1
|
Mim RA, Soorajkumar A, Kosaji N, Rahman MM, Sarker S, Karuvantevida N, Eshaque TB, Rahaman MA, Islam A, Chowdhury MSJ, Shams N, Uddin KMF, Akter H, Uddin M. Expanding deep phenotypic spectrum associated with atypical pathogenic structural variations overlapping 15q11-q13 imprinting region. Brain Behav 2024; 14:e3437. [PMID: 38616334 PMCID: PMC11016631 DOI: 10.1002/brb3.3437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND The 15q11-q13 region is a genetic locus with genes subject to genomic imprinting, significantly influencing neurodevelopment. Genomic imprinting is an epigenetic phenomenon that causes differential gene expression based on the parent of origin. In most diploid organisms, gene expression typically involves an equal contribution from both maternal and paternal alleles, shaping the phenotype. Nevertheless, in mammals, including humans, mice, and marsupials, the functional equivalence of parental alleles is not universally maintained. Notably, during male and female gametogenesis, parental alleles may undergo differential marking or imprinting, thereby modifying gene expression without altering the underlying DNA sequence. Neurodevelopmental disorders, such as Prader-Willi syndrome (PWS) (resulting from the absence of paternally expressed genes in this region), Angelman syndrome (AS) (associated with the absence of the maternally expressed UBE3A gene), and 15q11-q13 duplication syndrome (resulting from the two common forms of duplications-either an extra isodicentric 15 chromosome or an interstitial 15 duplication), are the outcomes of genetic variations in this imprinting region. METHODS Conducted a genomic study to identify the frequency of pathogenic variants impacting the 15q11-q13 region in an ethnically homogenous population from Bangladesh. Screened all known disorders from the DECIPHER database and identified variant enrichment within this cohort. Using the Horizon analysis platform, performed enrichment analysis, requiring at least >60% overlap between a copy number variation and a disorder breakpoint. Deep clinical phenotyping was carried out through multiple examination sessions to evaluate a range of clinical symptoms. RESULTS This study included eight individuals with clinically suspected PWS/AS, all previously confirmed through chromosomal microarray analysis, which revealed chromosomal breakpoints within the 15q11-q13 region. Among this cohort, six cases (75%) exhibited variable lengths of deletions, whereas two cases (25%) showed duplications. These included one type 2 duplication, one larger atypical duplication, one shorter type 2 deletion, one larger type 1 deletion, and four cases with atypical deletions. Furthermore, thorough clinical assessments led to the diagnosis of four PWS patients, two AS patients, and two individuals with 15q11-q13 duplication syndrome. CONCLUSION Our deep phenotypic observations identified a spectrum of clinical features that overlap and are unique to PWS, AS, and Dup15q syndromes. Our findings establish genotype-phenotype correlation for patients impacted by variable structural variations within the 15q11-q13 region.
Collapse
Affiliation(s)
- Rabeya Akter Mim
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
| | - Anjana Soorajkumar
- Center for Applied and Translational Genomics (CATG)Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai HealthDubaiUAE
| | - Noor Kosaji
- Center for Applied and Translational Genomics (CATG)Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai HealthDubaiUAE
| | - Muhammad Mizanur Rahman
- Department of Paediatric NeurologyBangabandhu Sheikh Mujib Medical UniversityDhakaBangladesh
| | - Shaoli Sarker
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
- Bangladesh Shishu Hospital and InstituteDhakaBangladesh
| | - Noushad Karuvantevida
- Center for Applied and Translational Genomics (CATG)Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai HealthDubaiUAE
| | | | - Md Atikur Rahaman
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
| | - Amirul Islam
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
- GenomeArc Inc.MississaugaOntarioCanada
| | - Mohammod Shah Jahan Chowdhury
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
- Ministry of Health and Family WelfareDhakaBangladesh
| | - Nusrat Shams
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
- National Institute of Neuroscience and HospitalDhakaBangladesh
| | - K. M. Furkan Uddin
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
| | - Hosneara Akter
- Genetics and Genomic Medicine Centre (GGMC)NeuroGen HealthcareDhakaBangladesh
| | - Mohammed Uddin
- Center for Applied and Translational Genomics (CATG)Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai HealthDubaiUAE
- GenomeArc Inc.MississaugaOntarioCanada
| |
Collapse
|
2
|
Bush L, Scott MN. Neuropsychological and ASD phenotypes in rare genetic syndromes: A critical review of the literature. Clin Neuropsychol 2021; 36:993-1027. [PMID: 34569897 DOI: 10.1080/13854046.2021.1980111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by core deficits in social communication and restricted and repetitive behaviors and interests. Recent advances in clinical genetics have improved our understanding of genetic syndromes associated with ASD, which has helped clarify distinct etiologies of ASD and document syndrome-specific profiles of neurocognitive strengths and weaknesses. Pediatric neuropsychologists have the potential to be impactful members of the care team for children with genetic syndromes and their families. METHOD We provide a critical review of the current literature related to the neuropsychological profiles of children with four genetic syndromes associated with ASD, including Tuberous Sclerosis Complex (TSC), fragile X syndrome (FXS), 22q11.2 deletion syndrome, and Angelman syndrome. Recommendations for assessment, intervention, and future directions are provided. RESULTS There is vast heterogeneity in terms of the cognitive, language, and developmental abilities of these populations. The within- and across-syndrome variability characteristic of genetic syndromes should be carefully considered during clinical evaluations, including possible measurement limitations, presence of intellectual disability, and important qualitative differences in the ASD-phenotypes across groups. CONCLUSIONS Individuals with genetic disorders pose challenging diagnostic and assessment questions. Pediatric neuropsychologists with expertise in neurodevelopmental processes are well suited to address these questions and identify profiles of neurocognitive strengths and weaknesses, tailor individualized recommendations, and provide diagnostic clarification.
Collapse
Affiliation(s)
- Lauren Bush
- Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Megan N Scott
- The Pritzker Department of Psychiatry and Behavioral Health, Ann & Robert H. Lurie Children's Hospital of Chicago, IL, USA
| |
Collapse
|
3
|
Chaudhary R, Agarwal V, Kaushik AS, Rehman M. Involvement of myocyte enhancer factor 2c in the pathogenesis of autism spectrum disorder. Heliyon 2021; 7:e06854. [PMID: 33981903 PMCID: PMC8082549 DOI: 10.1016/j.heliyon.2021.e06854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/09/2020] [Accepted: 04/15/2021] [Indexed: 12/29/2022] Open
Abstract
Myocyte enhancer factor 2 (MEF2), a family of transcription factor of MADS (minichromosome maintenance 1, agamous, deficiens and serum response factor)-box family needed in the growth and differentiation of a variety of human cells, such as neural, immune, endothelial, and muscles. As per existing literature, MEF2 transcription factors have also been associated with synaptic plasticity, the developmental mechanisms governing memory and learning, and several neurologic conditions, like autism spectrum disorders (ASDs). Recent genomic findings have ascertained a link between MEF2 defects, particularly in the MEF2C isoform and the ASD. In this review, we summarized a concise overview of the general regulation, structure and functional roles of the MEF2C transcription factor. We further outlined the potential role of MEF2C as a risk factor for various neurodevelopmental disorders, such as ASD, MEF2C Haploinsufficiency Syndrome and Fragile X syndrome.
Collapse
Affiliation(s)
- Rishabh Chaudhary
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Vipul Agarwal
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Arjun Singh Kaushik
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Mujeeba Rehman
- Department of Pharmaceutical Sciences, School of Biosciences and Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| |
Collapse
|
4
|
Beygo J, Buiting K, Ramsden SC, Ellis R, Clayton-Smith J, Kanber D. Update of the EMQN/ACGS best practice guidelines for molecular analysis of Prader-Willi and Angelman syndromes. Eur J Hum Genet 2019; 27:1326-1340. [PMID: 31235867 PMCID: PMC6777528 DOI: 10.1038/s41431-019-0435-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/20/2019] [Accepted: 05/07/2019] [Indexed: 11/23/2022] Open
Abstract
This article is an update of the best practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes published in 2010 in BMC Medical Genetics [1]. The update takes into account developments in terms of techniques, differential diagnoses and (especially) reporting standards. It highlights the advantages and disadvantages of each method and moreover, is meant to facilitate the interpretation of the obtained results - leading to improved standardised reports.
Collapse
Affiliation(s)
- Jasmin Beygo
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany.
| | - Karin Buiting
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Simon C Ramsden
- Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
| | - Rachael Ellis
- Department of Medical Genetics, Yorkhill NHS Trust, Yorkhill Hospital, Glasgow, G3 8SJ, UK
| | - Jill Clayton-Smith
- Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
- Division of Evolution and Genomic Sciences School of Biological Sciences University of Manchester, Manchester, UK
| | - Deniz Kanber
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany.
| |
Collapse
|
5
|
Khatri N, Man HY. The Autism and Angelman Syndrome Protein Ube3A/E6AP: The Gene, E3 Ligase Ubiquitination Targets and Neurobiological Functions. Front Mol Neurosci 2019; 12:109. [PMID: 31114479 PMCID: PMC6502993 DOI: 10.3389/fnmol.2019.00109] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/12/2019] [Indexed: 12/18/2022] Open
Abstract
UBE3A is a gene implicated in neurodevelopmental disorders. The protein product of UBE3A is the E3 ligase E6-associated protein (E6AP), and its expression in the brain is uniquely regulated via genetic imprinting. Loss of E6AP expression leads to the development of Angelman syndrome (AS), clinically characterized by lack of speech, abnormal motor development, and the presence of seizures. Conversely, copy number variations (CNVs) that result in the overexpression of E6AP are strongly associated with the development of autism spectrum disorders (ASDs), defined by decreased communication, impaired social interest, and increased repetitive behavior. In this review article, we focus on the neurobiological function of Ube3A/E6AP. As an E3 ligase, many functional target proteins of E6AP have been discovered, including p53, Arc, Ephexin5, and SK2. On a neuronal level, E6AP is widely expressed within the cell, including dendritic arbors, spines, and the nucleus. E6AP regulates neuronal morphological maturation and plays an important role in synaptic plasticity and cortical development. These molecular findings provide insight into our understanding of the molecular events underlying AS and ASDs.
Collapse
Affiliation(s)
- Natasha Khatri
- Department of Biology, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| |
Collapse
|
6
|
Langouët M, Glatt-Deeley HR, Chung MS, Dupont-Thibert CM, Mathieux E, Banda EC, Stoddard CE, Crandall L, Lalande M. Zinc finger protein 274 regulates imprinted expression of transcripts in Prader-Willi syndrome neurons. Hum Mol Genet 2019; 27:505-515. [PMID: 29228278 DOI: 10.1093/hmg/ddx420] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/01/2017] [Indexed: 01/09/2023] Open
Abstract
Prader-Willi syndrome (PWS) is characterized by neonatal hypotonia, developmental delay and hyperphagia/obesity and is caused by the absence of paternal contribution to chromosome 15q11-q13. Using induced pluripotent stem cell (iPSC) models of PWS, we previously discovered an epigenetic complex that is comprised of the zinc-finger protein ZNF274 and the SET domain bifurcated 1 (SETDB1) histone H3 lysine 9 (H3K9) methyltransferase and that silences the maternal alleles at the PWS locus. Here, we have knocked out ZNF274 and rescued the expression of silent maternal alleles in neurons derived from PWS iPSC lines, without affecting DNA methylation at the PWS-Imprinting Center (PWS-IC). This suggests that the ZNF274 complex is a separate imprinting mark that represses maternal PWS gene expression in neurons and is a potential target for future therapeutic applications to rescue the PWS phenotype.
Collapse
Affiliation(s)
- Maéva Langouët
- Department of Genetics and Genome Sciences, School of Medicine
| | | | - Michael S Chung
- Department of Genetics and Genome Sciences, School of Medicine
| | | | - Elodie Mathieux
- Department of Genetics and Genome Sciences, School of Medicine
| | - Erin C Banda
- Department of Genetics and Genome Sciences, School of Medicine
| | | | - Leann Crandall
- Department of Genetics and Genome Sciences, School of Medicine
| | - Marc Lalande
- Department of Genetics and Genome Sciences, School of Medicine.,Institute for Systems Genomics, University of Connecticut, Farmington, CT 06030-6403, USA
| |
Collapse
|
7
|
Abstract
UBE3A is a dual function protein consisting of ubiquitin ligase as well as transcriptional co-activator function. UBE3A gene is imprinted in the brain with preferential maternal-specific expression particularly in the neuron and loss of activity of the maternally inherited UBE3A causes Angelman syndrome (AS), characterized by severe mental retardation, lack of speech, seizures and autistic features. Interestingly, duplication, triplication, or gain-of-function mutations in the UBE3A gene are also linked with autism clinically distinguished by social impairments and stereotyped behaviors. These findings indicate that the expression and activity of UBE3A must be tightly regulated during brain development and UBE3A might be playing a crucial role in controlling synaptic function and plasticity through proteasome-mediated degradation as well as transcriptional regulation of its target proteins. In fact, several recent reports demonstrated the role of UBE3A in the modulation of synaptic function and plasticity. This review focuses on the critical role of UBE3A in regulating the synaptic function and how its altered activity is associated with autism.
Collapse
Affiliation(s)
- Naman Vatsa
- Cellular and Molecular Neuroscience Laboratory, National Brain Research Centre, Gurugram, India
| | - Nihar Ranjan Jana
- School of Bioscience, Indian Institute of Technology, Kharagpur, India
| |
Collapse
|
8
|
Tones M, Cross M, Simons C, Napier KR, Hunter A, Bellgard MI, Heussler H. Research protocol: The initiation, design and establishment of the Global Angelman Syndrome Registry. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2018; 62:431-443. [PMID: 29633452 DOI: 10.1111/jir.12482] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/18/2017] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Angelman syndrome (AS) is a rare neurodevelopmental disorder affecting between 1 in 15 000 and 1 in 24 000 individuals. The condition results in severe developmental and expressive language delays, motor impairments and a unique behavioural phenotype consisting of excessive laughter, smiling and sociability. While many studies have contributed knowledge about the causes and natural history of the syndrome, large scale longitudinal studies are required to advance research and therapeutics for this rare syndrome. METHOD This article describes the protocol for the Global Angelman Syndrome Registry, and some initial findings. Due to the rarity of AS and the variability in symptom presentation, the registry team will strive for complete case ascertainment. Parents and caregivers will submit data to the registry via a secure internet connection. The registry consists of 10 modules that cover patient demographics; developmental, diagnostic, medical and surgical history, behaviour and development, epilepsy, medications and interventions and sleep. RESULTS Since its launch at https://angelmanregistry.info in September 2016, almost 470 individuals with AS have been signed up to the registry worldwide: 59% are from North and South America, 23% are from Europe, 17% are from the Asia Pacific region and 1% are from the Middle East or Africa. The majority of registrants are children, with only 16% aged over 20 years. Most participants indicated a chromosome deletion (76%), with fewer participants indicating a mutation, uniparental disomy or imprinting defect (20%). CONCLUSION Findings indicate a need to consider recruitment strategies that target caregivers of older children and adults, and parents and caregivers from non-English speaking backgrounds.
Collapse
Affiliation(s)
- M Tones
- Developmental Paediatric Group, Mater Medical Research Institute, South Brisbane, Queensland, Australia
| | - M Cross
- Foundation for Angelman Syndrome Therapeutics Australia, Brisbane, Queensland, Australia
| | - C Simons
- Foundation for Angelman Syndrome Therapeutics Australia, Brisbane, Queensland, Australia
| | - K R Napier
- Murdoch University, Centre for Comparative Genomics, Murdoch, Western Australia, Australia
| | - A Hunter
- Murdoch University, Centre for Comparative Genomics, Murdoch, Western Australia, Australia
| | - M I Bellgard
- eResearch Directorate, Queensland University of Technology, Brisbane, Queensland, Australia
| | - H Heussler
- Centre for Children's Health Research University of Queensland, Australia
| |
Collapse
|
9
|
Wheeler AC, Sacco P, Cabo R. Unmet clinical needs and burden in Angelman syndrome: a review of the literature. Orphanet J Rare Dis 2017; 12:164. [PMID: 29037196 PMCID: PMC5644259 DOI: 10.1186/s13023-017-0716-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 10/05/2017] [Indexed: 11/25/2022] Open
Abstract
Background Angelman syndrome (AS) is a rare disorder with a relatively well-defined phenotype. Despite this, very little is known regarding the unmet clinical needs and burden of this condition, especially with regard to some of the most prevalent clinical features—movement disorders, communication impairments, behavior, and sleep. Main text A targeted literature review using electronic medical databases (e.g., PubMed) was conducted to identify recent studies focused on specific areas of the AS phenotype (motor, communication, behavior, sleep) as well as epidemiology, diagnostic processes, treatment, and burden. 142 articles were reviewed and summarized. Findings suggest significant impairment across the life span in all areas of function. While some issues may resolve as individuals get older (e.g., hyperactivity), others become worse (e.g., movement disorders, aggression, anxiety). There are no treatments focused on the underlying etiology, and the symptom-based therapies currently prescribed do not have much, if any, empirical support. Conclusions The lack of standardized treatment protocols or approved therapies, combined with the severity of the condition, results in high unmet clinical needs in the areas of motor functioning, communication, behavior, and sleep for individuals with AS and their families.
Collapse
Affiliation(s)
- Anne C Wheeler
- RTI International, 3040 Cornwallis Road, PO Box 12194, Research Triangle Park, NC, 27709-2194, USA.
| | - Patricia Sacco
- RTI Health Solutions, 200 Park Offices Drive, Research Triangle Park, NC, 27709, USA
| | - Raquel Cabo
- Ovid Therapeutics Inc., 1460 Broadway, New York, NY, 10036, USA
| |
Collapse
|
10
|
Low glycemic index treatment for seizure control in Angelman syndrome: A case series from the Center for Dietary Therapy of Epilepsy at the Massachusetts General Hospital. Epilepsy Behav 2017; 68:45-50. [PMID: 28109989 DOI: 10.1016/j.yebeh.2016.12.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/15/2016] [Accepted: 12/17/2016] [Indexed: 11/20/2022]
Abstract
The low glycemic index treatment, a dietary therapy that focuses on glycemic index and reduced carbohydrate intake, has been successful in reducing seizure frequency in the general epilepsy population. Epilepsy is a common feature of Angelman syndrome and seizures are often refractory to multiple medications, especially in those with maternal deletions. Dietary therapy has become a more frequently used option for treating epilepsy, often in combination with other antiepileptic drugs, due to its efficacy and favorable side effect profile. This study aimed to assess the effectiveness of the low glycemic index treatment for seizure control in Angelman syndrome. Through a retrospective medical record review of 23 subjects who utilized the low glycemic index treatment at the Clinic and Center for Dietary Therapy of Epilepsy at the Massachusetts General Hospital, we found that the high level of seizure control and favorable side effect profile make the low glycemic index treatment a viable treatment for seizures in Angelman syndrome. The majority of subjects in our cohort experienced some level of seizure reduction after initiating the diet, 5 (22%) maintained complete seizure freedom, 10 (43%) maintained seizure freedom except in the setting of illness or non-convulsive status epilepticus, 7 (30%) had a decrease in seizure frequency, and only 1 (4%) did not have enough information to determine seizure control post-initiation. The low glycemic index treatment monotherapy was successful for some subjects in our cohort but most subjects used an antiepileptic drug concurrently. Some subjects were able to maintain the same level of seizure control on a liberalized version of the low glycemic index treatment which included a larger amount of low glycemic carbohydrates. No correlation between the level of carbohydrate restriction and level of seizure control was found. Few subjects experienced side effects and those that did found them to be mild and easily treated. The efficacy of the low glycemic index treatment and its favorable side effect profile make it an excellent alternative or supplement to antiepileptic drug therapy for the treatment of seizures in Angelman syndrome.
Collapse
|
11
|
Hong SY, Chou IC, Lin WD, Tsai FJ. A case of Pitt-Hopkins syndrome presented with Angelman-like syndromic phenotypes. Biomedicine (Taipei) 2016; 6:25. [PMID: 27864810 PMCID: PMC5147553 DOI: 10.7603/s40681-016-0025-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/29/2016] [Indexed: 11/29/2022] Open
Abstract
Pitt-Hopkins syndrome (PTHS), caused by a TCF4 gene mutation, is a condition characterized by intellectual disability and developmental delay, breathing anomalies, epilepsy, and distinctive facial dysmorphism [1]. Its diverse clinical appearance causes pediatricians to confuse it with Angelman syndrome, which is considered one of the family members of Angelman-like syndrome. Herein, we report on a 4 y/o boy with PTHS and discuss its similarities and differences with Angelman syndrome. In doing so we hope to provide a feasible pathway to diagnose rare diseases, especially Angelman-like syndrome.
Collapse
Affiliation(s)
- Syuan-Yu Hong
- Department of Pediatrics, Children's Hospital, China Medical University Hospital, Taichung, 404, Taiwan
| | - I-Ching Chou
- Department of Pediatrics, Children's Hospital, China Medical University Hospital, Taichung, 404, Taiwan.,Department of Medical Research, China Medical University and Hospital, Taichung, 404, Taiwan
| | - Wei-De Lin
- Department of Medical Research, China Medical University and Hospital, Taichung, 404, Taiwan.,School of Post-baccalaureate Chinese Medicine, China Medical University, Taichung, 404, Taiwan
| | - Fuu-Jen Tsai
- Department of Pediatrics, Children's Hospital, China Medical University Hospital, Taichung, 404, Taiwan. .,Department of Medical Research, China Medical University and Hospital, Taichung, 404, Taiwan. .,Department of Pediatrics, China Medical University Hospital, No. 2 Yuh-Der Road, Taichung, 404, Taiwan.
| |
Collapse
|
12
|
Buiting K, Williams C, Horsthemke B. Angelman syndrome — insights into a rare neurogenetic disorder. Nat Rev Neurol 2016; 12:584-93. [DOI: 10.1038/nrneurol.2016.133] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
13
|
Seizure treatment in Angelman syndrome: A case series from the Angelman Syndrome Clinic at Massachusetts General Hospital. Epilepsy Behav 2016; 60:138-141. [PMID: 27206232 DOI: 10.1016/j.yebeh.2016.04.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/13/2016] [Accepted: 04/18/2016] [Indexed: 02/01/2023]
Abstract
Epilepsy is a common feature of Angelman syndrome (~80-90%), with the most common seizure types including myoclonic, atonic, atypical absence, focal, and generalized tonic-clonic. Seizure types are similar among the various genetic subtypes, but epilepsy in those with maternal deletions is more frequent and more refractory to medication. Treatment with older antiepileptic drugs such as valproic acid and clonazepam is effective, but these medications tend to have less favorable side effect profiles in Angelman syndrome compared with those in newer medications. This study aimed to assess the use of newer antiepileptic drug therapies in individuals with Angelman syndrome followed at the Angelman Syndrome Clinic at the Massachusetts General Hospital. Many of the subjects in this study were on valproic acid therapy prior to their initial evaluation and exhibited increased tremor, decreased balance, and/or regression of motor skills, which resolved after tapering off of this medication. Newer antiepileptic drugs such as levetiracetam, lamotrigine, and clobazam, and to a lesser extent topiramate, appeared to be as effective - if not more so - as valproic acid and clonazepam while offering more favorable side effect profiles. The low glycemic index treatment also provided effective seizure control with minimal side effects. The majority of subjects remained on combination therapy with levetiracetam, lamotrigine, and clobazam being the most commonly used medications, indicating a changing trend when compared with prior studies.
Collapse
|
14
|
Luk H, Lo IF. Angelman syndrome in Hong Kong Chinese: A 20 years’ experience. Eur J Med Genet 2016; 59:315-9. [DOI: 10.1016/j.ejmg.2016.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/13/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
|
15
|
Luk HM. Angelman-Like Syndrome: A Genetic Approach to Diagnosis with Illustrative Cases. Case Rep Genet 2016; 2016:9790169. [PMID: 26942024 PMCID: PMC4749774 DOI: 10.1155/2016/9790169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/14/2016] [Accepted: 01/14/2016] [Indexed: 11/23/2022] Open
Abstract
Epigenetic abnormalities in 15q11-13 imprinted region and UBE3A mutation are the two major mechanisms for molecularly confirmed Angelman Syndrome. However, there is 10% of clinically diagnosed Angelman Syndrome remaining test negative. With the advancement of genomic technology like array comparative genomic hybridization and next generation sequencing methods, it is found that some patients of these test negative Angelman-like Syndromes actually have alternative diagnoses. Accurate molecular diagnosis is paramount for genetic counseling and subsequent management. Despite overlapping phenotypes between Angelman and Angelman-like Syndrome, there are some subtle but distinct features which could differentiate them clinically. It would provide important clue during the diagnostic process for clinicians.
Collapse
Affiliation(s)
- Ho-Ming Luk
- Clinical Genetic Service, Department of Health, Kowloon, Hong Kong
| |
Collapse
|
16
|
The Antisense Transcriptome and the Human Brain. J Mol Neurosci 2015; 58:1-15. [PMID: 26697858 DOI: 10.1007/s12031-015-0694-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
Abstract
The transcriptome of a cell is made up of a varied array of RNA species, including protein-coding RNAs, long non-coding RNAs, short non-coding RNAs, and circular RNAs. The cellular transcriptome is dynamic and can change depending on environmental factors, disease state and cellular context. The human brain has perhaps the most diverse transcriptome profile that is enriched for many species of RNA, including antisense transcripts. Antisense transcripts are produced when both the plus and minus strand of the DNA helix are transcribed at a particular locus. This results in an RNA transcript that has a partial or complete overlap with an intronic or exonic region of the sense transcript. While antisense transcription is known to occur at some level in most organisms, this review focuses specifically on antisense transcription in the brain and how regulation of genes by antisense transcripts can contribute to functional aspects of the healthy and diseased brain. First, we discuss different techniques that can be used in the identification and quantification of antisense transcripts. This is followed by examples of antisense transcription and modes of regulatory function that have been identified in the brain.
Collapse
|
17
|
Blumberg SJ, Zablotsky B, Avila RM, Colpe LJ, Pringle BA, Kogan MD. Diagnosis lost: Differences between children who had and who currently have an autism spectrum disorder diagnosis. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2015; 20:783-95. [PMID: 26489772 DOI: 10.1177/1362361315607724] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Autism spectrum disorder diagnoses sometimes change due to misdiagnosis, maturation, or treatment. This study uses a probability-based national survey-the Survey of Pathways to Diagnosis and Services-to compare currently diagnosed (n = 1420) and previously diagnosed (n = 187) children aged 6-17 years based on retrospective parental reports of early concerns about their children's development, responses to those concerns by doctors and other healthcare providers, the type of provider who made the first autism spectrum disorder diagnosis, and the autism spectrum disorder subtype diagnoses received (if any). Propensity score matching was used to control for differences between the groups on children's current level of functioning and other current characteristics that may have been related to diagnosis loss. Approximately 13% of the children ever diagnosed with autism spectrum disorder were estimated to have lost the diagnosis, and parents of 74% of them believed it was changed due to new information. Previously diagnosed children were less likely to have parents with early concerns about verbal skills, nonverbal communication, learning, and unusual gestures or movements. They were also less likely to have been referred to and diagnosed by a specialist. Previously diagnosed children were less likely to have ever received a diagnosis of Asperger's disorder or autistic disorder.
Collapse
|
18
|
Sachdeva R, Donkers SJ, Kim SY. Angelman syndrome: A review highlighting musculoskeletal and anatomical aberrations. Clin Anat 2015; 29:561-7. [PMID: 26480021 DOI: 10.1002/ca.22659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 11/11/2022]
Abstract
Angelman's syndrome (AS) is a genetic neurodevelopment disorder. The cause is a known abnormality involving the maternal inherited ubiquitin-protein ligase (UBE3A) gene. Clinical characteristics universal to the disorder are well documented in the literature and include developmental delay, seizures, ataxia, altered tone, severely impaired speech and intellect, as well as an overall happy demeanor, frequent bouts of laughter, and hypermotoric behavior. Associated with this disorder are several musculoskeletal aberrations. To date, a review of case studies reporting on these musculoskeletal changes has not been carried out. Thus, the purpose of this paper was to provide an overview of the musculoskeletal changes present in individuals with AS. In our review of 21 case reports from 1965-2013, the most consistently reported anatomical changes were of the craniofacial region. These include microcephaly, brachycephaly, a palpable occipital groove, prognathism, and wide spaced teeth. Other musculoskeletal abnormalities less frequently reported in the literature include scoliosis, excessive lumbar lordosis, and pes planus. Given that the majority of the case reports reviewed was of young children, the possibility of underreporting musculoskeletal changes which may manifest in the later years of life may be present. Early diagnosis and interventions to minimize secondary complications are crucial to maintain quality of life. An overall multidisciplinary approach is emphasized to maximize developmental potential for these individuals. Future prospective studies that follow patients into adulthood are needed to better understand the prevalence and development of secondary musculoskeletal changes, which in turn can inform intervention techniques and preventative measures. Clin. Anat. 29:561-567, 2016. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Rohit Sachdeva
- School of Physical Therapy, University of Saskatchewan, Saskatoon, Canada
| | - Sarah J Donkers
- School of Physical Therapy, University of Saskatchewan, Saskatoon, Canada
| | - Soo Y Kim
- School of Physical Therapy, University of Saskatchewan, Saskatoon, Canada
| |
Collapse
|
19
|
Tan WH, Bird LM, Thibert RL, Williams CA. If not Angelman, what is it? A review of Angelman-like syndromes. Am J Med Genet A 2014; 164A:975-92. [PMID: 24779060 DOI: 10.1002/ajmg.a.36416] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Angelman syndrome (AS) is caused by a lack of expression of the maternally inherited UBE3A gene in the brain. However, about 10% of individuals with a clinical diagnosis of AS do not have an identifiable molecular defect. It is likely that most of those individuals have an AS-like syndrome that is clinically and molecularly distinct from AS. These AS-like syndromes can be broadly classified into chromosomal microdeletion and microduplication syndromes, and single-gene disorders. The microdeletion/microduplication syndromes are now easily identified by chromosomal microarray analysis and include Phelan–McDermid syndrome (chromosome 22q13.3 deletion), MBD5 haploinsufficiency syndrome (chromosome 2q23.1 deletion), and KANSL1 haploinsufficiency syndrome (chromosome 17q21.31 deletion). The single-gene disorders include Pitt–Hopkins syndrome (TCF4), Christianson syndrome (SLC9A6), Mowat–Wilson syndrome (ZEB2), Kleefstra syndrome (EHMT1), and Rett (MECP2) syndrome. They also include disorders due to mutations in HERC2, adenylosuccinase lyase (ADSL), CDKL5, FOXG1, MECP2 (duplications), MEF2C, and ATRX. Although many of these single-gene disorders can be caused by chromosomal microdeletions resulting in haploinsufficiency of the critical gene, the individual disorders are often caused by intragenic mutations that cannot be detected by chromosomal microarray analysis. We provide an overview of the clinical features of these syndromes, comparing and contrasting them with AS, in the hope that it will help guide clinicians in the diagnostic work-up of individuals with AS-like syndromes.
Collapse
|
20
|
Jiang YH, Wang Y, Xiu X, Choy KW, Pursley AN, Cheung SW. Genetic diagnosis of autism spectrum disorders: the opportunity and challenge in the genomics era. Crit Rev Clin Lab Sci 2014; 51:249-62. [PMID: 24878448 PMCID: PMC5937018 DOI: 10.3109/10408363.2014.910747] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A genetic etiology for autism spectrum disorders (ASDs) was first suggested from twin studies reported in the 1970s. The identification of gene mutations in syndromic ASDs provided evidence to support a genetic cause of ASDs. More recently, genome-wide copy number variant and sequence analyses have uncovered a list of rare and highly penetrant copy number variants (CNVs) or single nucleotide variants (SNVs) associated with ASDs, which has strengthened the claim of a genetic etiology for ASDs. Findings from research studies in the genetics of ASD now support an important role for molecular diagnostics in the clinical genetics evaluation of ASDs. Various molecular diagnostic assays including single gene tests, targeted multiple gene panels and copy number analysis should all be considered in the clinical genetics evaluation of ASDs. Whole exome sequencing could also be considered in selected clinical cases. However, the challenge that remains is to determine the causal role of genetic variants identified through molecular testing. Variable expressivity, pleiotropic effects and incomplete penetrance associated with CNVs and SNVs also present significant challenges for genetic counseling and prenatal diagnosis.
Collapse
Affiliation(s)
- Yong-Hui Jiang
- Department of Pediatrics and Neurobiology, Duke University School of Medicine, Durham, NC, USA
- Division of Neurology, The Children’s Hospital of Fudan University, Shanghai, People’s Republic of China
| | - Yi Wang
- Division of Neurology, The Children’s Hospital of Fudan University, Shanghai, People’s Republic of China
| | - Xu Xiu
- Division of Child Development and Health, The Children’s Hospital of Fudan University Shanghai, People’s Republic of China
| | - Kwong Wai Choy
- Department of Obstetrics and Gynecology, and Joint Centre with Utrecht University Genetic core, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
| | - Amber Nolen Pursley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sau W. Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
21
|
Kondapalli KC, Prasad H, Rao R. An inside job: how endosomal Na(+)/H(+) exchangers link to autism and neurological disease. Front Cell Neurosci 2014; 8:172. [PMID: 25002837 PMCID: PMC4066934 DOI: 10.3389/fncel.2014.00172] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/04/2014] [Indexed: 12/02/2022] Open
Abstract
Autism imposes a major impediment to childhood development and a huge emotional and financial burden on society. In recent years, there has been rapidly accumulating genetic evidence that links the eNHE, a subset of Na(+)/H(+) exchangers that localize to intracellular vesicles, to a variety of neurological conditions including autism, attention deficit hyperactivity disorder (ADHD), intellectual disability, and epilepsy. By providing a leak pathway for protons pumped by the V-ATPase, eNHE determine luminal pH and regulate cation (Na(+), K(+)) content in early and recycling endosomal compartments. Loss-of-function mutations in eNHE cause hyperacidification of endosomal lumen, as a result of imbalance in pump and leak pathways. Two isoforms, NHE6 and NHE9 are highly expressed in brain, including hippocampus and cortex. Here, we summarize evidence for the importance of luminal cation content and pH on processing, delivery and fate of cargo. Drawing upon insights from model organisms and mammalian cells we show how eNHE affect surface expression and function of membrane receptors and neurotransmitter transporters. These studies lead to cellular models of eNHE activity in pre- and post-synaptic neurons and astrocytes, where they could impact synapse development and plasticity. The study of eNHE has provided new insight on the mechanism of autism and other debilitating neurological disorders and opened up new possibilities for therapeutic intervention.
Collapse
Affiliation(s)
| | | | - Rajini Rao
- Department of Physiology, The Johns Hopkins University School of MedicineBaltimore, MD, USA
| |
Collapse
|
22
|
Abstract
"Angelman syndrome" (AS) is a neurodevelopmental disorder whose main features are intellectual disability, lack of speech, seizures, and a characteristic behavioral profile. The behavioral features of AS include a happy demeanor, easily provoked laughter, short attention span, hypermotoric behavior, mouthing of objects, sleep disturbance, and an affinity for water. Microcephaly and subtle dysmorphic features, as well as ataxia and other movement disturbances, are additional features seen in most affected individuals. AS is due to deficient expression of the ubiquitin protein ligase E3A (UBE3A) gene, which displays paternal imprinting. There are four molecular classes of AS, and some genotype-phenotype correlations have emerged. Much remains to be understood regarding how insufficiency of E6-AP, the protein product of UBE3A, results in the observed neurodevelopmental deficits. Studies of mouse models of AS have implicated UBE3A in experience-dependent synaptic remodeling.
Collapse
Affiliation(s)
- Lynne M Bird
- Department of Pediatrics, University of California, Division of Genetics, Rady Children’s Hospital, San Diego, California, USA
| |
Collapse
|
23
|
Heald M, Allen D, Villa D, Oliver C. Discrimination training reduces high rate social approach behaviors in Angelman syndrome: proof of principle. RESEARCH IN DEVELOPMENTAL DISABILITIES 2013; 34:1794-1803. [PMID: 23518390 DOI: 10.1016/j.ridd.2013.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 02/06/2013] [Accepted: 02/08/2013] [Indexed: 06/01/2023]
Abstract
This proof of principle study was designed to evaluate whether excessively high rates of social approach behaviors in children with Angelman syndrome (AS) can be modified using a multiple schedule design. Four children with AS were exposed to a multiple schedule arrangement, in which social reinforcement and extinction, cued using a novel stimulus, were alternated. Twenty-five to 35 discrimination training sessions were conducted and levels of approach behaviors were measured before and after the discrimination training for two children. All four participants evidenced discrimination between conditions of reinforcement and extinction after 16-20 teaching sessions as indicated by lower rates of social approach behaviors in the presence of the S(Δ) for extinction. Reversal effects for the two children for whom this design was implemented were evident. The results demonstrate that after repeated training, the use of a novel stimulus can serve as a cue for children with AS to discriminate adult availability. This is a potentially effective component of a broader intervention strategy but highlights the need for sustained teaching procedures within this population.
Collapse
Affiliation(s)
- M Heald
- Cerebra Centre for Neurodevelopmental Disorders, School of Psychology, University of Birmingham, Edgbaston B15 2TT, UK.
| | | | | | | |
Collapse
|
24
|
Daily J, Smith AG, Weeber EJ. Spatial and temporal silencing of the human maternal UBE3A gene. Eur J Paediatr Neurol 2012; 16:587-91. [PMID: 22560727 PMCID: PMC3419305 DOI: 10.1016/j.ejpn.2012.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 02/10/2012] [Accepted: 03/17/2012] [Indexed: 01/21/2023]
Abstract
Angelman syndrome (AS) is characterized by severe cognitive disruption, seizures, difficulty speaking and ataxia. Nearly all cases are attributed to the disruption or absence of the imprinted maternal copy of UBE3A, transcribing an E3-type ubiquitin ligase. Much of what is known about the molecular and biochemical changes in the CNS associated with AS has been obtained through this murine model. This widely used mouse model created by a null mutation of the maternal UBE3A gene recapitulates the major phenotypes characteristic of AS patients. The imprinting of maternal UBE3A was originally believed to be brain region specific; however recent reports using the AS mouse model have revealed a more wide-spread absence of the protein. The present study is the first to determine that the Ube3a protein ablation seen in the AS mouse model is also characteristic of AS patients and the silencing of the paternal UBE3A allele appears to be lifelong.
Collapse
Affiliation(s)
- Jennifer Daily
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | | | | |
Collapse
|
25
|
Understanding the pathogenesis of Angelman syndrome through animal models. Neural Plast 2012; 2012:710943. [PMID: 22830052 PMCID: PMC3399338 DOI: 10.1155/2012/710943] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 05/10/2012] [Accepted: 05/11/2012] [Indexed: 01/08/2023] Open
Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder characterized by severe mental retardation, lack of speech, ataxia, susceptibility to seizures, and unique behavioral features such as easily provoked smiling and laughter and autistic features. The disease is primarily caused by deletion or loss-of-function mutations of the maternally inherited UBE3A gene located within chromosome 15q11-q13. The UBE3A gene encodes a 100 kDa protein that functions as ubiquitin ligase and transcriptional coactivator. Emerging evidence now indicates that UBE3A plays a very important role in synaptic function and in regulation of activity-dependent synaptic plasticity. A number of animal models for AS have been generated to understand the disease pathogenesis. The most widely used model is the UBE3A-maternal-deficient mouse that recapitulates most of the essential features of AS including cognitive and motor abnormalities. This paper mainly discusses various animal models of AS and how these models provide fundamental insight into understanding the disease biology for potential therapeutic intervention.
Collapse
|
26
|
Park SH, Yoon JR, Kim HD, Lee JS, Lee YM, Kang HC. Epilepsy in Korean patients with Angelman syndrome. KOREAN JOURNAL OF PEDIATRICS 2012; 55:171-6. [PMID: 22670152 PMCID: PMC3362731 DOI: 10.3345/kjp.2012.55.5.171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/07/2011] [Accepted: 12/15/2011] [Indexed: 11/30/2022]
Abstract
Purpose The aim of this study was to investigate the natural history of epilepsy and response to anti-epileptic drug treatment in patients with Angelman syndrome (AS) in Korea. Methods We retrospectively reviewed the clinical records of 14 patients diagnosed with epilepsy out of a total of 17 patients with a genetic diagnosis of AS. These patients were seen at the Department of Pediatric Neurology at Severance Children's Hospital from March 2005 to March 2011. Results Fourteen (9 males and 5 females) subjects (82.3%) were diagnosed with epilepsy in AS. The most common seizure types were generalized tonic-clonic (n=9, 27%) and myoclonic (n=9, 27%), followed by atonic (n=8, 24%), atypical absence (n=4, 12%) and complex partial seizure (n=3, 9%). The most commonly prescribed antiepileptic drug (AED) was valproic acid (VPA, n=12, 86%), followed by lamotrigine (LTG, n=9, 64%), and topiramate (n=8, 57%). According to questionnaires that determined whether each AED was efficacious or not, VPA had the highest response rate and LTG was associated with the highest rate of seizure exacerbation. Complete control of seizures was achieved in 6 patients. Partial control was achieved in 7 patients, while one patient was not controlled. Conclusion Epilepsy is observed in the great majority of AS patients. It may have early onset and is often refractory to treatment. There are few reports about epilepsy in AS in Korea. This study will be helpful in understanding epilepsy in AS in Korea.
Collapse
Affiliation(s)
- Sung-Hee Park
- Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital, Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | | | | | | | | | | |
Collapse
|
27
|
Prasad AN, Rupar CA, Prasad C. Methylenetetrahydrofolate reductase (MTHFR) deficiency and infantile epilepsy. Brain Dev 2011; 33:758-69. [PMID: 21778025 DOI: 10.1016/j.braindev.2011.05.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/18/2011] [Accepted: 05/31/2011] [Indexed: 12/11/2022]
Abstract
OBJECTIVES A recessively inherited defect leading to deficiency of the enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) underlies one form of hyperhomocysteinemia. We describe the association of severe MTHFR deficiency and neurological manifestations with particular attention to neurodevelopment and evolution of epileptic seizures. METHODS Case study and review of literature. RESULTS A 9 year old female infant born to Caucasian non-consanguineous parents presented with infantile spasms and developmental regression in the first year. The biochemical profile of low plasma methionine (below detectable limits), and slightly elevated homocystine (3 μmol/L (0-trace) and homocystinuria (234 μmol/gm creatinine) (0-trace amounts) was suggestive of a disturbance in homocysteine metabolism. Plasma homocysteine measurements (30.7 μmol/L, normal <13.5 μmol/L) confirmed hyperhomocysteinemia. Enzyme assay in skin fibroblasts confirmed severe MTHFR deficiency (patient 0.92, control 13.3±4.6nmol/mg/h). Molecular genetic studies identified compound heterozygosity for 2 variant polymorphisms (c.677C>T, and c.1298A>C) and a splicing mutation (c.1348+1G>A). This is a novel mutation that removes a splice site at the end of exon 7 resulting in a premature stop codon that truncates the protein, losing exons 8-11. CSF neurotransmitter analysis showed an extremely low level of 5-methyl tetrahydrofolate of <5 (40-128 nmol/L). The course of epilepsy has been characterized by progression to severe epileptic encephalopathy. Periventricular white matter change consistent with demyelination is seen on MR imaging. Treatment protocols include; oral betaine, supplementation with methionine, folic acid, and 5-methyltetrahydrofolate with questionable benefit. Epileptic seizures remain pharmacoresistant to antiepileptic medications singly and in combinations. Frequent bouts of status epilepticus have led to multiple hospitalizations, and neurosurgical interventions (corpus callosotomy, vagal nerve stimulation). At age 9 years, the patient remains severely impaired by vertebral compressive and limb fractures secondary to severe osteoporosis. CONCLUSION Severe MTHFR deficiency is an important diagnostic consideration in infantile epileptic encephalopathies. Early diagnosis and specific treatment interventions are possible. Further research is needed into effective treatment of epilepsy and prevention of complications in this disorder. Genotype and phenotype correlations will be explored in the light of available biochemical and molecular genetic data.
Collapse
Affiliation(s)
- Asuri N Prasad
- Department of Pediatrics, University of Western Ontario, London, Canada.
| | | | | |
Collapse
|
28
|
Establishment of the first WHO international genetic reference panel for Prader Willi and Angelman syndromes. Eur J Hum Genet 2011; 19:857-64. [PMID: 21587322 DOI: 10.1038/ejhg.2011.59] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prader Willi and Angelman syndromes are clinically distinct genetic disorders both mapping to chromosome region 15q11-q13, which are caused by a loss of function of paternally or maternally inherited genes in the region, respectively. With clinical diagnosis often being difficult, particularly in infancy, confirmatory genetic diagnosis is essential to enable clinical intervention. However, the latter is challenged by the complex genetics behind both disorders and the unmet need for characterised reference materials to aid accurate molecular diagnosis. With this in mind, a panel of six genotyping reference materials for Prader Willi and Angelman syndromes was developed, which should be stable for many years and available to all diagnostic laboratories. The panel comprises three Prader Willi syndrome materials (two with different paternal deletions, and one with maternal uniparental disomy (UPD)) and three Angelman syndrome materials (one with a maternal deletion, one with paternal UPD or an epigenetic imprinting centre defect, and one with a UBE3A point mutation). Genomic DNA was bulk-extracted from Epstein-Barr virus-transformed lymphoblastoid cell lines established from consenting patients, and freeze-dried as aliquots in glass ampoules. In total, 37 laboratories from 26 countries participated in a collaborative study to assess the suitability of the panel. Participants evaluated the blinded, triplicate materials using their routine diagnostic methods against in-house controls or externally sourced uncertified reference materials. The panel was established by the Expert Committee on Biological Standardization of the World Health Organization as the first International Genetic Reference Panel for Prader Willi and Angelman syndromes.
Collapse
|
29
|
Adams D, Horsler K, Oliver C. Age related change in social behavior in children with Angelman syndrome. Am J Med Genet A 2011; 155A:1290-7. [PMID: 21567915 DOI: 10.1002/ajmg.a.33964] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 12/30/2010] [Indexed: 11/06/2022]
Abstract
We investigated the relationship between age and laughing and smiling in children with Angelman syndrome. Twenty-four children with Angelman syndrome were exposed to three experimentally manipulated conditions: proximity only, restricted social interaction, and social interaction. Children smiled the most in the social interaction condition and the least in the proximity only condition confirming the effect of social interaction on these behaviors. There was a decline in smiling and laughing in the oldest group (13.4-15.9 years) only in the social interaction condition. This trajectory of a decline in resource soliciting behaviors with age is consistent with predictions based on kinship theory.
Collapse
Affiliation(s)
- Dawn Adams
- Cerebra Centre for Neurodevelopmental Disorders, School of Psychology, University of Birmingham, UK
| | | | | |
Collapse
|
30
|
Tan WH, Bacino CA, Skinner SA, Anselm I, Barbieri-Welge R, Bauer-Carlin A, Beaudet AL, Bichell TJ, Gentile JK, Glaze DG, Horowitz LT, Kothare SV, Lee HS, Nespeca MP, Peters SU, Sahoo T, Sarco D, Waisbren SE, Bird LM. Angelman syndrome: Mutations influence features in early childhood. Am J Med Genet A 2011; 155A:81-90. [PMID: 21204213 PMCID: PMC3563320 DOI: 10.1002/ajmg.a.33775] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder caused by a lack of expression of the maternal copy of UBE3A. Although the "classic" features of AS are well described, few large-scale studies have delineated the clinical features in AS. We present baseline data from 92 children with a molecular diagnosis of AS between 5 and 60 months old who are enrolled in the National Institutes of Health Rare Diseases Clinical Research Network Angelman Syndrome Natural History Study from January 2006 to March 2008. Seventy-four percent of participants had deletions, 14% had either uniparental disomy (UPD) or imprinting defects, and 12% had UBE3A mutations. Participants with UPD/imprinting defects were heavier (P = 0.0002), while those with deletions were lighter, than the general population (P < 0.0001). Twenty out of 92 participants were underweight, all of whom had deletions or UBE3A mutations. Eight out of 92 participants (6/13 (46%) with UPD/imprinting defects and 2/11 (18%) with UBE3A mutations) were obese. Seventy-four out of 92 participants (80%) had absolute or relative microcephaly. No participant was macrocephalic. The most common behavioral findings were mouthing behavior (95%), short attention span (92%), ataxic or broad-based gait (88%), history of sleep difficulties (80%), and fascination with water (75%). Frequent, easily provoked laughter was observed in 60%. Clinical seizures were reported in 65% of participants but all electroencephalograms (EEGs) were abnormal. We conclude that the most characteristic feature of AS is the neurobehavioral phenotype, but specific EEG findings are highly sensitive for AS. Obesity is common among those with UPD/imprinting defects.
Collapse
Affiliation(s)
- Wen-Hann Tan
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Division of Genetics, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Carlos A. Bacino
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Kleberg Genetics Clinic, Texas Children’s Hospital; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Steven A. Skinner
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Greenwood Genetic Center, Greenwood, South Carolina
| | - Irina Anselm
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Neurology, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Rene Barbieri-Welge
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Developmental Services, Rady Children’s Hospital San Diego, San Diego, California
| | - Astrid Bauer-Carlin
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Greenwood Genetic Center, Greenwood, South Carolina
| | - Arthur L. Beaudet
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Kleberg Genetics Clinic, Texas Children’s Hospital; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Terry Jo Bichell
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Vanderbilt Kennedy Center, Vanderbilt University, Nashville, Tennessee
| | - Jennifer K. Gentile
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Psychiatry, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Daniel G. Glaze
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Texas Children’s Hospital; Section of Neurology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Lucia T. Horowitz
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Greenwood Genetic Center, Greenwood, South Carolina
| | - Sanjeev V. Kothare
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Neurology, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Hye-Seung Lee
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Pediatric Epidemiology Center, Department of Pediatrics, University of South Florida, Tampa, Florida
| | - Mark P. Nespeca
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Division of Neurology, Rady Children’s Hospital San Diego, Department of Neuroscience, University of California, San Diego, California
| | - Sarika U. Peters
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Meyer Center for Developmental Pediatrics, Texas Children’s Hospital; Section of Developmental Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Trilochan Sahoo
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Dean Sarco
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Neurology, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Susan E. Waisbren
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Department of Psychiatry, Children’s Hospital Boston; Harvard Medical School, Boston, Massachusetts
| | - Lynne M. Bird
- NIH Rare Diseases Clinical Research Network—Angelman, Rett, & Prader-Willi Syndromes Consortium
- Division of Genetics/Dysmorphology, Rady Children’s Hospital San Diego; Department of Pediatrics, University of California, San Diego, California
| |
Collapse
|
31
|
Ohgaki R, van IJzendoorn SCD, Matsushita M, Hoekstra D, Kanazawa H. Organellar Na+/H+ exchangers: novel players in organelle pH regulation and their emerging functions. Biochemistry 2010; 50:443-50. [PMID: 21171650 DOI: 10.1021/bi101082e] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Mammalian Na+/H+ exchangers (NHEs) play a fundamental role in cellular ion homeostasis. NHEs exhibit an appreciable variation in expression, regulation, and physiological function, dictated by their dynamics in subcellular localization and/or interaction with regulatory proteins. In recent years, a subgroup of NHEs consisting of four isoforms has been identified, and its members predominantly localize to the membranes of the Golgi apparatus and endosomes. These organellar NHEs constitute a family of transporters with an emerging function in the regulation of luminal pH and in intracellular membrane trafficking as expressed, for example, in cell polarity development. Moreover, specific roles of a variety of cofactors, regulating the intracellular dynamics of these transporters, are also becoming apparent, thereby providing further insight into their mechanism of action and overall functioning. Interestingly, organellar NHEs have been related to mental disorders, implying a potential role in the brain, thus expanding the physiological significance of these transporters.
Collapse
Affiliation(s)
- Ryuichi Ohgaki
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, Japan
| | | | | | | | | |
Collapse
|
32
|
Buiting K. Prader-Willi syndrome and Angelman syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:365-76. [DOI: 10.1002/ajmg.c.30273] [Citation(s) in RCA: 247] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
33
|
Ramsden SC, Clayton-Smith J, Birch R, Buiting K. Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes. BMC MEDICAL GENETICS 2010; 11:70. [PMID: 20459762 PMCID: PMC2877670 DOI: 10.1186/1471-2350-11-70] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 05/11/2010] [Indexed: 11/26/2022]
Abstract
Background Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are clinically distinct neurodevelopmental genetic disorders that map to 15q11-q13. The primary phenotypes are attributable to loss of expression of imprinted genes within this region which can arise by means of a number of mechanisms. The most sensitive single approach to diagnosing both PWS and AS is to study methylation patterns within 15q11-q13; however many techniques exist for this purpose. Given the diversity of techniques available, there is a need for consensus testing and reporting guidelines. Methods Testing and reporting guidelines have been drawn up and agreed in accordance with the procedures of the UK Clinical Molecular Genetics Society and the European Molecular Genetics Quality Network. Results A practical set of molecular genetic testing and reporting guidelines has been developed for these two disorders. In addition, advice is given on appropriate reporting policies, including advice on test sensitivity and recurrence risks. In considering test sensitivity, the possibility of differential diagnoses is discussed. Conclusion An agreed set of practice guidelines has been developed for the diagnostic molecular genetic testing of PWS and AS.
Collapse
Affiliation(s)
- Simon C Ramsden
- National Genetics Reference Laboratory (Manchester), Saint Mary's Hospital, Hathersage Road, Manchester M13OJH, UK.
| | | | | | | |
Collapse
|
34
|
Abstract
AIMS Over the past decade, genetic tests have become available for numerous heritable disorders, especially those whose inheritance follows the Mendelian model. Autism spectrum disorders (ASDs) represent a group of developmental disorders with a strong genetic basis. During the past few years, genetic research in ASDs has been successful in identifying several vulnerability loci and a few cytogenetic abnormalities or single-base mutations implicated in the causation of autism. METHOD In this study the literature was reviewed to highlight genotype-phenotype correlations between causal gene mutations or cytogenetic abnormalities and behavioural or morphological phenotypes. RESULTS Based on this knowledge, practical information is offered to help clinicians pursue targeted genetic testing of individuals with autism whose clinical phenotype is suggestive of a specific genetic or genomic aetiology. INTERPRETATION Comprehensive research into the molecular mechanism of autism is required to aid the development of disease-specific targeted therapies. In order to transfer this recently acquired knowledge into clinical practice, it is critical to define a set of phenotypic inclusion criteria that must be met by affected probands to justify their enrolment in a specific genetic testing programme.
Collapse
Affiliation(s)
- Ahmet O Caglayan
- Kayseri Education and Research Hospital, Department of Medical Genetics, Kayseri, Turkey.
| |
Collapse
|
35
|
Thibert RL, Conant KD, Braun EK, Bruno P, Said RR, Nespeca MP, Thiele EA. Epilepsy in Angelman syndrome: A questionnaire-based assessment of the natural history and current treatment options. Epilepsia 2009; 50:2369-76. [PMID: 19453717 DOI: 10.1111/j.1528-1167.2009.02108.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ronald L Thibert
- Department of Neurology, Pediatric Epilepsy Program, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | | | | | | | | | | | | |
Collapse
|
36
|
González Alvaredo S, Sanz Rojo R, García Santiago J, Gaztañaga Expósito R, Bengoa A, Pérez-Yarza EG. [Genetic diagnostic criteria in cases of mental retardation and development of idiopathic origin]. An Pediatr (Barc) 2009; 69:446-53. [PMID: 19128747 DOI: 10.1157/13128001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Different studies show that mental retardation affects 1-3% of the population, and in about 50 % of the cases the aetiology is unknown. The uncertainty on the aetiology, and recurrence, means that prevention of mental retardation can have serious, therapeutic, social, and even economic repercussions. The key is to obtain an accurate diagnosis, proving a clinical hypothesis by the accomplishment of the most suitable genetic tests. Due to the increasing development of the technology in the field of the genetics, and the availability of new tests, this article reviews the criteria established in the practice guidelines from different scientific societies (paediatric, neurological and genetic) with respect to their use in diagnosis and integrates them from the point of view of their use in mental retardation and developmental delay.
Collapse
Affiliation(s)
- S González Alvaredo
- Laboratorio de Genética, Hospital Donostia, Donostia-San Sebastián, Guipúzcoa, Spain.
| | | | | | | | | | | |
Collapse
|
37
|
Abstract
Adenylosuccinate lyase deficiency is a rare autosomal disorder of de novo purine synthesis, which results in the accumulation of succinylpurines in body fluids. Patients with adenylosuccinate lyase deficiency show a variable combination of mental retardation, epilepsy and autistic features and are usually discovered during screens for unexplained encephalopathy using the Bratton-Marshall assay that reveals the excretion of the succinylaminoimidazolecarboxamide riboside (SAICAr). Here, we report on two sisters aged 11 and 12 years presented with global developmental delay, motor apraxia, severe speech deficits, seizures and behavioural features, which combined excessive laughter, a very happy disposition, hyperactivity, a short attention span, the mouthing of objects, tantrums and stereotyped movements that gave a behavioural profile mimicking Angelman syndrome. Both patients had an increased succinyladenosine/SAICAr ratio of 1.6, and exhibited a novel homozygous missense mutation (c.674T>C; p.Met225Thr) in the exon 6 of the ADSL gene. We suggest that these clinical features might be a new presentation of adenylosuccinate lyase deficiency. On the basis of this observation, although adenylosuccinate lyase deficiency is a rare disorder, this diagnosis should be considered in patients with mental retardation and a behavioural profile suggestive of Angelman syndrome.
Collapse
|
38
|
Crespi B. Genomic imprinting in the development and evolution of psychotic spectrum conditions. Biol Rev Camb Philos Soc 2008; 83:441-93. [PMID: 18783362 DOI: 10.1111/j.1469-185x.2008.00050.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
I review and evaluate genetic and genomic evidence salient to the hypothesis that the development and evolution of psychotic spectrum conditions have been mediated in part by alterations of imprinted genes expressed in the brain. Evidence from the genetics and genomics of schizophrenia, bipolar disorder, major depression, Prader-Willi syndrome, Klinefelter syndrome, and other neurogenetic conditions support the hypothesis that the etiologies of psychotic spectrum conditions commonly involve genetic and epigenetic imbalances in the effects of imprinted genes, with a bias towards increased relative effects from imprinted genes with maternal expression or other genes favouring maternal interests. By contrast, autistic spectrum conditions, including Kanner autism, Asperger syndrome, Rett syndrome, Turner syndrome, Angelman syndrome, and Beckwith-Wiedemann syndrome, commonly engender increased relative effects from paternally expressed imprinted genes, or reduced effects from genes favouring maternal interests. Imprinted-gene effects on the etiologies of autistic and psychotic spectrum conditions parallel the diametric effects of imprinted genes in placental and foetal development, in that psychotic spectrum conditions tend to be associated with undergrowth and relatively-slow brain development, whereas some autistic spectrum conditions involve brain and body overgrowth, especially in foetal development and early childhood. An important role for imprinted genes in the etiologies of psychotic and autistic spectrum conditions is consistent with neurodevelopmental models of these disorders, and with predictions from the conflict theory of genomic imprinting.
Collapse
Affiliation(s)
- Bernard Crespi
- Department of Biosciences, Simon Fraser University, Burnaby BCV5A1S6, Canada.
| |
Collapse
|
39
|
Sadikovic B, Al-Romaih K, Squire J, Zielenska M. Cause and consequences of genetic and epigenetic alterations in human cancer. Curr Genomics 2008; 9:394-408. [PMID: 19506729 PMCID: PMC2691666 DOI: 10.2174/138920208785699580] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/06/2008] [Accepted: 05/08/2008] [Indexed: 12/16/2022] Open
Abstract
Both genetic and epigenetic changes contribute to development of human cancer. Oncogenomics has primarily focused on understanding the genetic basis of neoplasia, with less emphasis being placed on the role of epigenetics in tumourigenesis. Genomic alterations in cancer vary between the different types and stages, tissues and individuals. Moreover, genomic change ranges from single nucleotide mutations to gross chromosomal aneuploidy; which may or may not be associated with underlying genomic instability. Collectively, genomic alterations result in widespread deregulation of gene expression profiles and the disruption of signalling networks that control proliferation and cellular functions. In addition to changes in DNA and chromosomes, it has become evident that oncogenomic processes can be profoundly influenced by epigenetic mechanisms. DNA methylation is one of the key epigenetic factors involved in regulation of gene expression and genomic stability, and is biologically necessary for the maintenance of many cellular functions. While there has been considerable progress in understanding the impact of genetic and epigenetic mechanisms in tumourigenesis, there has been little consideration of the importance of the interplay between these two processes. In this review we summarize current understanding of the role of genetic and epigenetic alterations in human cancer. In addition we consider the associated interactions of genetic and epigenetic processes in tumour onset and progression. Furthermore, we provide a model of tumourigenesis that addresses the combined impact of both epigenetic and genetic alterations in cancer cells.
Collapse
Affiliation(s)
- B Sadikovic
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada
- The Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada
| | - K Al-Romaih
- The Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada
| | - J.A Squire
- The Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada
| | - M Zielenska
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada
| |
Collapse
|
40
|
Abstract
Angelman syndrome has been suggested as a disease model of neurogenetic developmental condition with a specific behavioral phenotype. It is due to lack of expression of the UBE3A gene, an imprinted gene located on chromosome 15q. Here we review the main features of this phenotype, characterized by happy demeanor with prominent smiling, poorly specific laughing and general exuberance, associated with hypermotor behavior, stereotypies, and reduced behavioral adaptive skills despite proactive social contact. All these phenotypic characteristics are currently difficult to quantify and have been subject to some differences in interpretation. For example, prevalence of autistic disorder is still debated. Many of these features may occur in other syndromic or nonsyndromic forms of severe intellectual disability, but their combination, with particularly prominent laughter and smiling may be specific of Angelman syndrome. Management of problematic behaviors is primarily based on behavioral approaches, though psychoactive medication (eg, neuroleptics or antidepressants) may be required.
Collapse
Affiliation(s)
- Karine Pelc
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB)Brussels, Belgium
| | - Guy Cheron
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles (ULB)Brussels, Belgium
| | - Bernard Dan
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB)Brussels, Belgium
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles (ULB)Brussels, Belgium
| |
Collapse
|
41
|
Davies W, Lynn PMY, Relkovic D, Wilkinson LS. Imprinted genes and neuroendocrine function. Front Neuroendocrinol 2008; 29:413-27. [PMID: 18206218 DOI: 10.1016/j.yfrne.2007.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 11/20/2007] [Accepted: 12/03/2007] [Indexed: 12/28/2022]
Abstract
Imprinted genes are monoallelically expressed in a parent-of-origin dependent manner. Whilst the full functional repertoire of these genes remains obscure, they are generally highly expressed in the brain and are often involved in fundamental neural processes. Besides influencing brain neurochemistry, imprinted genes are important in the development and function of the hypothalamus and pituitary gland, key sites of neuroendocrine regulation. Moreover, imprinted genes may directly modulate hormone-dependent signalling cascades, both in the brain and elsewhere. Much of our knowledge about imprinted gene function has come from studying knockout mice and human disorders of imprinting. One such disorder is Prader-Willi syndrome, a neuroendocrine disorder characterised by hypothalamic abnormalities and aberrant feeding behaviour. Through examining the role of imprinted genes in neuroendocrine function, it may be possible to shed light on the neurobiological basis of feeding and aspects of social behaviour and underlying cognition, and to provide insights into disorders where these functions go awry.
Collapse
Affiliation(s)
- William Davies
- Behavioural Genetics Group, Department of Psychological Medicine and School of Psychology, School of Medicine, University of Cardiff, Cardiff, UK.
| | | | | | | |
Collapse
|
42
|
Mowat--Wilson syndrome: the clinical report with the novel mutation in ZFHX1B (exon 8: c.2372del C; p.T791fsX816). Childs Nerv Syst 2008; 24:615-8. [PMID: 18259761 DOI: 10.1007/s00381-007-0557-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 06/25/2007] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Mowat-Wilson syndrome is a congenital syndrome caused by a defect of the transcriptional repressor ZFHX1B (SIP1) gene on the chromosome 2q22-q23. The genotype-phenotype analysis confirmed that ZFHX1B deletions and mutations result in a recognizable facial dysmorphism with a multiple congenital anomaly and mental retardation. CASE REPORT This report is about one new patient from Croatia with the typical phenotype. Molecular genetic studies showed the novel mutation in ZFHX1B (exon 8: c.2372del C; p.T791fsX816). This mutation has not been reported before. The literature is reviewed. CONCLUSION Mowat-Wilson syndrome is a newly described congenital syndrome and should be considered in any individual with characteristic facial features and mental retardation in associations with congenital malformations.
Collapse
|
43
|
SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome. Am J Hum Genet 2008; 82:1003-10. [PMID: 18342287 PMCID: PMC2427207 DOI: 10.1016/j.ajhg.2008.01.013] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 12/20/2007] [Accepted: 01/09/2008] [Indexed: 12/20/2022] Open
Abstract
Linkage analysis and DNA sequencing in a family exhibiting an X-linked mental retardation (XLMR) syndrome, characterized by microcephaly, epilepsy, ataxia, and absent speech and resembling Angelman syndrome, identified a deletion in the SLC9A6 gene encoding the Na(+)/H(+) exchanger NHE6. Subsequently, other mutations were found in a male with mental retardation (MR) who had been investigated for Angelman syndrome and in two XLMR families with epilepsy and ataxia, including the family designated as having Christianson syndrome. Therefore, mutations in SLC9A6 cause X-linked mental retardation. Additionally, males with findings suggestive of unexplained Angelman syndrome should be considered as potential candidates for SLC9A6 mutations.
Collapse
|
44
|
Ronan A, Buiting K, Dudding T. Atypical Angelman syndrome with macrocephaly due to a familial imprinting center deletion. Am J Med Genet A 2007; 146A:78-82. [DOI: 10.1002/ajmg.a.31952] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
45
|
Walz NC. Parent Report of Stereotyped Behaviors, Social Interaction, and Developmental Disturbances in Individuals with Angelman Syndrome. J Autism Dev Disord 2006; 37:940-7. [PMID: 17019625 DOI: 10.1007/s10803-006-0233-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Research examining autistic symptoms in Angelman syndrome (AS) is limited. The goal of this study was to further characterize the nature of stereotyped behaviors, social interaction deficits, and developmental disturbances in individuals with AS. Parents of 248 individuals between the ages of 3 and 22 completed a survey of autistic symptomatology by mail, the Gilliam Autism Rating Scale. Results confirmed a high degree of developmental delay and limited expressive language skills. In terms of stereotyped behaviors and social interaction, areas of convergence and divergence between AS and behaviors typically associated with autism spectrum disorders are described. The relationship between child characteristics (age, gender, seizure disorder, genetic subtype) and autistic symptomatology are discussed.
Collapse
Affiliation(s)
- Nicolay Chertkoff Walz
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MLC 3015, Cincinnati, OH 45229-3039, USA.
| |
Collapse
|
46
|
Abstract
PURPOSE Clinical geneticists are often asked to evaluate patients with autism spectrum disorders (ASDs) in reference to questions about cause and recurrence risk. Recent advances in diagnostic testing technology have greatly increased the options available to them. It is not currently clear what the overall diagnostic yield of a battery of tests, either collectively or individually, might be. The purpose of this study was to evaluate the diagnostic yield of a stepwise approach we have implemented in our clinics. METHODS We used a three-tiered neurogenetic evaluation scheme designed to determine the cause of ASDs in patients referred for clinical genetic consultation. We reviewed the results of our diagnostic evaluations on all patients referred with a confirmed diagnosis of autism over a 3-year period. RESULTS By using this approach, we found an overall diagnostic yield for ASDs of more than 40%. This represents a significant increase in the diagnostic yield reported just a few years ago. CONCLUSIONS Given the implications of these diagnoses on recurrence risk and associated medical conditions, a targeted neurogenetic evaluation of all persons with ASDs seems warranted. We discuss the issues in the future implementation of a fourth tier to the evaluation with the potential for an even higher diagnostic yield.
Collapse
Affiliation(s)
- G Bradley Schaefer
- Munroe-Meyer Institute for Genetics and Rehabilitation, 985430 University of Nebraska Medical Center, Omaha, NE 68198, USA
| | | |
Collapse
|
47
|
Santos M, Coelho PA, Maciel P. Chromatin remodeling and neuronal function: exciting links. GENES BRAIN AND BEHAVIOR 2006; 5 Suppl 2:80-91. [PMID: 16681803 DOI: 10.1111/j.1601-183x.2006.00227.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Regulation of gene expression occurs at different levels, from DNA to protein, and through various mechanisms. One of them is modification of the chromatin structure, which is involved in the definition of transcriptional active and inactive regions of the chromosomes. These phenomena are associated with reversible chemical modifications of the genetic material rather than with variability within the DNA sequences inherited by the individual and are therefore called 'epigenetic' modifications. Ablation of the molecular players responsible for epigenetic modifications often gives rise to neurological and behavioral phenotypes in humans and in mouse models, suggesting a relevant function for chromatin remodeling in central nervous system function, particularly in the adaptive response of the brain to stimuli. We will discuss several human disorders that are due to altered epigenetic mechanisms, with special focus on Rett syndrome.
Collapse
Affiliation(s)
- M Santos
- Life and Health Sciences Research Institute, Health Sciences School, University of Minho, Braga, Portugal
| | | | | |
Collapse
|
48
|
Williams CA, Beaudet AL, Clayton-Smith J, Knoll JH, Kyllerman M, Laan LA, Magenis RE, Moncla A, Schinzel AA, Summers JA, Wagstaff J. Angelman syndrome 2005: updated consensus for diagnostic criteria. Am J Med Genet A 2006; 140:413-8. [PMID: 16470747 DOI: 10.1002/ajmg.a.31074] [Citation(s) in RCA: 412] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 1995, a consensus statement was published for the purpose of summarizing the salient clinical features of Angelman syndrome (AS) to assist the clinician in making a timely and accurate diagnosis. Considering the scientific advances made in the last 10 years, it is necessary now to review the validity of the original consensus criteria. As in the original consensus project, the methodology used for this review was to convene a group of scientists and clinicians, with experience in AS, to develop a concise consensus statement, supported by scientific publications where appropriate. It is hoped that this revised consensus document will facilitate further clinical study of individuals with proven AS, and assist in the evaluation of those who appear to have clinical features of AS but have normal laboratory diagnostic testing.
Collapse
Affiliation(s)
- Charles A Williams
- Department of Pediatrics, Division of Genetics, R.C. Philips Unit, University of Florida, Gainesville, Florida 32610, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Venturin M, Moncini S, Villa V, Russo S, Bonati MT, Larizza L, Riva P. Mutations and novel polymorphisms in coding regions and UTRs of CDK5R1 and OMG genes in patients with non-syndromic mental retardation. Neurogenetics 2006; 7:59-66. [PMID: 16425041 DOI: 10.1007/s10048-005-0026-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Accepted: 11/29/2005] [Indexed: 11/25/2022]
Abstract
Mental retardation (MR) is displayed by 57% of NF1 patients with microdeletion syndrome as a result of 17q11.2 region haploinsufficiency. We considered the cyclin-dependent kinase 5 regulatory subunit 1 (CDK5R1) and oligodendrocyte-myelin glycoprotein (OMG) genes, mapping in the NF1 microdeleted region, as candidate genes for MR susceptibility. CDK5R1 encodes for a neurone-specific activator of cyclin-dependent kinase 5 (CDK5) involved in neuronal migration during central nervous system development. OMG encodes for an inhibitor of neurite outgrowth by the binding to the Nogo-66 receptor (RTN4R). CDK5R1 and OMG genes are characterized by large 3' and 5' untranslated regions (UTRs), where we predict the presence of several transcription/translation regulatory elements. We screened 100 unrelated Italian patients affected by unspecific MR for mutations in CDK5R1 and OMG coding regions and in their 3' or 5' UTRs. Four novel mutations and two novel polymorphisms for CDK5R1 and three novel mutations for OMG were detected, including two missense changes (c.323C>T; A108V in CDK5R1 and c.1222A>G; T408A in OMG), one synonymous codon variant (c.532C>T; L178L in CDK5R1), four variants in CDK5R1 3'UTR and two changes in OMG 5'UTR. All the mutations were absent in 370 chromosomes from normal subjects. The allelic frequencies of the two novel polymorphisms in CDK5R1 3'UTR were established in both 185 normal and 100 mentally retarded subjects. Prediction of mRNA and protein secondary structures revealed that two changes lead to putative structural alterations in the mutated c.2254C>G CDK5R1 3'UTR and in OMG T408A gene product.
Collapse
Affiliation(s)
- Marco Venturin
- Department of Biology and Genetics, Medical Faculty, University of Milan, Via Viotti 3/5, 20133, Milan, Italy
| | | | | | | | | | | | | |
Collapse
|
50
|
Oiglane-Shlik E, Talvik T, Zordania R, Põder H, Kahre T, Raukas E, Ilus T, Tasa G, Bartsch O, Väisänen ML, Ounap K. Prevalence of Angelman syndrome and Prader–Willi syndrome in Estonian children: Sister syndromes not equally represented. Am J Med Genet A 2006; 140:1936-43. [PMID: 16906556 DOI: 10.1002/ajmg.a.31423] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In 2000-2004, we performed a focused search for individuals with Angelman syndrome (AS) and Prader-Willi syndrome (PWS) aiming to establish the prevalence data for the individuals born between 1984 and 2004 in Estonia. All persons with probable AS or PWS (n = 184) were studied using the DNA methylation test. Individuals with abnormal methylation were all further tested by chromosomal and FISH analysis, and if necessary for uniparental disomy and UBE3A gene mutation. Nineteen cases with abnormal methylation test result were identified. Seven of them had AS, including six (85.7%) due to 15q11-13 deletion and one paternal UPD15. Twelve subjects had PWS: 4 (33%) 15q11-13 deletions, 6 (50%) maternal UPD15, 1 unbalanced chromosome 14;15 translocation resulting in a chromosome 15pter-q13 deletion, and 1 Robertsonian 15q;15q translocation. The minimum livebirth prevalence in 1984-2004 for AS was 1:52,181 (95% CI 1:25,326-1:1,29,785) and for PWS 1:30,439 (95% CI 1:17,425-1:58,908). The livebirth prevalence of AS and PWS increased within this period, but the change was statistically significant only for PWS (P = 0.032), from expected 1:88,495 (95% CI 1:24,390-1:3,22,580) to expected 1:12,547 (95% CI 1:540-1:29,154). Six individuals with AS and 11 with PWS were alive on the prevalence day (January 1, 2005), indicating the point prevalence proportion of 1:56,112 (95% CI 1:25,780-1:1,52,899) and 1:30,606 (95% CI 1:17,105-1:61,311), respectively. Our results showing the birth prevalence of AS 1.7 times less than PWS challenge the opinion that both syndromes are equally represented, and are in line with the view that mutations in sperm and oocytes occur at different frequencies.
Collapse
|