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Kay C, Leonard H, Smith J, Wong K, Downs J. Genotype and sleep independently predict mental health in Rett syndrome: an observational study. J Med Genet 2023; 60:951-959. [PMID: 37055168 DOI: 10.1136/jmg-2022-108905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 03/26/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Rett syndrome is a genetically caused neurodevelopmental disorder associated with severe impairments and complex comorbidities. This study examined predictors of anxiety and depression in Rett syndrome, including genotype. METHODS The International Rett Syndrome Database, InterRett, was the data source for this observational study. Associations between genotype, functional abilities, comorbidities, anxiety and depression were estimated with univariate and multivariate regression models. An additional regression model for anxiety included use of an anxiety medication as a predictor variable. RESULTS The sample included 210 individuals aged 6-51 years of whom 54 (25.7%) were on psychotropic medication for anxiety or depression. Individuals with the p.Arg294* variant had the highest anxiety scores, as did those with insomnia or excessive daytime sleepiness, irrespective of anxiety medication use. Individuals with the p.Arg306Cys variant had the lowest depression scores, as did those with insomnia or excessive daytime sleepiness. CONCLUSION Findings indicated that genotype and sleep have implications for mental health in Rett syndrome, suggesting that anticipatory guidance and proactive management of poor sleep could improve mental health. More research is needed to understand the effects of psychometric medications, which cannot be inferred from this cross-sectional study.
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Affiliation(s)
- Cayla Kay
- School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Helen Leonard
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Jeremy Smith
- School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Kingsley Wong
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia, Australia
- Curtin School of Allied Healt, Curtin University, Perth, Western Australia, Australia
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2
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McKnight D, Bean L, Karbassi I, Beattie K, Bienvenu T, Bonin H, Fang P, Chrisodoulou J, Friez M, Helgeson M, Krishnaraj R, Meng L, Mighion L, Neul J, Percy A, Ramsden S, Zoghbi H, Das S. Recommendations by the ClinGen Rett/Angelman-like expert panel for gene-specific variant interpretation methods. Hum Mutat 2022; 43:1097-1113. [PMID: 34837432 PMCID: PMC9135956 DOI: 10.1002/humu.24302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/05/2021] [Accepted: 11/21/2021] [Indexed: 11/11/2022]
Abstract
The genes MECP2, CDKL5, FOXG1, UBE3A, SLC9A6, and TCF4 present unique challenges for current ACMG/AMP variant interpretation guidelines. To address those challenges, the Rett and Angelman-like Disorders Variant Curation Expert Panel (Rett/AS VCEP) drafted gene-specific modifications. A pilot study was conducted to test the clarity and accuracy of using the customized variant interpretation criteria. Multiple curators obtained the same interpretation for 78 out of the 87 variants (~90%), indicating appropriate usage of the modified guidelines the majority of times by all the curators. The classification of 13 variants changed using these criteria specifications compared to when the variants were originally curated and as present in ClinVar. Many of these changes were due to internal data shared from laboratory members however some changes were because of changes in strength of criteria. There were no two-step classification changes and only 1 clinically relevant change (Likely pathogenic to VUS). The Rett/AS VCEP hopes that these gene-specific variant curation rules and the assertions provided help clinicians, clinical laboratories, and others interpret variants in these genes but also other fully penetrant, early-onset genes associated with rare disorders.
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Affiliation(s)
| | | | | | | | | | | | | | - John Chrisodoulou
- Murdoch Childrens Research Institute and the University of Melbourne,University of Sydney
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Zhang H, Romero H, Schmidt A, Gagova K, Qin W, Bertulat B, Lehmkuhl A, Milden M, Eck M, Meckel T, Leonhardt H, Cardoso MC. MeCP2-induced heterochromatin organization is driven by oligomerization-based liquid–liquid phase separation and restricted by DNA methylation. Nucleus 2022; 13:1-34. [PMID: 35156529 PMCID: PMC8855868 DOI: 10.1080/19491034.2021.2024691] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Hui Zhang
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Hector Romero
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Annika Schmidt
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Katalina Gagova
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Weihua Qin
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - Bianca Bertulat
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Anne Lehmkuhl
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Manuela Milden
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Malte Eck
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Tobias Meckel
- Department of Chemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - M. Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
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4
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MECP2-related conditions in males: A systematic literature review and 8 additional cases. Eur J Paediatr Neurol 2021; 34:7-13. [PMID: 34271245 DOI: 10.1016/j.ejpn.2021.05.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/25/2021] [Accepted: 05/25/2021] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To present a cohort of 8 males and perform a systematic review of all published cases with a single copy of MECP2 carrying a pathogenic variant. METHODS We reviewed medical records of males with a single copy of MECP2 carrying a pathogenic variant. We searched in Medline (Pubmed) and Embase to collect all articles which included well-characterized males with a single copy of MECP2 carrying a pathogenic or likely pathogenic variant in MECP2 (1999-2020). RESULTS The literature search yielded a total of 3,185 publications, of which 58 were included in our systematic review. We were able to collect information on 27 published patients with severe neonatal encephalopathy, 47 individuals with isolated or familial mental retardation X-linked 13 (XLMR13), as well as 24 individuals with isolated or familial Pyramidal signs, parkinsonism, and macroorchidism (PPM-X). In our cohort, we met eight individuals aged 4 to 19-year-old at the last evaluation. Three MECP2-associated phenotypes were seen in male carriers of a single copy of the gene: severe neonatal encephalopathy (n = 5); X-linked intellectual deficiency 13 (n = 2); and pyramidal signs, parkinsonism, and macroorchidism (PPM-X) (n = 1). Two novel de novo variants [p.(Gly252Argfs∗7) and p.(Tyr132Cys)] were detected. CONCLUSION In males, the MECP2 pathogenic variants can be associated with different phenotypes, including neonatal severe encephalopathy, intellectual deficiency, or late-onset parkinsonism and spasticity. The typical RS phenotype is not expected in males, except in those with Klinefelter syndrome or somatic mosaicism for MECP2.
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5
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Mao Y, Evans EE, Mishra V, Balch L, Eberhardt A, Zauderer M, Gold WA. Anti-Semaphorin 4D Rescues Motor, Cognitive, and Respiratory Phenotypes in a Rett Syndrome Mouse Model. Int J Mol Sci 2021; 22:ijms22179465. [PMID: 34502373 PMCID: PMC8431088 DOI: 10.3390/ijms22179465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 01/09/2023] Open
Abstract
Rett syndrome is a neurodevelopmental disorder caused by mutations of the methyl-CpG binding protein 2 gene. Abnormal physiological functions of glial cells contribute to pathogenesis of Rett syndrome. Semaphorin 4D (SEMA4D) regulates processes central to neuroinflammation and neurodegeneration including cytoskeletal structures required for process extension, communication, and migration of glial cells. Blocking SEMA4D-induced gliosis may preserve normal glial and neuronal function and rescue neurological dysfunction in Rett syndrome. We evaluated the pre-clinical therapeutic efficacy of an anti-SEMA4D monoclonal antibody in the Rett syndrome Mecp2T158A transgenic mouse model and investigated the contribution of glial cells as a proposed mechanism of action in treated mice and in primary glial cultures isolated from Mecp2T158A/y mutant mice. SEMA4D is upregulated in neurons while glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1-positive cells are upregulated in Mecp2T158A/y mice. Anti-SEMA4D treatment ameliorates Rett syndrome-specific symptoms and improves behavioural functions in both pre-symptomatic and symptomatic cohorts of hemizygous Mecp2T158A/y male mice. Anti-SEMA4D also reduces astrocyte and microglia activation in vivo. In vitro experiments demonstrate an abnormal cytoskeletal structure in mutant astrocytes in the presence of SEMA4D, while anti-SEMA4D antibody treatment blocks SEMA4D–Plexin B1 signaling and mitigates these abnormalities. These results suggest that anti-SEMA4D immunotherapy may be an effective treatment option to alleviate symptoms and improve cognitive and motor function in Rett syndrome.
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Affiliation(s)
- Yilin Mao
- Molecular Neurobiology Research Laboratory, Kids Neuroscience Centre, Kids Research, The Children’s Hospital at Westmead, Westmead, NSW 2145, Australia;
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Elizabeth E. Evans
- Vaccinex Inc., Rochester, NY 14620, USA; (E.E.E.); (V.M.); (L.B.); (A.E.); (M.Z.)
| | - Vikas Mishra
- Vaccinex Inc., Rochester, NY 14620, USA; (E.E.E.); (V.M.); (L.B.); (A.E.); (M.Z.)
| | - Leslie Balch
- Vaccinex Inc., Rochester, NY 14620, USA; (E.E.E.); (V.M.); (L.B.); (A.E.); (M.Z.)
| | - Allison Eberhardt
- Vaccinex Inc., Rochester, NY 14620, USA; (E.E.E.); (V.M.); (L.B.); (A.E.); (M.Z.)
| | - Maurice Zauderer
- Vaccinex Inc., Rochester, NY 14620, USA; (E.E.E.); (V.M.); (L.B.); (A.E.); (M.Z.)
| | - Wendy A. Gold
- Molecular Neurobiology Research Laboratory, Kids Neuroscience Centre, Kids Research, The Children’s Hospital at Westmead, Westmead, NSW 2145, Australia;
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia
- Molecular Neurobiology Research Laboratory, The Children’s Medical Research Institute, Westmead, NSW 2145, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia
- Correspondence:
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6
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Good KV, Vincent JB, Ausió J. MeCP2: The Genetic Driver of Rett Syndrome Epigenetics. Front Genet 2021; 12:620859. [PMID: 33552148 PMCID: PMC7859524 DOI: 10.3389/fgene.2021.620859] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/05/2021] [Indexed: 12/24/2022] Open
Abstract
Mutations in methyl CpG binding protein 2 (MeCP2) are the major cause of Rett syndrome (RTT), a rare neurodevelopmental disorder with a notable period of developmental regression following apparently normal initial development. Such MeCP2 alterations often result in changes to DNA binding and chromatin clustering ability, and in the stability of this protein. Among other functions, MeCP2 binds to methylated genomic DNA, which represents an important epigenetic mark with broad physiological implications, including neuronal development. In this review, we will summarize the genetic foundations behind RTT, and the variable degrees of protein stability exhibited by MeCP2 and its mutated versions. Also, past and emerging relationships that MeCP2 has with mRNA splicing, miRNA processing, and other non-coding RNAs (ncRNA) will be explored, and we suggest that these molecules could be missing links in understanding the epigenetic consequences incurred from genetic ablation of this important chromatin modifier. Importantly, although MeCP2 is highly expressed in the brain, where it has been most extensively studied, the role of this protein and its alterations in other tissues cannot be ignored and will also be discussed. Finally, the additional complexity to RTT pathology introduced by structural and functional implications of the two MeCP2 isoforms (MeCP2-E1 and MeCP2-E2) will be described. Epigenetic therapeutics are gaining clinical popularity, yet treatment for Rett syndrome is more complicated than would be anticipated for a purely epigenetic disorder, which should be taken into account in future clinical contexts.
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Affiliation(s)
- Katrina V. Good
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - John B. Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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7
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Naegelin Y, Kuhle J, Schädelin S, Datta AN, Magon S, Amann M, Barro C, Ramelli GP, Heesom K, Barde YA, Weber P, Kappos L. Fingolimod in children with Rett syndrome: the FINGORETT study. Orphanet J Rare Dis 2021; 16:19. [PMID: 33407685 PMCID: PMC7789265 DOI: 10.1186/s13023-020-01655-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/20/2020] [Indexed: 11/10/2022] Open
Abstract
Background Rett syndrome (RS) is a severe neurodevelopmental disorder for which there is no approved therapy.
This study aimed to assess safety and efficacy of oral fingolimod in children with RS using a pre-post and case–control design. Methods At the University of Basel Children’s Hospital, Basel, Switzerland, children with RS were included if they were older than 6 years and met the established diagnostic criteria of RS, including a positive MeCP2 mutation. Participants were observed 6 months before and after treatment and received 12 months of fingolimod treatment. Serum samples of 50 children without RS served as reference for brain-derived neurotrophic factor (BDNF) measurements. Primary outcome measures were safety and efficacy, the latter measured by change in levels of BDNF in serum/CSF (cerebrospinal fluid) and change in deep gray matter volumes measured by magnetic resonance imaging (MRI). Secondary outcome measure was efficacy measured by change in clinical scores [Vineland Adaptive Behaviour Scale (VABS), Rett Severity Scale (RSSS) and Hand Apraxia Scale (HAS)]. Results Six children with RS (all girls, mean and SD age 11.3 ± 3.1 years) were included. Serum samples of 50 children without RS (25 females, mean and SD age 13.5 ± 3.9 years) served as reference for BDNF measurements. No serious adverse events occurred. Primary and secondary outcome measures were not met. CSF BDNF levels were associated with all clinical scores: RSSS (estimate − 0.04, mult.effect 0.96, CI [0.94; 0.98], p = 0.03), HAS (estimate − 0.09, mult.effect 0.91, CI [0.89; 0.94], p < 0.01) and VABS (communication: estimate 0.03, mult.effect 1.03, CI [1.02; 1.04], p < 0.01/daily living: estimate 0.03, mult.effect 1.03, CI [1.02; 1.04], p < 0.01/social skills: estimate 0.07, mult.effect 1.08, CI [1.05; 1.11], p < 0.01/motoric skills: estimate 0.04, mult.effect 1.04, CI [1.03; 1.06], p = 0.02). Conclusions In children with RS, treatment with fingolimod was safe. The study did not provide supportive evidence for an effect of fingolimod on clinical, laboratory, and imaging measures. CSF BDNF levels were associated with clinical scores, indicating a need to further evaluate its potential as a biomarker for RS. This finding should be further validated in independent patient groups. Trial Registration Clinical Trials.gov NCT02061137, registered on August 27th 2013, https://clinicaltrials.gov/ct2/show/study/NCT02061137.
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Affiliation(s)
- Yvonne Naegelin
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research, Biomedicine and Biomedical Engineering, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland. .,School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
| | - Jens Kuhle
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research, Biomedicine and Biomedical Engineering, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland
| | - Sabine Schädelin
- Clinical Trial Unit, Department of Clinical Research, University Hospital Basel, 4031, Basel, Switzerland
| | - Alexandre N Datta
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, 4056, Basel, Switzerland
| | - Stefano Magon
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research, Biomedicine and Biomedical Engineering, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland
| | - Michael Amann
- Medical Image Analysis Center (MIAC) AG, 4051, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, 4123, Allschwil, Switzerland
| | - Christian Barro
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research, Biomedicine and Biomedical Engineering, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland
| | - Gian Paolo Ramelli
- Neuropediatric Unit, Pediatric Institute of Southern Switzerland, 6500, Bellinzona, Switzerland
| | - Kate Heesom
- University of Bristol Proteomics Facility, Bristol, BS8 1TD, UK
| | - Yves-Alain Barde
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - Peter Weber
- Department of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, 4056, Basel, Switzerland
| | - Ludwig Kappos
- Neurologic Clinic and Policlinic, Departments of Medicine, Clinical Research, Biomedicine and Biomedical Engineering, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland
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Gomes AR, Fernandes TG, Vaz SH, Silva TP, Bekman EP, Xapelli S, Duarte S, Ghazvini M, Gribnau J, Muotri AR, Trujillo CA, Sebastião AM, Cabral JMS, Diogo MM. Modeling Rett Syndrome With Human Patient-Specific Forebrain Organoids. Front Cell Dev Biol 2020; 8:610427. [PMID: 33363173 PMCID: PMC7758289 DOI: 10.3389/fcell.2020.610427] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/23/2020] [Indexed: 12/17/2022] Open
Abstract
Engineering brain organoids from human induced pluripotent stem cells (hiPSCs) is a powerful tool for modeling brain development and neurological disorders. Rett syndrome (RTT), a rare neurodevelopmental disorder, can greatly benefit from this technology, since it affects multiple neuronal subtypes in forebrain sub-regions. We have established dorsal and ventral forebrain organoids from control and RTT patient-specific hiPSCs recapitulating 3D organization and functional network complexity. Our data revealed a premature development of the deep-cortical layer, associated to the formation of TBR1 and CTIP2 neurons, and a lower expression of neural progenitor/proliferative cells in female RTT dorsal organoids. Moreover, calcium imaging and electrophysiology analysis demonstrated functional defects of RTT neurons. Additionally, assembly of RTT dorsal and ventral organoids revealed impairments of interneuron’s migration. Overall, our models provide a better understanding of RTT during early stages of neural development, demonstrating a great potential for personalized diagnosis and drug screening.
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Affiliation(s)
- Ana Rita Gomes
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Tiago G Fernandes
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Sandra H Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Teresa P Silva
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Evguenia P Bekman
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,The Discoveries Centre for Regenerative and Precision Medicine (Lisbon Campus), Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Sara Xapelli
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sofia Duarte
- Department of Pediatric Neurology, Centro Hospitalar Universitário de Lisboa Central, Lisbon, Portugal
| | - Mehrnaz Ghazvini
- Erasmus MC iPS Facility, Erasmus Medical Center, University Medical Center, Rotterdam, Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus Medical Center, University Medical Center, Rotterdam, Netherlands
| | - Alysson R Muotri
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, United States.,Rady Children's Hospital San Diego, School of Medicine, University of California, San Diego, La Jolla, CA, United States.,Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States.,Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA, United States.,Center for Academic Research and Training in Anthropogeny, La Jolla, CA, United States
| | - Cleber A Trujillo
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, United States.,Rady Children's Hospital San Diego, School of Medicine, University of California, San Diego, La Jolla, CA, United States.,Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Ana M Sebastião
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joaquim M S Cabral
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Maria Margarida Diogo
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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9
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Saikusa T, Kawaguchi M, Tanioka Tetsu T T, Nabatame Shin N S, Takahashi S, Yuge K, Nagamitsu SI, Takahashi T, Yamashita Y, Kobayashi Y, Hirayama C, Kakuma T, Matsuishi T, Itoh M. Meaningful word acquisition is associated with walking ability over 10 years in Rett syndrome. Brain Dev 2020; 42:705-712. [PMID: 32684376 DOI: 10.1016/j.braindev.2020.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/29/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate walking ability in Japanese patients with Rett syndrome (RTT). METHODS Walking ability was assessed in 100 female Japanese patients with RTT using univariate and multivariate analysis in all age groups, and in patients over 10 years of age. We analyzed walking ability and confounding factors including prenatal-perinatal histories, developmental milestones, somatic and head growth, anthropometric data, body mass index, age of loss of purposeful hand use, age at onset of stereotypic hand movement, history of autistic behavior, age at regression, presence or absence of seizures, and the results of MECP2 genetic examination from the Japanese Rett syndrome database. RESULTS Univariate analysis revealed that acquisition of walking in all age groups was significantly correlated with the acquisition of meaningful words, microcephaly, and crawling (P < 0.0001, P = 0.005, P < 0.0001, respectively). Univariate analysis revealed that walking ability over 10 years of age was significantly correlated with acquisition of meaningful words, microcephaly, and body mass index (P < 0,0001, P = 0.005, P = 0.0018, respectively). MECP2 mutations R306C, R133C, and R294X were significantly associated with different acquisition of crawling (P = 0.004) and walking (P = 0.01). Multivariate analysis revealed that only acquisition of meaningful words was significantly correlated with walking ability over 10 years of age. This trend excluded the genetic effects of R306C, R133C, and R294X. CONCLUSIONS Meaningful word acquisition was robustly associated with walking ability over 10 years. Prognosis of walking ability may be predicted by the acquisition of meaningful words. This information is potentially useful for early intervention and the planning of comprehensive treatment for young children with RTT.
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Affiliation(s)
- Tomoko Saikusa
- Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Machiko Kawaguchi
- Biostatistics Center, Kurume University, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | | | - Shin Nabatame Shin N
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Satoru Takahashi
- Department of Pediatrics, Asahikawa University, Asahikawa 078-8510, Japan
| | - Kotaro Yuge
- Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Shin-Ichiro Nagamitsu
- Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Tomoyuki Takahashi
- Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Yushiro Yamashita
- Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Yasuyuki Kobayashi
- Japan Rett Syndrome Association, 2-29-20-101 Kamiigusa, Suginami, Tokyo 167-002, Japan
| | - Chisato Hirayama
- Sakuranbokai-Rett Syndrome, 63-2-101 Kawatsu, Iizuka, Fukuoka, Japan
| | - Tatsuyuki Kakuma
- Biostatistics Center, Kurume University, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Toyojiro Matsuishi
- Research Center for Children, Research Center for Rett Syndrome, St. Mary's Hospital, Kurume, Fukuoka 830-8543, Japan.
| | - Masayuki Itoh
- Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-machi, Kodaira, Tokyo 187-8502, Japan
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10
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MacKay CI, Wong K, Demarest ST, Benke TA, Downs J, Leonard H. Exploring genotype-phenotype relationships in the CDKL5 deficiency disorder using an international dataset. Clin Genet 2020; 99:157-165. [PMID: 33047306 DOI: 10.1111/cge.13862] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/20/2020] [Accepted: 10/09/2020] [Indexed: 12/24/2022]
Abstract
Characterized by early-onset seizures, global developmental delay and severe motor deficits, CDKL5 deficiency disorder is caused by pathogenic variants in the cyclin-dependent kinase-like 5 gene. Previous efforts to investigate genotype-phenotype relationships have been limited due to small numbers of recurrent mutations and small cohort sizes. Using data from the International CDKL5 Disorder Database we examined genotype-phenotype relationships for 13 recurrent CDKL5 variants and the previously analyzed historic variant groupings. We have applied the CDKL5 Developmental Score (CDS) and an adapted version of the CDKL5 Clinical Severity Assessment (CCSA), to grade the severity of phenotype and developmental outcomes for 285 individuals with CDKL5 variants. Comparisons of adapted CCSA and CDS between recurrent variants and variant groups were performed using multiple linear regression adjusting for age and sex. Individuals with the missense variant, p.Arg178Trp, had the highest mean adapted CCSA and lowest mean developmental scores. Other variants producing severe phenotypes included p.Arg559* and p.Arg178Gln. Variants producing milder phenotypes included p.Arg134*, p.Arg550*, and p.Glu55Argfs*20. There are observed differences in phenotype severity and developmental outcomes for individuals with different CDKL5 variants. However, the historic variant groupings did not seem to reflect differences in phenotype severity or developmental outcomes as clearly as analyzed by individual variants.
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Affiliation(s)
- Conor I MacKay
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Kingsley Wong
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Scott T Demarest
- Children's Hospital Colorado, Aurora, Colorado, USA.,Departments of Pediatrics and Neurology, University of Colorado at Denver, Aurora, Colorado, USA
| | - Tim A Benke
- Children's Hospital Colorado, Aurora, Colorado, USA.,Departments of Pediatrics, Pharmacology, Neurology and Otolaryngology, University of Colorado at Denver, Aurora, Colorado, USA
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia, Australia
| | - Helen Leonard
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
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11
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Cutri-French C, Armstrong D, Saby J, Gorman C, Lane J, Fu C, Peters SU, Percy A, Neul JL, Marsh ED. Comparison of Core Features in Four Developmental Encephalopathies in the Rett Natural History Study. Ann Neurol 2020; 88:396-406. [PMID: 32472944 DOI: 10.1002/ana.25797] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Rett syndrome, CDKL5-deficiency disorder, FOXG1 disorder, and MECP2 duplication disorder are developmental encephalopathies with shared and distinct features. Although they are historically linked, no direct comparison has been performed. The first head-to-head comparison of clinical features in these conditions is presented. METHODS Comprehensive clinical information was collected from 793 individuals enrolled in the Rett and Rett-Related Disorders Natural History Study. Clinical features including clinical severity, regression, and seizures were cross-sectionally compared between diagnoses to test the hypothesis that these are 4 distinct disorders. RESULTS Distinct patterns of clinical severity, seizure onset age, and regression were present. Individuals with CDKL5-deficency disorder were the most severely affected and had the youngest age at seizure onset (2 months), whereas children with MECP2 duplication syndrome had the oldest median age at seizure onset (64 months) and lowest severity scores. Rett syndrome and FOGX1 were intermediate in both features. Smaller head circumference correlates with increased severity in all disorders and earlier age at seizure onset in MECP2 duplication syndrome. Developmental regression occurred in all Rett syndrome participants (median = 18 months) but only 23 to 34% of the other disorders. Seizure incidence prior to the baseline visit was highest for CDKL5 deficiency disorder (96.2%) and lowest for Rett syndrome (47.5%). Other clinical features including seizure types and frequency differed among groups. INTERPRETATION Although these developmental encephalopathies share many clinical features, clear differences in severity, regression, and seizures warrant considering them as unique disorders. These results will aid in the development of disease-specific severity scales, precise therapeutics, and future clinical trials. ANN NEUROL 2020;88:396-406.
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Affiliation(s)
- Clare Cutri-French
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dallas Armstrong
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Joni Saby
- Division of Radiology Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Casey Gorman
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Jane Lane
- Department of Pediatrics, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Cary Fu
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Sarika U Peters
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alan Percy
- Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jeffrey L Neul
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eric D Marsh
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.,Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
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12
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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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13
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Caffarelli C, Gonnelli S, Pitinca MDT, Camarri S, Al Refaie A, Hayek J, Nuti R. Methyl-CpG-binding protein 2 (MECP2) mutation type is associated with bone disease severity in Rett syndrome. BMC MEDICAL GENETICS 2020; 21:21. [PMID: 32005172 PMCID: PMC6995101 DOI: 10.1186/s12881-020-0960-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 01/23/2020] [Indexed: 01/04/2023]
Abstract
Background More than 95% of individuals with RTT have mutations in methyl-CpG-binding protein 2 (MECP2), whose protein product modulates gene transcription. The disorder is caused by mutations in a single gene and the disease severity in affected individuals can be quite variable. Specific MECP2 mutations may lead phenotypic variability and different degrees of disease severity. It is known that low bone mass is a frequent and early complication of subjects with Rett syndrome. As a consequence of the low bone mass Rett girls are at an increased risk of fragility fractures. This study aimed to investigate if specific MECP2 mutations may affects the degree of involvement of the bone status in Rett subjects. Methods In 232 women with Rett syndrome (mean age 13.8 ± 8.3 yrs) we measured bone mineral density at whole body and at femur (BMD-FN and BMD-TH) by using a DXA machine (Hologic QDR 4500). QUS parameters were assessed at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time: BTT). Moreover, ambulation capacity (independent or assisted), fracture history and presence of scoliosis were assessed. We divided the subjects with the most common point mutations in two group based on genotype-phenotype severity; in particular, there has been consensus in recognising that the mutations R106T, R168X, R255X, R270X are considered more severe. Results As aspect, BMD-WB, BMD-FN and BMD-TH were lower in subjects with Rett syndrome that present the most severe mutations with respect to subjects with Rett syndrome with less severe mutations, but the difference was statistically significant only for BMD-FN and BMD-TH (p < 0.05). Also both AD-SoS and BTT values were lower in subjects that present the most severe mutations with respect to less severe mutations but the difference was not statistically significant. Moreover, subjects with Rett syndrome with more severe mutations present a higher prevalence of scoliosis (p < 0.05) and of inability to walk (p < 0.05). Conclusion This study confirms that MECP2 mutation type is a strong predictor of disease severity in subjects with Rett syndrome. In particular, the subjects with more severe mutation present a greater deterioration of bone status, and a higher prevalence of scoliosis and inability to walk.
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Affiliation(s)
- Carla Caffarelli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy.
| | - Stefano Gonnelli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy
| | - Maria Dea Tomai Pitinca
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy
| | - Silvia Camarri
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy
| | - Antonella Al Refaie
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy
| | - Joussef Hayek
- Paediatrics Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Ranuccio Nuti
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy
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14
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Hettiarachchi D, Neththikumara NF, Pathirana BAPS, Dissanayake VHW. Variant Profile of MECP2 Gene in Sri Lankan Patients with Rett Syndrome. J Autism Dev Disord 2019; 50:118-126. [DOI: 10.1007/s10803-019-04230-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Genomic insights into MeCP2 function: A role for the maintenance of chromatin architecture. Curr Opin Neurobiol 2019; 59:174-179. [PMID: 31430649 DOI: 10.1016/j.conb.2019.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/07/2019] [Indexed: 01/05/2023]
Abstract
Methyl-CpG binding protein 2 (MeCP2) plays fundamental roles in the nervous system, as both gain-of-function and loss-of-function of MECP2 are associated with severe neurological conditions. Understanding the molecular function of MeCP2 will not only provide insights into the pathogenesis of MeCP2-related disorders, but will also shed light on the epigenetic regulation of neuronal function. In the past few years, a number of studies have provided mechanistic evidence that MeCP2 recruits co-repressor complexes to particular sequences of methylated DNA. Additionally, innovative design and high-throughput sequencing technologies have provided opportunities to study the effects of MeCP2 on the neuronal transcriptome at an unprecedented level of detail, demonstrating that MeCP2 modulates gene expression in a context-specific manner. These findings have raised new questions and challenged current models of MeCP2 function. In this review, we describe several recent developments, highlight future challenges, and articulate a model by which MeCP2 functions as an organizer of chromatin architecture to modulate global gene expression in the nervous system.
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16
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Chernushyn S, Gulkovskyi R, Livshits L. Novel Mutation in the MECP2 Gene Identified in a Group of Rett Syndrome Patients from Ukraine. CYTOL GENET+ 2018. [DOI: 10.3103/s0095452718040023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Shovlin S, Tropea D. Transcriptome level analysis in Rett syndrome using human samples from different tissues. Orphanet J Rare Dis 2018; 13:113. [PMID: 29996871 PMCID: PMC6042368 DOI: 10.1186/s13023-018-0857-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/27/2018] [Indexed: 01/06/2023] Open
Abstract
The mechanisms of neuro-genetic disorders have been mostly investigated in the brain, however, for some pathologies, transcriptomic analysis in multiple tissues represent an opportunity and a challenge to understand the consequences of the genetic mutation. This is the case for Rett Syndrome (RTT): a neurodevelopmental disorder predominantly affecting females that is characterised by a loss of purposeful movements and language accompanied by gait abnormalities and hand stereotypies. Although the genetic aetiology is largely associated to Methyl CpG binding protein 2 (MECP2) mutations, linking the pathophysiology of RTT and its clinical symptoms to direct molecular mechanisms has been difficult.One approach used to study the consequences of MECP2 dysfunction in patients, is to perform transcriptomic analysis in tissues derived from RTT patients or Induced Pluripotent Stem cells. The growing affordability and efficiency of this approach has led to a far greater understanding of the complexities of RTT syndrome but is also raised questions about previously held convictions such as the regulatory role of MECP2, the effects of different molecular mechanisms in different tissues and role of X Chromosome Inactivation in RTT.In this review we consider the results of a number of different transcriptomic analyses in different patients-derived preparations to unveil specific trends in differential gene expression across the studies. Although the analyses present limitations- such as the limited sample size- overlaps exist across these studies, and they report dysregulations in three main categories: dendritic connectivity and synapse maturation, mitochondrial dysfunction, and glial cell activity.These observations have a direct application to the disorder and give insights on the altered mechanisms in RTT, with implications on potential diagnostic criteria and treatments.
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Affiliation(s)
- Stephen Shovlin
- Neuropsychiatric Genetics Research Group, Trinity Translational Medicine Institute- TTMI, St James Hospital, D8, Dublin, Ireland
| | - Daniela Tropea
- Neuropsychiatric Genetics Research Group, Trinity Translational Medicine Institute- TTMI, St James Hospital, D8, Dublin, Ireland
- Trinity College Institute of Neuroscience, TCIN, Loyd Building, Dublin2, Dublin, Ireland
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18
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Vineeth VS, Dutta UR, Tallapaka K, Das Bhowmik A, Dalal A. Whole exome sequencing identifies a novel 5 Mb deletion at 14q12 region in a patient with global developmental delay, microcephaly and seizures. Gene 2018; 673:56-60. [PMID: 29920362 DOI: 10.1016/j.gene.2018.06.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/11/2018] [Accepted: 06/14/2018] [Indexed: 01/04/2023]
Abstract
Rett syndrome is a neurodevelopmental disorder affecting the nervous, musculoskeletal and gastroenteric systems. Affected individuals show normal neonatal development for 6-18 months followed by sudden growth arrest, psychomotor retardation and a broad spectrum of clinical features. Sequence variants in MECP2 gene have been identified as the major genetic etiology accounting for 90-95% of patients. Apart from MECP2, pathogenic sequence variants and copy number variants of FOXG1 gene lead to congenital type of Rett syndrome which is a more severe form and characterised by absence of early normal development as seen in classical Rett syndrome. In this report we describe a female child with global developmental delay, microcephaly and myoclonic seizures harbouring a 5 Mb deletion in 14q12 locus resulting in deletion of single copy of brain specific genes FOXG1, PRKD1 and NOVA1. Whole exome sequencing ruled out any possible role of other pathogenic single nucleotide variants and/or indels as the etiology for the observed phenotype. However, copy number variation analysis from the whole exome data detected a ~ 5 Mb microdeletion at the long arm of chromosome 14q12 region. The deletion was confirmed through array Comparative Genomic Hybridization and validated by quantitative PCR. Further, parents were analysed for mosaicism through metaphase Fluorescence in-situ Hybridisation. Our report broadens the phenotype of atypical Rett syndrome and reiterates the role of exome sequencing not only in detection of point mutation/small indels but also for detection of large deletions/duplication in coding regions.
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Affiliation(s)
- Venugopal S Vineeth
- Diagnostics Division, Centre for DNA Fingerprinting & Diagnostics, Hyderabad, India
| | - Usha R Dutta
- Diagnostics Division, Centre for DNA Fingerprinting & Diagnostics, Hyderabad, India
| | - Karthik Tallapaka
- Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, India
| | - Aneek Das Bhowmik
- Diagnostics Division, Centre for DNA Fingerprinting & Diagnostics, Hyderabad, India.
| | - Ashwin Dalal
- Diagnostics Division, Centre for DNA Fingerprinting & Diagnostics, Hyderabad, India
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19
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First report of an unusual novel double mutation affecting the transcription repression domain of MeCP2 and causing a severe phenotype of Rett syndrome: Molecular analyses and computational investigation. Biochem Biophys Res Commun 2018; 497:93-101. [PMID: 29421650 DOI: 10.1016/j.bbrc.2018.02.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
Abstract
Rett syndrome is an X-linked neurodevelopmental disorder that develops a profound intellectual and motor disability and affects 1 from 10 000 to 15 000 live female births. This disease is characterized by a period of apparently normal development until 6-18 months of age when motor and communication abilities regress which is caused by mutations occurred in the X-linked MECP2 gene, encoding the methyl-CpG binding protein 2. This research study reports a molecular analysis via an exhaustive gene sequencing which reveals an unusual novel double mutation (c.695 G > T; c.880C > T) located in a highly conserved region in MECP2 gene affecting the transcription repression domain (TRD) of MeCP2 protein and leading for the first time to a severe phenotype of Rett syndrome. Moreover, a computational investigation of MECP2 mutations demonstrates that the novel mutation c.695 G > T is highly deleterious which affects the MeCP2 protein showing also an adverse impact on MECP2 gene expression and resulting in an affected folding and decreased stability of MECP2 structures. Thus, the altered TRD domain engenders a disrupted process of MECP2 functions. Therefore, this is the first study which highlights a novel double mutation among the transcription repression domain (TRD) of MeCP2 protein in Rett patient with a severe clinical phenotype in North Africa region.
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20
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Gold WA, Krishnarajy R, Ellaway C, Christodoulou J. Rett Syndrome: A Genetic Update and Clinical Review Focusing on Comorbidities. ACS Chem Neurosci 2018; 9:167-176. [PMID: 29185709 DOI: 10.1021/acschemneuro.7b00346] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rett syndrome (RTT) is a unique neurodevelopmental disorder that primarily affects females resulting in severe cognitive and physical disabilities. Despite the commendable collective efforts of the research community to better understand the genetics and underlying biology of RTT, there is still no cure. However, in the past 50 years, since the first report of RTT, steady progress has been made in the accumulation of clinical and molecular information resulting in the identification of a number of genes associated with RTT and associated phenotypes, improved diagnostic criteria, natural history studies, curation of a number of databases capturing genotypic and phenotypic data, a number of promising clinical trials and exciting novel therapeutic options which are currently being tested in laboratory and clinical settings. This Review focuses on the current knowledge of the clinical aspects of RTT, with particular attention being paid to clinical trials and the comorbidities of the disorder as well as the genetic etiology and the recognition of new diseases genes.
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Affiliation(s)
- Wendy A Gold
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Rahul Krishnarajy
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Carolyn Ellaway
- Genetic
Metabolic Disorders Service, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - John Christodoulou
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Neurodevelopmental
Genomics Research Group, Murdoch Children’s Research Institute,
and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC 3010, Australia
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21
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Yon DK, Park JE, Kim SJ, Shim SH, Chae KY. A sibship with duplication of Xq28 inherited from the mother; genomic characterization and clinical outcomes. BMC MEDICAL GENETICS 2017; 18:30. [PMID: 28302064 PMCID: PMC5356410 DOI: 10.1186/s12881-017-0394-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 03/07/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND Loss-of-function mutations in methyl-CpG-binding protein 2 (MECP2; MIM *300005) results in the Rett syndrome, whereas gain-of-function mutations are associated with the MECP2 duplication syndrome. METHODS We did research on a family with two brothers showing Xq28 duplication syndrome using various molecular cytogenetic techniques such as multiplex ligation-dependent probe amplification and array-based genomic hybridization. RESULTS The duplicated region had several genes including MECP2 and interleukin-1 receptor associated kinase 1 (IRAK1; MIM *300283). MECP2 and IRAK1 were associated with the neurological phenotypes in dose-sensitive and dose-critical manner. The brothers demonstrated severe intellectual disability, autistic features, generalized hypotonia, recurrent infections, epilepsy, choreiform movements such as hand-wringing movement, and moderate increased spasticity with the lower limbs. The X-inactivation test showed a complete skewed X inactivation pattern of mother. In this reason, the mother had the same loci duplication but showed significantly little neurological manifestation compared to the two sons. CONCLUSIONS MECP2/IRAK1 duplication at Xq28 is inherited as an X-linked recessive trait and male-specific disorder associated with severe intellectual disability. We tried to analyze the information of the relationship between neuropsychiatric phenotype and the extent of duplication at Xq28 by comparing with previous reports.
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Affiliation(s)
- Dong Keon Yon
- Department of Pediatrics, CHA Bundang Medical Center, School of Medicine, CHA University, 351 Yatap-dong, Bundang-gu, Seongnam, 463-712 Republic of Korea
| | - Ji Eun Park
- Genetics Laboratory, Fertility Center, CHA Gangnam Medical Center, School of Medicine, CHA University, 606-13 Yeoksam-dong, Gangnam-gu, Seoul, 06135 Republic of Korea
| | - Seung Jun Kim
- GenoLifeCare Division, BioCore, Seoul, Republic of Korea
| | - Sung Han Shim
- Genetics Laboratory, Fertility Center, CHA Gangnam Medical Center, School of Medicine, CHA University, 606-13 Yeoksam-dong, Gangnam-gu, Seoul, 06135 Republic of Korea
- Department of Biomedical Science, College of Life Science, CHA University, 335 Pankyo-ro, Bundang-gu, Seongnam, 13488 Republic of Korea
| | - Kyu Young Chae
- Department of Pediatrics, CHA Bundang Medical Center, School of Medicine, CHA University, 351 Yatap-dong, Bundang-gu, Seongnam, 463-712 Republic of Korea
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22
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Genotype-phenotype relationship among Egyptian children with Rett syndrome. J Egypt Public Health Assoc 2017; 90:133-7. [PMID: 26544843 DOI: 10.1097/01.epx.0000469901.73624.7a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Rett syndrome (RTT) is an X-linked dominant neurodegenerative disorder with various MECP2 mutations. RTT is one of the most common causes of severe intellectual and complex disability in girls. Therefore, the aims of the study were as follows: to highlight the clinical manifestations of RTT; to present the genotype-phenotype relationship; and to assess the possible relation between severity score, clinical manifestations, and MECP2 gene mutations. PATIENTS AND METHODS The present cross-sectional study included 15 girls with typical RTT, diagnosed according to the international criteria of RTT. All included patients were followed up at the pediatric neurology clinic, Cairo University Specialized Pediatric Hospital. They were subjected to screening of the entire coding region of the MECP2 gene (MECP2A and MECP2B) using denaturing high-performance liquid chromatography. The clinical severity was assessed among RTT cases using the International Scoring System. RESULTS Stereotypic hand movements were present in all cases, acquired microcephaly was present in 73.3% of cases, autistic features in 66.7% of cases, recurrent seizures in 53.3% of cases, delayed language development in 46.6% of cases, deterioration of speech in 53.3% of cases, and growth retardation and peripheral vasomotor changes in 46.6% of cases. Positive mutations were detected in 10 cases (66.66%): heterozygous for p.R270X mutation (three cases), heterozygous for p.R255X mutation (three cases), and heterozygous for p.R168X nonsense mutation (four cases). Microcephaly, seizures, growth retardation, and autistic features were more frequent in patients with a mutated gene; it was also observed that walking ability was more frequent in patients without a mutation.; thus, genotype-phenotype relationship was confirmed. The relationship between severity score and MECP2 mutation was detected in three cases with severe RTT, but there was no relationship between the severity score and specific MECP2 mutation. There was a relationship between the severity score and the clinical manifestations of RTT. CONCLUSION Mutations of MECP2 analysis were detected in 66.7% of RTT cases. There were relationships between the severity score, clinical manifestations, and MECP2 gene mutations. However, there was no relationship between the severity score and specific MECP2 gene mutation.
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23
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Gomathi M, Balachandar V. Novel therapeutic approaches: Rett syndrome and human induced pluripotent stem cell technology. Stem Cell Investig 2017; 4:20. [PMID: 28447035 DOI: 10.21037/sci.2017.02.11] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 02/21/2017] [Indexed: 01/28/2023]
Abstract
Recent advances in induced pluripotent stem cell (iPSC) technology target screening and discovering of therapeutic agents for the possible cure of human diseases. Human induced pluripotent stem cells (hiPSC) are the right kind of platform for testing potency of specific active compounds. Ayurveda, the Indian traditional system of medicine developed between 2,500 and 500 BC, is a science involving the intelligent formulations of herbs and minerals. It can serve as a "goldmine" for novel neuroprotective agents used for centuries to treat neurological disorders. This review discusses limitations in screening drugs for neurological disorders and the advantages offered by hiPSC integrated with Indian traditional system of medicine. We begin by describing the current state of hiPSC technology in research on Rett syndrome (RTT) followed by the current controversies in RTT research combined with the emergence of patient-specific hiPSC that indicate an urgent need for researchers to understand the etiology and drug mechanism. We conclude by offering recommendations to reinforce the screening of active compounds present in the ayurvedic medicines using the human induced pluripotent neural model system for research involving drug discovery for RTT. This integrative approach will fill the current knowledge gap in the traditional medicines and drug discovery.
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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-641 046, Tamil Nadu, India
| | - Vellingiri Balachandar
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
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Leonard H, Cobb S, Downs J. Clinical and biological progress over 50 years in Rett syndrome. Nat Rev Neurol 2016; 13:37-51. [PMID: 27934853 DOI: 10.1038/nrneurol.2016.186] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Jenny Downs
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
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Balachandar V, Dhivya V, Gomathi M, Mohanadevi S, Venkatesh B, Geetha B. A review of Rett syndrome (RTT) with induced pluripotent stem cells. Stem Cell Investig 2016; 3:52. [PMID: 27777941 DOI: 10.21037/sci.2016.09.05] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/08/2016] [Indexed: 11/06/2022]
Abstract
Human induced pluripotent stem cells (hiPSCs) are pluripotent stem cells generated from somatic cells by the introduction of a combination of pluripotency-associated genes such as OCT4, SOX2, along with either KLF4 and c-MYC or NANOG and LIN28 via retroviral or lentiviral vectors. Most importantly, hiPSCs are similar to human embryonic stem cells (hESCs) functionally as they are pluripotent and can potentially differentiate into any desired cell type when provided with the appropriate cues, but do not have the ethical issues surrounding hESCs. For these reasons, hiPSCs have huge potential in translational medicine such as disease modeling, drug screening, and cellular therapy. Indeed, patient-specific hiPSCs have been generated for a multitude of diseases, including many with a neurological basis, in which disease phenotypes have been recapitulated in vitro and proof-of-principle drug screening has been performed. As the techniques for generating hiPSCs are refined and these cells become a more widely used tool for understanding brain development, the insights they produce must be understood in the context of the greater complexity of the human genome and the human brain. Disease models using iPS from Rett syndrome (RTT) patient's fibroblasts have opened up a new avenue of drug discovery for therapeutic treatment of RTT. The analysis of X chromosome inactivation (XCI) upon differentiation of RTT-hiPSCs into neurons will be critical to conclusively demonstrate the isolation of pre-XCI RTT-hiPSCs in comparison to post-XCI RTT-hiPSCs. The current review projects on iPSC studies in RTT as well as XCI in hiPSC were it suggests for screening new potential therapeutic targets for RTT in future for the benefit of RTT patients. In conclusion, patient-specific drug screening might be feasible and would be particularly helpful in disorders where patients frequently have to try multiple drugs before finding a regimen that works.
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Affiliation(s)
- Vellingiri Balachandar
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
| | - Venkatesan Dhivya
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
| | - Mohan Gomathi
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
| | - Subramaniam Mohanadevi
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
| | - Balasubramanian Venkatesh
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
| | - Bharathi Geetha
- Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India
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Williams AA, Mehler VJ, Mueller C, Vonhoff F, White R, Duch C. Apoptotic Activity of MeCP2 Is Enhanced by C-Terminal Truncating Mutations. PLoS One 2016; 11:e0159632. [PMID: 27442528 PMCID: PMC4956225 DOI: 10.1371/journal.pone.0159632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 07/05/2016] [Indexed: 11/22/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a widely abundant, multifunctional protein most highly expressed in post-mitotic neurons. Mutations causing Rett syndrome and related neurodevelopmental disorders have been identified along the entire MECP2 locus, but symptoms vary depending on mutation type and location. C-terminal mutations are prevalent, but little is known about the function of the MeCP2 C-terminus. We employ the genetic efficiency of Drosophila to provide evidence that expression of p.Arg294* (more commonly identified as R294X), a human MECP2 E2 mutant allele causing truncation of the C-terminal domains, promotes apoptosis of identified neurons in vivo. We confirm this novel finding in HEK293T cells and then use Drosophila to map the region critical for neuronal apoptosis to a small sequence at the end of the C-terminal domain. In vitro studies in mammalian systems previously indicated a role of the MeCP2 E2 isoform in apoptosis, which is facilitated by phosphorylation at serine 80 (S80) and decreased by interactions with the forkhead protein FoxG1. We confirm the roles of S80 phosphorylation and forkhead domain transcription factors in affecting MeCP2-induced apoptosis in Drosophila in vivo, thus indicating mechanistic conservation between flies and mammalian cells. Our findings are consistent with a model in which C- and N-terminal interactions are required for healthy function of MeCP2.
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Affiliation(s)
- Alison A. Williams
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Vera J. Mehler
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - Fernando Vonhoff
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, Connecticut, United States of America
| | - Robin White
- Institute of Physiology, University Medical Center, Mainz, Germany
| | - Carsten Duch
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
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Halbach N, Smeets EE, Julu P, Witt-Engerström I, Pini G, Bigoni S, Hansen S, Apartopoulos F, Delamont R, van Roozendaal K, Scusa MF, Borelli P, Candel M, Curfs L. Neurophysiology versus clinical genetics in Rett syndrome: A multicenter study. Am J Med Genet A 2016; 170:2301-9. [PMID: 27354166 PMCID: PMC5157762 DOI: 10.1002/ajmg.a.37812] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 05/30/2016] [Indexed: 12/25/2022]
Abstract
Many studies have attempted to establish the genotype–phenotype correlation in Rett syndrome (RTT). Cardiorespiratory measurements provide robust objective data, to correlate with each of the different clinical phenotypes. It has important implications for the management and treatment of this syndrome. The aim of this study was to correlate the genotype with the quantitative cardiorespiratory data obtained by neurophysiological measurement combined with a clinical severity score. This international multicenter study was conducted in four European countries from 1999 to 2012. The study cohort consisted of a group of 132 well‐defined RTT females aged between 2 and 43 years with extended clinical, molecular, and neurophysiological assessments. Diagnosis of RTT was based on the consensus criteria for RTT and molecular confirmation. Genotype–phenotype analyses of clinical features and cardiorespiratory data were performed after grouping mutations by the same type and localization or having the same putative biological effect on the MeCP2 protein, and subsequently on eight single recurrent mutations. A less severe phenotype was seen in females with CTS, p.R133C, and p.R294X mutations. Autonomic disturbances were present in all females, and not restricted to nor influenced by one specific group or any single recurrent mutation. The objective information from non‐invasive neurophysiological evaluation of the disturbed central autonomic control is of great importance in helping to organize the lifelong care for females with RTT. Further research is needed to provide insights into the pathogenesis of autonomic dysfunction, and to develop evidence‐based management in RTT. © 2016 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals, Inc.
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Affiliation(s)
- Nicky Halbach
- Netherlands Rett Expertise Center-GKC, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Eric E Smeets
- Netherlands Rett Expertise Center-GKC, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Peter Julu
- Neurodegeneration and Neuroinflamation, Imperial College London, London, United Kingdom.,The National Swedish Rett Center, Frösön, Sweden
| | | | - Giorgio Pini
- Tuscany Rett Center, Versilia Hospital, Camaiore (Lucca), Italy
| | - Stefania Bigoni
- Medical Genetic Unit, Ferrara University Hospital, Ferrara, Italy
| | - Stig Hansen
- Institute of Neurological Sciences, Southern General Hospital, NHS Greater, Glasgow and Clyde, Ferrara, United Kingdom
| | - Flora Apartopoulos
- Institute of Neurological Sciences, Southern General Hospital, NHS Greater, Glasgow and Clyde, Ferrara, United Kingdom
| | - Robert Delamont
- Regional Neuroscience Center, King's College Hospital NHS Foundation Trust and King's College London, London, United Kingdom
| | - Kees van Roozendaal
- Clinical Genomics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Maria F Scusa
- Tuscany Rett Center, Versilia Hospital, Camaiore (Lucca), Italy
| | - Paolo Borelli
- Division of Neurology, Versilia Hospital, Camaiore (Lucca), Italy
| | - Math Candel
- Department of Methodology and Statistics, School for Public Health and Primary Care CAPHRI, Maastricht University, Maastricht, The Netherlands
| | - Leopold Curfs
- Netherlands Rett Expertise Center-GKC, Maastricht University Medical Center, Maastricht, The Netherlands
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Boban S, Wong K, Epstein A, Anderson B, Murphy N, Downs J, Leonard H. Determinants of sleep disturbances in Rett syndrome: Novel findings in relation to genotype. Am J Med Genet A 2016; 170:2292-300. [PMID: 27255190 DOI: 10.1002/ajmg.a.37784] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/11/2016] [Indexed: 11/11/2022]
Abstract
Rett syndrome is a rare but severe neurological disorder associated with a mutation in the methyl CpG binding protein 2 (MECP2) gene. Sleep problems and epilepsy are two of many comorbidities associated with this disorder. This study investigated the prevalence and determinants of sleep problems in Rett syndrome using an international sample. Families with a child with a confirmed Rett syndrome diagnosis and a MECP2 mutation registered in the International Rett Syndrome Phenotype Database (InterRett) were invited to participate. Questionnaires were returned by 364/461 (78.9%) either in web-based or paper format. Families completed the Sleep Disturbance Scale for Children and provided information on the presence, nature, and frequency of their child's sleep problems. Multivariate multinomial regression was used to investigate the relationships between selected sleep problems, age group, and genotype and linear regression for the relationships between sleep disturbance scales and a range of covariates. Night waking was the most prevalent sleep problem affecting over 80% with nearly half (48.3%) currently waking often at night. Initiating and maintaining sleep was most disturbed for younger children and those with a p.Arg294* mutation. Severe seizure activity was associated with poor sleep after adjusting for age group, mutation type, and mobility. We were surprised to find associations between the p.Arg294* mutation and some sleep disturbances given that other aspects of its phenotype are milder. These findings highlight the complexities of aberrant MECP2 function in Rett syndrome and explain some of the variation in manifestation of sleep disturbances. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sharolin Boban
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Kingsley Wong
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Amy Epstein
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Barbara Anderson
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Nada Murphy
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
| | - Jenny Downs
- Telethon Kids Institute, The University of Western Australia, Perth, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Helen Leonard
- Telethon Kids Institute, The University of Western Australia, Perth, Australia
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MECP2 mutations in Czech patients with Rett syndrome and Rett-like phenotypes: novel mutations, genotype–phenotype correlations and validation of high-resolution melting analysis for mutation scanning. J Hum Genet 2016; 61:617-25. [DOI: 10.1038/jhg.2016.19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/06/2016] [Accepted: 02/15/2016] [Indexed: 02/04/2023]
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Cuddapah VA, Sinifunanya EN, Percy AK, Olsen ML. MeCP2 in the regulation of neural activity: Rett syndrome pathophysiological perspectives. Degener Neurol Neuromuscul Dis 2015; 5:103-116. [PMID: 32669918 PMCID: PMC7337177 DOI: 10.2147/dnnd.s61269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/23/2015] [Indexed: 11/23/2022] Open
Abstract
Rett syndrome (RTT), an X-linked neurodevelopment disorder, occurs in approximately one out of 10,000 females. Individuals afflicted by RTT display a constellation of signs and symptoms, affecting nearly every organ system. Most striking are the neurological manifestations, including regression of language and motor skills, increased seizure activity, autonomic dysfunction, and aberrant regulation of breathing patterns. The majority of girls with RTT have mutations in the gene encoding for methyl-CpG binding protein 2 (MeCP2). Since the discovery of this genetic cause of RTT in 1999, there has been an accelerated pace of research seeking to understand the role of MeCP2 in the brain in the hope of developing a disease-modifying therapy for RTT. In this study, we review the clinical features of RTT and then explore the latest mechanistic studies in order to explain how a mutation in MeCP2 leads to these unique features. We cover in detail studies examining the role of MeCP2 in neuronal physiology, as well as recent evidence that implicates a key role for glia in the pathogenesis of RTT. In the past 20 years, these basic and clinical studies have yielded an extraordinary understanding of RTT; as such, we end this narrative review considering the translation of these studies into clinical trials for the treatment of RTT.
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Affiliation(s)
| | | | - Alan K Percy
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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Pantaleón F G, Juvier R T. [Molecular basis of Rett syndrome: A current look]. ACTA ACUST UNITED AC 2015; 86:142-51. [PMID: 26239053 DOI: 10.1016/j.rchipe.2015.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 02/09/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED Rett syndrome (RS) is a neurodevelopmental disorder that exclusively affects girls, and occurs along with autism. It is very uncommon, and has five distinct forms, one classic and the others atypical, which generally compromise manual skills, language, and mobility, and widely associated with the appearance of stereotypy and early epilepsy. With the aim of updating the information about RS, a search was performed in the computer data bases of PubMed, Hinari, SCIELO and Medline, as well as consulting other web sites including OMIM, ORPHANET, GeneMap, Genetests, Proteins and Gene, using the descriptors "Síndrome de Rett", "genes y Síndrome de Rett", "Rett Syndrome gene", "Rett Syndrome", "Rett Syndrome gene therapy", and "Rett Syndrome review". Of the 1,348 articles found, 42 articles were selected, which reported 3 genes causing the syndrome: MECP2, CDKL5 and FOXG. The MECP2 gene is mutated in 80% of patients with classic RS, as well as in 40% of those affected by any of its atypical forms. RS with early epilepsy and the congenital variant are mainly due to variations in the CDKL5 and FOXG1 genes, respectively. CONCLUSIONS The diagnosis of RS is based on clinical criteria. However, the advances in molecular biology and genetics have opened a wide range of possibilities for diagnosing the different clinical forms that could not be classified before. Molecular analysis can help confirm the clinical criteria and provided information as regards the prognosis of the patient.
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Affiliation(s)
- Gretta Pantaleón F
- Departamento de Genética Molecular, Hospital Clínico Quirúrgico Hermanos Ameijeiras, La Habana, Cuba
| | - Tamara Juvier R
- Instituto de Neurología y Neurocirugía Prof. Rafael Estrada, La Habana, Cuba.
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Abstract
Two severe, progressive neurological disorders characterized by intellectual disability, autism, and developmental regression, Rett syndrome and MECP2 duplication syndrome, result from loss and gain of function, respectively, of the same critical gene, methyl-CpG-binding protein 2 (MECP2). Neurons acutely require the appropriate dose of MECP2 to function properly but do not die in its absence or overexpression. Instead, neuronal dysfunction can be reversed in a Rett syndrome mouse model if MeCP2 function is restored. Thus, MECP2 disorders provide a unique window into the delicate balance of neuronal health, the power of mouse models, and the importance of chromatin regulation in mature neurons. In this Review, we will discuss the clinical profiles of MECP2 disorders, the knowledge acquired from mouse models of the syndromes, and how that knowledge is informing current and future clinical studies.
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Abstract
Rett syndrome (RTT) is a syndromic autism spectrum disorder caused by loss-of-function mutations in MECP2. The methyl CpG binding protein 2 binds methylcytosine and 5-hydroxymethycytosine at CpG sites in promoter regions of target genes, controlling their transcription by recruiting co-repressors and co-activators. Several preclinical studies in mouse models have identified rational molecular targets for drug therapies aimed at correcting the underlying neural dysfunction. These targeted therapies are increasingly translating into human clinical trials. In this review, we present an overview of RTT and describe the current state of preclinical studies in methyl CpG binding protein 2-based mouse models, as well as current clinical trials in individuals with RTT.
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Affiliation(s)
- Lucas Pozzo-Miller
- />Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Sandipan Pati
- />Department of Neurology, Epilepsy Division, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
| | - Alan K. Percy
- />Department of Pediatrics, Civitan International Research Center, The University of Alabama at Birmingham, Birmingham, AL USA
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Tükel Ş, Björelius H, Henningsson G, McAllister A, Eliasson AC. Motor functions and adaptive behaviour in children with childhood apraxia of speech. INTERNATIONAL JOURNAL OF SPEECH-LANGUAGE PATHOLOGY 2015; 17:470-480. [PMID: 25740430 DOI: 10.3109/17549507.2015.1010578] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
PURPOSE Undiagnosed motor and behavioural problems have been reported for children with childhood apraxia of speech (CAS). This study aims to understand the extent of these problems by determining the profile of and relationships between speech/non-speech oral, manual and overall body motor functions and adaptive behaviours in CAS. METHOD Eighteen children (five girls and 13 boys) with CAS, 4 years 4 months to 10 years 6 months old, participated in this study. The assessments used were the Verbal Motor Production Assessment for Children (VMPAC), Bruininks-Oseretsky Test of Motor Proficiency (BOT-2) and Adaptive Behaviour Assessment System (ABAS-II). RESULT Median result of speech/non-speech oral motor function was between -1 and -2 SD of the mean VMPAC norms. For BOT-2 and ABAS-II, the median result was between the mean and -1 SD of test norms. However, on an individual level, many children had co-occurring difficulties (below -1 SD of the mean) in overall and manual motor functions and in adaptive behaviour, despite few correlations between sub-tests. CONCLUSION In addition to the impaired speech motor output, children displayed heterogeneous motor problems suggesting the presence of a global motor deficit. The complex relationship between motor functions and behaviour may partly explain the undiagnosed developmental difficulties in CAS.
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Wang H, Pati S, Pozzo-Miller L, Doering LC. Targeted pharmacological treatment of autism spectrum disorders: fragile X and Rett syndromes. Front Cell Neurosci 2015; 9:55. [PMID: 25767435 PMCID: PMC4341567 DOI: 10.3389/fncel.2015.00055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 02/05/2015] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorders (ASDs) are genetically and clinically heterogeneous and lack effective medications to treat their core symptoms. Studies of syndromic ASDs caused by single gene mutations have provided insights into the pathophysiology of autism. Fragile X and Rett syndromes belong to the syndromic ASDs in which preclinical studies have identified rational targets for drug therapies focused on correcting underlying neural dysfunction. These preclinical discoveries are increasingly translating into exciting human clinical trials. Since there are significant molecular and neurobiological overlaps among ASDs, targeted treatments developed for fragile X and Rett syndromes may be helpful for autism of different etiologies. Here, we review the targeted pharmacological treatment of fragile X and Rett syndromes and discuss related issues in both preclinical studies and clinical trials of potential therapies for the diseases.
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Affiliation(s)
- Hansen Wang
- Faculty of Medicine, University of Toronto, 1 King's College Circle Toronto, ON, Canada
| | - Sandipan Pati
- Department of Neurology, Epilepsy Division, The University of Alabama at Birmingham Birmingham, AL, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, Civitan International Research Center, The University of Alabama at Birmingham Birmingham, AL, USA
| | - Laurie C Doering
- Faculty of Health Sciences, Department of Pathology and Molecular Medicine, McMaster University Hamilton, ON, Canada
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Co-occurrence of Dystonic and Dyskinetic Tongue Movements with Oral Apraxia in Post-regression Dysphagia in Classical Rett Syndrome Years of Life 1 Through 5. Dysphagia 2014; 30:128-38. [DOI: 10.1007/s00455-014-9587-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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Chapleau CA, Lane J, Pozzo-Miller L, Percy AK. Evaluation of current pharmacological treatment options in the management of Rett syndrome: from the present to future therapeutic alternatives. ACTA ACUST UNITED AC 2014; 8:358-69. [PMID: 24050745 DOI: 10.2174/15748847113086660069] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/14/2013] [Accepted: 02/21/2013] [Indexed: 11/22/2022]
Abstract
Neurodevelopmental disorders are a large family of conditions of genetic or environmental origin that are characterized by deficiencies in cognitive and behavioral functions. The therapeutic management of individuals with these disorders is typically complex and is limited to the treatment of specific symptoms that characterize each disorder. The neurodevelopmental disorder Rett syndrome (RTT) is the leading cause of severe intellectual disability in females. Mutations in the gene encoding the transcriptional regulator methyl-CpG-binding protein 2 (MECP2), located on the X chromosome, have been confirmed in more than 95% of individuals meeting diagnostic criteria for classical RTT. RTT is characterized by an uneventful early infancy followed by stagnation and regression of growth, motor, language, and social skills later in development. This review will discuss the genetics, pathology, and symptoms that distinguish RTT from other neurodevelopmental disorders associated with intellectual disability. Because great progress has been made in the basic and clinical science of RTT, the goal of this review is to provide a thorough assessment of current pharmacotherapeutic options to treat the symptoms associated with this disorder. Furthermore, we will highlight recent discoveries made with novel pharmacological interventions in experimental preclinical phases, and which have reversed pathological phenotypes in mouse and cell culture models of RTT and may result in clinical trials.
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Affiliation(s)
- Christopher A Chapleau
- Department of Pediatrics, CIRC-320, The University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294-0021, USA.
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Neul JL, Lane JB, Lee HS, Geerts S, Barrish JO, Annese F, Baggett LM, Barnes K, Skinner SA, Motil KJ, Glaze DG, Kaufmann WE, Percy AK. Developmental delay in Rett syndrome: data from the natural history study. J Neurodev Disord 2014; 6:20. [PMID: 25071871 PMCID: PMC4112822 DOI: 10.1186/1866-1955-6-20] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 07/18/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Early development appears normal in Rett syndrome (OMIM #312750) and may be more apparent than real. A major purpose of the Rett Syndrome (RTT) Natural History Study (NHS) was to examine achievement of developmental skills or abilities in classic and atypical RTT and assess phenotype-genotype relations in classic RTT. METHODS Developmental skills in four realms, gross and fine motor, and receptive and expressive communication from initial enrollment and longitudinal assessments for up to 7 years, were assessed from 542 females meeting criteria for classic RTT and 96 females with atypical RTT divided into two groups: 50 with better and 46 with poorer functional scores. Data were analyzed for age at acquisition and loss of developmental features and for phenotype-genotype effects. Acquired, lost, and retained skills were compared between classic RTT and atypical RTT with better or poorer functional scores using Fisher's Exact test. To examine if the mean total score from the Motor Behavioral Assessment during follow-up differed for acquiring a skill, we used a generalized estimating equation assuming compound symmetry correlation structure within a subject. A general linear model was used to examine whether the mean age of acquisition or loss of a developmental skill differed by mutation type. P values <0.05 were considered significant and were two-sided without adjustment for multiple testing. Statistical analyses utilized SAS 9.3 (SAS Institute, Cary, NC, USA). RESULTS Early developmental skills or abilities were often acquired albeit later than normal. More complex motor and communication acquisitions were delayed or absent. Clinical severity was less in those achieving the respective skill. Individuals with R133C, R294X, and R306C point mutations and 3' truncations tended to have better developmental outcomes. CONCLUSIONS Early developmental skills were acquired by many, but clear differences from normal emerged, particularly in skills expected after age 6 months. When comparing clinical severity, greater acquisition of specific skills was associated with specific mutations, confirming the impression that these mutations confer milder developmental abnormalities. These data may serve for planning and interpretation of early intervention studies in RTT. TRIAL REGISTRATION This NHS study, clinicaltrials.gov (NCT00296764), represents the largest group of RTT participants assessed repeatedly by direct examination.
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Affiliation(s)
- Jeffrey L Neul
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA ; Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Jane B Lane
- Civitan International Research Center, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294-0021, USA
| | - Hye-Seung Lee
- Pediatrics Epidemiology Center, University of South Florida, Tampa, FL 33620, USA
| | - Suzanne Geerts
- Civitan International Research Center, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294-0021, USA
| | - Judy O Barrish
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fran Annese
- Greenwood Genetic Center, Greenwood, SC 29646, USA
| | | | - Katherine Barnes
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Kathleen J Motil
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel G Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Walter E Kaufmann
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alan K Percy
- Civitan International Research Center, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294-0021, USA
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Dajani R, Koo SE, Sullivan GJ, Park IH. Investigation of Rett syndrome using pluripotent stem cells. J Cell Biochem 2014; 114:2446-53. [PMID: 23744605 DOI: 10.1002/jcb.24597] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/28/2013] [Indexed: 01/23/2023]
Abstract
Rett syndrome (RTT) is one of most prevalent female neurodevelopmental disorders. De novo mutations in X-linked MECP2 are mostly responsible for RTT. Since the identification of MeCP2 as the underlying cause of RTT, murine models have contributed to understanding the pathophysiology of RTT and function of MeCP2. Reprogramming is a procedure to produce induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors. iPSCs obtain similar features as embryonic stem cells and are capable of self-renewing and differentiating into cells of all three layers. iPSCs have been utilized in modeling human diseases in vitro. Neurons differentiated from RTT-iPSCs showed the recapitulation of RTT phenotypes. Despite the early success, genetic and epigenetic instability upon reprogramming and ensuing maintenance of iPSCs raise concerns in using RTT-iPSCs as an accurate in vitro model. Here, we update the current iPSC-based RTT modeling, and its concerns and challenges.
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Affiliation(s)
- Rana Dajani
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, 10 Amistad 201B, New Haven, Connecticut, 06520; Department of Biology and Biotechnology, Hashemite University, Zarqa, P.O. Box 150459 13133, Jordan
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Cuddapah VA, Pillai RB, Shekar KV, Lane JB, Motil KJ, Skinner SA, Tarquinio DC, Glaze DG, McGwin G, Kaufmann WE, Percy AK, Neul JL, Olsen ML. Methyl-CpG-binding protein 2 (MECP2) mutation type is associated with disease severity in Rett syndrome. J Med Genet 2014. [PMID: 24399845 DOI: 10.1136/jmedgenet‐2013‐102113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Rett syndrome (RTT), a neurodevelopmental disorder that primarily affects girls, is characterised by a period of apparently normal development until 6-18 months of age when motor and communication abilities regress. More than 95% of individuals with RTT have mutations in methyl-CpG-binding protein 2 (MECP2), whose protein product modulates gene transcription. Surprisingly, although the disorder is caused by mutations in a single gene, disease severity in affected individuals can be quite variable. To explore the source of this phenotypic variability, we propose that specific MECP2 mutations lead to different degrees of disease severity. METHODS Using a database of 1052 participants assessed over 4940 unique visits, the largest cohort of both typical and atypical RTT patients studied to date, we examined the relationship between MECP2 mutation status and various phenotypic measures over time. RESULTS In general agreement with previous studies, we found that particular mutations, such as p.Arg133Cys, p.Arg294X, p.Arg306Cys, 3° truncations and other point mutations, were relatively less severe in both typical and atypical RTT. In contrast, p.Arg106Trp, p.Arg168X, p.Arg255X, p.Arg270X, splice sites, deletions, insertions and deletions were significantly more severe. We also demonstrated that, for most mutation types, clinical severity increases with age. Furthermore, of the clinical features of RTT, ambulation, hand use and age at onset of stereotypies are strongly linked to overall disease severity. CONCLUSIONS We have confirmed that MECP2 mutation type is a strong predictor of disease severity. These data also indicate that clinical severity continues to become progressively worse regardless of initial severity. These findings will allow clinicians and families to anticipate and prepare better for the needs of individuals with RTT.
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Affiliation(s)
- Vishnu Anand Cuddapah
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Cuddapah VA, Pillai RB, Shekar KV, Lane JB, Motil KJ, Skinner SA, Tarquinio DC, Glaze DG, McGwin G, Kaufmann WE, Percy AK, Neul JL, Olsen ML. Methyl-CpG-binding protein 2 (MECP2) mutation type is associated with disease severity in Rett syndrome. J Med Genet 2014; 51:152-8. [PMID: 24399845 DOI: 10.1136/jmedgenet-2013-102113] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Rett syndrome (RTT), a neurodevelopmental disorder that primarily affects girls, is characterised by a period of apparently normal development until 6-18 months of age when motor and communication abilities regress. More than 95% of individuals with RTT have mutations in methyl-CpG-binding protein 2 (MECP2), whose protein product modulates gene transcription. Surprisingly, although the disorder is caused by mutations in a single gene, disease severity in affected individuals can be quite variable. To explore the source of this phenotypic variability, we propose that specific MECP2 mutations lead to different degrees of disease severity. METHODS Using a database of 1052 participants assessed over 4940 unique visits, the largest cohort of both typical and atypical RTT patients studied to date, we examined the relationship between MECP2 mutation status and various phenotypic measures over time. RESULTS In general agreement with previous studies, we found that particular mutations, such as p.Arg133Cys, p.Arg294X, p.Arg306Cys, 3° truncations and other point mutations, were relatively less severe in both typical and atypical RTT. In contrast, p.Arg106Trp, p.Arg168X, p.Arg255X, p.Arg270X, splice sites, deletions, insertions and deletions were significantly more severe. We also demonstrated that, for most mutation types, clinical severity increases with age. Furthermore, of the clinical features of RTT, ambulation, hand use and age at onset of stereotypies are strongly linked to overall disease severity. CONCLUSIONS We have confirmed that MECP2 mutation type is a strong predictor of disease severity. These data also indicate that clinical severity continues to become progressively worse regardless of initial severity. These findings will allow clinicians and families to anticipate and prepare better for the needs of individuals with RTT.
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Affiliation(s)
- Vishnu Anand Cuddapah
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Lyst MJ, Ekiert R, Ebert DH, Merusi C, Nowak J, Selfridge J, Guy J, Kastan NR, Robinson ND, de Lima Alves F, Rappsilber J, Greenberg ME, Bird A. Rett syndrome mutations abolish the interaction of MeCP2 with the NCoR/SMRT co-repressor. Nat Neurosci 2013; 16:898-902. [PMID: 23770565 DOI: 10.1038/nn.3434] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 05/12/2013] [Indexed: 12/12/2022]
Abstract
Rett syndrome (RTT) is a severe neurological disorder that is caused by mutations in the MECP2 gene. Many missense mutations causing RTT are clustered in the DNA-binding domain of MeCP2, suggesting that association with chromatin is critical for its function. We identified a second mutational cluster in a previously uncharacterized region of MeCP2. We found that RTT mutations in this region abolished the interaction between MeCP2 and the NCoR/SMRT co-repressor complexes. Mice bearing a common missense RTT mutation in this domain exhibited severe RTT-like phenotypes. Our data are compatible with the hypothesis that brain dysfunction in RTT is caused by a loss of the MeCP2 'bridge' between the NCoR/SMRT co-repressors and chromatin.
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Affiliation(s)
- Matthew J Lyst
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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Hagebeuk EEO, Bijlmer RPGM, Koelman JHTM, Poll-The BT. Respiratory disturbances in rett syndrome: don't forget to evaluate upper airway obstruction. J Child Neurol 2012; 27:888-92. [PMID: 22290859 DOI: 10.1177/0883073811429859] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Rett syndrome is characterized by loss of motor and social functions, development of stereotypic hand movements, seizures, and breathing disturbances. This study evaluates the presence of overnight respiratory disturbances. Polysomnography in combination with a questionnaire (the Sleep Disturbance Scale for Children) was performed in 12 Dutch patients with Rett. Respiratory disturbances were present in all, clinically relevant in 10 (apnea hypopnea per hour 1.0-14.5). In 8 children, central apneas were present during the day often with obstructive apneas at night. In 6, obstructive sleep apnea syndrome was diagnosed, in 3 severe, with frequent oxygen desaturations. Significant respiratory complaints were present in 3 patients, all had obstructive sleep apnea syndrome. Of the 12 patients with Rett, 8 (67%) snored, and in 5 obstructive sleep apnea syndrome was present. In children, hypertrophied tonsils and adenoids are a common cause of obstructive sleep apnea syndrome, which may benefit from therapeutic intervention. We recommend performing polysomnography in patients with Rett syndrome and respiratory complaints.
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Cheval H, Guy J, Merusi C, De Sousa D, Selfridge J, Bird A. Postnatal inactivation reveals enhanced requirement for MeCP2 at distinct age windows. Hum Mol Genet 2012; 21:3806-14. [PMID: 22653753 DOI: 10.1093/hmg/dds208] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Rett Syndrome is a neurological disorder caused by mutations in the X-linked MECP2 gene. Mouse models where Mecp2 is inactivated or mutated recapitulate several features of the disorder and have demonstrated a requirement for the protein to ensure brain function in adult mice. We deleted the Mecp2 gene in ~80% of brain cells at three postnatal ages to determine whether the need for MeCP2 varies with age. Inactivation at all three time points induced Rett-like phenotypes and caused premature death of the animals. We find two threshold ages beyond which the requirement for MeCP2 markedly increases in stringency. The earlier threshold (8-14 weeks), when inactivated mice develop symptoms, represents early adulthood in the mouse and coincides with the period when Mecp2-null mice exhibit terminal symptoms. Unexpectedly, we identified a later age threshold (30-45 weeks) beyond which an 80% reduction in MeCP2 is incompatible with life. This finding suggests an enhanced role for MeCP2 in the aging brain.
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Affiliation(s)
- Hélène Cheval
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK
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MeCP2 mutation results in compartment-specific reductions in dendritic branching and spine density in layer 5 motor cortical neurons of YFP-H mice. PLoS One 2012; 7:e31896. [PMID: 22412847 PMCID: PMC3296699 DOI: 10.1371/journal.pone.0031896] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 01/17/2012] [Indexed: 01/30/2023] Open
Abstract
Rett Syndrome (RTT) is a neurodevelopmental disorder predominantly caused by mutations in the X-linked gene MECP2. A primary feature of the syndrome is the impaired maturation and maintenance of excitatory synapses in the central nervous system (CNS). Different RTT mouse models have shown that particular Mecp2 mutations have highly variable effects on neuronal architecture. Distinguishing MeCP2 mutant cellular phenotypes therefore demands analysis of specific mutations in well-defined neuronal subpopulations. We examined a transgenically labeled subset of cortical neurons in YFP-H mice crossed with the Mecp2(tm1.1Jae) mutant line. YFP(+) Layer 5 pyramidal neurons in the motor cortex of wildtype and hemizygous mutant male mice were examined for differences in dendrite morphology and spine density. Total basal dendritic length was decreased by 18.6% due to both shorter dendrites and reduced branching proximal to the soma. Tangential dendrite lengths in the apical tuft were reduced by up to 26.6%. Spine density was reduced by 47.4% in the apical tuft and 54.5% in secondary apical dendrites, but remained unaffected in primary apical and proximal basal dendrites. We also found that MeCP2 mutation reduced the number of YFP(+) cells in YFP-H mice by up to 72% in various cortical regions without affecting the intensity of YFP expression in individual cells. Our results support the view that the effects of MeCP2 mutation are highly context-dependent and cannot be generalized across mutation types and cell populations.
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Hagebeuk EEO, Duran M, Koelman JHTM, Abeling NGGM, Vyth A, Poll-The BT. Folinic acid supplementation in Rett syndrome patients does not influence the course of the disease: a randomized study. J Child Neurol 2012; 27:304-9. [PMID: 21868372 DOI: 10.1177/0883073811417184] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Rett syndrome is a neurodevelopmental disorder in girls, related to mutations in MECP2 gene. It has been postulated that low 5-methyltetrahydrofolate (5-MTHF) levels are present in cerebrospinal fluid. Folinic acid demonstrated clinical improvement. However, because studies have produced conflicting results, we performed a randomized, double-blind crossover, long-term, follow-up study on folinic acid. Eight Rett syndrome patients received both folinic acid and placebo, for 1 year each. Measurements included plasma folate, 5-MTHF, and clinical outcome scores like Rett Syndrome Motor Behavioral Assessment, Hand Apraxia Scale, and the parental Overall Well-Being Index. In 2 patients, low 5-MTHF levels were present. Folinic acid supplementation increased cerebrospinal fluid 5-MTHF levels, but with no objective evidence of clinical improvement. The Overall Well-Being Index showed a significant difference in favor of folinic acid, not confirmed objectively. In our double-blind randomized study, folinic acid supplementation resulted in increased 5-MTHF levels, but with no objective signs of clinical improvement.
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Affiliation(s)
- Eveline E O Hagebeuk
- Academic Medical Center, Department of Pediatric Neurology, Amsterdam, The Netherlands.
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Linking epigenetics to human disease and Rett syndrome: the emerging novel and challenging concepts in MeCP2 research. Neural Plast 2012; 2012:415825. [PMID: 22474603 PMCID: PMC3306986 DOI: 10.1155/2012/415825] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 11/15/2011] [Indexed: 02/08/2023] Open
Abstract
Epigenetics refer to inheritable changes beyond DNA sequence that control cell identity and morphology. Epigenetics play key roles in development and cell fate commitments and highly impact the etiology of many human diseases. A well-known link between epigenetics and human disease is the X-linked MECP2 gene, mutations in which lead to the neurological disorder, Rett Syndrome. Despite the fact that MeCP2 was discovered about 20 years ago, our current knowledge about its molecular function is not comprehensive. While MeCP2 was originally found to bind methylated DNA and interact with repressor complexes to inhibit and silence its genomic targets, recent studies have challenged this idea. Indeed, depending on its interacting protein partners and target genes, MeCP2 can act either as an activator or as a repressor. Furthermore, it is becoming evident that although Rett Syndrome is a progressive and postnatal neurological disorder, the consequences of MeCP2 deficiencies initiate much earlier and before birth. To comprehend the novel and challenging concepts in MeCP2 research and to design effective therapeutic strategies for Rett Syndrome, a targeted collaborative effort from scientists in multiple research areas to clinicians is required.
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Molecular analysis of MECP2 gene in Egyptian patients with Rett syndrome. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2012. [DOI: 10.1016/j.ejmhg.2011.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Halbach NSJ, Smeets EEJ, van den Braak N, van Roozendaal KEP, Blok RMJ, Schrander-Stumpel CTRM, Frijns JP, Maaskant MA, Curfs LMG. Genotype-phenotype relationships as prognosticators in Rett syndrome should be handled with care in clinical practice. Am J Med Genet A 2011; 158A:340-50. [PMID: 22190343 DOI: 10.1002/ajmg.a.34418] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 10/04/2011] [Indexed: 11/10/2022]
Abstract
Rett syndrome (RTT; OMIM 312750) is an X-linked dominant neurodevelopmental disorder leading to cognitive and motor impairment, epilepsy, and autonomic dysfunction in females. Since the discovery that RTT is caused by mutations in MECP2, large retrospective genotype-phenotype correlation studies have been performed. A number of general genotype-phenotype relationships were confirmed and specific disorder profiles were described. Nevertheless, conflicting results are still under discussion, partly due to the variability in classification of mutations, assessment tools, and structure of the data sets. The aim of this study was to investigate relationships between genotype and specific clinical data collected by the same experienced physician in a well-documented RTT cohort, and evaluate its prognostic value in counseling young parents with a newly diagnosed RTT girl regarding her future outcome. The Maastricht-Leuven Rett Syndrome Database is a register of 137 molecularly confirmed clinical RTT cases, containing both molecular and clinical data on examination and follow up by the same experienced physician. Although the general genotype-phenotype relationships were confirmed, the clinical severity was still found to be very variable. We therefore recommend caution in using genotype-phenotype data in the prognosis of outcome for children in Rett syndrome. Early diagnosis, early intervention, and preventive management are imperative for better outcomes and better quality of daily life for RTT females and their families.
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Affiliation(s)
- Nicky S J Halbach
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
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Rett syndrome mutation MeCP2 T158A disrupts DNA binding, protein stability and ERP responses. Nat Neurosci 2011; 15:274-83. [PMID: 22119903 PMCID: PMC3267879 DOI: 10.1038/nn.2997] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 10/28/2011] [Indexed: 11/08/2022]
Abstract
Mutations in the MECP2 gene cause the autism spectrum disorder Rett Syndrome (RTT). One of the most common mutations associated with RTT occurs at MeCP2 Threonine 158 converting it to Methionine (T158M) or Alanine (T158A). To understand the role of T158 mutation in the pathogenesis of RTT, we generated knockin mice recapitulating MeCP2 T158A mutation. Here we show a causal role for T158A mutation in the development of RTT-like phenotypes including developmental regression, motor dysfunction, and learning and memory deficits. These phenotypes resemble those in Mecp2-null mice and manifest through a reduction in MeCP2 binding to methylated DNA and a decrease in MeCP2 protein stability. Importantly, the age-dependent development of event-related neuronal responses are disrupted by MeCP2 mutation, suggesting that impaired neuronal circuitry underlies the pathogenesis of RTT and that assessment of event-related potentials may serve as a biomarker for RTT and treatment evaluation.
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