vellingiri Balachandar
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
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16
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Ramirez JM, Karlen-Amarante M, Wang JDJ, Bush NE, Carroll MS, Weese-Mayer DE, Huff A. The Pathophysiology of Rett Syndrome With a Focus on Breathing Dysfunctions. Physiology (Bethesda) 2020; 35:375-390. [PMID: 33052774 PMCID: PMC7864239 DOI: 10.1152/physiol.00008.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT), an X-chromosome-linked neurological disorder, is characterized by serious pathophysiology, including breathing and feeding dysfunctions, and alteration of cardiorespiratory coupling, a consequence of multiple interrelated disturbances in the genetic and homeostatic regulation of central and peripheral neuronal networks, redox state, and control of inflammation. Characteristic breath-holds, obstructive sleep apnea, and aerophagia result in intermittent hypoxia, which, combined with mitochondrial dysfunction, causes oxidative stress-an important driver of the clinical presentation of RTT.
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Affiliation(s)
- Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
- Departments of Neurological Surgery and Pediatrics, University of Washington School of Medicine, Seattle, Washington
| | - Marlusa Karlen-Amarante
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP), Araraquara, Brazil
| | - Jia-Der Ju Wang
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
| | - Nicholas E Bush
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
| | - Michael S Carroll
- Data Analytics and Reporting, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Debra E Weese-Mayer
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, Washington
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17
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Young DR, Suter B, Levine JT, Glaze DG, Layne CS. Characteristic behaviors associated with gait of individuals with Rett syndrome. Disabil Rehabil 2020; 44:1508-1515. [PMID: 32931336 DOI: 10.1080/09638288.2020.1820084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Individuals with Rett syndrome (RTT) exhibit impaired motor performance and gait performance, leading to decreased quality of life. Currently, there is no robust observational instrument to identify gait characteristics in RTT. Current scales are limited as individuals with intellectual disorders may be unable to understand instructions. Our primary purpose was to utilize video analysis to characterize the behaviors associated with walking in individuals with RTT and explore the relationship between behaviors during overground and during treadmill walking. METHODS Fourteen independently ambulatory females with RTT were video-taped and observed during overground and treadmill walking. Their gait was codified into an observational checklist to reveal prominent features associated with gait in this population. RESULTS Participants exhibited similar rates of freezing, veering, and hand stereotypies between overground and treadmill walking; however, freeze duration was shortened during treadmill walking. Toe walking was prominently exhibited during overground, but not treadmill walking. During both walking modes, participants required extensive external motivation to maintain their walking patterns. CONCLUSIONS Results identify several gait characteristics observable during overground and treadmill walking. In general, participants behaved similarly during overground and treadmill walking. We conclude that both overground and treadmill walking are appropriate tools to evaluate gait in this population.Implications for rehabilitationLocomotor rehabilitation may increase the quantity of walking performed by the patients, which can alleviate negative effects of the sedentary lifestyle commonly observed in patients with Rett syndrome (RTT).Video analysis of natural walking can be an effective tool to characterize gait in patients with RTT which does not require particular instructions which may not be fully understood.Both overground and treadmill walking are appropriate means of evaluating gait in individuals with RTT.
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Affiliation(s)
- David R Young
- Department of Health and Human Performance, University of Houston, Houston, TX, USA.,Center for Neuromotor and Biomechanics Research, University of Houston, Houston, TX, USA
| | - Bernhard Suter
- Blue Bird Circle Rett Center, Texas Children's Hospital, Houston, TX, USA.,Baylor College of Medicine, Houston, TX, USA
| | - Jackson T Levine
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Daniel G Glaze
- Blue Bird Circle Rett Center, Texas Children's Hospital, Houston, TX, USA.,Baylor College of Medicine, Houston, TX, USA
| | - Charles S Layne
- Department of Health and Human Performance, University of Houston, Houston, TX, USA.,Center for Neuromotor and Biomechanics Research, University of Houston, Houston, TX, USA.,Center for Neuro-Engineering and Cognitive Science, University of Houston, Houston, TX, USA
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18
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Sandweiss AJ, Brandt VL, Zoghbi HY. Advances in understanding of Rett syndrome and MECP2 duplication syndrome: prospects for future therapies. Lancet Neurol 2020; 19:689-698. [PMID: 32702338 DOI: 10.1016/s1474-4422(20)30217-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 01/07/2023]
Abstract
The X-linked gene encoding MECP2 is involved in two severe and complex neurodevelopmental disorders. Loss of function of the MeCP2 protein underlies Rett syndrome, whereas duplications of the MECP2 locus cause MECP2 duplication syndrome. Research on the mechanisms by which MeCP2 exerts effects on gene expression in neurons, studies of animal models bearing different disease-causing mutations, and more in-depth observations of clinical presentations have clarified some issues even as they have raised further questions. Yet there is enough evidence so far to suggest possible approaches to therapy for these two diseases that could go beyond attempting to address specific signs and symptoms (of which there are many) and instead target the pathophysiology underlying MECP2 disorders. Further work could bring antisense oligonucleotides, deep brain stimulation, and gene therapy into the clinic within the next decade or so.
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Affiliation(s)
- Alexander J Sandweiss
- Department of Pediatrics, Section of Neurology and Developmental Neurosciences, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Vicky L Brandt
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Huda Y Zoghbi
- Department of Pediatrics, Section of Neurology and Developmental Neurosciences, Baylor College of Medicine, Houston, TX, USA; Howard Hughes Medical Institute, and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA.
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19
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Johnson CM, Cui N, Xing H, Wu Y, Jiang C. The antitussive cloperastine improves breathing abnormalities in a Rett Syndrome mouse model by blocking presynaptic GIRK channels and enhancing GABA release. Neuropharmacology 2020; 176:108214. [PMID: 32622786 DOI: 10.1016/j.neuropharm.2020.108214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 06/12/2020] [Accepted: 06/14/2020] [Indexed: 12/21/2022]
Abstract
Rett Syndrome (RTT) is an X-linked neurodevelopmental disorder caused mainly by mutations in the MECP2 gene. One of the major RTT features is breathing dysfunction characterized by periodic hypo- and hyperventilation. The breathing disorders are associated with increased brainstem neuronal excitability, which can be alleviated with GABA agonists. Since neuronal hypoexcitability occurs in the forebrain of RTT models, it is necessary to find pharmacological agents with a relative preference to brainstem neurons. Here we show evidence for the improvement of breathing disorders of Mecp2-disrupted mice with the brainstem-acting drug cloperastine (CPS) and its likely neuronal targets. CPS is an over-the-counter cough medicine that has an inhibitory effect on brainstem neuronal networks. In Mecp2-disrupted mice, CPS (30 mg/kg, i.p.) decreased the occurrence of apneas/h and breath frequency variation. GIRK currents expressed in HEK cells were inhibited by CPS with IC50 1 μM. Whole-cell patch clamp recordings in locus coeruleus (LC) and dorsal tegmental nucleus (DTN) neurons revealed an overall inhibitory effect of CPS (10 μM) on neuronal firing activity. Such an effect was reversed by the GABAA receptor antagonist bicuculline (20 μM). Voltage clamp studies showed that CPS increased GABAergic sIPSCs in LC cells, which was blocked by the GABAB receptor antagonist phaclofen. Functional GABAergic connections of DTN neurons with LC cells were shown. These results suggest that CPS improves breathing dysfunction in Mecp2-null mice by blocking GIRK channels in synaptic terminals and enhancing GABA release.
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Affiliation(s)
- Christopher M Johnson
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA, 30303, USA
| | - Ningren Cui
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA, 30303, USA
| | - Hao Xing
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA, 30303, USA
| | - Yang Wu
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA, 30303, USA
| | - Chun Jiang
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA, 30303, USA.
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20
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Carroll MS, Ramirez JM, Weese-Mayer DE. Diurnal variation in autonomic regulation among patients with genotyped Rett syndrome. J Med Genet 2020; 57:786-793. [PMID: 32156713 DOI: 10.1136/jmedgenet-2019-106601] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/07/2020] [Accepted: 02/05/2020] [Indexed: 01/03/2023]
Abstract
BACKGROUND Rett syndrome is a severe neurological disorder with a range of disabling autonomic and respiratory symptoms and resulting predominantly from variants in the methyl-CpG binding protein 2 gene on the long arm of the X-chromosome. As basic research begins to suggest potential treatments, sensitive measures of the dynamic phenotype are needed to evaluate the results of these research efforts. Here we test the hypothesis that the physiological fingerprint of Rett syndrome in a naturalistic environment differs from that of controls, and differs among genotypes within Rett syndrome. METHODS A comprehensive array of heart rate variability, cardiorespiratory coupling and cardiac repolarisation measures were evaluated from an existing database of overnight and daytime inhome ambulatory recordings in 47 cases and matched controls. RESULTS Differences between girls with Rett syndrome and matched controls were apparent in a range of autonomic measures, and suggest a shift towards sympathetic activation and/or parasympathetic inactivation. Daily temporal trends analysed in the context of circadian rhythms reveal alterations in amplitude and phase of diurnal patterns of autonomic balance. Further analysis by genotype class confirms a graded presentation of the Rett syndrome phenotype such that patients with early truncating mutations were most different from controls, while late truncating and missense mutations were least different from controls. CONCLUSIONS Comprehensive autonomic measures from extensive inhome physiological measurements can detect subtle variations in the phenotype of girls with Rett syndrome, suggesting these techniques are suitable for guiding novel therapies.
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Affiliation(s)
- Michael Sean Carroll
- Data Analytics and Reporting, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA .,Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Neurological Surgery, University of Washington, Seattle, Washington, USA
| | - Debra E Weese-Mayer
- Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
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21
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Kadam SD, Sullivan BJ, Goyal A, Blue ME, Smith-Hicks C. Rett Syndrome and CDKL5 Deficiency Disorder: From Bench to Clinic. Int J Mol Sci 2019; 20:ijms20205098. [PMID: 31618813 PMCID: PMC6834180 DOI: 10.3390/ijms20205098] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Rett syndrome (RTT) and CDKL5 deficiency disorder (CDD) are two rare X-linked developmental brain disorders with overlapping but distinct phenotypic features. This review examines the impact of loss of methyl-CpG-binding protein 2 (MeCP2) and cyclin-dependent kinase-like 5 (CDKL5) on clinical phenotype, deficits in synaptic- and circuit-homeostatic mechanisms, seizures, and sleep. In particular, we compare the overlapping and contrasting features between RTT and CDD in clinic and in preclinical studies. Finally, we discuss lessons learned from recent clinical trials while reviewing the findings from pre-clinical studies.
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Affiliation(s)
- Shilpa D Kadam
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Brennan J Sullivan
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Archita Goyal
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Mary E Blue
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Constance Smith-Hicks
- The Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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22
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Banerjee A, Miller MT, Li K, Sur M, Kaufmann WE. Towards a better diagnosis and treatment of Rett syndrome: a model synaptic disorder. Brain 2019; 142:239-248. [PMID: 30649225 DOI: 10.1093/brain/awy323] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/31/2018] [Indexed: 12/21/2022] Open
Abstract
With the recent 50th anniversary of the first publication on Rett syndrome, and the almost 20 years since the first report on the link between Rett syndrome and MECP2 mutations, it is important to reflect on the tremendous advances in our understanding and their implications for the diagnosis and treatment of this neurodevelopmental disorder. Rett syndrome features an interesting challenge for biologists and clinicians, as the disorder lies at the intersection of molecular mechanisms of epigenetic regulation and neurophysiological alterations in synapses and circuits that together contribute to severe pathophysiological endophenotypes. Genetic, clinical, and neurobiological evidences support the notion that Rett syndrome is primarily a synaptic disorder, and a disease model for both intellectual disability and autism spectrum disorder. This review examines major developments in both recent neurobiological and preclinical findings of Rett syndrome, and to what extent they are beginning to impact our understanding and management of the disorder. It also discusses potential applications of knowledge on synaptic plasticity abnormalities in Rett syndrome to its diagnosis and treatment.
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Affiliation(s)
- Abhishek Banerjee
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zürich, Zürich, Switzerland
| | - Meghan T Miller
- Roche Pharma Research and Early Development, Roche Innovation Center, F. Hoffman-La Roche, Basel, Switzerland
| | - Keji Li
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA, USA
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA, USA
| | - Walter E Kaufmann
- Department of Human Genetics, Emory University School of Medicine, Atlanta GA, USA
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23
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Crespi BJ. Comparative psychopharmacology of autism and psychotic-affective disorders suggests new targets for treatment. Evol Med Public Health 2019; 2019:149-168. [PMID: 31548888 PMCID: PMC6748779 DOI: 10.1093/emph/eoz022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/07/2019] [Indexed: 12/13/2022] Open
Abstract
The first treatments showing effectiveness for some psychiatric disorders, such as lithium for bipolar disorder and chlorpromazine for schizophrenia, were discovered by accident. Currently, psychiatric drug design is seen as a scientific enterprise, limited though it remains by the complexity of brain development and function. Relatively few novel and effective drugs have, however, been developed for many years. The purpose of this article is to demonstrate how evolutionary biology can provide a useful framework for psychiatric drug development. The framework is based on a diametrical nature of autism, compared with psychotic-affective disorders (mainly schizophrenia, bipolar disorder and depression). This paradigm follows from two inferences: (i) risks and phenotypes of human psychiatric disorders derive from phenotypes that have evolved along the human lineage and (ii) biological variation is bidirectional (e.g. higher vs lower, faster vs slower, etc.), such that dysregulation of psychological traits varies in two opposite ways. In this context, the author review the evidence salient to the hypothesis that autism and psychotic-affective disorders represent diametrical disorders in terms of current, proposed and potential psychopharmacological treatments. Studies of brain-derived neurotrophic factor, the PI3K pathway, the NMDA receptor, kynurenic acid metabolism, agmatine metabolism, levels of the endocannabinoid anandamide, antidepressants, anticonvulsants, antipsychotics, and other treatments, demonstrate evidence of diametric effects in autism spectrum disorders and phenotypes compared with psychotic-affective disorders and phenotypes. These findings yield insights into treatment mechanisms and the development of new pharmacological therapies, as well as providing an explanation for the longstanding puzzle of antagonism between epilepsy and psychosis. Lay Summary: Consideration of autism and schizophrenia as caused by opposite alterations to brain development and function leads to novel suggestions for pharmacological treatments.
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Affiliation(s)
- Bernard J Crespi
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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Vidal S, Xiol C, Pascual-Alonso A, O'Callaghan M, Pineda M, Armstrong J. Genetic Landscape of Rett Syndrome Spectrum: Improvements and Challenges. Int J Mol Sci 2019; 20:ijms20163925. [PMID: 31409060 PMCID: PMC6719047 DOI: 10.3390/ijms20163925] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/08/2019] [Accepted: 08/10/2019] [Indexed: 02/06/2023] Open
Abstract
Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that primarily affects females, resulting in severe cognitive and physical disabilities, and is one of the most prevalent causes of intellectual disability in females. More than fifty years after the first publication on Rett syndrome, and almost two decades since the first report linking RTT to the MECP2 gene, the research community's effort is focused on obtaining a better understanding of the genetics and the complex biology of RTT and Rett-like phenotypes without MECP2 mutations. Herein, we review the current molecular genetic studies, which investigate the genetic causes of RTT or Rett-like phenotypes which overlap with other genetic disorders and document the swift evolution of the techniques and methodologies employed. This review also underlines the clinical and genetic heterogeneity of the Rett syndrome spectrum and provides an overview of the RTT-related genes described to date, many of which are involved in epigenetic gene regulation, neurotransmitter action or RNA transcription/translation. Finally, it discusses the importance of including both phenotypic and genetic diagnosis to provide proper genetic counselling from a patient's perspective and the appropriate treatment.
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Affiliation(s)
- Silvia Vidal
- Sant Joan de Déu Research Foundation, 08950 Barcelona, Spain
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - Clara Xiol
- Sant Joan de Déu Research Foundation, 08950 Barcelona, Spain
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - Ainhoa Pascual-Alonso
- Sant Joan de Déu Research Foundation, 08950 Barcelona, Spain
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - M O'Callaghan
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, 08950 Barcelona, Spain
- Neurology Service, Hospital Sant Joan de Déu, 08950 Barcelona, Spain
- CIBER-ER (Biomedical Network Research Center for Rare Diseases), Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain
| | - Mercè Pineda
- Sant Joan de Déu Research Foundation, 08950 Barcelona, Spain
| | - Judith Armstrong
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, 08950 Barcelona, Spain.
- CIBER-ER (Biomedical Network Research Center for Rare Diseases), Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain.
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, 08950 Barcelona, Spain.
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Cosentino L, Vigli D, Franchi F, Laviola G, De Filippis B. Rett syndrome before regression: A time window of overlooked opportunities for diagnosis and intervention. Neurosci Biobehav Rev 2019; 107:115-135. [PMID: 31108160 DOI: 10.1016/j.neubiorev.2019.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 05/10/2019] [Accepted: 05/15/2019] [Indexed: 11/29/2022]
Abstract
Rett syndrome (RTT) is a rare neurological disorder primarily affecting females, causing severe cognitive, social, motor and physiological impairments for which no cure currently exists. RTT clinical diagnosis is based on the peculiar progression of the disease, since patients show an apparently normal initial development with a subsequent sudden regression at around 2 years of age. Accumulating evidences are rising doubts regarding the absence of early impairments, hence questioning the concept of regression. We reviewed the published literature addressing the pre-symptomatic stage of the disease in both patients and animal models with a particular focus on behavioral, physiological and brain abnormalities. The emerging picture delineates subtle, but reliable impairments that precede the onset of overt symptoms whose bases are likely set up already during embryogenesis. Some of the outlined alterations appear transient, suggesting compensatory mechanisms to occur in the course of development. There is urgent need for more systematic developmental analyses able to detect early pathological markers to be used as diagnostic tools and precocious targets of time-specific interventions.
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Affiliation(s)
- Livia Cosentino
- Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Daniele Vigli
- Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Francesca Franchi
- Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Giovanni Laviola
- Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | - Bianca De Filippis
- Center for Behavioral Sciences and Mental Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
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Singh J, Santosh P. Key issues in Rett syndrome: emotional, behavioural and autonomic dysregulation (EBAD) - a target for clinical trials. Orphanet J Rare Dis 2018; 13:128. [PMID: 30064458 PMCID: PMC6069816 DOI: 10.1186/s13023-018-0873-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 07/10/2018] [Indexed: 02/02/2023] Open
Abstract
Complex neurodevelopmental disorders need multi-disciplinary treatment approaches for optimal care. The clinical effectiveness of treatments is limited in patients with rare genetic syndromes with multisystem morbidity. Emotional and behavioural dysregulation is common across many neurodevelopmental disorders. It can manifest in children across multiple diagnostic groups, including those on the autism spectrum and in rare genetic syndromes such as Rett Syndrome (RTT). There is, however a remarkable scarcity in the literature on the impact of the autonomic component on emotional and behavioural regulation in these disorders, and on the longer-term outcomes on disorder burden.RTT is a debilitating and often life-threatening disorder involving multiple overlapping physiological systems. Autonomic dysregulation otherwise known as dysautonomia is a cardinal feature of RTT characterised by an imbalance between the sympathetic and parasympathetic arms of the autonomic nervous system. Unlocking the autonomic component of emotional and behavioural dysregulation would be central in reducing the impairment seen in patients with RTT. In this vein, Emotional, Behavioural and Autonomic Dysregulation (EBAD) would be a useful construct to target for treatment which could mitigate burden and improve the quality of life of patients.RTT can be considered as a congenital dysautonomia and because EBAD can give rise to impairments occurring in multiple overlapping physiological systems, understanding these physiological responses arising out of EBAD would be a critical part to consider when planning treatment strategies and improving clinical outcomes in these patients. Biometric guided pharmacological and bio-feedback therapy for the behavioural and emotional aspects of the disorder offers an attracting perspective to manage EBAD in these patients. This can also allow for the stratification of patients into clinical trials and could ultimately help streamline the patient care pathway for optimal outcomes.The objectives of this review are to emphasise the key issues relating to the management of EBAD in patients with RTT, appraise clinical trials done in RTT from the perspective of autonomic physiology and to discuss the potential of EBAD as a target for clinical trials.
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Affiliation(s)
- Jatinder Singh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Paramala Santosh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK. .,Centre for Interventional Paediatric Psychopharmacology and Rare Diseases, South London and Maudsley NHS Foundation Trust, London, UK.
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Abstract
Rett Syndrome is a severe neurological disorder mainly due to
de novo mutations in the methyl-CpG-binding protein 2 gene (
MECP2). Mecp2 is known to play a role in chromatin organization and transcriptional regulation. In this review, we report the latest advances on the molecular function of Mecp2 and the new animal and cellular models developed to better study Rett syndrome. Finally, we present the latest innovative therapeutic approaches, ranging from classical pharmacology to correct symptoms to more innovative approaches intended to cure the pathology.
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Affiliation(s)
- Yann Ehinger
- Aix Marseille Univ, INSERM, MMG, 13385 Marseille, France
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