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Signorini C, Leoncini S, Durand T, Galano JM, Guy A, Bultel-Poncé V, Oger C, Lee JCY, Ciccoli L, Hayek J, De Felice C. Circulating 4-F 4t-Neuroprostane and 10-F 4t-Neuroprostane Are Related to MECP2 Gene Mutation and Natural History in Rett Syndrome. Int J Mol Sci 2021; 22:ijms22084240. [PMID: 33921863 PMCID: PMC8073126 DOI: 10.3390/ijms22084240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/10/2021] [Accepted: 04/15/2021] [Indexed: 12/20/2022] Open
Abstract
Neuroprostanes, a family of non-enzymatic metabolites of the docosahexaenoic acid, have been suggested as potential biomarkers for neurological diseases. Objective biological markers are strongly needed in Rett syndrome (RTT), which is a progressive X-linked neurodevelopmental disorder that is mainly caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene with a predominant multisystemic phenotype. The aim of the study is to assess a possible association between MECP2 mutations or RTT disease progression and plasma levels of 4(RS)-4-F4t-neuroprostane (4-F4t-NeuroP) and 10(RS)-10-F4t-neuroprostane (10-F4t-NeuroP) in typical RTT patients with proven MECP2 gene mutation. Clinical severity and disease progression were assessed using the Rett clinical severity scale (RCSS) in n = 77 RTT patients. The 4-F4t-NeuroP and 10-F4t-NeuroP molecules were totally synthesized and used to identify the contents of the plasma of the patients. Neuroprostane levels were related to MECP2 mutation category (i.e., early truncating, gene deletion, late truncating, and missense), specific hotspot mutations (i.e., R106W, R133C, R168X, R255X, R270X, R294X, R306C, and T158M), and disease stage (II through IV). Circulating 4-F4t-NeuroP and 10-F4t-NeuroP were significantly related to (i) the type of MECP2 mutations where higher levels were associated to gene deletions (p ≤ 0.001); (ii) severity of common hotspot MECP2 mutation (large deletions, R168X, R255X, and R270X); (iii) disease stage, where higher concentrations were observed at stage II (p ≤ 0.002); and (iv) deficiency in walking (p ≤ 0.0003). This study indicates the biological significance of 4-F4t-NeuroP and 10-F4t-NeuroP as promising molecules to mark the disease progression and potentially gauge genotype-phenotype associations in RTT.
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Affiliation(s)
- Cinzia Signorini
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy;
- Correspondence: (C.S.); (C.D.F.); Tel.: +39-0577-234499 (C.S.)
| | - Silvia Leoncini
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
- Child Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Jean-Marie Galano
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Alexandre Guy
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Valérie Bultel-Poncé
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | - Camille Oger
- Institut des Biomolécules Max Mousseron, (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, CEDEX 5, 34093 Montpellier, France; (T.D.); (J.-M.G.); (A.G.); (V.B.-P.); (C.O.)
| | | | - Lucia Ciccoli
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy;
| | - Joussef Hayek
- Child Neuropsychiatry Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
- Pediatric Speciality Center “L’Isola di Bau”, 50052 Certaldo, Florence, Italy
| | - Claudio De Felice
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, 53100 Siena, Italy;
- Correspondence: (C.S.); (C.D.F.); Tel.: +39-0577-234499 (C.S.)
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Henriksen MW, Breck H, Sejersted Y, Diseth T, von Tetzchner S, Paus B, Skjeldal OH. Genetic and clinical variations in a Norwegian sample diagnosed with Rett syndrome. Brain Dev 2020; 42:484-495. [PMID: 32336485 DOI: 10.1016/j.braindev.2020.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND PURPOSE Rett syndrome (RTT) is a neurodevelopmental disorder mainly caused by mutations in MECP2. The diagnostic criteria of RTT are clinical; mutations in MECP2 are neither diagnostic nor necessary, and a mutation in another gene does not exclude RTT. We attempted to correlate genotype and phenotype to see if there are significant clinical associations. METHODS All available females diagnosed with RTT in Norway were invited to the study. Parents were interviewed, the girl or woman with RTT examined and medical records reviewed. All diagnoses were revisited according to the current diagnostic criteria and exome-based sequencing analyses were performed in individuals without an identified causative mutation. Participants were categorized according to genotypes and RTT diagnosis. Individuals with RTT with and without mutations in MECP2 were compared. RESULTS Ninety-one individuals were included. A presumed causative mutation was identified in 86 individuals, of these, mutations in MECP2 in 77 individuals and mutations in SMC1A, SYNGAP1, SCN1A, CDKL5, FOXG1 or chromosome 13q in nine. Seventy-two individuals fulfilled the diagnostic criteria for classic and 12 for atypical RTT. Significant differences in early development, loss of hand use and language, intense eye gaze and the presence of early onset epilepsy were revealed in individuals with RTT according to their MECP2 genotypic status. CONCLUSION Using the current diagnostic criteria, genetic and clinical variation in RTT is considerable. Significant differences between individuals with RTT with and without MECP2 mutations indicate that MECP2 is a major determinant for the clinical phenotype in individuals with RTT.
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Affiliation(s)
- Mari Wold Henriksen
- Department of Neurology, Drammen Hospital, Vestre Viken Hospital Trust, P.O. Box 800, 3004 Drammen, Norway; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, P.O. Box 1171, Blindern 0318, Oslo, Norway.
| | - Hilde Breck
- Department of Habilitation, Innlandet Hospital Trust, Anders Sandvigs v. 17, 2629 Lillehammer, Norway; Department of Psychology, University of Oslo, P.O. Box 1094, Blindern 0317, Oslo, Norway
| | - Yngve Sejersted
- Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424 Oslo, Norway
| | - Trond Diseth
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, P.O. Box 1171, Blindern 0318, Oslo, Norway
| | - Stephen von Tetzchner
- Department of Psychology, University of Oslo, P.O. Box 1094, Blindern 0317, Oslo, Norway
| | - Benedicte Paus
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, P.O. Box 1171, Blindern 0318, Oslo, Norway; Department of Medical Genetics, Oslo University Hospital, Box 4950, 0424 Oslo, Norway
| | - Ola H Skjeldal
- Gillberg Neuropsychiatry Centre, Sahlgrenska Academy, University of Gothenburg, Kungsgatan 12, 41119 Gothenburg, Sweden
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Wen Y, Wang J, Zhang Q, Chen Y, Wu X, Bao X. MECP2 mutation spectrum and its clinical characteristics in a Chinese cohort. Clin Genet 2020; 98:240-250. [PMID: 32472557 DOI: 10.1111/cge.13790] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 05/24/2020] [Accepted: 05/25/2020] [Indexed: 01/08/2023]
Abstract
The dysfunction of methyl-CpG-binding protein 2 (MeCP2) is associated with several neurological disorders, of which Rett syndrome (RTT) is the most prominent. This study focused on a Chinese patient cohort with MECP2 mutations, and analyzed the characteristics of these mutations and their clinical manifestations. In total, 666 patients were identified with 126 different MECP2 mutations, including 22 novel mutations. Over 80% of patients carried an MECP2 mutation on exon 4. Nonsense and missense mutations were the most commonly reported types. Missense mutations were mainly located on methyl-CpG-binding domain (MBD), and nonsense mutations predominantly occurred on transcription repression domain (TRD) and inter domain. The predilection site of large deletion was exon 3 and/or exon 4. Patients with p.R133C, p.R294*, p.R306C, and C-terminal domain (CTD) deletions were less severely affected. Significant differences were found in ambulation ability, hand function, and language among different mutation groups. Three female patients with MECP2 mutations (1 with p.R306P and 2 with p.R309W) only presented with intellectual disability/developmental delay (ID/DD), and no obvious RTT symptoms were reported. Eight male individuals with MECP2 mutations were also identified in this study, including 2 diagnosed with typical RTT, 3 with atypical RTT and 3 with ID/DD.
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Affiliation(s)
- Yongxin Wen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiaping Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Qingping Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yan Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xinhua Bao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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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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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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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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Alexandrou A, Papaevripidou I, Alexandrou IM, Theodosiou A, Evangelidou P, Kousoulidou L, Tanteles G, Christophidou‐Anastasiadou V, Sismani C. De novo mosaic MECP2 mutation in a female with Rett syndrome. Clin Case Rep 2019; 7:366-370. [PMID: 30847208 PMCID: PMC6389470 DOI: 10.1002/ccr3.1985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 10/30/2018] [Accepted: 12/11/2018] [Indexed: 01/08/2023] Open
Abstract
We describe a female with Rett syndrome carrying a rare de novo mosaic nonsense mutation on MECP2 gene, with random X-chromosome inactivation. Rett syndrome severity in females depends on mosaicism level and tissue specificity, X-chromosome inactivation, epigenetics and environment. Rett syndrome should be considered in both males and females.
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Affiliation(s)
- Angelos Alexandrou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Ioannis Papaevripidou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Ioanna Maria Alexandrou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Athina Theodosiou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Paola Evangelidou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Ludmila Kousoulidou
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - George Tanteles
- Department of Clinical GeneticsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Violetta Christophidou‐Anastasiadou
- Department of Clinical GeneticsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
- Archbishop Makarios III Medical CentreNicosiaCyprus
| | - Carolina Sismani
- Department of Cytogenetics and GenomicsThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
- The Cyprus School of Molecular MedicineNicosiaCyprus
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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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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] [MESH Headings] [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 Wiley Periodicals, Inc.
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Affiliation(s)
- Nicky Halbach
- Netherlands Rett Expertise Center–GKCMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Eric E. Smeets
- Netherlands Rett Expertise Center–GKCMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Peter Julu
- Neurodegeneration and NeuroinflamationImperial College LondonLondonUnited Kingdom
- The National Swedish Rett CenterFrösönSweden
| | | | - Giorgio Pini
- Tuscany Rett CenterVersilia HospitalCamaiore (Lucca)Italy
| | | | - Stig Hansen
- Institute of Neurological SciencesSouthern General Hospital, NHS Greater, Glasgow and ClydeFerraraUnited Kingdom
| | - Flora Apartopoulos
- Institute of Neurological SciencesSouthern General Hospital, NHS Greater, Glasgow and ClydeFerraraUnited Kingdom
| | - Robert Delamont
- Regional Neuroscience CenterKing's College Hospital NHS Foundation Trust and King's College LondonLondonUnited Kingdom
| | - Kees van Roozendaal
- Clinical GenomicsMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Maria F. Scusa
- Tuscany Rett CenterVersilia HospitalCamaiore (Lucca)Italy
| | - Paolo Borelli
- Division of NeurologyVersilia HospitalCamaiore (Lucca)Italy
| | - Math Candel
- Department of Methodology and StatisticsSchool for Public Health and Primary Care CAPHRI, Maastricht UniversityMaastrichtThe Netherlands
| | - Leopold Curfs
- Netherlands Rett Expertise Center–GKCMaastricht University Medical CenterMaastrichtThe Netherlands
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Homozygous c.1160C>T (P38L) in the MECP2 gene in a female Rett syndrome patient. J Clin Neurosci 2016; 25:127-9. [PMID: 26755454 DOI: 10.1016/j.jocn.2015.08.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 08/21/2015] [Accepted: 08/25/2015] [Indexed: 11/22/2022]
Abstract
Rett syndrome is a severe X-linked dominant neurodevelopmental disorder. Mutations in the MECP2 gene on chromosome Xq28 have been shown to be the cause of Rett syndrome. Sequencing of the MECP2 gene in a patient with clinical suspicion of Rett syndrome revealed c.1160C>T (P387L) in exon 4 of the MECP2 gene homozygously. Females with Rett syndrome are usually heterozygous for a mutation in MECP2. Uniparental disomy as a probable cause for the homozygous presence of this mutation was ruled out by quantitative fluorescence-polymerase chain reaction. Moreover to our knowledge this mutation has only been reported in males with X-linked mental retardation (MRX). We hypothesize that the presence of this mutation c.1160C>T (P387L) in the homozygous form is responsible for the Rett syndrome-like phenotype seen in this patient. This novel report reveals for the first time the homozygous presence of a mutation which has hitherto only been reported in males with MRX.
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Rietveld L, Stuss DP, McPhee D, Delaney KR. Genotype-specific effects of Mecp2 loss-of-function on morphology of Layer V pyramidal neurons in heterozygous female Rett syndrome model mice. Front Cell Neurosci 2015; 9:145. [PMID: 25941473 PMCID: PMC4403522 DOI: 10.3389/fncel.2015.00145] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/29/2015] [Indexed: 01/29/2023] Open
Abstract
Rett syndrome (RTT) is a progressive neurological disorder primarily caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). The heterozygous female brain consists of mosaic of neurons containing both wild-type MeCP2 (MeCP2+) and mutant MeCP2 (MeCP2-). Three-dimensional morphological analysis was performed on individually genotyped layer V pyramidal neurons in the primary motor cortex of heterozygous (Mecp2(+/-) ) and wild-type (Mecp2(+/+) ) female mice ( > 6 mo.) from the Mecp2(tm1.1Jae) line. Comparing basal dendrite morphology, soma and nuclear size of MeCP2+ to MeCP2- neurons reveals a significant cell autonomous, genotype specific effect of Mecp2. MeCP2- neurons have 15% less total basal dendritic length, predominantly in the region 70-130 μm from the cell body and on average three fewer branch points, specifically loss in the second and third branch orders. Soma and nuclear areas of neurons of mice were analyzed across a range of ages (5-21 mo.) and X-chromosome inactivation (XCI) ratios (12-56%). On average, MeCP2- somata and nuclei were 15 and 13% smaller than MeCP2+ neurons respectively. In most respects branching morphology of neurons in wild-type brains (MeCP2 WT) was not distinguishable from MeCP2+ but somata and nuclei of MeCP2 WT neurons were larger than those of MeCP2+ neurons. These data reveal cell autonomous effects of Mecp2 mutation on dendritic morphology, but also suggest non-cell autonomous effects with respect to cell size. MeCP2+ and MeCP2- neuron sizes were not correlated with age, but were correlated with XCI ratio. Unexpectedly the MeCP2- neurons were smallest in brains where the XCI ratio was highly skewed toward MeCP2+, i.e., wild-type. This raises the possibility of cell non-autonomous effects that act through mechanisms other than globally secreted factors; perhaps competition for synaptic connections influences cell size and morphology in the genotypically mosaic brain of RTT model mice.
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Affiliation(s)
- Leslie Rietveld
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - David P Stuss
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - David McPhee
- Department of Biology, University of Victoria Victoria, BC, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria Victoria, BC, Canada
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Nissenkorn A, Levy-Drummer RS, Bondi O, Renieri A, Villard L, Mari F, Mencarelli MA, Lo Rizzo C, Meloni I, Pineda M, Armstrong J, Clarke A, Bahi-Buisson N, Mejaski BV, Djuric M, Craiu D, Djukic A, Pini G, Bisgaard AM, Melegh B, Vignoli A, Russo S, Anghelescu C, Veneselli E, Hayek J, Ben-Zeev B. Epilepsy in Rett syndrome--lessons from the Rett networked database. Epilepsia 2015; 56:569-76. [PMID: 25789914 DOI: 10.1111/epi.12941] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Rett syndrome is an X-linked dominant neurodevelopmental disorder caused by mutations in the MECP2 gene, and characterized by cognitive and communicative regression, loss of hand use, and midline hand stereotypies. Epilepsy is a core symptom, but literature is controversial regarding genotype-phenotype correlation. Analysis of data from a large cohort should overcome this shortcoming. METHODS Data from the Rett Syndrome Networked Database on 1,248 female patients were included. Data on phenotypic and genotypic parameters, age of onset, severity of epilepsy, and type of seizures were collected. Statistical analysis was done using the IBM SPSS Version 21 software, logistic regression, and Kaplan-Meier survival curves. RESULTS Epilepsy was present in 68.1% of the patients, with uncontrolled seizures in 32.6% of the patients with epilepsy. Mean age of onset of epilepsy was 4.68 ± (standard deviation) 3.5 years. Younger age of onset was correlated to severity of epilepsy (Spearman correlation r = 0.668, p < 0.01). Patients with late truncating deletions had lower prevalence of epilepsy. Compared to them, the p.R133C mutation, associated with a milder Rett phenotype, increased the risk for epilepsy (odds ratio [OR] 2.46, confidence interval [CI] 95% 1.3-4.66), but not for severe epilepsy. The p.R255X mutation conferred an increased risk for epilepsy (OR 2.07, CI 95% 1.2-3.59) as well as for severe epilepsy (OR 3.4, CI 95% 1.6-7.3). The p.T158M and p.C306C mutations relatively increased the risk for severe epilepsy (OR 3.09 and 2.69, CI 95% 1.48-6.4 and 1.19-6.05, respectively), but not for epilepsy occurrence. SIGNIFICANCE Various mutations in the MECP2 gene have a different influence on epilepsy, unrelated to the severity of the general Rett phenotype. This might suggest a site-specific effect of MeCp2 on epileptic pathways. Further investigation of these mechanisms should promote better understanding of epileptogenesis in Rett syndrome.
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Affiliation(s)
- Andreea Nissenkorn
- Pediatric Neurology Unit and Rett National Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel HaShomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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13
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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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14
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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: 207] [Impact Index Per Article: 20.7] [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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15
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Maortua H, Martínez-Bouzas C, García-Ribes A, Martínez MJ, Guillen E, Domingo MR, Calvo MT, Guitart M, Gabau E, Botella MP, Gener B, Rubio I, López-Aríztegui MA, Tejada MI. MECP2 gene study in a large cohort: testing of 240 female patients and 861 healthy controls (519 females and 342 males). J Mol Diagn 2013; 15:723-9. [PMID: 23810759 DOI: 10.1016/j.jmoldx.2013.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 05/08/2013] [Accepted: 05/15/2013] [Indexed: 11/24/2022] Open
Abstract
The MECP2 gene located on Xq28 is one of the most important genes contributing to the spectrum of neurodevelopmental disorders. Therefore, we present our experience in the molecular study of this gene. MECP2 was thoroughly tested for the presence of mutations (sequencing of four exons and rearrangements) in 120 female patients: 28 with classic Rett syndrome, five with atypical Rett syndrome, and 87 with heterogeneous phenotypes with some Rett-like features. Another 120 female patients with intellectual disability of unknown origin were also studied, but in these cases we only tested exons 3 and 4. Finally, 861 healthy controls (519 females and 342 males) were also studied for exon 3 and 4. Eighteen different pathological mutations were found, five of them previously undescribed, and four large deletions detected by multiplex ligation-dependent probe amplification. All were de novo mutations not present in the parents. In conclusion, i) MECP2 is one of the most important genes in the diagnosis of genetic intellectual disability in females; ii) MECP2 must be studied not only in patients with classical/atypical Rett syndrome but also in patients with other phenotypes related to Rett syndrome; and iii) for the new variants, it is important to perform complementary studies, including the analysis of large populations of healthy individuals and the use of in silico programs.
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Affiliation(s)
- Hiart Maortua
- Molecular Genetics Laboratory, Genetics Service, BioCruces Health Research Institute, Cruces University Hospital, Barakaldo-Bizkaia, Spain
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16
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Larsson G, Julu POO, Witt Engerström I, Sandlund M, Lindström B. Normal reactions to orthostatic stress in Rett syndrome. RESEARCH IN DEVELOPMENTAL DISABILITIES 2013; 34:1897-1905. [PMID: 23584170 DOI: 10.1016/j.ridd.2013.02.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/23/2013] [Accepted: 02/24/2013] [Indexed: 06/02/2023]
Abstract
The aim of this study was to investigate orthostatic reactions in females with Rett syndrome (RTT), and also whether the severity of the syndrome had an impact on autonomic reactions. Based on signs of impaired function of the central autonomic system found in RTT, it could be suspected that orthostatic reactions were affected. The orthostatic reactions in 21 females with RTT and 14 normally developed females matched by age were investigated when they rose from a sitting position, and during standing for 3 min. Reactions of the heart, the blood pressure and the time for recovery of systolic blood pressure, were studied in real time, heartbeat by heartbeat, simultaneously. There was no difference between participants with RTT and the normally developed controls regarding general orthostatic reactions (heart rate, systolic and diastolic blood pressure, and mean arterial pressure) when getting up from a sitting position, and when standing erect for 3 min. In the specific immediate response by the heart to standing up, the 30:15 ratio, significantly lower values were found for females with RTT. In the RTT group, the maximum fall of systolic blood pressure showed a tendency to a larger decrease, and the initial decrease in systolic blood pressure was significantly faster. The time for recovery of systolic blood pressure from standing erect did not differ between groups. At baseline the females with RTT had significantly lower systolic blood pressure and a tendency to a higher heart rate. The results do not indicate any autonomic limitations for people with RTT in getting up from a sitting position and standing. The participants with RTT had normal orthostatic reactions indicated by the heart and blood pressure responses when standing erect for 3min. A faster initial drop in systolic blood pressure in people with RTT was notable.
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Affiliation(s)
- Gunilla Larsson
- Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
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17
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Dolce A, Ben-Zeev B, Naidu S, Kossoff EH. Rett syndrome and epilepsy: an update for child neurologists. Pediatr Neurol 2013; 48:337-45. [PMID: 23583050 DOI: 10.1016/j.pediatrneurol.2012.11.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/12/2012] [Indexed: 01/01/2023]
Abstract
Rett syndrome, a neurogenetic disorder predominantly affecting females, has many characteristic features including psychomotor retardation, impaired language development, hand stereotypies, gait dysfunction, and acquired microcephaly. Although each of these features undoubtedly contributes to the morbidity of this neurologic disorder, epilepsy is perhaps one of the most well-described and problematic, affecting as many as 50%-90% of patients. Seizures can often be refractory, requiring polytherapy and consideration of nonpharmacologic management (e.g., ketogenic diets and vagus nerve stimulation). In addition, many nonepileptic symptoms of Rett syndrome can occasionally be difficult to differentiate from seizures making clinical management and family counseling challenging. Our goal in this review is to better define the clinical and electrophysiological aspects of the epilepsy associated with Rett syndrome and provide practical guidance regarding management.
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Affiliation(s)
- Alison Dolce
- Johns Hopkins Hospital, Baltimore, Maryland, USA.
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18
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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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Khajuria R, Gupta N, Sapra S, Gulati S, Ghosh M, Kalra V, Kabra M. Novel non-identical MECP2 mutations in Rett syndrome family: a rare presentation. Brain Dev 2012; 34:28-31. [PMID: 21300488 DOI: 10.1016/j.braindev.2011.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 12/26/2010] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Rett syndrome (RS), an X-linked neurodevelopmental disorder and the common cause of mental retardation in females, is caused by methyl CpG binding protein 2 (MECP2) gene mutations with a frequency of more than 95% in classical Rett patients. Majority of RS cases are sporadic but few familial cases caused by either skewed X-chromosome inactivation in healthy female carriers or mosaicism in male carriers are also reported. Most of the times, the mutation carried in a family is the same as found in affected child. METHODS AND RESULTS Here we report a unique family carrying non-identical MECP2 mutations in exon 2 wherein the proband with classical RS was carrying a de-novo early truncating frameshift mutation while her asymptomatic mother was carrying a missense mutation, both predicted as pathogenic mutations. CONCLUSIONS These findings further validate the importance of MECP2 mutation screening in parents of all mutation positive patients and careful evaluation of the pathogenicity of the mutation found in asymptomatic carriers before providing genetic counseling to the family. The results also propose the role of other factors including other gene mutations, environmental and epigenetics factors in modifying the expression of MECP2 mutations.
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Affiliation(s)
- Rajni Khajuria
- Genetics Unit, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi 110029, India
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20
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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: 26] [Impact Index Per Article: 2.0] [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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21
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Temudo T, Santos M, Ramos E, Dias K, Vieira JP, Moreira A, Calado E, Carrilho I, Oliveira G, Levy A, Barbot C, Fonseca M, Cabral A, Cabral P, Monteiro J, Borges L, Gomes R, Mira G, Pereira SA, Santos M, Fernandes A, Epplen JT, Sequeiros J, Maciel P. Rett syndrome with and without detected MECP2 mutations: an attempt to redefine phenotypes. Brain Dev 2011; 33:69-76. [PMID: 20116947 DOI: 10.1016/j.braindev.2010.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 01/02/2010] [Accepted: 01/07/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND The diagnosis of Rett syndrome (RTT) is based on a set of clinical criteria, irrespective of mutation status. The aims of this study were (1) to define the clinical differences existing between patients with Rett syndrome with (Group I) and without a MECP2 mutation (Group II), and (2) to characterize the phenotypes associated with the more common MECP2 mutations. PATIENTS AND METHODS We analyzed 87 patients fulfilling the clinical criteria for RTT. All were observed and videotaped by the same paediatric neurologist. Seven common mutations were considered separately, and associated clinical features analysed. RESULTS Comparing Group I and II, we found differences concerning psychomotor development prior to onset, acquisition of propositive manipulation and language, and evolving autistic traits. Based on age at observation, we found differences in eye pointing, microcephaly, growth, number of stereotypies, rigidity, ataxia and ataxic-rigid gait, and severity score. Patients with truncating differed from those with missense mutations regarding acquisition of propositive words and independent gait, before the beginning of the disease, and microcephaly, growth, foot length, dystonia, rigidity and severity score, at the time of observation. Patients with the R168X mutation had a more severe phenotype, whereas those with R133C showed a less severe one. Patients with R294X had a hyperactive behaviour, and those with T158M seemed to be particularly ataxic and rigid. CONCLUSION A clear regressive period (with loss of prehension and language, deceleration of growth) and the presence of more than three different stereotypies, rigidity and ataxic-rigid gait seemed to be very helpful in differentiating Group I from Group II.
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Affiliation(s)
- Teresa Temudo
- Unidade de Neuropediatria, Serviço de Pediatria, Hospital Geral de Santo António, Porto, Portugal.
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22
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Fehr S, Downs J, Bebbington A, Leonard H. Atypical presentations and specific genotypes are associated with a delay in diagnosis in females with Rett syndrome. Am J Med Genet A 2010; 152A:2535-42. [PMID: 20815036 DOI: 10.1002/ajmg.a.33640] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
There is often delay between onset of Rett syndrome symptoms and its diagnosis, possibly related to symptom presentation or socio-demographic factors. We hypothesized that girls with an atypical presentation or whose family had a lower socio-economic status would receive a later diagnosis. Female subjects with a confirmed diagnosis of Rett syndrome were sourced from the Australian Rett Syndrome and InterRett Databases. Variables analyzed included timing and development of symptoms; MECP2 mutation type; parental occupation and education; maternal age and birth order. Residential location and socio-economic status were also analyzed for the Australian cases. Linear regression was used to determine relationships between these factors and age at diagnosis. A total of 909 cases were included. An older age of diagnosis was associated with later loss of hand function and speech, later onset of hand stereotypies and the presence of the p.R133C or p.R294X MECP2 mutation. Socio-economic factors did not predict age of diagnosis for Australian families. For families participating in the InterRett database, a younger age of diagnosis was associated with higher levels of parental education or occupation. A clinical picture consistent with the classic presentation of Rett syndrome is associated with an earlier diagnosis. Clinicians need to be alerted to the variable presentation of Rett syndrome including the milder phenotypes of cases with the p.R133C or p.R294X mutation. Educational resources to assist this understanding including guidance on when to request genetic testing could be useful to streamline the process of diagnosis in Rett syndrome.
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Affiliation(s)
- Stephanie Fehr
- The Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia
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23
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King BH, Lord C. Is schizophrenia on the autism spectrum? Brain Res 2010; 1380:34-41. [PMID: 21078305 DOI: 10.1016/j.brainres.2010.11.031] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/31/2010] [Accepted: 11/07/2010] [Indexed: 12/31/2022]
Abstract
With the ongoing consideration of the diagnostic criteria for mental disorders that is active in the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) and International Classification of Diseases (ICD-11) revision processes, it is timely to review the phenomenological overlap between autism and schizophrenia. These disorders have at various times been regarded alternatively as closely related and as non-overlapping and incompatible. Nevertheless, there are several reports in the literature that have described individuals with both autism and schizophrenia, and the broader phenotypes of these disorders clearly intersect. Recent studies reveal theory of mind deficits in both disorders, and mirror neuron impairments also appear to be shared. There also may be similar connectivity deficits emerging in functional imaging studies, and both disorders share several genetic signals that are being identified through detection of copy number variants. Taken together, these data suggest that it may be time to revisit the possibility that these disorders are related.
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Affiliation(s)
- Bryan H King
- University of Washington and Seattle Children's Autism Center, Seattle, WA 98105, USA.
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Marco EJ, Skuse DH. Autism-lessons from the X chromosome. Soc Cogn Affect Neurosci 2010; 1:183-93. [PMID: 18985105 DOI: 10.1093/scan/nsl028] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 09/18/2006] [Indexed: 02/06/2023] Open
Abstract
Recognized cases of autism spectrum disorders are on the rise. It is unclear whether this increase is attributable to secular trends in biological susceptibility, or to a change in diagnostic practices and recognition. One hint concerning etiological influences is the universally reported male excess (in the range of 4:1 to 10:1). Evidence suggests that genetic influences from the X chromosome play a crucial role in engendering this male vulnerability. In this review, we discuss three categories of genetic disease that highlight the importance of X-linked genes in the manifestation of an autistic phenotype: aneuploides (Turner syndrome and Klinefelter syndrome), trinucleotide expansions (Fragile X syndrome) and nucleotide mutations (Rett Syndrome, Neuroligins 3 & 4, and SLC6A8). The lessons from these diseases include an understanding of autistic features as a broad phenotype rather than as a single clinical entity, the role of multiple genes either alone or in concert with the manifestation of autistic features, and the role of epigenetic factors such as imprinting and X-inactivation in the expression of disease severity. Better understanding of the clinical phenotypes of social cognition and the molecular neurogenetics of X-linked gene disorders will certainly provide additional tools for understanding autism in the years to come.
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Affiliation(s)
- Elysa J Marco
- Behavioral and Brain Sciences Unit, Institute of Child Health, London, UK
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MacDonald JL, Roskams AJ. Epigenetic regulation of nervous system development by DNA methylation and histone deacetylation. Prog Neurobiol 2009; 88:170-83. [PMID: 19554713 DOI: 10.1016/j.pneurobio.2009.04.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alterations in the epigenetic modulation of gene expression have been implicated in several developmental disorders, cancer, and recently, in a variety of mental retardation and complex psychiatric disorders. A great deal of effort is now being focused on why the nervous system may be susceptible to shifts in activity of epigenetic modifiers. The answer may simply be that the mammalian nervous system must first produce the most complex degree of developmental patterning in biology and hardwire cells functionally in place postnatally, while still allowing for significant plasticity in order for the brain to respond to a rapidly changing environment. DNA methylation and histone deacetylation are two major epigenetic modifications that contribute to the stability of gene expression states. Perturbing DNA methylation, or disrupting the downstream response to DNA methylation - methyl-CpG-binding domain proteins (MBDs) and histone deacetylases (HDACs) - by genetic or pharmacological means, has revealed a critical requirement for epigenetic regulation in brain development, learning, and mature nervous system stability, and has identified the first distinct gene sets that are epigenetically regulated within the nervous system. Epigenetically modifying chromatin structure in response to different stimuli appears to be an ideal mechanism to generate continuous cellular diversity and coordinate shifts in gene expression at successive stages of brain development - all the way from deciding which kind of a neuron to generate, through to how many synapses a neuron can support. Here, we review the evidence supporting a role for DNA methylation and histone deacetylation in nervous system development and mature function, and present a basis from which to understand how the clinical use of HDAC inhibitors may impact nervous system function.
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Affiliation(s)
- Jessica L MacDonald
- Life Sciences Institute, Department of Zoology, University of British Columbia, BC, V6T 1Z3, Vancouver, Canada
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Jülich K, Horn D, Burfeind P, Erler T, Auber B. A novel MECP2 mutation in a boy with neonatal encephalopathy and facial dysmorphism. J Pediatr 2009; 155:140-3. [PMID: 19559301 DOI: 10.1016/j.jpeds.2009.01.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 12/19/2008] [Accepted: 01/09/2009] [Indexed: 11/26/2022]
Abstract
Methly-CpG-binding protein 2 (MECP2) mutations cause Rett syndrome in females. Here we report on a male infant with neonatal encephalopathy, myoclonic jerks, and irregular breathing patterns caused by a novel frameshift mutation in the MECP2 gene. In addition he has facial dysmorphisms previously not described in these patients.
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Affiliation(s)
- Kristina Jülich
- Department of Pediatric Neurology, Charité-University Medical Center, Berlin, Germany.
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Louise S, Fyfe S, Bebbington A, Bahi-Buisson N, Anderson A, Pineda M, Percy A, Ben Zeev B, Wu XR, Bao X, Mac Leod P, Armstrong J, Leonard H. InterRett, a model for international data collection in a rare genetic disorder. RESEARCH IN AUTISM SPECTRUM DISORDERS 2009; 3:10.1016/j.rasd.2008.12.004. [PMID: 24348750 PMCID: PMC3858578 DOI: 10.1016/j.rasd.2008.12.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Rett syndrome (RTT) is a rare genetic disorder within the autistic spectrum. This study compared socio-demographic, clinical and genetic characteristics of the international database, InterRett, and the population based Australian Rett syndrome database (ARSD). It also explored the strengths and limitations of InterRett in comparison with other studies. A literature review compared InterRett with RTT population-based and case-based studies of thirty or more cases that investigated genotype and/or phenotype relationships. Questionnaire data were used to determine case status and to investigate the comparability of InterRett and ARSD. Twenty four case series, five population based studies and a MECP2 mutation database were identified of which twenty one (70%) collected phenotype and genotype data. Only three studies were representative of their underlying case population and many had low numbers. Of one thousand one hundred and fourteen InterRett subjects, nine hundred and thirty five born after 1976 could be verified as Rett cases and compared with the two hundred and ninety five ARSD subjects. Although more InterRett families had higher education and occupation levels and their children were marginally less severe, the distribution of MECP2 mutation types was similar. The InterRett can be used with confidence to investigate genotype phenotype associations and clinical variation in RTT and provides an exemplary international model for other rare disorders.
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Affiliation(s)
- Sandra Louise
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
| | - Sue Fyfe
- Curtin University, Perth, Western Australia
| | - Ami Bebbington
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
| | - Nadia Bahi-Buisson
- Université René Descartes - Paris V, Hopital Necker Enfants Malades, Paris, France
| | - Alison Anderson
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
| | | | - Alan Percy
- Civitan International Research Centre, University of Alabama, Birmingham, Alabama, USA
| | - Bruria Ben Zeev
- Safra Pediatric Hospital, Sheba Medical Center, Ramat-Gan, Israel
| | - Xi Ru Wu
- Peking University First Hospital, Beijing, China
| | - Xinhua Bao
- Peking University First Hospital, Beijing, China
| | | | | | - Helen Leonard
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
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Renieri A, Mari F, Mencarelli MA, Scala E, Ariani F, Longo I, Meloni I, Cevenini G, Pini G, Hayek G, Zappella M. Diagnostic criteria for the Zappella variant of Rett syndrome (the preserved speech variant). Brain Dev 2009; 31:208-16. [PMID: 18562141 DOI: 10.1016/j.braindev.2008.04.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 04/18/2008] [Accepted: 04/22/2008] [Indexed: 11/16/2022]
Abstract
The preserved speech variant is the milder form of Rett syndrome: affected girls show the same stages of this condition and by the second half of the first decade are making slow progress in manual and verbal abilities. They walk without help, and may be able to make simple drawings and write a few words. Most of them can speak in sentences. Autistic behavior can often be observed. We previously described several cases in the pre-molecular era and subsequently reported a survey of 12 cases with MECP2 mutations. Seventeen new patients with the preserved speech variant and a proven MECP2 mutation have been clinically evaluated. Additional clinical data of our previously described cases are reported. These 29 preserved speech variant cases were compared with 129 classic Rett patients using a clinical severity score system including 22 different signs. There was both statistical and clinical evidence of the existence of this variant. On the basis of their abilities these girls can be distinguished as low-, intermediate- and high-functioning. Girls of the last two groups show a greater homogeneity: they speak in sentences, use their hands more easily, have normal somatic features, mild neurovegetative abnormalities, with autistic behavior in 76%, epilepsy in 30%, while girls of the first group are closer to classic Rett syndrome. The majority of patients carries either missense mutations (especially the p.R133C change) or late truncating mutations in the MECP2 gene. These results confirm the existence of this variant of Rett syndrome (Zappella variant), a clear example of progress of manual and verbal abilities, and not of a "preserved speech" and suggest corresponding diagnostic criteria.
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Affiliation(s)
- A Renieri
- Medical Genetics, Molecular Biology Department, University of Siena, Viale Bracci, 2, Siena 53100, Italy.
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29
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A novel hypomorphic MECP2 point mutation is associated with a neuropsychiatric phenotype. Hum Genet 2008; 124:615-23. [PMID: 18989701 DOI: 10.1007/s00439-008-0585-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 10/28/2008] [Indexed: 10/21/2022]
Abstract
The MECP2 gene on Xq28 encodes a transcriptional repressor, which binds to and modulates expression of active genes. Mutations in MECP2 cause classic or preserved speech variant Rett syndrome and intellectual disability in females and early demise or marked neurodevelopmental handicap in males. The consequences of a hypomorphic Mecp2 allele were recently investigated in a mouse model, which developed obesity, motor, social, learning, and behavioral deficits, predicting a human neurobehavioral syndrome. Here, we describe mutation analysis of a nondysmorphic female proband and her father who presented with primarily neuropsychiatric manifestations and obesity with relative sparing of intelligence, language, growth, and gross motor skills. We identified and characterized a novel missense mutation (c.454C>G; p.P152A) in the critical methyl-binding domain of MeCP2 that disrupts MeCP2 functional activity. We show that a gradient of impairment is present when the p.P152A mutation is compared with an allelic p.P152R mutation, which causes classic Rett syndrome and another Rett syndrome-causing mutation, such that protein-heterochromatin binding observed by immunofluorescence and immunoblotting is wild-type > P152A > P152R > T158 M, consistent with the severity of the observed phenotype. Our findings provide evidence for very mild phenotypes in humans associated with partial reduction of MeCP2 function arising from subtle variation in MECP2.
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DOWNS JA, BEBBINGTON A, JACOBY P, MSALL M, MCILROY O, FYFE S, BAHI-BUISSON N, KAUFMANN WE, LEONARD H. Gross motor profile in rett syndrome as determined by video analysis. Neuropediatrics 2008; 39:205-10. [PMID: 19165708 PMCID: PMC4122214 DOI: 10.1055/s-0028-1104575] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Movement impairment is a fundamental but variable component of the Rett syndrome phenotype. This study used video supplemented by parent report data to describe the gross motor profile in females with Rett syndrome (n=99) and to investigate the impact of age, genotype, scoliosis and hand stereotypies. Factor analysis enabled the calculation of general and complex gross motor skills scores. Most subjects were able to sit, slightly less than half were able to walk and a minority were able to transfer without assistance. General gross motor skills declined with age and were poorer in those who had surgically treated scoliosis but not conservatively managed scoliosis. Complex gross motor skills did not decline with age and were better in those without scoliosis. Those with a p.R133C, p.R294X, or a p.R255X mutation appear to have better motor skills overall than those with a p.R270X or large deletion mutation. Motor scores were not related to the frequency of hand stereotypies. This information is useful for the clinician and family when planning support strategies and interventions.
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Affiliation(s)
- Jennepher Anne DOWNS
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia
| | - Ami BEBBINGTON
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia
| | - Peter JACOBY
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia
| | - Michael MSALL
- University of Chicago Comer and LaRabida Children’s Hospitals, Kennedy Center, Institute of Molecular Pediatric Sciences & Section of Developmental and Behavioral Pediatrics, 5841 S. Maryland Ave., MC0900, Chicago, Illinois 60637
| | - Orla MCILROY
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia
| | - Sue FYFE
- School of Public Health, Curtin University of Technology, Perth, Western Australia
| | - Nadia BAHI-BUISSON
- Pediatric Neurology, Necker Enfants Malades Hospital Paris, F-75015 France - University Paris V Rene Descartes Paris F-75005 France, Inserm, U663, Paris, F-75015 France; University Rene Descartes, Paris V, F-75005
| | - Walter E. KAUFMANN
- Center for Genetic Disorders of Cognition & Behavior, Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Helen LEONARD
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia
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Halbach NS, Smeets EE, Schrander-Stumpel CT, van Schrojenstein Lantman de Valk HH, Maaskant MA, Curfs LM. Aging in people with specific genetic syndromes: Rett syndrome. Am J Med Genet A 2008; 146A:1925-32. [DOI: 10.1002/ajmg.a.32361] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Young DJ, Bebbington A, Anderson A, Ravine D, Ellaway C, Kulkarni A, de Klerk N, Kaufmann WE, Leonard H. The diagnosis of autism in a female: could it be Rett syndrome? Eur J Pediatr 2008; 167:661-9. [PMID: 17684768 DOI: 10.1007/s00431-007-0569-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 07/02/2007] [Indexed: 10/23/2022]
Abstract
The overlap between autism and Rett syndrome clinical features has led to many cases of Rett syndrome being initially diagnosed with infantile autism or as having some autistic features. Both conditions seriously disrupt social and language development and are often accompanied by repetitive, nonpurposeful stereotypic hand movements. The aims of this study were to compare the early and subsequent clinical courses of female subjects with Rett syndrome categorised by whether or not a diagnosis of autism had been proposed before Rett syndrome had been diagnosed and compare the spectrum of methyl-CpG binding protein 2 (MECP2) mutations identified among the two groups. This study made use of a total of 313 cases recorded in two databases: the Australian Rett Syndrome Database (ARSD) and the International Rett Syndrome Phenotype Database (InterRett). Cases with an initial diagnosis of autism had significantly milder Rett syndrome symptoms and were more likely to remain ambulant, to have some functional hand use and not to have developed a scoliosis. Females with the p.R306C or p.T158M mutations in the MECP2 gene were more likely to have an initial diagnosis of autism, and the specific Rett syndrome symptoms were noted at a later age. We recommend that females who are initially considered to have autism be carefully monitored for the evolution of the signs and symptoms of Rett syndrome.
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Affiliation(s)
- Deidra J Young
- Centre for Child Health Research, Telethon Institute for Child Health Research, University of Western Australia, Perth, WA, Australia.
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33
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Scala E, Longo I, Ottimo F, Speciale C, Sampieri K, Katzaki E, Artuso R, Mencarelli MA, D'Ambrogio T, Vonella G, Zappella M, Hayek G, Battaglia A, Mari F, Renieri A, Ariani F. MECP2 deletions and genotype-phenotype correlation in Rett syndrome. Am J Med Genet A 2008; 143A:2775-84. [PMID: 17968969 DOI: 10.1002/ajmg.a.32002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rett syndrome is a neurodevelopmental disorder that represents one of the most common genetic causes of mental retardation in girls. MECP2 point mutations in exons 2-4 account for about 80% of classic Rett cases and for a lower percentage of variant patients. We investigated the genetic cause in 77 mutation-negative Rett patients (33 classic, 31 variant, and 13 Rett-like cases) by searching missed MECP2 defects. DHPLC analysis of exon 1 and MLPA analysis allowed us to identify the defect in 17 Rett patients: one exon 1 point mutation (c.47_57del) in a classic case and 16 MECP2 large deletions (15/33 classic and 1/31 variant cases). One identical intragenic MECP2 deletion, probably due to gonadal mosaicism, was found in two sisters with discordant phenotype: one classic and one "highly functioning" preserved speech variant. This result indicates that other epigenetic or genetic factors, beside MECP2, may contribute to phenotype modulation. Three out of 16 MECP2 deletions extend to the adjacent centromeric IRAK1 gene. A putative involvement of the hemizygosity of this gene in the ossification process is discussed. Finally, results reported here clearly indicate that MECP2 large deletions are a common cause of classic Rett, and MLPA analysis is mandatory in MECP2-negative patients, especially in those more severely affected (P = 0.044).
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Affiliation(s)
- Elisa Scala
- Medical Genetics, Molecular Biology Department, University of Siena, Siena, Italy
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Voutoufianakis S, Psoni S, Vorgia P, Tsekoura F, Kekou K, Traeger-Synodinos J, Kitsiou S, Kanavakis E, Fryssira H. Coinheritance of mutated SMN1 and MECP2 genes in a child with phenotypic features of spinal muscular atrophy (SMA) type II and Rett syndrome. Eur J Paediatr Neurol 2007; 11:235-9. [PMID: 17276711 DOI: 10.1016/j.ejpn.2006.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 12/05/2006] [Accepted: 12/11/2006] [Indexed: 11/22/2022]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular autosomal recessive disease characterized by progressive muscle weakness and atrophy combined with motor neuron degeneration caused by mutations in the SMN 1 gene locus (5q11.2-13.2). Rett syndrome (RS) is an X-linked dominant neurodevelopmental disorder caused by mutations in MECP2 (Xq28) and characterized by normal development until 6-12 months of age, followed by regression with loss of acquired skills, gradual onset of microcephaly, stereotypic hand movements and psychomotor delay. We report a 6-year-old girl who, at 2 years of age, presented with hypotonia, psychomotor delay, amyotrophy and areflexia of the lower extremities. Molecular DNA analysis (PCR-RFLP's) for SMA type II revealed that both exons 7 and 8 of SMN 1 gene were deleted. Over the past 4 years, onset of stereotypic hand-washing movements, epileptic seizures, microcephaly, hyperventilation/breath-holding attacks and severe psychomotor delay raised the suspicion of the coexistence of RS. DNA analysis (DGGE and sequencing) identified the hotspot missense mutation R306C (c.916C>T) in exon 4 of the MECP2 gene. The coinheritance of SMA and RS, two rare monogenic syndromes in the same patient, has not been previously reported. Thorough clinical evaluation in combination with DNA analysis, allowed accurate diagnosis, providing valuable information for the genetic counseling of the family.
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Affiliation(s)
- S Voutoufianakis
- Pediatric Department of Venizelion General Hospital Iraklion, Crete, Greece
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Abstract
Rett syndrome (RS) is an X-linked neurodevelopmental disorder and the second most common cause of genetic mental retardation in females. Different mutations in MECP2 are found in up to 95% of typical cases of RS. This mainly neuronal expressed gene functions as a major transcription repressor. Extensive studies on girls who have RS and mouse models are aimed at finding main gene targets for MeCP2 protein and defining neuropathologic changes caused by its defects. Studies comparing autistic features in RS with idiopathic autism and mentally retarded patients are presented. Decreased dendritic arborization is common to RS and autism, leading to further research on similarities in pathogenesis, including MeCP2 protein levels in autistic brains and MeCP2 effects on genes connected to autism, like DLX5 and genes on 15q11-13 region. This area also is involved in Angelman syndrome, which has many similarities to RS. Despite these connections, MECP2 mutations in nonspecific autistic and mentally retarded populations are rare.
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Affiliation(s)
- Bruria Ben Zeev Ghidoni
- Pediatric Neurology Unit, Safra Pediatric Hospital, Sheba Medical Center, Ramat-Gan, Israel.
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Sampieri K, Meloni I, Scala E, Ariani F, Caselli R, Pescucci C, Longo I, Artuso R, Bruttini M, Mencarelli MA, Speciale C, Causarano V, Hayek G, Zappella M, Renieri A, Mari F. Italian Rett database and biobank. Hum Mutat 2007; 28:329-35. [PMID: 17186495 DOI: 10.1002/humu.20453] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rett syndrome is the second most common cause of severe mental retardation in females, with an incidence of approximately 1 out of 10,000 live female births. In addition to the classic form, a number of Rett variants have been described. MECP2 gene mutations are responsible for about 90% of classic cases and for a lower percentage of variant cases. Recently, CDKL5 mutations have been identified in the early onset seizures variant and other atypical Rett patients. While the high percentage of MECP2 mutations in classic patients supports the hypothesis of a single disease gene, the low frequency of mutated variant cases suggests genetic heterogeneity. Since 1998, we have performed clinical evaluation and molecular analysis of a large number of Italian Rett patients. The Italian Rett Syndrome (RTT) database has been developed to share data and samples of our RTT collection with the scientific community (http://www.biobank.unisi.it). This is the first RTT database that has been connected with a biobank. It allows the user to immediately visualize the list of available RTT samples and, using the "Search by" tool, to rapidly select those with specific clinical and molecular features. By contacting bank curators, users can request the samples of interest for their studies. This database encourages collaboration projects with clinicians and researchers from around the world and provides important resources that will help to better define the pathogenic mechanisms underlying Rett syndrome.
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Affiliation(s)
- Katia Sampieri
- Medical Genetics Unit, Department of Molecular Biology, University of Siena, Siena, Italy
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Fyfe S, Downs J, McIlroy O, Burford B, Lister J, Reilly S, Laurvick CL, Philippe C, Msall M, Kaufmann WE, Ellaway C, Leonard H. Development of a Video-based Evaluation Tool in Rett Syndrome. J Autism Dev Disord 2006; 37:1636-46. [PMID: 17180458 DOI: 10.1007/s10803-006-0293-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 09/20/2006] [Indexed: 11/30/2022]
Abstract
This paper describes the development of a video-based evaluation tool for use in Rett syndrome (RTT). Components include a parent-report checklist, and video filming and coding protocols that contain items on eating, drinking, communication, hand function and movements, personal care and mobility. Ninety-seven of the 169 families who initially agreed to participate returned a videotape within 8 months of the first request. Subjects whose videos were returned had a similar age profile to those who did not provide a video but were more likely to have classical than atypical RTT. Evidence of the content and social validity and inter-rater reliability on 11 videos is provided. Video may provide detailed, objective assessment of function and behaviour in RTT.
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Affiliation(s)
- S Fyfe
- Curtin University of Technology, Perth, WA, Australia
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38
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Jian L, Nagarajan L, de Klerk N, Ravine D, Bower C, Anderson A, Williamson S, Christodoulou J, Leonard H. Predictors of seizure onset in Rett syndrome. J Pediatr 2006; 149:542-7. [PMID: 17011329 DOI: 10.1016/j.jpeds.2006.06.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 04/26/2006] [Accepted: 06/09/2006] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To investigate risk factors for seizure onset in Rett syndrome. STUDY DESIGN Information on presence and age at onset of seizures, perinatal and developmental history, and genetic status was abstracted on 275 cases in the Australian Rett Syndrome Database. Cox and Weibull regression were used to investigate and provide a model for predicting the effects of genetic and developmental factors on age at seizure onset. RESULTS Seizures were reported in 81% of 275 cases; the median age of onset was 48 months. Not having gained the ability to walk (P = .003) and developmental problems in the first 10 months of age (P = .04) were associated with an almost 2-fold increased risk of seizures. Cases without a detectable MECP2 mutation had a higher risk of seizure onset up to 4 years of age (P < .001) but a lower risk after 4 years (P = .08). CONCLUSIONS Seizure onset in Rett syndrome is associated with early developmental factors and with genotype. Information on these factors can be used to predict age at seizure onset after diagnosis.
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Affiliation(s)
- Le Jian
- Centre for Child Health Research, The University of Western Australia, Telethon Institute for Child Health Research, Perth, Western Australia, Australia
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39
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Archer H, Evans J, Leonard H, Colvin L, Ravine D, Christodoulou J, Williamson S, Charman T, Bailey MES, Sampson J, de Klerk N, Clarke A. Correlation between clinical severity in patients with Rett syndrome with a p.R168X or p.T158M MECP2 mutation, and the direction and degree of skewing of X-chromosome inactivation. J Med Genet 2006; 44:148-52. [PMID: 16905679 PMCID: PMC2598067 DOI: 10.1136/jmg.2006.045260] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder that is usually associated with mutations in the MECP2 gene. The most common mutations in the gene are p.R168X and p.T158M. The influence of X-chromosome inactivation (XCI) on clinical severity in patients with RTT with these mutations was investigated, taking into account the extent and direction of skewing. METHODS Female patients and their parents were recruited from the UK and Australia. Clinical severity was measured by the Pineda Severity and Kerr profile scores. The degree of XCI and its direction relative to the X chromosome parent of origin were measured in DNA prepared from peripheral blood leucocytes, and allele-specific polymerase chain reaction was used to determine the parental origin of mutation. Combining these, the percentage of cells expected to express the mutant allele was calculated. RESULTS Linear regression analysis was undertaken for fully informative cases with p.R168X (n = 23) and p.T158M (n = 20) mutations. A statistically significant increase in clinical severity with increase in the proportion of active mutated allele was shown for both the p.R168X and p.T158M mutations. CONCLUSIONS XCI may vary in neurological and haematological tissues. However, these data are the first to show a relationship between the degree and direction of XCI in leucocytes and clinical severity in RTT, although the clinical utility of this in giving a prognosis for individual patients is unclear.
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Affiliation(s)
- Hayley Archer
- Institute of Medical Genetics, Cardiff University, University Hospital of Wales, Cardiff, UK
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40
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Knudsen GPS, Neilson TCS, Pedersen J, Kerr A, Schwartz M, Hulten M, Bailey MES, Orstavik KH. Increased skewing of X chromosome inactivation in Rett syndrome patients and their mothers. Eur J Hum Genet 2006; 14:1189-94. [PMID: 16823396 DOI: 10.1038/sj.ejhg.5201682] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Rett syndrome is a largely sporadic, X-linked neurological disorder with a characteristic phenotype, but which exhibits substantial phenotypic variability. This variability has been partly attributed to an effect of X chromosome inactivation (XCI). There have been conflicting reports regarding incidence of skewed X inactivation in Rett syndrome. In rare familial cases of Rett syndrome, favourably skewed X inactivation has been found in phenotypically normal carrier mothers. We have investigated the X inactivation pattern in DNA from blood and buccal cells of sporadic Rett patients (n=96) and their mothers (n=84). The mean degree of skewing in blood was higher in patients (70.7%) than controls (64.9%). Unexpectedly, the mothers of these patients also had a higher mean degree of skewing in blood (70.8%) than controls. In accordance with these findings, the frequency of skewed (XCI > or =80%) X inactivation in blood was also higher in both patients (25%) and mothers (30%) than in controls (11%). To test whether the Rett patients with skewed X inactivation were daughters of skewed mothers, 49 mother-daughter pairs were analysed. Of 14 patients with skewed X inactivation, only three had a mother with skewed X inactivation. Among patients, mildly affected cases were shown to be more skewed than more severely affected cases, and there was a trend towards preferential inactivation of the paternally inherited X chromosome in skewed cases. These findings, particularly the greater degree of X inactivation skewing in Rett syndrome patients, are of potential significance in the analysis of genotype-phenotype correlations in Rett syndrome.
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Affiliation(s)
- Gun Peggy S Knudsen
- Faculty Division Rikshospitalet, Department of Medical Genetics, University of Oslo, Oslo, Norway.
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Bienvenu T, Chelly J. Molecular genetics of Rett syndrome: when DNA methylation goes unrecognized. Nat Rev Genet 2006; 7:415-26. [PMID: 16708070 DOI: 10.1038/nrg1878] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The discovery that Rett syndrome is caused by mutations that affect the methyl-CpG-binding protein MeCP2 provided a major breakthrough in understanding this severe neurodevelopmental disorder. Animal models and expression studies have contributed to defining the role of MeCP2 in development, highlighting its contribution to postnatal neuronal morphogenesis and function. Furthermore, in vitro assays and microrray studies have delineated the potential molecular mechanisms of MeCP2 function, and have indicated a role in the transcriptional silencing of specific target genes. As well as unravelling the mechanisms that underlie Rett syndrome, these studies provide more general insights into how DNA-methylation patterns are recognized and translated into biological outcomes.
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Affiliation(s)
- Thierry Bienvenu
- Institut Cochin, Départment de Génétique et Developpement, Paris, F-75014 France
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Archer HL, Evans JC, Millar DS, Thompson PW, Kerr AM, Leonard H, Christodoulou J, Ravine D, Lazarou L, Grove L, Verity C, Whatley SD, Pilz DT, Sampson JR, Clarke AJ. NTNG1 mutations are a rare cause of Rett syndrome. Am J Med Genet A 2006; 140:691-4. [PMID: 16502428 PMCID: PMC2577736 DOI: 10.1002/ajmg.a.31133] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A translocation that disrupted the netrin G1 gene (NTNG1) was recently reported in a patient with the early seizure variant of Rett syndrome (RTT). The netrin G1 protein (NTNG1) has an important role in the developing central nervous system, particularly in axonal guidance, signalling and NMDA receptor function and was a good candidate gene for RTT. We recruited 115 patients with RTT (females: 25 classic and 84 atypical; 6 males) but no mutation in the MECP2 gene. For those 52 patients with epileptic seizure onset in the first 6 months of life, CDKL5 mutations were also excluded. We aimed to determine whether mutations in NTNG1 accounted for a significant subset of patients with RTT, particularly those with the early onset seizure variant and other atypical presentations. We sequenced the nine coding exons of NTNG1 and identified four sequence variants, none of which were likely to be pathogenic. Mutations in the NTNG1 gene appear to be a rare cause of RTT but NTNG1 function demands further investigation in relation to the central nervous system pathophysiology of the disorder.
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Affiliation(s)
- Hayley L Archer
- Institute of Medical Genetics, Cardiff University, University Hospital of Wales, Cardiff, United Kingdom.
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