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McKnight D, Bean L, Karbassi I, Beattie K, Bienvenu T, Bonin H, Fang P, Chrisodoulou J, Friez M, Helgeson M, Krishnaraj R, Meng L, Mighion L, Neul J, Percy A, Ramsden S, Zoghbi H, Das S. Recommendations by the ClinGen Rett/Angelman-like expert panel for gene-specific variant interpretation methods. Hum Mutat 2022; 43:1097-1113. [PMID: 34837432 PMCID: PMC9135956 DOI: 10.1002/humu.24302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/05/2021] [Accepted: 11/21/2021] [Indexed: 11/11/2022]
Abstract
The genes MECP2, CDKL5, FOXG1, UBE3A, SLC9A6, and TCF4 present unique challenges for current ACMG/AMP variant interpretation guidelines. To address those challenges, the Rett and Angelman-like Disorders Variant Curation Expert Panel (Rett/AS VCEP) drafted gene-specific modifications. A pilot study was conducted to test the clarity and accuracy of using the customized variant interpretation criteria. Multiple curators obtained the same interpretation for 78 out of the 87 variants (~90%), indicating appropriate usage of the modified guidelines the majority of times by all the curators. The classification of 13 variants changed using these criteria specifications compared to when the variants were originally curated and as present in ClinVar. Many of these changes were due to internal data shared from laboratory members however some changes were because of changes in strength of criteria. There were no two-step classification changes and only 1 clinically relevant change (Likely pathogenic to VUS). The Rett/AS VCEP hopes that these gene-specific variant curation rules and the assertions provided help clinicians, clinical laboratories, and others interpret variants in these genes but also other fully penetrant, early-onset genes associated with rare disorders.
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Affiliation(s)
| | | | | | | | | | | | | | - John Chrisodoulou
- Murdoch Childrens Research Institute and the University of Melbourne,University of Sydney
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2
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HDAC inhibitor ameliorates behavioral deficits in Mecp2 308/y mouse model of Rett syndrome. Brain Res 2021; 1772:147670. [PMID: 34582789 DOI: 10.1016/j.brainres.2021.147670] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/23/2023]
Abstract
Rett syndrome (RTT) is a rare X-linked neurodevelopmental disorder. More than 95% of classic RETT syndrome cases result from pathogenic variants in the methyl-CpG binding protein 2 (MECP2) gene. Nevertheless, it has been established that a spectrum of neuropsychiatric phenotypes is associated with MECP2 variants in both females and males. We previously reported that microtubule growth velocity and vesicle transport directionality are altered in Mecp2-deficient astrocytes from newborn Mecp2-deficient mice compared to that of their wild-type littermates suggesting deficit in microtubule dynamics. In this study, we report that administration of tubastatin A, a selective HDAC6 inhibitor, restored microtubule dynamics in Mecp2-deficient astrocytes. We furthermore report that daily doses of tubastatin A reversed early impaired exploratory behavior in male Mecp2308/y mice. These findings are a first step toward the validation of a novel treatment for RTT.
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3
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MECP2-related conditions in males: A systematic literature review and 8 additional cases. Eur J Paediatr Neurol 2021; 34:7-13. [PMID: 34271245 DOI: 10.1016/j.ejpn.2021.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/25/2021] [Accepted: 05/25/2021] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To present a cohort of 8 males and perform a systematic review of all published cases with a single copy of MECP2 carrying a pathogenic variant. METHODS We reviewed medical records of males with a single copy of MECP2 carrying a pathogenic variant. We searched in Medline (Pubmed) and Embase to collect all articles which included well-characterized males with a single copy of MECP2 carrying a pathogenic or likely pathogenic variant in MECP2 (1999-2020). RESULTS The literature search yielded a total of 3,185 publications, of which 58 were included in our systematic review. We were able to collect information on 27 published patients with severe neonatal encephalopathy, 47 individuals with isolated or familial mental retardation X-linked 13 (XLMR13), as well as 24 individuals with isolated or familial Pyramidal signs, parkinsonism, and macroorchidism (PPM-X). In our cohort, we met eight individuals aged 4 to 19-year-old at the last evaluation. Three MECP2-associated phenotypes were seen in male carriers of a single copy of the gene: severe neonatal encephalopathy (n = 5); X-linked intellectual deficiency 13 (n = 2); and pyramidal signs, parkinsonism, and macroorchidism (PPM-X) (n = 1). Two novel de novo variants [p.(Gly252Argfs∗7) and p.(Tyr132Cys)] were detected. CONCLUSION In males, the MECP2 pathogenic variants can be associated with different phenotypes, including neonatal severe encephalopathy, intellectual deficiency, or late-onset parkinsonism and spasticity. The typical RS phenotype is not expected in males, except in those with Klinefelter syndrome or somatic mosaicism for MECP2.
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4
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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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5
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First-line exome sequencing in Palestinian and Israeli Arabs with neurological disorders is efficient and facilitates disease gene discovery. Eur J Hum Genet 2020; 28:1034-1043. [PMID: 32214227 PMCID: PMC7382450 DOI: 10.1038/s41431-020-0609-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 02/26/2020] [Accepted: 03/10/2020] [Indexed: 12/22/2022] Open
Abstract
A high rate of consanguinity leads to a high prevalence of autosomal recessive disorders in inbred populations. One example of inbred populations is the Arab communities in Israel and the Palestinian Authority. In the Palestinian Authority in particular, due to limited access to specialized medical care, most patients do not receive a genetic diagnosis and can therefore neither receive genetic counseling nor possibly specific treatment. We used whole-exome sequencing as a first-line diagnostic tool in 83 Palestinian and Israeli Arab families with suspected neurogenetic disorders and were able to establish a probable genetic diagnosis in 51% of the families (42 families). Pathogenic, likely pathogenic or highly suggestive candidate variants were found in the following genes extending and refining the mutational and phenotypic spectrum of these rare disorders: ACO2, ADAT3, ALS2, AMPD2, APTX, B4GALNT1, CAPN1, CLCN1, CNTNAP1, DNAJC6, GAMT, GPT2, KCNQ2, KIF11, LCA5, MCOLN1, MECP2, MFN2, MTMR2, NT5C2, NTRK1, PEX1, POLR3A, PRICKLE1, PRKN, PRX, SCAPER, SEPSECS, SGCG, SLC25A15, SPG11, SYNJ1, TMCO1, and TSEN54. Further, this cohort has proven to be ideal for prioritization of new disease genes. Two separately published candidate genes (WWOX and PAX7) were identified in this study. Analyzing the runs of homozygosity (ROHs) derived from the Exome sequencing data as a marker for the rate of inbreeding, revealed significantly longer ROHs in the included families compared with a German control cohort. The total length of ROHs correlated with the detection rate of recessive disease-causing variants. Identification of the disease-causing gene led to new therapeutic options in four families.
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6
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Aldosary M, Al-Bakheet A, Al-Dhalaan H, Almass R, Alsagob M, Al-Younes B, AlQuait L, Mustafa OM, Bulbul M, Rahbeeni Z, Alfadhel M, Chedrawi A, Al-Hassnan Z, AlDosari M, Al-Zaidan H, Al-Muhaizea MA, AlSayed MD, Salih MA, AlShammari M, Faiyaz-Ul-Haque M, Chishti MA, Al-Harazi O, Al-Odaib A, Kaya N, Colak D. Rett Syndrome, a Neurodevelopmental Disorder, Whole-Transcriptome, and Mitochondrial Genome Multiomics Analyses Identify Novel Variations and Disease Pathways. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2020; 24:160-171. [PMID: 32105570 DOI: 10.1089/omi.2019.0192] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder reported worldwide in diverse populations. RTT is diagnosed primarily in females, with clinical findings manifesting early in life. Despite the variable rates across populations, RTT has an estimated prevalence of ∼1 in 10,000 live female births. Among 215 Saudi Arabian patients with neurodevelopmental and autism spectrum disorders, we identified 33 patients with RTT who were subsequently examined by genome-wide transcriptome and mitochondrial genome variations. To the best of our knowledge, this is the first in-depth molecular and multiomics analyses of a large cohort of Saudi RTT cases with a view to informing the underlying mechanisms of this disease that impact many patients and families worldwide. The patients were unrelated, except for 2 affected sisters, and comprised of 25 classic and eight atypical RTT cases. The cases were screened for methyl-CpG binding protein 2 (MECP2), CDKL5, FOXG1, NTNG1, and mitochondrial DNA (mtDNA) variants, as well as copy number variations (CNVs) using a genome-wide experimental strategy. We found that 15 patients (13 classic and two atypical RTT) have MECP2 mutations, 2 of which were novel variants. Two patients had novel FOXG1 and CDKL5 variants (both atypical RTT). Whole mtDNA sequencing of the patients who were MECP2 negative revealed two novel mtDNA variants in two classic RTT patients. Importantly, the whole-transcriptome analysis of our RTT patients' blood and further comparison with previous expression profiling of brain tissue from patients with RTT revealed 77 significantly dysregulated genes. The gene ontology and interaction network analysis indicated potentially critical roles of MAPK9, NDUFA5, ATR, SMARCA5, RPL23, SRSF3, and mitochondrial dysfunction, oxidative stress response and MAPK signaling pathways in the pathogenesis of RTT genes. This study expands our knowledge on RTT disease networks and pathways as well as presents novel mutations and mtDNA alterations in RTT in a population sample that was not previously studied.
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Affiliation(s)
- Mazhor Aldosary
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - AlBandary Al-Bakheet
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Hesham Al-Dhalaan
- Department of Neuroscience, and King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Rawan Almass
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Maysoon Alsagob
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Banan Al-Younes
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Laila AlQuait
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Osama Mufid Mustafa
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Mustafa Bulbul
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, Genetics Division, Department of Pediatrics, King Abdullah Specialized Children Hospital, Riyadh, Saudi Arabia
| | - Aziza Chedrawi
- Department of Neuroscience, and King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Zuhair Al-Hassnan
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Mohammed AlDosari
- Center for Pediatric Neurosciences, Cleveland Clinic, Cleveland, Ohio
| | - Hamad Al-Zaidan
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Mohammad A Al-Muhaizea
- Department of Neuroscience, and King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Moeenaldeen D AlSayed
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Mustafa A Salih
- Division of Pediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mai AlShammari
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | | | - Mohammad Azhar Chishti
- Department of Biochemistry, King Khalid Hospital, King Saud University, Riyadh, Saudi Arabia
| | - Olfat Al-Harazi
- Department of Biostatistics, Epidemiology, and Scientific Computing, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Ali Al-Odaib
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Namik Kaya
- Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Dilek Colak
- Department of Biostatistics, Epidemiology, and Scientific Computing, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
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7
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Inui T, Iwama K, Miyabayashi T, Sato R, Okubo Y, Endo W, Togashi N, Kakisaka Y, Kikuchi A, Mizuguchi T, Kure S, Matsumoto N, Haginoya K. Two males with sick sinus syndrome in a family with 0.6 kb deletions involving major domains in MECP2. Eur J Med Genet 2019; 63:103769. [PMID: 31536832 DOI: 10.1016/j.ejmg.2019.103769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 09/05/2019] [Accepted: 09/15/2019] [Indexed: 10/26/2022]
Abstract
Mutations in methyl-CpG-binding protein 2 (MECP2) in males can lead to various phenotypes, ranging from neonatal encephalopathy to intellectual disability. In this study, using Nord's method of next-generation sequencing in three siblings, we identified a 0.6 kb deletion involving the transcriptional repression domain (TRD). Two males and one female had intellectual disability and apnea, but none met the criteria of Rett syndrome. Both males had sick sinus syndrome and severe tracheomalacia that resulted in early death. The mother, with skewed X-inactivation, had no symptoms. Therefore, this mutation is pathological for both males and females, resulting in sick sinus syndrome and severe tracheomalacia with strong reproducibility in males. Deletions involving major domains in MECP2 can result in a severe phenotype, and deletion of the TRD domain can cause severe autonomic nervous system dysregulation in males in these cases.
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Affiliation(s)
- Takehiko Inui
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan.
| | - Kazuhiro Iwama
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan; Department of Pediatrics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Takuya Miyabayashi
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan
| | - Ryo Sato
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan
| | - Yukimune Okubo
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan
| | - Wakaba Endo
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Noriko Togashi
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan
| | - Yosuke Kakisaka
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Shigeo Kure
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Kazuhiro Haginoya
- Department of Pediatric Neurology, Miyagi Children's Hospital, 4-3-17 Ochiai, Aoba-ku, Sendai-shi, Miyagi, 989-3126, Japan; Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
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8
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Schönewolf‐Greulich B, Bisgaard A, Dunø M, Jespersgaard C, Rokkjær M, Hansen LK, Tsoutsou E, Sofokleous C, Topcu M, Kaur S, Van Bergen NJ, Brøndum‐Nielsen K, Larsen MJ, Sørensen KP, Christodoulou J, Fagerberg CR, Tümer Z. Mosaic
MECP2
variants in males with classical Rett syndrome features, including stereotypical hand movements. Clin Genet 2018; 95:403-408. [DOI: 10.1111/cge.13473] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Bitten Schönewolf‐Greulich
- Department of Paediatrics and Adolescent MedicineCenter for Rett Syndrome, Rigshospitalet Copenhagen Denmark
- Kennedy Center, Department of Clinical GeneticsCopenhagen University Hospital, Rigshospitalet Copenhagen Denmark
| | - Anne‐Marie Bisgaard
- Department of Paediatrics and Adolescent MedicineCenter for Rett Syndrome, Rigshospitalet Copenhagen Denmark
| | - Morten Dunø
- Department of Clinical GeneticsCopenhagen University Hospital, Rigshospitalet Copenhagen Denmark
| | - Cathrine Jespersgaard
- Kennedy Center, Department of Clinical GeneticsCopenhagen University Hospital, Rigshospitalet Copenhagen Denmark
| | - Mette Rokkjær
- Department of PediatricsKolding Hospital Kolding Denmark
| | - Lars K. Hansen
- Hans Christian Andersen Children's HospitalOdense University Hospital Odense Denmark
| | - Eirini Tsoutsou
- Medical Genetics DepartmentNational and Kapodistrian University of Athens, “Aghia Sophia” Children's Hospital Athens Greece
| | - Christalena Sofokleous
- Medical Genetics DepartmentNational and Kapodistrian University of Athens, “Aghia Sophia” Children's Hospital Athens Greece
| | - Meral Topcu
- Department of Medical Genetics, Hacettepe Medical School Ankara Turkey
| | - Simran Kaur
- Department of Paediatrics, Murdoch Children's Research InstituteUniversity of Melbourne Melbourne Australia
| | - Nicole J. Van Bergen
- Department of Paediatrics, Murdoch Children's Research InstituteUniversity of Melbourne Melbourne Australia
| | - Karen Brøndum‐Nielsen
- Department of Clinical GeneticsCopenhagen University Hospital, Rigshospitalet Copenhagen Denmark
| | - Martin J. Larsen
- Department of Clinical GeneticsOdense University Hospital Odense Denmark
| | | | - John Christodoulou
- Department of Paediatrics, Murdoch Children's Research InstituteUniversity of Melbourne Melbourne Australia
| | | | - Zeynep Tümer
- Kennedy Center, Department of Clinical GeneticsCopenhagen University Hospital, Rigshospitalet Copenhagen Denmark
- Department of Clinical MedicineFaculty of Health and Medical Sciences, University of Copenhagen Copenhagen Denmark
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9
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Kyle SM, Vashi N, Justice MJ. Rett syndrome: a neurological disorder with metabolic components. Open Biol 2018; 8:170216. [PMID: 29445033 PMCID: PMC5830535 DOI: 10.1098/rsob.170216] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/18/2018] [Indexed: 02/06/2023] Open
Abstract
Rett syndrome (RTT) is a neurological disorder caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2), a ubiquitously expressed transcriptional regulator. Despite remarkable scientific progress since its discovery, the mechanism by which MECP2 mutations cause RTT symptoms is largely unknown. Consequently, treatment options for patients are currently limited and centred on symptom relief. Thought to be an entirely neurological disorder, RTT research has focused on the role of MECP2 in the central nervous system. However, the variety of phenotypes identified in Mecp2 mutant mouse models and RTT patients implicate important roles for MeCP2 in peripheral systems. Here, we review the history of RTT, highlighting breakthroughs in the field that have led us to present day. We explore the current evidence supporting metabolic dysfunction as a component of RTT, presenting recent studies that have revealed perturbed lipid metabolism in the brain and peripheral tissues of mouse models and patients. Such findings may have an impact on the quality of life of RTT patients as both dietary and drug intervention can alter lipid metabolism. Ultimately, we conclude that a thorough knowledge of MeCP2's varied functional targets in the brain and body will be required to treat this complex syndrome.
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Affiliation(s)
- Stephanie M Kyle
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Neeti Vashi
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A1
| | - Monica J Justice
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada M5G 0A4
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A1
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10
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Schönewolf-Greulich B, Bisgaard AM, Møller R, Dunø M, Brøndum-Nielsen K, Kaur S, Van Bergen N, Lunke S, Eggers S, Jespersgaard C, Christodoulou J, Tümer Z. Clinician’s guide to genes associated with Rett-like phenotypes-Investigation of a Danish cohort and review of the literature. Clin Genet 2018; 95:221-230. [DOI: 10.1111/cge.13153] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 12/16/2022]
Affiliation(s)
- B. Schönewolf-Greulich
- Center for Rett Syndrome, Kennedy Center, Department of Paediatrics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
- Applied Human Molecular Genetics, Kennedy Center, Department of Clinical Genetics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
| | - A-M. Bisgaard
- Center for Rett Syndrome, Kennedy Center, Department of Paediatrics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
| | - R.S. Møller
- Danish Epilepsy Centre; Dianalund Denmark
- Institute for Regional Health Services; University of Southern Denmark; Odense Denmark
| | - M. Dunø
- Department of Clinical Genetics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
| | - K. Brøndum-Nielsen
- Department of Clinical Genetics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
| | - S. Kaur
- Neurodevelopmental Genomics Research Group; Murdoch Children's Research Institute; Melbourne Australia
- Department of Paediatrics; Melbourne Medical School, University of Melbourne; Melbourne Australia
| | - N.J. Van Bergen
- Neurodevelopmental Genomics Research Group; Murdoch Children's Research Institute; Melbourne Australia
- Department of Paediatrics; Melbourne Medical School, University of Melbourne; Melbourne Australia
| | - S. Lunke
- Translational Genomics Unit; Murdoch Children’s Research Institute; Melbourne Australia
| | - S. Eggers
- Translational Genomics Unit; Murdoch Children’s Research Institute; Melbourne Australia
| | - C. Jespersgaard
- Applied Human Molecular Genetics, Kennedy Center, Department of Clinical Genetics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
| | - J. Christodoulou
- Neurodevelopmental Genomics Research Group; Murdoch Children's Research Institute; Melbourne Australia
- Department of Paediatrics; Melbourne Medical School, University of Melbourne; Melbourne Australia
| | - Z. Tümer
- Applied Human Molecular Genetics, Kennedy Center, Department of Clinical Genetics; Copenhagen University Hospital, Rigshospitalet; Copenhagen Denmark
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11
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Giorgio E, Brussino A, Biamino E, Belligni EF, Bruselles A, Ciolfi A, Caputo V, Pizzi S, Calcia A, Di Gregorio E, Cavalieri S, Mancini C, Pozzi E, Ferrero M, Riberi E, Borelli I, Amoroso A, Ferrero GB, Tartaglia M, Brusco A. Exome sequencing in children of women with skewed X-inactivation identifies atypical cases and complex phenotypes. Eur J Paediatr Neurol 2017; 21:475-484. [PMID: 28027854 DOI: 10.1016/j.ejpn.2016.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/03/2016] [Accepted: 12/11/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND More than 100 X-linked intellectual disability (X-LID) genes have been identified to be involved in 10-15% of intellectual disability (ID). METHOD To identify novel possible candidates, we selected 18 families with a male proband affected by isolated or syndromic ID. Pedigree and/or clinical presentation suggested an X-LID disorder. After exclusion of known genetic diseases, we identified seven cases whose mother showed a skewed X-inactivation (>80%) that underwent whole exome sequencing (WES, 50X average depth). RESULTS WES allowed to solve the genetic basis in four cases, two of which (Coffin-Lowry syndrome, RPS6K3 gene; ATRX syndrome, ATRX gene) had been missed by previous clinical/genetics tests. One further ATRX case showed a complex phenotype including pontocerebellar atrophy (PCA), possibly associated to an unidentified PCA gene mutation. In a case with suspected Lujan-Fryns syndrome, a c.649C>T (p.Pro217Ser) MECP2 missense change was identified, likely explaining the neurological impairment, but not the marfanoid features, which were possibly associated to the p.Thr1020Ala variant in fibrillin 1. Finally, a c.707T>G variant (p.Phe236Cys) in the DMD gene was identified in a patient retrospectively recognized to be affected by Becker muscular dystrophy (BMD, OMIM 300376). CONCLUSION Overall, our data show that WES may give hints to solve complex ID phenotypes with a likely X-linked transmission, and that a significant proportion of these orphan conditions might result from concomitant mutations affecting different clinically associated genes.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | | | - Elisa Biamino
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Elga Fabia Belligni
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Alessandro Bruselles
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Viviana Caputo
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Simone Pizzi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Alessandro Calcia
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Eleonora Di Gregorio
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy; Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Turin, Italy
| | - Simona Cavalieri
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Cecilia Mancini
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Elisa Pozzi
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Marta Ferrero
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Evelise Riberi
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Iolanda Borelli
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Antonio Amoroso
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy; Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Turin, Italy.
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Ronen GM, Brady LI, Tarnopolsky MA. Males With MECP2 C-terminal-Related Atypical Rett Syndromes and Their Carrier Mothers. Pediatr Neurol 2017; 67:98-101. [PMID: 28089766 DOI: 10.1016/j.pediatrneurol.2016.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/05/2016] [Accepted: 10/09/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND This communication examines the expanding phenotypes of the MECP2 C-terminal atypical Rett syndromes in males and their affected carrier mothers. DESCRIPTIONS We describe three males with normal karyotypes who presented with congenital evolving complex neurodevelopmental encephalopathies with multifaceted symptomatology of hypotonia, epilepsy, ataxia, spasticity, movement disorders, behavioral issues, severe intellectual impairment, and communication skills, and a protracted regression phase followed by stabilization. These phenotypes did not prompt us to identify atypical Rett syndrome early in childhood. RESULTS Genetic analysis identified the two brothers with C-terminal truncation and the third male with C-terminal missense mutations. These mutations were inherited from their mothers, both of whom had incompletely characterized modest intellectual, mental health, social, and gastrointestinal impairments. Neither was independently able to care properly for their son(s). CONCLUSIONS Mutations of the MECP2 gene should be considered early in males with hypotonia, developmental delay, profound intellectual impairment, and seizures, associated with a mother with psychosocial, cognitive, and gastrointestinal impairments. Counseling and supporting mildly affected mothers requires both medical and social efforts.
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Affiliation(s)
- Gabriel M Ronen
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.
| | - Lauren I Brady
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Mark A Tarnopolsky
- Departments of Pediatrics and Medicine, McMaster University, Hamilton, Ontario, Canada
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13
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Veeraragavan S, Wan YW, Connolly DR, Hamilton SM, Ward CS, Soriano S, Pitcher MR, McGraw CM, Huang SG, Green JR, Yuva LA, Liang AJ, Neul JL, Yasui DH, LaSalle JM, Liu Z, Paylor R, Samaco RC. Loss of MeCP2 in the rat models regression, impaired sociability and transcriptional deficits of Rett syndrome. Hum Mol Genet 2016; 25:3284-3302. [PMID: 27365498 PMCID: PMC5179927 DOI: 10.1093/hmg/ddw178] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/18/2016] [Accepted: 06/08/2016] [Indexed: 01/31/2023] Open
Abstract
Mouse models of the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) have advanced our understanding of Rett syndrome (RTT). RTT is a 'prototypical' neurodevelopmental disorder with many clinical features overlapping with other intellectual and developmental disabilities (IDD). Therapeutic interventions for RTT may therefore have broader applications. However, the reliance on the laboratory mouse to identify viable therapies for the human condition may present challenges in translating findings from the bench to the clinic. In addition, the need to identify outcome measures in well-chosen animal models is critical for preclinical trials. Here, we report that a novel Mecp2 rat model displays high face validity for modelling psychomotor regression of a learned skill, a deficit that has not been shown in Mecp2 mice. Juvenile play, a behavioural feature that is uniquely present in rats and not mice, is also impaired in female Mecp2 rats. Finally, we demonstrate that evaluating the molecular consequences of the loss of MeCP2 in both mouse and rat may result in higher predictive validity with respect to transcriptional changes in the human RTT brain. These data underscore the similarities and differences caused by the loss of MeCP2 among divergent rodent species which may have important implications for the treatment of individuals with disease-causing MECP2 mutations. Taken together, these findings demonstrate that the Mecp2 rat model is a complementary tool with unique features for the study of RTT and highlight the potential benefit of cross-species analyses in identifying potential disease-relevant preclinical outcome measures.
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Affiliation(s)
- Surabi Veeraragavan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Daniel R Connolly
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Christopher S Ward
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sirena Soriano
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Meagan R Pitcher
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Christopher M McGraw
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sharon G Huang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Lisa A Yuva
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Agnes J Liang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Section of Neurology
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Dag H Yasui
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Janine M LaSalle
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Zhandong Liu
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Rodney C Samaco
- Department of Molecular and Human Genetics
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
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