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Madeo SF, Zagaroli L, Vandelli S, Calcaterra V, Crinò A, De Sanctis L, Faienza MF, Fintini D, Guazzarotti L, Licenziati MR, Mozzillo E, Pajno R, Scarano E, Street ME, Wasniewska M, Bocchini S, Bucolo C, Buganza R, Chiarito M, Corica D, Di Candia F, Francavilla R, Fratangeli N, Improda N, Morabito LA, Mozzato C, Rossi V, Schiavariello C, Farello G, Iughetti L, Salpietro V, Salvatoni A, Giordano M, Grugni G, Delvecchio M. Endocrine features of Prader-Willi syndrome: a narrative review focusing on genotype-phenotype correlation. Front Endocrinol (Lausanne) 2024; 15:1382583. [PMID: 38737552 PMCID: PMC11082343 DOI: 10.3389/fendo.2024.1382583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/12/2024] [Indexed: 05/14/2024] Open
Abstract
Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.
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Affiliation(s)
- Simona F. Madeo
- Department of Medical and Surgical Sciences for Mother, Children and Adults, Pediatric Unit, University of Modena and Reggio Emilia, Modena, Italy
| | - Luca Zagaroli
- Department of Pediatrics, University of L’Aquila, L’Aquila, Italy
| | - Sara Vandelli
- Department of Medical and Surgical Sciences for Mother, Children and Adults, Post-Graduate School of Pediatrics, University of Modena and Reggio Emilia, Modena, Italy
| | - Valeria Calcaterra
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy
- Pediatric Department, Buzzi Children’s Hospital, Milano, Italy
| | - Antonino Crinò
- Center for Rare Diseases and Congenital Defects, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Luisa De Sanctis
- Pediatric Endocrinology, Regina Margherita Children Hospital – Department of Public Health and Pediatric Sciences, University of Torino, Torino, Italy
| | - Maria Felicia Faienza
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University of Bari “Aldo Moro”, Bari, Italy
| | - Danilo Fintini
- Prader Willi Reference Center, Endocrinology and Diabetology Unit, Pediatric University Department, IRCCS Bambino Gesù Children Hospital, Rome, Italy
| | - Laura Guazzarotti
- Pediatric Endocrinology Unit, University Hospital of Padova, Padova, Italy
| | - Maria Rosaria Licenziati
- Neuro-endocrine Diseases and Obesity Unit, Department of Neurosciences, Santobono-Pausilipon Children’s Hospital, Naples, Italy
| | - Enza Mozzillo
- Department of Translational and Medical Science, Section of Pediatrics, University of Naples Federico II, Naples, Italy
| | - Roberta Pajno
- Pediatric Unit, IRCCS San Raffaele Institute, Milan, Italy
| | - Emanuela Scarano
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Maria E. Street
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Department of Medicine and Surgery, University Hospital of Parma, Parma, Italy
| | - Malgorzata Wasniewska
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
- Pediatric Unit, Gaetano Martino University Hospital of Messina, Messina, Italy
| | - Sarah Bocchini
- Prader Willi Reference Center, Endocrinology and Diabetology Unit, Pediatric University Department, IRCCS Bambino Gesù Children Hospital, Rome, Italy
| | - Carmen Bucolo
- Pediatric Unit, IRCCS San Raffaele Institute, Milan, Italy
| | - Raffaele Buganza
- Pediatric Endocrinology, Regina Margherita Children Hospital – Department of Public Health and Pediatric Sciences, University of Torino, Torino, Italy
| | - Mariangela Chiarito
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University of Bari “Aldo Moro”, Bari, Italy
| | - Domenico Corica
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
- Pediatric Unit, Gaetano Martino University Hospital of Messina, Messina, Italy
| | - Francesca Di Candia
- Department of Translational and Medical Science, Section of Pediatrics, University of Naples Federico II, Naples, Italy
| | | | - Nadia Fratangeli
- Division of Auxology, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Verbania, Italy
| | - Nicola Improda
- Neuro-endocrine Diseases and Obesity Unit, Department of Neurosciences, Santobono-Pausilipon Children’s Hospital, Naples, Italy
| | | | - Chiara Mozzato
- Child and Women Health Department, University of Padova, Padova, Italy
| | - Virginia Rossi
- Pediatric Department, Buzzi Children’s Hospital, Milano, Italy
| | | | - Giovanni Farello
- Department of Clinical Medicine, Public Health, Life and Environmental Sciences, University of L’Aquila, L’Aquila, Italy
| | - Lorenzo Iughetti
- Department of Medical and Surgical Sciences for Mother, Children and Adults, Pediatric Unit, University of Modena and Reggio Emilia, Modena, Italy
| | - Vincenzo Salpietro
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy
| | | | - Mara Giordano
- Laboratory of Genetics, Struttura Complessa a Direzione Universitaria (SCDU) Biochimica Clinica, Ospedale Maggiore della Carità, Novara, Italy
- Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Graziano Grugni
- Division of Auxology, Istituto Auxologico Italiano, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Verbania, Italy
| | - Maurizio Delvecchio
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy
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Sabatino L, Lapi D, Del Seppia C. Factors and Mechanisms of Thyroid Hormone Activity in the Brain: Possible Role in Recovery and Protection. Biomolecules 2024; 14:198. [PMID: 38397435 PMCID: PMC10886502 DOI: 10.3390/biom14020198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/29/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Thyroid hormones (THs) are essential in normal brain development, and cognitive and emotional functions. THs act through a cascade of events including uptake by the target cells by specific cell membrane transporters, activation or inactivation by deiodinase enzymes, and interaction with nuclear thyroid hormone receptors. Several thyroid responsive genes have been described in the developing and in the adult brain and many studies have demonstrated a systemic or local reduction in TH availability in neurologic disease and after brain injury. In this review, the main factors and mechanisms associated with the THs in the normal and damaged brain will be evaluated in different regions and cellular contexts. Furthermore, the most common animal models used to study the role of THs in brain damage and cognitive impairment will be described and the use of THs as a potential recovery strategy from neuropathological conditions will be evaluated. Finally, particular attention will be given to the link observed between TH alterations and increased risk of Alzheimer's Disease (AD), the most prevalent neurodegenerative and dementing condition worldwide.
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Affiliation(s)
- Laura Sabatino
- Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56124 Pisa, Italy;
| | - Dominga Lapi
- Department of Biology, University of Pisa, 56127 Pisa, Italy;
| | - Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56124 Pisa, Italy;
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Montanucci L, Lewis-Smith D, Collins RL, Niestroj LM, Parthasarathy S, Xian J, Ganesan S, Macnee M, Brünger T, Thomas RH, Talkowski M, Helbig I, Leu C, Lal D. Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals. Nat Commun 2023; 14:4392. [PMID: 37474567 PMCID: PMC10359300 DOI: 10.1038/s41467-023-39539-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 06/16/2023] [Indexed: 07/22/2023] Open
Abstract
Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice.
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Affiliation(s)
- Ludovica Montanucci
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA
| | - David Lewis-Smith
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- Clinical Neurosciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ryan L Collins
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, USA
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA
| | | | - Shridhar Parthasarathy
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Julie Xian
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Shiva Ganesan
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Marie Macnee
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Tobias Brünger
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Rhys H Thomas
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- Clinical Neurosciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Michael Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, USA
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA
| | - Ingo Helbig
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA.
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T, Cambridge, MA, USA.
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, US.
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, USA.
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology (M.I.T.) and Harvard, Cambridge, USA.
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T, Cambridge, MA, USA.
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, US.
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4
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Ariyanfar S, Good DJ. Analysis of SNHG14: A Long Non-Coding RNA Hosting SNORD116, Whose Loss Contributes to Prader-Willi Syndrome Etiology. Genes (Basel) 2022; 14:97. [PMID: 36672838 PMCID: PMC9858946 DOI: 10.3390/genes14010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/14/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
The Small Nucleolar Host Gene 14 (SNHG14) is a host gene for small non-coding RNAs, including the SNORD116 small nucleolar C/D box RNA encoding locus. Large deletions of the SNHG14 locus, as well as microdeletions of the SNORD116 locus, lead to the neurodevelopmental genetic disorder Prader-Willi syndrome. This review will focus on the SNHG14 gene, its expression patterns, its role in human cancer, and the possibility that single nucleotide variants within the locus contribute to human phenotypes in the general population. This review will also include new in silico data analyses of the SNHG14 locus and new in situ RNA expression patterns of the Snhg14 RNA in mouse midbrain and hindbrain regions.
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Affiliation(s)
| | - Deborah J. Good
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24060, USA
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Proteins and Proteases of Prader-Willi Syndrome: A Comprehensive Review and Perspectives. Biosci Rep 2022; 42:231361. [PMID: 35621394 PMCID: PMC9208313 DOI: 10.1042/bsr20220610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/16/2022] [Accepted: 05/20/2022] [Indexed: 11/17/2022] Open
Abstract
Prader–Willi Syndrome (PWS) is a rare complex genetic disease that is associated with pathological disorders that include endocrine disruption, developmental, neurological, and physical problems as well as intellectual, and behavioral dysfunction. In early stage, PWS is characterized by respiratory distress, hypotonia, and poor sucking ability, causing feeding concern and poor weight gain. Additional features of the disease evolve over time. These include hyperphagia, obesity, developmental, cognitive delay, skin picking, high pain threshold, short stature, growth hormone deficiency, hypogonadism, strabismus, scoliosis, joint laxity, or hip dysplasia. The disease is associated with a shortened life expectancy. There is no cure for PWS, although interventions are available for symptoms management. PWS is caused by genetic defects in chromosome 15q11.2-q13, and categorized into three groups, namely Paternal deletion, Maternal uniparental disomy, and Imprinting defect. PWS is confirmed through genetic testing and DNA-methylation analysis. Studies revealed that at least two key proteins namely MAGEL-2 and NECDIN along with two proteases PCSK1 and PCSK2 are linked to PWS. Herein, we summarize our current understanding and knowledge about the role of these proteins and enzymes in various biological processes associated with PWS. The review also describes how loss and/or impairment of functional activity of these macromolecules can lead to hormonal disbalance by promoting degradation of secretory granules and via inhibition of proteolytic maturation of precursor-proteins. The present review will draw attention of researchers, scientists, and academicians engaged in PWS study and will help to identify potential targets and molecular pathways for PWS intervention and treatment.
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Zaletaev DV, Nemtsova MV, Strelnikov VV. Epigenetic Regulation Disturbances on Gene Expression in Imprinting Diseases. Mol Biol 2022. [DOI: 10.1134/s0026893321050149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Baldini L, Robert A, Charpentier B, Labialle S. Phylogenetic and molecular analyses identify SNORD116 targets involved in the Prader Willi syndrome. Mol Biol Evol 2021; 39:6454102. [PMID: 34893870 PMCID: PMC8789076 DOI: 10.1093/molbev/msab348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The eutherian-specific SNORD116 family of repeated box C/D snoRNA genes is suspected to play a major role in the Prader–Willi syndrome (PWS), yet its molecular function remains poorly understood. Here, we combined phylogenetic and molecular analyses to identify candidate RNA targets. Based on the analysis of several eutherian orthologs, we found evidence of extensive birth-and-death and conversion events during SNORD116 gene history. However, the consequences for phylogenetic conservation were heterogeneous along the gene sequence. The standard snoRNA elements necessary for RNA stability and association with dedicated core proteins were the most conserved, in agreement with the hypothesis that SNORD116 generate genuine snoRNAs. In addition, one of the two antisense elements typically involved in RNA target recognition was largely dominated by a unique sequence present in at least one subset of gene paralogs in most species, likely the result of a selective effect. In agreement with a functional role, this ASE exhibited a hybridization capacity with putative mRNA targets that was strongly conserved in eutherians. Moreover, transient downregulation experiments in human cells showed that Snord116 controls the expression and splicing levels of these mRNAs. The functions of two of them, diacylglycerol kinase kappa and Neuroligin 3, extend the description of the molecular bases of PWS and reveal unexpected molecular links with the Fragile X syndrome and autism spectrum disorders.
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Affiliation(s)
- Laeya Baldini
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
| | - Anne Robert
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
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Zhang K, Liu S, Gu W, Lv Y, Yu H, Gao M, Wang D, Zhao J, Li X, Gai Z, Zhao S, Liu Y, Yuan Y. Transmission of a Novel Imprinting Center Deletion Associated With Prader-Willi Syndrome Through Three Generations of a Chinese Family: Case Presentation, Differential Diagnosis, and a Lesson Worth Thinking About. Front Genet 2021; 12:630650. [PMID: 34504512 PMCID: PMC8421676 DOI: 10.3389/fgene.2021.630650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
Prader–Willi syndrome (PWS) is a complex genetic syndrome caused by the loss of function of genes in 15q11-q13 that are subject to regulation by genomic imprinting and expressed from the paternal allele only. The main clinical features of PWS patients are hypotonia during the neonatal and infantile stages, accompanied by delayed neuropsychomotor development, hyperphagia, obesity, hypogonadism, short stature, small hands and feet, mental disabilities, and behavioral problems. However, PWS has a clinical overlap with other disorders, especially those with other gene variations or chromosomal imbalances but sharing part of the similar clinical manifestations with PWS, which are sometimes referred to as Prader–Willi syndrome-like (PWS-like) disorders. Furthermore, it is worth mentioning that significant obesity as a consequence of hyperphagia in PWS usually develops between the ages of 1 and 6 years, which makes early diagnosis difficult. Thus, PWS is often not clinically recognized in infants and, on the other hand, may be wrongly suspected in obese and intellectually disabled patients. Therefore, an accurate investigation is necessary to differentiate classical PWS from PWS-like phenotypes, which is imperative for further treatment. For PWS, it is usually sporadic, and very rare family history and affected siblings have been described. Here, we report the clinical and molecular findings in a three-generation family with a novel 550-kb microdeletion affecting the chromosome 15 imprinting center (IC). Overall, the present study finds that the symptoms of our patient are somewhat different from those of typical PWS cases diagnosed and given treatment in our hospital. The familial occurrence and clinical features were challenging to our diagnostic strategy. The microdeletion included a region within the complex small nuclear ribonucleoprotein polypeptide protein N (SNRPN) gene locus encompassing the PWS IC and was identified by using a variety of techniques. Haplotype studies suggest that the IC microdeletion was vertically transmitted from an unaffected paternal grandmother to an unaffected father and then caused PWS in two sibling grandchildren when the IC microdeletion was inherited paternally. Based on the results of our study, preimplantation genetic diagnosis (PGD) was applied successfully to exclude imprinting deficiency in preimplantation embryos before transfer into the mother’s uterus. Our study may be especially instructive regarding accurate diagnosis, differential diagnosis, genetic counseling, and PGD for familial PWS patients.
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Affiliation(s)
- Kaihui Zhang
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China.,Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China.,State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Shu Liu
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Wenjun Gu
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Yuqiang Lv
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Haihua Yu
- Neonatal Intensive Care Unit, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Min Gao
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Dong Wang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Jianyuan Zhao
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Xiaoying Li
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Shimin Zhao
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yi Liu
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Jinan, China
| | - Yiyuan Yuan
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China.,State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
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Li J, Chen W, Li D, Gu S, Liu X, Dong Y, Jin L, Zhang C, Li S. Conservation of Imprinting and Methylation of MKRN3, MAGEL2 and NDN Genes in Cattle. Animals (Basel) 2021; 11:1985. [PMID: 34359112 PMCID: PMC8300276 DOI: 10.3390/ani11071985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/25/2021] [Accepted: 06/30/2021] [Indexed: 01/02/2023] Open
Abstract
Genomic imprinting is the epigenetic mechanism of transcriptional regulation that involves differential DNA methylation modification. Comparative analysis of imprinted genes between species can help us to investigate the biological significance and regulatory mechanisms of genomic imprinting. MKRN3, MAGEL2 and NDN are three maternally imprinted genes identified in the human PWS/AS imprinted locus. This study aimed to assess the allelic expression of MKRN3, MAGEL2 and NDN and to examine the differentially methylated regions (DMRs) of bovine PWS/AS imprinted domains. An expressed single-nucleotide polymorphism (SNP)-based approach was used to investigate the allelic expression of MKRN3, MAGEL2 and NDN genes in bovine adult tissues and placenta. Consistent with the expression in humans and mice, we found that the MKRN3, MAGEL2 and NDN genes exhibit monoallelic expression in bovine somatic tissues and the paternal allele expressed in the bovine placenta. Three DMRs, PWS-IC, MKRN3 and NDN DMR, were identified in the bovine PWS/AS imprinted region by analysis of the DNA methylation status in bovine tissues using the bisulfite sequencing method and were located in the promoter and exon 1 of the SNRPN gene, NDN promoter and 5' untranslated region (5'UTR) of MKRN3 gene, respectively. The PWS-IC DMR is a primary DMR inherited from the male or female gamete, but NDN and MKRN3 DMR are secondary DMRs that occurred after fertilization by examining the methylation status in gametes.
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Affiliation(s)
- Junliang Li
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Weina Chen
- Department of Traditional Chinese Medicine, Hebei University, Baoding 071000, China;
| | - Dongjie Li
- College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang 050081, China;
| | - Shukai Gu
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Xiaoqian Liu
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Yanqiu Dong
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Lanjie Jin
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Cui Zhang
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
| | - Shijie Li
- College of Life Science, Agricultural University of Hebei, Baoding 071000, China; (J.L.); (S.G.); (X.L.); (Y.D.); (L.J.)
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Pellikaan K, van Woerden GM, Kleinendorst L, Rosenberg AGW, Horsthemke B, Grosser C, van Zutven LJCM, van Rossum EFC, van der Lely AJ, Resnick JL, Brüggenwirth HT, van Haelst MM, de Graaff LCG. The Diagnostic Journey of a Patient with Prader-Willi-Like Syndrome and a Unique Homozygous SNURF-SNRPN Variant; Bio-Molecular Analysis and Review of the Literature. Genes (Basel) 2021; 12:genes12060875. [PMID: 34200226 PMCID: PMC8227738 DOI: 10.3390/genes12060875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022] Open
Abstract
Prader–Willi syndrome (PWS) is a rare genetic condition characterized by hypotonia, intellectual disability, and hypothalamic dysfunction, causing pituitary hormone deficiencies and hyperphagia, ultimately leading to obesity. PWS is most often caused by the loss of expression of a cluster of genes on chromosome 15q11.2-13. Patients with Prader–Willi-like syndrome (PWLS) display features of the PWS phenotype without a classical PWS genetic defect. We describe a 46-year-old patient with PWLS, including hypotonia, intellectual disability, hyperphagia, and pituitary hormone deficiencies. Routine genetic tests for PWS were normal, but a homozygous missense variant NM_003097.3(SNRPN):c.193C>T, p.(Arg65Trp) was identified. Single nucleotide polymorphism array showed several large regions of homozygosity, caused by high-grade consanguinity between the parents. Our functional analysis, the ‘Pipeline for Rapid in silico, in vivo, in vitro Screening of Mutations’ (PRiSM) screen, showed that overexpression of SNRPN-p.Arg65Trp had a dominant negative effect, strongly suggesting pathogenicity. However, it could not be confirmed that the variant was responsible for the phenotype of the patient. In conclusion, we present a unique homozygous missense variant in SNURF-SNRPN in a patient with PWLS. We describe the diagnostic trajectory of this patient and the possible contributors to her phenotype in light of the current literature on the genotype–phenotype relationship in PWS.
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Affiliation(s)
- Karlijn Pellikaan
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands;
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Lotte Kleinendorst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Anna G. W. Rosenberg
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Bernhard Horsthemke
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
| | - Christian Grosser
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
- Praxis für Humangenetik Tübingen, 72076 Tuebingen, Germany
| | - Laura J. C. M. van Zutven
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Elisabeth F. C. van Rossum
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Obesity Center CGG, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands
| | - Aart J. van der Lely
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
| | - James L. Resnick
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA;
| | - Hennie T. Brüggenwirth
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Mieke M. van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Laura C. G. de Graaff
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Academic Centre for Growth Disorders, Erasmus MC Rotterdam, 3015 GD Rotterdam, The Netherlands
- Correspondence: ; Tel.: +31-618843010
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Soeda S, Saito R, Fujii A, Tojo S, Tokumura Y, Taniura H. Abnormal DNA methylation in pluripotent stem cells from a patient with Prader-Willi syndrome results in neuronal differentiation defects. Stem Cell Res 2021; 53:102351. [PMID: 33895503 DOI: 10.1016/j.scr.2021.102351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 03/09/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022] Open
Abstract
DNA methylation is a common method of gene expression regulation, and this form of regulation occurs in the neurodevelopmental disorder Prader-Willi syndrome (PWS). Gene expression regulation via methylation is important for humans, although there is little understanding of the role of methylation in neuronal differentiation. We characterized the cellular differentiation potential of iPS cells derived from a patient with PWS with abnormal methylation (M-iPWS cells). A comparative genomic hybridization (CGH) array revealed that, unlike iPWS cells (deletion genes type), the abnormally methylated M-iPWS cells had no deletion in the15q11.2-q13 chromosome region. In addition, methylation-specific PCR showed that M-iPWS cells had strong methylation in CpG island of the small nuclear ribonucleoprotein polypeptide N (SNRPN) on both alleles. To assess the effect of abnormal methylation on cell differentiation, the M-iPWS and iPWS cells were induced to differentiate into embryoid bodies (EBs). The results suggest that iPWS and M-iPWS cells are defective at differentiation into ectoderm. Neural stem cells (NSCs) and neurons derived from M-iPWS cells had fewer NSCs and mature neurons with low expression of NSCs and neuronal markers. We conclude that expression of the downstream of genes in the PWS region regulated by methylation is involved in neuronal differentiation.
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Affiliation(s)
- Shuhei Soeda
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan.
| | - Ryo Saito
- Advanced Clinical Research Center, Southern Tohoku Research Institute for Neuroscience, Kanagawa 215-0026, Japan; Core Research Facilities for Basic Science, The Jikei University School of Medicine, Tokyo 105-8471, Japan
| | - Ai Fujii
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Shusei Tojo
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Yuka Tokumura
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Hideo Taniura
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan
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Kummerfeld DM, Raabe CA, Brosius J, Mo D, Skryabin BV, Rozhdestvensky TS. A Comprehensive Review of Genetically Engineered Mouse Models for Prader-Willi Syndrome Research. Int J Mol Sci 2021; 22:3613. [PMID: 33807162 PMCID: PMC8037846 DOI: 10.3390/ijms22073613] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 02/05/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a neurogenetic multifactorial disorder caused by the deletion or inactivation of paternally imprinted genes on human chromosome 15q11-q13. The affected homologous locus is on mouse chromosome 7C. The positional conservation and organization of genes including the imprinting pattern between mice and men implies similar physiological functions of this locus. Therefore, considerable efforts to recreate the pathogenesis of PWS have been accomplished in mouse models. We provide a summary of different mouse models that were generated for the analysis of PWS and discuss their impact on our current understanding of corresponding genes, their putative functions and the pathogenesis of PWS. Murine models of PWS unveiled the contribution of each affected gene to this multi-facetted disease, and also enabled the establishment of the minimal critical genomic region (PWScr) responsible for core symptoms, highlighting the importance of non-protein coding genes in the PWS locus. Although the underlying disease-causing mechanisms of PWS remain widely unresolved and existing mouse models do not fully capture the entire spectrum of the human PWS disorder, continuous improvements of genetically engineered mouse models have proven to be very powerful and valuable tools in PWS research.
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Affiliation(s)
- Delf-Magnus Kummerfeld
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Carsten A. Raabe
- Research Group Regulatory Mechanisms of Inflammation, Institute of Medical Biochemistry (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Juergen Brosius
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
- Institutes for Systems Genetics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Dingding Mo
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China;
| | - Boris V. Skryabin
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Timofey S. Rozhdestvensky
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
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Chung MS, Langouët M, Chamberlain SJ, Carmichael GG. Prader-Willi syndrome: reflections on seminal studies and future therapies. Open Biol 2020; 10:200195. [PMID: 32961075 PMCID: PMC7536080 DOI: 10.1098/rsob.200195] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022] Open
Abstract
Prader-Willi syndrome (PWS) is caused by the loss of function of the paternally inherited 15q11-q13 locus. This region is governed by genomic imprinting, a phenomenon in which genes are expressed exclusively from one parental allele. The genomic imprinting of the 15q11-q13 locus is established in the germline and is largely controlled by a bipartite imprinting centre. One part, termed the Prader-Willi syndrome imprinting center (PWS-IC), comprises a CpG island that is unmethylated on the paternal allele and methylated on the maternal allele. The second part, termed the Angelman syndrome imprinting centre, is required to silence the PWS_IC in the maternal germline. The loss of the paternal contribution of the imprinted 15q11-q13 locus most frequently occurs owing to a large deletion of the entire imprinted region but can also occur through maternal uniparental disomy or an imprinting defect. While PWS is considered a contiguous gene syndrome based on large-deletion and uniparental disomy patients, the lack of expression of only non-coding RNA transcripts from the SNURF-SNRPN/SNHG14 may be the primary cause of PWS. Patients with small atypical deletions of the paternal SNORD116 cluster alone appear to have most of the PWS related clinical phenotypes. The loss of the maternal contribution of the 15q11-q13 locus causes a separate and distinct condition called Angelman syndrome. Importantly, while much has been learned about the regulation and expression of genes and transcripts deriving from the 15q11-q13 locus, there remains much to be learned about how these genes and transcripts contribute at the molecular level to the clinical traits and developmental aspects of PWS that have been observed.
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Affiliation(s)
| | | | | | - Gordon G. Carmichael
- Department of Genetics and Genome Sciences, UCONN Health, 400 Farmington Avenue, Farmington, CT 06030, USA
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Germain ND, Levine ES, Chamberlain SJ. IPSC Models of Chromosome 15Q Imprinting Disorders: From Disease Modeling to Therapeutic Strategies. ADVANCES IN NEUROBIOLOGY 2020; 25:55-77. [PMID: 32578144 DOI: 10.1007/978-3-030-45493-7_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The chromosome 15q11-q13 region of the human genome is regulated by genomic imprinting, an epigenetic phenomenon in which genes are expressed exclusively from one parental allele. Several genes within the 15q11-q13 region are expressed exclusively from the paternally inherited chromosome 15. At least one gene UBE3A, shows exclusive expression of the maternal allele, but this allele-specific expression is restricted to neurons. The appropriate regulation of imprinted gene expression across chromosome 15q11-q13 has important implications for human disease. Three different neurodevelopmental disorders result from aberrant expression of imprinted genes in this region: Prader-Willi syndrome (PWS), Angelman syndrome (AS), and 15q duplication syndrome.
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Affiliation(s)
- Noelle D Germain
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Eric S Levine
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Stormy J Chamberlain
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT, USA
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15
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Lewis MW, Vargas-Franco D, Morse DA, Resnick JL. A mouse model of Angelman syndrome imprinting defects. Hum Mol Genet 2019; 28:220-229. [PMID: 30260400 DOI: 10.1093/hmg/ddy345] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/21/2018] [Indexed: 02/07/2023] Open
Abstract
Angelman syndrome, Prader-Will syndrome and Dup15q syndrome map to a cluster of imprinted genes located at 15q11-q13. Imprinting at this domain is regulated by an imprinting control region consisting of two distinct elements, the Angelman syndrome imprinting center (AS-IC) and the Prader-Willi syndrome imprinting center (PWS-IC). Individuals inheriting deletions of the AS-IC exhibit reduced expression of the maternally expressed UBE3A gene and biallelic expression of paternal-only genes. We have previously demonstrated that AS-IC activity partly consists of providing transcription across the PWS-IC in oocytes, and that these transcripts are necessary for maternal imprinting of Snrpn. Here we report a novel mouse mutation that truncates transcripts prior to transiting the PWS-IC and results in a domain-wide imprinting defect. These results confirm a transcription-based model for imprint setting at this domain. The imprinting defect can be preempted by removal of the transcriptional block in oocytes, but not by its removal in early embryos. Imprinting defect mice exhibit several traits often found in individuals with Angelman syndrome imprinting defects.
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Affiliation(s)
- Michael W Lewis
- Department of Molecular Genetics and Microbiology College of Medicine University of Florida, Gainsvile, FL, USA
| | - Dorianmarie Vargas-Franco
- Department of Molecular Genetics and Microbiology College of Medicine University of Florida, Gainsvile, FL, USA
| | - Deborah A Morse
- Department of Molecular Genetics and Microbiology College of Medicine University of Florida, Gainsvile, FL, USA
| | - James L Resnick
- Department of Molecular Genetics and Microbiology College of Medicine University of Florida, Gainsvile, FL, USA
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16
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Kim Y, Wang SE, Jiang YH. Epigenetic therapy of Prader-Willi syndrome. Transl Res 2019; 208:105-118. [PMID: 30904443 PMCID: PMC6527448 DOI: 10.1016/j.trsl.2019.02.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 01/05/2023]
Abstract
Prader-Willi syndrome (PWS) is a complex and multisystem neurobehavioral disorder. The molecular mechanism of PWS is deficiency of paternally expressed gene gene or genes from the chromosome 15q11-q13. Due to imprinted gene regulation, the same genes in the maternal chromosome 15q11-q13 are structurally intact but transcriptionally repressed by an epigenetic mechanism. The unique molecular defect underlying PWS renders an exciting opportunity to explore epigenetic-based therapy to reactivate the expression of repressed PWS genes from the maternal chromosome. Inactivation of H3K9m3 methyltransferase SETDB1 and zinc finger protein ZNF274 results in reactivation of SNRPN and SNORD116 cluster from the maternal chromosomes in PWS patient iPSCs and iPSC-derived neurons, respectively. High content screening of small molecule libraries using cells derived from transgenic mice carrying the SNRPN-EGFP fusion protein has discovered that inhibitors of EHMT2/G9a, a histone 3 lysine 9 methyltransferase, are capable of reactivating expression of paternally expressed SNRPN and SNORD116 from the maternal chromosome, both in cultured PWS patient-derived fibroblasts and in a PWS mouse model. Treatment with an EMHT2/G9a inhibitor also rescues perinatal lethality and failure to thrive phenotypes in a PWS mouse model. These findings present the first evidence to support a proof-of-principle for epigenetic-based therapy for the PWS in humans.
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Affiliation(s)
- Yuna Kim
- Department of Pediatrics, Duke University of School of Medicine, Durham, North Carolina
| | - Sung Eun Wang
- Department of Pediatrics, Duke University of School of Medicine, Durham, North Carolina
| | - Yong-Hui Jiang
- Department of Pediatrics, Duke University of School of Medicine, Durham, North Carolina; Department of Neurobiology, Duke University of School of Medicine, Durham, North Carolina; Department of Program in Genetics and Genomics, Duke University of School of Medicine, Durham, North Carolina; Department of Program in Cellular and Molecular Biology, Duke University of School of Medicine, Durham, North Carolina.
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Nguyen KV. Potential epigenomic co-management in rare diseases and epigenetic therapy. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2019; 38:752-780. [PMID: 31079569 DOI: 10.1080/15257770.2019.1594893] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The purpose of this review is to highlight the impact of the alternative splicing process on human disease. Epigenetic regulation determines not only what parts of the genome are expressed but also how they are spliced. The recent progress in the field of epigenetics has important implications for the study of rare diseases. The role of epigenetics in rare diseases is a key issue in molecular physiology and medicine because not only rare diseases can benefit from epigenetic research, but can also provide useful principles for other common and complex disorders such as cancer, cardiovascular, type 2 diabetes, obesity, and neurological diseases. Predominantly, epigenetic modifications include DNA methylation, histone modification, and RNA-associated silencing. These modifications in the genome regulate numerous cellular activities. Disruption of epigenetic regulation process can contribute to the etiology of numerous diseases during both prenatal and postnatal life. Here, I discuss current knowledge about this matter including some current epigenetic therapies and future directions in the field by emphasizing on the RNA-based therapy via antisense oligonucleotides to correct splicing defects.
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Affiliation(s)
- Khue Vu Nguyen
- a Department of Medicine, Biochemical Genetics and Metabolism, The Mitochondrial and Metabolic Disease Center, School of Medicine, University of California, San Diego , San Diego , CA , USA.,b Department of Pediatrics, UC San Diego School of Medicine , La Jolla , CA , USA
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18
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Hartin SN, Hossain WA, Francis D, Godler DE, Barkataki S, Butler MG. Analysis of the Prader-Willi syndrome imprinting center using droplet digital PCR and next-generation whole-exome sequencing. Mol Genet Genomic Med 2019; 7:e00575. [PMID: 30793526 PMCID: PMC6465664 DOI: 10.1002/mgg3.575] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/13/2018] [Accepted: 01/02/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Detailed analysis of imprinting center (IC) defects in individuals with Prader-Willi syndrome (PWS) is not readily available beyond chromosomal microarray (MA) analysis, and such testing is important for a more accurate diagnosis and recurrence risks. This is the first feasibility study of newly developed droplet digital polymerase chain reaction (ddPCR) examining DNA copy number differences in the PWS IC region of those with IC defects. METHODS The study cohort included 17 individuals without 15q11-q13 deletions or maternal disomy but with IC defects as determined by genotype analysis showing biparental inheritance. Seven sets of parents and two healthy, unrelated controls were also analyzed. RESULTS Copy number differences were distinguished by comparing the number of positive droplets detected by IC probes to those from a chromosome 15 reference probe, GABRβ3. The ddPCR findings were compared to results from other methods including MA, and whole-exome sequencing (WES) with 100% concordance. The study also estimated the frequency of IC microdeletions and identified gene variants by WES that may impact phenotypes including CPT2 and NTRK1 genes. CONCLUSION Droplet digital polymerase chain reaction is a cost-effective method that can be used to confirm the presence of microdeletions in PWS with impact on genetic counseling and recurrence risks for families.
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Affiliation(s)
- Samantha N. Hartin
- Departments of Psychiatry & Behavioral Sciences and PediatricsUniversity of Kansas Medical CenterKansas CityKansas
| | - Waheeda A. Hossain
- Departments of Psychiatry & Behavioral Sciences and PediatricsUniversity of Kansas Medical CenterKansas CityKansas
| | - David Francis
- Cyto‐molecular Diagnostic Research LaboratoryRoyal Children's Hospital, Victorian Clinical Genetics Services and Murdoch Children's Research InstituteMelbourneVictoriaAustralia
| | - David E. Godler
- Cyto‐molecular Diagnostic Research LaboratoryRoyal Children's Hospital, Victorian Clinical Genetics Services and Murdoch Children's Research InstituteMelbourneVictoriaAustralia
| | | | - Merlin G. Butler
- Departments of Psychiatry & Behavioral Sciences and PediatricsUniversity of Kansas Medical CenterKansas CityKansas
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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.
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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
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Butler MG, Miller JL, Forster JL. Prader-Willi Syndrome - Clinical Genetics, Diagnosis and Treatment Approaches: An Update. Curr Pediatr Rev 2019; 15:207-244. [PMID: 31333129 PMCID: PMC7040524 DOI: 10.2174/1573396315666190716120925] [Citation(s) in RCA: 167] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Prader-Willi Syndrome (PWS) is a neurodevelopmental genomic imprinting disorder with lack of expression of genes inherited from the paternal chromosome 15q11-q13 region usually from paternal 15q11-q13 deletions (about 60%) or maternal uniparental disomy 15 or both 15s from the mother (about 35%). An imprinting center controls the expression of imprinted genes in the chromosome 15q11-q13 region. Key findings include infantile hypotonia, a poor suck, failure to thrive and hypogonadism/hypogenitalism. Short stature and small hands/feet due to growth and other hormone deficiencies, hyperphagia and marked obesity occur in early childhood, if uncontrolled. Cognitive and behavioral problems (tantrums, compulsions, compulsive skin picking) are common. OBJECTIVE Hyperphagia and obesity with related complications are major causes of morbidity and mortality in PWS. This report will describe an accurate diagnosis with determination of specific genetic subtypes, appropriate medical management and best practice treatment approaches. METHODS AND RESULTS An extensive literature review was undertaken related to genetics, clinical findings and laboratory testing, clinical and behavioral assessments and summary of updated health-related information addressing the importance of early PWS diagnosis and treatment. A searchable, bulleted and formatted list of topics is provided utilizing a Table of Contents approach for the clinical practitioner. CONCLUSION Physicians and other health care providers can use this review with clinical, genetic and treatment summaries divided into sections pertinent in the context of clinical practice. Frequently asked questions by clinicians, families and other interested participants or providers will be addressed.
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Affiliation(s)
- Merlin G Butler
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS, United States
| | - Jennifer L Miller
- Department of Pediatrics, University of Florida School of Medicine, Gainesville, FL, United States
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21
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Costa RA, Ferreira IR, Cintra HA, Gomes LHF, Guida LDC. Genotype-Phenotype Relationships and Endocrine Findings in Prader-Willi Syndrome. Front Endocrinol (Lausanne) 2019; 10:864. [PMID: 31920975 PMCID: PMC6923197 DOI: 10.3389/fendo.2019.00864] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a complex imprinting disorder related to genomic errors that inactivate paternally-inherited genes on chromosome 15q11-q13 with severe implications on endocrine, cognitive and neurologic systems, metabolism, and behavior. The absence of expression of one or more genes at the PWS critical region contributes to different phenotypes. There are three molecular mechanisms of occurrence: paternal deletion of the 15q11-q13 region; maternal uniparental disomy 15; or imprinting defects. Although there is a clinical diagnostic consensus criteria, DNA methylation status must be confirmed through genetic testing. The endocrine system can be the most affected in PWS, and growth hormone replacement therapy provides improvement in growth, body composition, and behavioral and physical attributes. A key feature of the syndrome is the hypothalamic dysfunction that may be the basis of several endocrine symptoms. Clinical and molecular complexity in PWS enhances the importance of genetic diagnosis in therapeutic definition and genetic counseling. So far, no single gene mutation has been described to contribute to this genetic disorder or related to any exclusive symptoms. Here we proposed to review individually disrupted genes within the PWS critical region and their reported clinical phenotypes related to the syndrome. While genes such as MKRN3, MAGEL2, NDN, or SNORD115 do not address the full spectrum of PWS symptoms and are less likely to have causal implications in PWS major clinical signs, SNORD116 has emerged as a critical, and possibly, a determinant candidate in PWS, in the recent years. Besides that, the understanding of the biology of the PWS SNORD genes is fairly low at the present. These non-coding RNAs exhibit all the hallmarks of RNA methylation guides and can be incorporated into ribonucleoprotein complexes with possible hypothalamic and endocrine functions. Also, DNA conservation between SNORD sequences across placental mammals strongly suggests that they have a functional role as RNA entities on an evolutionary basis. The broad clinical spectrum observed in PWS and the absence of a clear genotype-phenotype specific correlation imply that the numerous genes involved in the syndrome have an additive deleterious effect on different phenotypes when deficiently expressed.
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Pólvora-Brandão D, Joaquim M, Godinho I, Aprile D, Álvaro AR, Onofre I, Raposo AC, Pereira de Almeida L, Duarte ST, da Rocha ST. Loss of hierarchical imprinting regulation at the Prader-Willi/Angelman syndrome locus in human iPSCs. Hum Mol Genet 2018; 27:3999-4011. [PMID: 30102380 PMCID: PMC6240739 DOI: 10.1093/hmg/ddy274] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/18/2018] [Accepted: 07/18/2018] [Indexed: 12/13/2022] Open
Abstract
The human chr15q11-q13 imprinted cluster is linked to several disorders, including Prader-Willi (PWS) and Angelman (AS) syndromes. Recently, disease modeling approaches based on induced pluripotent stem cells (iPSCs) have been used to study these syndromes. A concern regarding the use of these cells for imprinted disease modeling is the numerous imprinting defects found in many iPSCs. Here, by reprogramming skin fibroblasts from a control and AS individuals, we generated several iPSC lines and addressed the stability of imprinting status across the PWS/AS domain. We focused on three important regulatory DNA elements which are all differentially methylated regions (DMRs), methylated on the maternal allele: the PWS imprinting center (PWS-IC), which is a germline DMR and the somatic NDN and MKRN3 DMRs, hierarchically controlled by PWS-IC. Normal PWS-IC methylation pattern was maintained in most iPSC lines; however, loss of maternal methylation in one out of five control iPSC lines resulted in a monoallelic to biallelic switch for many imprinted genes in this domain. Surprisingly, MKRN3 DMR was found aberrantly hypermethylated in all control and AS iPSCs, regardless of the methylation status of the PWS-IC master regulator. This suggests a loss of hierarchical control of imprinting at PWS/AS region. We confirmed these results in established iPSC lines derived using different reprogramming procedures. Overall, we show that hierarchy of imprinting control in donor cells might not apply to iPSCs, accounting for their spectrum of imprinting alterations. Such differences in imprinting regulation should be taken into consideration for the use of iPSCs in disease modeling.
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Affiliation(s)
- Duarte Pólvora-Brandão
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
| | - Mariana Joaquim
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
| | - Inês Godinho
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
| | - Domenico Aprile
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
| | - Ana Rita Álvaro
- CNC - Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Isabel Onofre
- CNC - Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Cláudia Raposo
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
| | - Luís Pereira de Almeida
- CNC - Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra,Coimbra, Portugal
| | - Sofia T Duarte
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
- Hospital D. Estefânia, Centro Hospitalar Lisboa Central, Lisboa, Portugal
| | - Simão T da Rocha
- Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisboa, Portugal
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Rosen ED, Kaestner KH, Natarajan R, Patti ME, Sallari R, Sander M, Susztak K. Epigenetics and Epigenomics: Implications for Diabetes and Obesity. Diabetes 2018; 67:1923-1931. [PMID: 30237160 PMCID: PMC6463748 DOI: 10.2337/db18-0537] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/12/2018] [Indexed: 12/17/2022]
Abstract
The American Diabetes Association convened a research symposium, "Epigenetics and Epigenomics: Implications for Diabetes and Obesity" on 17-19 November 2017. International experts in genetics, epigenetics, computational biology, and physiology discussed the current state of understanding of the relationships between genetics, epigenetics, and environment in diabetes and examined existing evidence for the role of epigenetic factors in regulating metabolism and the risk of diabetes and its complications. The authors summarize the presentations, which highlight how the complex interactions between genes and environment may in part be mediated through epigenetic changes and how information about nutritional and other environmental stimuli can be transmitted to the next generation. In addition, the authors present expert consensus on knowledge gaps and research recommendations for the field.
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Affiliation(s)
- Evan D Rosen
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Boston, MA
- Harvard Medical School, Boston, MA
| | - Klaus H Kaestner
- Department of Genetics and Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | | | - Mary-Elizabeth Patti
- Harvard Medical School, Boston, MA
- Research Division, Joslin Diabetes Center, Boston, MA
| | | | - Maike Sander
- University of California, San Diego, La Jolla, CA
| | - Katalin Susztak
- Department of Genetics and Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
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Abstract
Codon usage depends on mutation bias, tRNA-mediated selection, and the need for high efficiency and accuracy in translation. One codon in a synonymous codon family is often strongly over-used, especially in highly expressed genes, which often leads to a high dN/dS ratio because dS is very small. Many different codon usage indices have been proposed to measure codon usage and codon adaptation. Sense codon could be misread by release factors and stop codons misread by tRNAs, which also contribute to codon usage in rare cases. This chapter outlines the conceptual framework on codon evolution, illustrates codon-specific and gene-specific codon usage indices, and presents their applications. A new index for codon adaptation that accounts for background mutation bias (Index of Translation Elongation) is presented and contrasted with codon adaptation index (CAI) which does not consider background mutation bias. They are used to re-analyze data from a recent paper claiming that translation elongation efficiency matters little in protein production. The reanalysis disproves the claim.
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Geets E, Meuwissen MEC, Van Hul W. Clinical, molecular genetics and therapeutic aspects of syndromic obesity. Clin Genet 2018; 95:23-40. [PMID: 29700824 DOI: 10.1111/cge.13367] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/05/2018] [Accepted: 04/16/2018] [Indexed: 12/13/2022]
Abstract
Obesity has become a major health problem worldwide. To date, more than 25 different syndromic forms of obesity are known in which one (monogenic) or multiple (polygenic) genes are involved. This review gives an overview of these forms and focuses more in detail on 6 syndromes: Prader Willi Syndrome and Prader Willi like phenotype, Bardet Biedl Syndrome, Alström Syndrome, Wilms tumor, Aniridia, Genitourinary malformations and mental Retardation syndrome and 16p11.2 (micro)deletions. Years of research provided plenty of information on the molecular genetics of these disorders and the obesity phenotype leading to a more individualized treatment of the symptoms, however, many questions still remain unanswered. As these obesity syndromes have different signs and symptoms in common, it makes it difficult to accurately diagnose patients which may result in inappropriate treatment of the disease. Therefore, the big challenge for clinicians and scientists is to more clearly differentiate all syndromic forms of obesity to provide conclusive genetic explanations and eventually deliver accurate genetic counseling and treatment. In addition, further delineation of the (functions of the) underlying genes with the use of array- or next-generation sequencing-based technology will be helpful to unravel the mechanisms of energy metabolism in the general population.
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Affiliation(s)
- E Geets
- Department of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - M E C Meuwissen
- Department of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - W Van Hul
- Department of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
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Epigenetics of Circadian Rhythms in Imprinted Neurodevelopmental Disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 157:67-92. [PMID: 29933957 DOI: 10.1016/bs.pmbts.2017.11.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA sequence information alone cannot account for the immense variability between chromosomal alleles within diverse cell types in the brain, whether these differences are observed across time, cell type, or parental origin. The complex control and maintenance of gene expression and modulation are regulated by a multitude of molecular and cellular mechanisms that layer on top of the genetic code. The integration of genetic and environmental signals required for regulating brain development and function is achieved in part by a dynamic epigenetic landscape that includes DNA methylation, histone modifications, and noncoding RNAs. These epigenetic mechanisms establish and maintain core biological processes, including genomic imprinting and entrainment of circadian rhythms. This chapter will focus on how the epigenetic layers of DNA methylation and long, noncoding RNAs interact with circadian rhythms at specific imprinted chromosomal loci associated with the human neurodevelopmental disorders Prader-Willi, Angelman, Kagami-Ogata, and Temple syndromes.
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Hartin SN, Hossain WA, Weisensel N, Butler MG. Three siblings with Prader-Willi syndrome caused by imprinting center microdeletions and review. Am J Med Genet A 2018; 176:886-895. [PMID: 29437285 DOI: 10.1002/ajmg.a.38627] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/21/2017] [Accepted: 01/16/2018] [Indexed: 12/14/2022]
Abstract
Prader-Willi syndrome (PWS) is a complex genetic imprinting disorder characterized by childhood obesity, short stature, hypogonadism/hypogenitalism, hypotonia, cognitive impairment, and behavioral problems. Usually PWS occurs sporadically due to the loss of paternally expressed genes on chromosome 15 with the majority of individuals having the 15q11-q13 region deleted. Examples of familial PWS have been reported but rarely. To date 13 families have been reported with more than one child with PWS and without a 15q11-q13 deletion secondary to a chromosome 15 translocation, inversion, or uniparental maternal disomy 15. Ten of those 13 families were shown to carry microdeletions in the PWS imprinting center. The microdeletions were found to be of paternal origin in nine of the ten cases in which family studies were carried out. Using a variety of techniques, the microdeletions were identified in regions within the complex SNRPN gene locus encompassing the PWS imprinting center. Here, we report the clinical and genetic findings in three adult siblings with PWS caused by a microdeletion in the chromosome 15 imprinting center inherited from an unaffected father that controls the activity of genes in the 15q11-q13 region and summarize the 13 reported cases in the literature.
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Affiliation(s)
- Samantha N Hartin
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
| | - Waheeda A Hossain
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
| | | | - Merlin G Butler
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
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Two approaches reveal a new paradigm of 'switchable or genetics-influenced allele-specific DNA methylation' with potential in human disease. Cell Discov 2017; 3:17038. [PMID: 29387450 PMCID: PMC5787696 DOI: 10.1038/celldisc.2017.38] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/29/2017] [Indexed: 12/11/2022] Open
Abstract
Imprinted genes are vulnerable to environmental influences during early embryonic development, thereby contributing to the onset of disease in adulthood. Monoallelic methylation at several germline imprints has been reported as DNMT1-dependent. However, which of these two epigenetic attributes, DNMT1-dependence or allelic methylation, renders imprinted genes susceptible to environmental stressors has not been determined. Herein, we developed a new approach, referred to as NORED, to identify 2468 DNMT1-dependent DNA methylation patterns in the mouse genome. We further developed an algorithm based on a genetic variation-independent approach (referred to as MethylMosaic) to detect 2487 regions with bimodal methylation patterns. Two approaches identified 207 regions, including known imprinted germline allele-specific methylation patterns (ASMs), that were both NORED and MethylMosaic regions. Examination of methylation in four independent mouse embryonic stem cell lines shows that two regions identified by both NORED and MethylMosaic (Hcn2 and Park7) did not display parent-of-origin-dependent allelic methylation. In these four F1 hybrid cell lines, genetic variation in Cast allele at Hcn2 locus introduces a transcription factor binding site for MTF-1 that may predispose Cast allelic hypomethylation in a reciprocal cross with either C57 or 129 strains. In contrast, each allele of Hcn2 ASM in J1 inbred cell line and Park7 ASM in four F1 hybrid cell lines seems to exhibit similar propensity to be either hypo- or hypermethylated, suggesting a ‘random, switchable’ ASM. Together with published results, our data on ASMs prompted us to propose a hypothesis of regional ‘autosomal chromosome inactivation (ACI)’ that may control a subset of autosomal genes. Therefore, our results open a new avenue to understand monoallelic methylation and provide a rich resource of candidate genes to examine in environmental and nutritional exposure models.
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Cao Y, AlHumaidi SS, Faqeih EA, Pitel BA, Lundquist P, Aypar U. A novel deletion of SNURF/SNRPN exon 1 in a patient with Prader-Willi-like phenotype. Eur J Med Genet 2017; 60:416-420. [PMID: 28554868 DOI: 10.1016/j.ejmg.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023]
Abstract
Here we report the smallest deletion involving SNURF/SNRPN that causes major symptoms of Prader-Willi syndrome (PWS), including hypotonia, dysmorphic features, intellectual disability, and obesity. A female patient with the aforementioned and additional features was referred to the Mayo Clinic Cytogenetics laboratory for genetic testing. Chromosomal microarray analysis and subsequent Sanger sequencing identified a de novo 6.4 kb deletion at 15q11.2, containing exon 1 of the SNURF gene and exon 1 of the shortest isoform of the SNRPN gene. SNURF/SNRPN exon 1, which is methylated on the silent maternal allele, is associated with acetylated histones on the expressed paternal allele. This region also overlaps with the PWS-imprinting center (IC). Subsequent molecular methylation analysis was performed using methylation-specific MLPA (MS-MLPA), which characterized that the deletion of SNURF/SNRPN exon 1 was paternal in origin, consistent with the PWS-like phenotype. Since SNURF/SNRPN gene and the PWS-IC are known to regulate snoRNAs, it is likely that the PWS-like phenotype observed in patients with paternal SNURF/SNRPN deletion is due to the disrupted expression of SNORD116 snoRNAs.
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Affiliation(s)
- Yang Cao
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Susan S AlHumaidi
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Beth A Pitel
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Patrick Lundquist
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Umut Aypar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States.
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Shamsi MB, Firoz AS, Imam SN, Alzaman N, Samman MA. Epigenetics of human diseases and scope in future therapeutics. J Taibah Univ Med Sci 2017; 12:205-211. [PMID: 31435241 PMCID: PMC6695077 DOI: 10.1016/j.jtumed.2017.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/19/2017] [Accepted: 04/24/2017] [Indexed: 12/31/2022] Open
Abstract
Epigenetics is the study of nucleotide modifications that are heritable and act as regulatory mechanisms without changing the nucleotide sequence of the genome. Exogenous cues such as environment, lifestyle, nutrition, stress, and psychological factors affect epigenetic mechanisms. This mechanism is in concordance with the genetic information that plays an important role during prenatal and postnatal life of an individual. Recent epigenetic studies have revealed the potential of epigenetics in elucidating the mechanisms of different diseases. In this review, we discuss basic epigenetic mechanisms and their roles in health and disease. In addition, reported aberrations in epigenetic regulation for some common human diseases are described. Finally, we address some epigenetic approaches that have shown potential for targeted treatment of diseases.
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Affiliation(s)
- Monis B Shamsi
- Center for Genetics & Inherited Diseases, Taibah University, Almadinah Almunawwarah, KSA
| | - Abdul S Firoz
- Center for Genetics & Inherited Diseases, Taibah University, Almadinah Almunawwarah, KSA
| | - Syed N Imam
- Department of Anatomy, College of Medicine, Taibah University, Almadinah Almunawwarah, KSA
| | - Naweed Alzaman
- Department of Internal Medicine, College of Medicine, Taibah University, Almadinah Almunawwarah, KSA
| | - Muhammad A Samman
- Center for Genetics & Inherited Diseases, Taibah University, Almadinah Almunawwarah, KSA
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Orsso CE, Mackenzie M, Alberga AS, Sharma AM, Richer L, Rubin DA, Prado CM, Haqq AM. The use of magnetic resonance imaging to characterize abnormal body composition phenotypes in youth with Prader-Willi syndrome. Metabolism 2017; 69:67-75. [PMID: 28285653 DOI: 10.1016/j.metabol.2017.01.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Magnetic resonance imaging (MRI) provides detailed assessment of body composition compartments. No studies have employed state-of-the-art MRI methods to accurately examine abdominal adipose tissue (AT) and skeletal muscle in youth with Prader-Willi syndrome (PWS). Therefore, this study aimed to describe AT distribution and skeletal muscle in the abdominal region of youth with PWS using MRI. METHODS Anthropometric measures and whole-abdominal T1-weighted MRI were performed in sixteen (5 males and 11 females) youth diagnosed with PWS, and seventeen (10 males and 7 females) youth who did not have PWS (controls). Volume of subcutaneous, visceral, intermuscular, and total AT, and skeletal muscle in the abdominal region were quantified using a semiautomatic procedure. Results were summarized using median and interquartile range (IQR, 25th-75th), and ANCOVA test was used (with age and sex as covariates) to examine differences in body composition compartments between PWS and control group. RESULTS PWS group had similar age (10.5, 6.6-13.9 vs. 12.8, 10.0-14.4years; P=0.14) and BMI z-score (0.5, 0.2-1.3 vs. 0.2, -0.3 to 1.0; P=0.33) when compared with controls. Significant differences were observed in absolute volumes of total AT (PWS: 4.1, 2.0-6.6L; control: 2.9, 2.0-4.5L; P=0.01), subcutaneous AT (PWS: 2.8, 1.4-4.8L; control: 1.8, 1.1-3.2L; P=0.01), and intermuscular AT (PWS: 0.3, 0.1-0.4L; control: 0.3, 0.2-0.3L; P<0.005). Visceral AT/subcutaneous AT was lower in PWS (0.4, 0.3-0.5) compared to controls (0.5, 0.4-0.6), P=0.01. In addition, skeletal muscle volume was lower in PWS (1.5, 1.0-2.6L) compared to controls (3.1, 1.6-3.9L), P=0.03. Ratios of abdominal AT compartments to skeletal muscle were all higher in PWS compared to controls (all P<0.005). CONCLUSIONS PWS youth have greater abdominal adiposity, particularly subcutaneous AT and intermuscular AT, and lower volume of skeletal muscle compared to controls. The decreased ratio of visceral AT/subcutaneous AT in youth with PWS suggests an improved metabolic profile for the level of adiposity present; however, elevated ratios of AT to skeletal muscle suggest a sarcopenic obesity-like phenotype, which could lead to worse health outcomes.
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Affiliation(s)
- Camila E Orsso
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 2E1; Department of Pediatrics, University of Alberta, 11405-87 Avenue, Edmonton, AB, Canada T6G 2R3
| | - Michelle Mackenzie
- Department of Pediatrics, University of Alberta, 11405-87 Avenue, Edmonton, AB, Canada T6G 2R3
| | - Angela S Alberga
- Department of Exercise Science, Concordia University, 7141 Sherbrooke Street West, Office SP-165.06, Montreal, QB, Canada H4B1R6
| | - Arya M Sharma
- Department of Medicine, 1-116 Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, AB, Canada T6G 2E1
| | - Lawrence Richer
- Department of Pediatrics, University of Alberta, 11405-87 Avenue, Edmonton, AB, Canada T6G 2R3
| | - Daniela A Rubin
- Department of Kinesiology, California State University, Fullerton, 800 N. State College Blvd, CA 92834, USA
| | - Carla M Prado
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-002 Li Ka Shing Centre, Edmonton, AB, Canada T6G 2E1
| | - Andrea M Haqq
- Department of Pediatrics, University of Alberta, 11405-87 Avenue, Edmonton, AB, Canada T6G 2R3.
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32
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Sato M. Early Origin and Evolution of the Angelman Syndrome Ubiquitin Ligase Gene Ube3a. Front Cell Neurosci 2017; 11:62. [PMID: 28326016 PMCID: PMC5339648 DOI: 10.3389/fncel.2017.00062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/22/2017] [Indexed: 12/20/2022] Open
Abstract
The human Ube3a gene encodes an E3 ubiquitin ligase and exhibits brain-specific genomic imprinting. Genetic abnormalities that affect the maternal copy of this gene cause the neurodevelopmental disorder Angelman syndrome (AS), which is characterized by severe mental retardation, speech impairment, seizure, ataxia and some unique behavioral phenotypes. In this review article, I highlight the evolution of the Ube3a gene and its imprinting to provide evolutionary insights into AS. Recent comparative genomic studies have revealed that Ube3a is most phylogenetically similar to HECTD2 among the human HECT (homologous to the E6AP carboxyl terminus) family of E3 ubiquitin ligases, and its distant evolutionary origin can be traced to common ancestors of fungi and animals. Moreover, a gene more similar to Ube3a than HECTD2 is found in a range of eukaryotes from amoebozoans to basal metazoans, but is lost in later lineages. Unlike in mice and humans, Ube3a expression is biallelic in birds, monotremes, marsupials and insects. The imprinting domain that governs maternal expression of Ube3a was formed from non-imprinted elements following multiple chromosomal rearrangements after diversification of marsupials and placental mammals. Hence, the evolutionary origins of Ube3a date from long before the emergence of the nervous system, although its imprinted expression was acquired relatively recently. These observations suggest that exogenous expression and functional analyses of ancient Ube3a orthologs in mammalian neurons will facilitate the evolutionary understanding of AS.
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Affiliation(s)
- Masaaki Sato
- Graduate School of Science and Engineering and Brain and Body System Science Institute, Saitama UniversitySaitama, Japan
- RIKEN Brain Science InstituteWako, Japan
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33
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Abstract
Bioinformatic analysis can not only accelerate drug target identification and drug candidate screening and refinement, but also facilitate characterization of side effects and predict drug resistance. High-throughput data such as genomic, epigenetic, genome architecture, cistromic, transcriptomic, proteomic, and ribosome profiling data have all made significant contribution to mechanismbased drug discovery and drug repurposing. Accumulation of protein and RNA structures, as well as development of homology modeling and protein structure simulation, coupled with large structure databases of small molecules and metabolites, paved the way for more realistic protein-ligand docking experiments and more informative virtual screening. I present the conceptual framework that drives the collection of these high-throughput data, summarize the utility and potential of mining these data in drug discovery, outline a few inherent limitations in data and software mining these data, point out news ways to refine analysis of these diverse types of data, and highlight commonly used software and databases relevant to drug discovery.
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Affiliation(s)
- Xuhua Xia
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Ottawa Institute of Systems Biology, Ottawa K1H 8M5, Canada
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34
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Butler MG. Benefits and limitations of prenatal screening for Prader-Willi syndrome. Prenat Diagn 2016; 37:81-94. [PMID: 27537837 DOI: 10.1002/pd.4914] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/15/2022]
Abstract
This review summarizes the status of genetic laboratory testing in Prader-Willi syndrome (PWS) with different genetic subtypes, most often a paternally derived 15q11-q13 deletion and discusses benefits and limitations related to prenatal screening. Medical literature was searched for prenatal screening and genetic laboratory testing methods in use or under development and discussed in relationship to PWS. Genetic testing includes six established laboratory diagnostic approaches for PWS with direct application to prenatal screening. Ultrasonographic, obstetric and cytogenetic reports were summarized in relationship to the cause of PWS and identification of specific genetic subtypes including maternal disomy 15. Advances in genetic technology were described for diagnosing PWS specifically DNA methylation and high-resolution chromosomal SNP microarrays as current tools for genetic screening and incorporating next generation DNA sequencing for noninvasive prenatal testing (NIPT) using cell-free fetal DNA. Positive experiences are reported with NIPT for detection of numerical chromosomal problems (aneuploidies) but not for structural problems (microdeletions). These reports will be discussed along with future directions for genetic screening of PWS. In summary, this review describes and discusses the status of established and ongoing genetic testing options for PWS applicable in prenatal screening including NIPT and future directions for early diagnosis in PWS. © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Merlin G Butler
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS, USA
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Cheon CK. Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome. Ann Pediatr Endocrinol Metab 2016; 21:126-135. [PMID: 27777904 PMCID: PMC5073158 DOI: 10.6065/apem.2016.21.3.126] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 11/29/2022] Open
Abstract
The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.
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Affiliation(s)
- Chong Kun Cheon
- Division of Pediatric Endocrinology and Metabolism, Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University School of Medicine, Yangsan, Korea
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Butler MG, Lee J, Cox DM, Manzardo AM, Gold JA, Miller JL, Roof E, Dykens E, Kimonis V, Driscoll DJ. Growth Charts for Prader-Willi Syndrome During Growth Hormone Treatment. Clin Pediatr (Phila) 2016; 55:957-74. [PMID: 26842920 PMCID: PMC5922433 DOI: 10.1177/0009922815617973] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The purpose of the current study was to develop syndrome-specific standardized growth curves for growth hormone-treated Prader-Willi syndrome (PWS) individuals aged 0 to 18 years. Anthropometric growth-related measures were obtained on 171 subjects with PWS who were treated with growth hormone for at least 40% of their lifespan. They had no history of scoliosis. PWS standardized growth curves were developed for 7 percentile ranges using the LMS method for weight, height, head circumference, weight/length, and BMI along with normative 3rd, 50th, and 97th percentiles plotted using control data from the literature and growth databases. Percentiles were plotted on growth charts for comparison purposes. Growth hormone treatment appears to normalize stature and markedly improves weight in PWS compared with standardized curves for non-growth hormone-treated PWS individuals. Growth chart implications and recommended usage are discussed.
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Affiliation(s)
| | | | - Devin M. Cox
- University of Kansas Medical Center, Kansas City, KS, USA
| | | | - June-Anne Gold
- Loma Linda University Medical School, Loma Linda, CA, USA
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Aypar U, Hoppman NL, Thorland EC, Dawson DB. Patients with mosaic methylation patterns of the Prader-Willi/Angelman Syndrome critical region exhibit AS-like phenotypes with some PWS features. Mol Cytogenet 2016; 9:26. [PMID: 27006693 PMCID: PMC4802915 DOI: 10.1186/s13039-016-0233-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/09/2016] [Indexed: 01/29/2023] Open
Abstract
Background Loss of expression of imprinted genes in the 15q11.2-q13 region is known to cause either Prader-Willi syndrome (PWS) or Angelman syndrome (AS), depending on the parent of origin. In some patients (1 % in PWS and 2–4 % in AS), the disease is due to aberrant imprinting or gene silencing, or both. Results We report here a 4-year-old boy on whom a chromosomal microarray (CMA) was performed due to mild hand tremors, mild developmental delays, and clumsiness. CMA revealed absence of heterozygosity (AOH) spanning the entire chromosome 15, suggesting uniparental isodisomy 15. The patient had no definitive phenotypic features of PWS or AS. Methylation-sensitive multiplex ligation-dependent probe amplification (MS-MLPA) was performed to determine the parent of origin of the uniparental disomy (UPD) by examining methylation status at maternally imprinted sites. Interestingly, our patient had a mosaic methylation pattern. We identified nine additional previously tested patients with a similar mosaic methylation pattern. CMA was performed on these individuals retrospectively to test whether patients with mosaic methylation are more likely to have UPD of chromosome 15. Of the nine patients, only one had regions of AOH on chromosome 15; however, this patient had numerous regions of AOH on multiple chromosomes suggestive of consanguinity. Conclusion The patients with mosaic methylation had milder or atypical features of AS, and the majority also had some features characteristic of PWS. We suggest that quantitative methylation analysis be performed for cases of atypical PWS or AS. It is also important to follow up with methylation testing when whole-chromosome isodisomy is detected.
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Affiliation(s)
- Umut Aypar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
| | - Nicole L Hoppman
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
| | - Erik C Thorland
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
| | - D Brian Dawson
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
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Abstract
Genetic causes for human disorders are being discovered at an unprecedented pace. A growing subclass of disease-causing mutations involves changes in the epigenome or in the abundance and activity of proteins that regulate chromatin structure. This article focuses on research that has uncovered human diseases that stem from such epigenetic deregulation. Disease may be caused by direct changes in epigenetic marks, such as DNA methylation, commonly found to affect imprinted gene regulation. Also described are disease-causing genetic mutations in epigenetic modifiers that either affect chromatin in trans or have a cis effect in altering chromatin configuration.
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Affiliation(s)
- Huda Y Zoghbi
- Howard Hughes Medical Institute, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
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Hurren BJ, Flack NAMS. Prader-Willi Syndrome: A spectrum of anatomical and clinical features. Clin Anat 2016; 29:590-605. [PMID: 26749552 DOI: 10.1002/ca.22686] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/04/2016] [Indexed: 12/26/2022]
Abstract
Prader-Willi Syndrome (PWS) is estimated to affect 400,000 people worldwide. First described clinically in 1956, PWS is now known to be a result of a genetic mutation, involving Chromosome 15. The phenotypical appearance of individuals with the syndrome follows a similar developmental course. During infancy, universal hypotonia accompanied by feeding problems, hypogonadism, and dolichocephaly are evident. Characteristic facial features such as narrow bifrontal diameter, almond-shaped eyes, and small mouth (with downturned corners and thin upper lip) may also be evident at this stage. In early childhood, the craniofacial features become more obvious and a global developmental delay is observed. Simultaneously, individuals develop hyperphagia that leads to excessive or rapid weight gain, which, if untreated, exists throughout their lifespan and may predispose them to numerous, serious health issues. The standard tool for differential diagnosis of PWS is genetic screening; however, clinicians also need to be aware of the characteristic features of this disorder, including differences between the genetic subtypes. As the clinical manifestations of the syndrome vary between individuals and become evident at different developmental time points, early assessment is hindered. This article focuses on the clinical and anatomical manifestations of the syndrome and highlights the areas of discrepancy and limitations within the existing literature. Clin. Anat. 29:590-605, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bradley J Hurren
- Department of Anatomy, University of Otago, Dunedin, 9016, New Zealand
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Qi Y, Purtell L, Fu M, Lee NJ, Aepler J, Zhang L, Loh K, Enriquez RF, Baldock PA, Zolotukhin S, Campbell LV, Herzog H. Snord116 is critical in the regulation of food intake and body weight. Sci Rep 2016; 6:18614. [PMID: 26726071 PMCID: PMC4698587 DOI: 10.1038/srep18614] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/23/2015] [Indexed: 12/27/2022] Open
Abstract
Prader-Willi syndrome (PWS) is the predominant genetic cause of obesity in humans. Recent clinical reports have suggested that micro-deletion of the Snord116 gene cluster can lead to PWS, however, the extent of the contributions of the encoded snoRNAs is unknown. Here we show that mice lacking Snord116 globally have low birth weight, increased body weight gain, energy expenditure and hyperphagia. Consistent with this, microarray analysis of hypothalamic gene expression revealed a significant alteration in feeding related pathways that was also confirmed by in situ hybridisation. Importantly, selective deletion of Snord116 only from NPY expressing neurons mimics almost exactly the global deletion phenotype including the persistent low birth weight, increased body weight gain in early adulthood, increased energy expenditure and hyperphagia. Mechanistically, the lack of Snord116 in NPY neurons leads to the upregulation of NPY mRNA consistent with the hyperphagic phenotype and suggests a critical role of Snord116 in the control of NPY neuronal functions that might be dysregulated in PWS.
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Affiliation(s)
- Yue Qi
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Louise Purtell
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Melissa Fu
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Nicola J Lee
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Julia Aepler
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Lei Zhang
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Kim Loh
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Ronaldo F Enriquez
- Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Paul A Baldock
- Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Sergei Zolotukhin
- Department of Pediatrics, College of Medicine, Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, USA
| | - Lesley V Campbell
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia.,School of Medical Sciences, University of NSW, NSW, Australia
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Butler MG, Manzardo AM, Forster JL. Prader-Willi Syndrome: Clinical Genetics and Diagnostic Aspects with Treatment Approaches. Curr Pediatr Rev 2016; 12:136-66. [PMID: 26592417 PMCID: PMC6742515 DOI: 10.2174/1573396312666151123115250] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a neuro-developmental genetic disorder due to lack of expression of genes inherited from the paternal chromosome 15q11-q13 region with three main genetic subtypes. These include paternal 15q11-q13 deletion (about 70% of cases), maternal uniparental disomy 15 or both 15s from the mother (20-30% of cases), and defects in the imprinting center (1-3%) which controls the expression of imprinted genes in this chromosome region. Clinical manifestations include infantile hypotonia with a poor suck resulting in failure to thrive, short stature, small hands/feet and hypogonadism/hypogenitalism due to growth and other hormone deficiencies, hyperphagia and excessive weight gain with obesity and cognitive and behavioral problems including obsessive compulsions, tantrums and self-injury. The phenotype is likely related to hypothalamic dysfunction. OBJECTIVE Hyperphagia and obesity with related complications are major causes of morbidity and mortality in PWS requiring accurate diagnosis, appropriate medical management and treatment; the major objective of our report. METHODS AND RESULTS An extensive review of the literature was undertaken including genetics, clinical and behavioral aspects, and updated health-related information addressing the importance of early diagnosis and treatment of individuals with Prader-Willi syndrome. A searchable, bulleted and formatted list of topics related to this obesity syndrome was provided utilizing a Table of Contents approach for the clinical practitioner. CONCLUSIONS Physicians and other health care providers can use this review with clinical, genetic and treatment summaries divided into sections that are pertinent in the context of clinical practice. Finally, frequently asked questions by clinicians, families and other interested participants will be addressed.
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Affiliation(s)
- Merlin G Butler
- University of Kansas Medical Center, Department of Psychiatry and Behavioral Sciences, 3901 Rainbow Boulevard, MS 4015, Kansas City, Kansas 66160, USA.
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Johnson L, Manzardo AM, Miller JL, Driscoll DJ, Butler MG. Elevated plasma oxytocin levels in children with Prader-Willi syndrome compared with healthy unrelated siblings. Am J Med Genet A 2015; 170:594-601. [PMID: 26615966 DOI: 10.1002/ajmg.a.37488] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/05/2015] [Indexed: 11/07/2022]
Abstract
Prader-Willi syndrome (PWS) is a rare genetic disorder associated with distinct abnormal behaviors including hyperphagia, profound social deficits, and obsessive-compulsive tendencies. PWS males showed reduced oxytocin receptor (OTR) gene expression and density in the hypothalamic paraventricular nucleus that may play a role in PWS psychopathology. Oxytocin is an anorexigenic neuropeptide similar to vasopressin that is associated with social cognition and obsessive-compulsive behavior. To evaluate oxytocin biology in PWS, we examined overnight fasting plasma oxytocin levels in 23 children with PWS (mean ± SD age: 8.2 ± 2.0 year) having genetic confirmation and 18 age matched healthy unrelated siblings without PWS (mean ± SD age: 8.2 ± 2.3 year) and a similar gender ratio under the same clinical assessments, specimen processing and laboratory conditions. Multiplex immune assays were carried out using the Milliplex Human Neuropeptide Magnetic panel and the Luminex system. Natural log-transformed oxytocin levels were analyzed using general linear model adjusting for diagnosis, gender, age and body mass index (BMI). Oxytocin plasma levels were significantly elevated in children with PWS (168 ± 121 pg/ml) compared with unrelated and unaffected siblings without the diagnosis of PWS (64.8 ± 83.8 pg/ml, F = 8.8, P < 0.01) and the diagnosis of PWS predicted oxytocin level (F = 9.5, P < 0.003) in controlled regression analysis with an overall model fit R(2) = 0.33 (P < 0.01). The symptoms of hyperphagia, anxiety and repetitive behaviors classically seen in PWS may be related to the disruption of oxytocin responsivity or feedback in the hypothalamic paraventricular nucleus possibly influencing vasopressin signaling. Further study is needed to characterize oxytocin function in PWS.
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Affiliation(s)
- Lisa Johnson
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
| | - Ann M Manzardo
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
| | - Jennifer L Miller
- Department of Pediatrics, University of Florida Medical Center, Gainesville, Florida
| | - Daniel J Driscoll
- Department of Pediatrics, University of Florida Medical Center, Gainesville, Florida
| | - Merlin G Butler
- Departments of Psychiatry and Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas
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Krefft M, Frydecka D, Adamowski T, Misiak B. From Prader-Willi syndrome to psychosis: translating parent-of-origin effects into schizophrenia research. Epigenomics 2015; 6:677-88. [PMID: 25531260 DOI: 10.2217/epi.14.52] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a relatively rare disorder that originates from paternally inherited deletions and maternal disomy (mUPD) within the 15q11-q13 region or alterations in the PWS imprinting center. Evidence is accumulating that mUPD underlies high prevalence of psychosis among PWS patients. Several genes involved in differentiation and survival of neurons as well as neurotransmission known to act in the development of PWS have been also implicated in schizophrenia. In this article, we provide an overview of genetic and epigenetic underpinnings of psychosis in PWS indicating overlapping points in the molecular background of PWS and schizophrenia. Simultaneously, we highlight the need for studies investigating genetic and epigenetic makeup of the 15q11-q13 in schizophrenia indicating promising candidate genes.
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Affiliation(s)
- Maja Krefft
- Department of Psychiatry, 10 Pasteur Street, Wroclaw Medical University, 50-367 Wroclaw, Poland
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Massah S, Beischlag TV, Prefontaine GG. Epigenetic events regulating monoallelic gene expression. Crit Rev Biochem Mol Biol 2015; 50:337-58. [PMID: 26155735 DOI: 10.3109/10409238.2015.1064350] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In mammals, generally it is assumed that the genes inherited from each parent are expressed to similar levels. However, it is now apparent that in non-sex chromosomes, 6-10% of genes are selected for monoallelic expression. Monoallelic expression or allelic exclusion is established either in an imprinted (parent-of-origin) or a stochastic manner. The stochastic model explains random selection while the imprinted model describes parent-of-origin specific selection of alleles for expression. Allelic exclusion occurs during X chromosome inactivation, parent-of-origin expression of imprinted genes and stochastic monoallelic expression of cell surface molecules, clustered protocadherin (PCDH) genes. Mis-regulation or loss of allelic exclusion contributes to developmental diseases. Epigenetic mechanisms are fundamental players that determine this type of expression despite a homogenous genetic background. DNA methylation and histone modifications are two mediators of the epigenetic phenomena. The majority of DNA methylation is found on cytosines of the CpG dinucleotide in mammals. Several covalent modifications of histones change the electrostatic forces between DNA and histones modifying gene expression. Long-range chromatin interactions organize chromatin into transcriptionally permissive and prohibitive regions leading to simultaneous regulation of gene expression and repression. Non-coding RNAs (ncRNAs) are also players in regulating gene expression. Together, these epigenetic mechanisms fine-tune gene expression levels essential for normal development and survival. In this review, first we discuss what is known about monoallelic gene expression. Then, we focus on the molecular mechanisms that regulate expression of three monoallelically expressed gene classes: the X-linked genes, selected imprinted genes and PCDH genes.
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Affiliation(s)
- Shabnam Massah
- a The Faculty of Health Sciences , Simon Fraser University , Burnaby , BC , Canada
| | - Timothy V Beischlag
- a The Faculty of Health Sciences , Simon Fraser University , Burnaby , BC , Canada
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Kishimoto R, Tamada K, Liu X, Okubo H, Ise S, Ohta H, Ruf S, Nakatani J, Kohno N, Spitz F, Takumi T. Model mice for 15q11-13 duplication syndrome exhibit late-onset obesity and altered lipid metabolism. Hum Mol Genet 2015; 24:4559-72. [PMID: 26002101 DOI: 10.1093/hmg/ddv187] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
Copy number variations on human chromosome 15q11-q13 have been implicated in several neurodevelopmental disorders. A paternal loss or duplication of the Prader-Willi syndrome/Angelman syndrome (PWS/AS) region confers a risk of obesity, although the mechanism remains a mystery due to a lack of an animal model that accurately recreates the obesity phenotype. We performed detailed analyses of mice with duplication of PWS/AS locus (6 Mb) generated by chromosome engineering and found that animals with a paternal duplication of this region (patDp/+) show late-onset obesity, high sensitivity for high-fat diet, high levels of blood leptin and insulin without an increase in food intake. We show that prior to becoming obese, young patDp/+ mice already had enlarged white adipocytes. Transcriptome analysis of adipose tissue revealed an up-regulation of Secreted frizzled-related protein 5 (Sfrp5), known to promote adipogenesis. We additionally generated a new mouse model of paternal duplication focusing on a 3 Mb region (3 Mb patDp/+) within the PWS/AS locus. These mice recapitulate the obese phenotypes including expansion of visceral adipose tissue. Our results suggest paternally expressed genes in PWS/AS locus play a significant role for the obesity and identify new potential targets for future research and treatment of obesity.
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Affiliation(s)
- Rui Kishimoto
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - Kota Tamada
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - Xiaoxi Liu
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Hiroko Okubo
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Satoko Ise
- Banyu Tsukuba Research Institute, Tsukuba, Ibaraki 300-2611, Japan
| | - Hisashi Ohta
- Banyu Tsukuba Research Institute, Tsukuba, Ibaraki 300-2611, Japan
| | - Sandra Ruf
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jin Nakatani
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Ohtsu, Shiga 520-2192, Japan and
| | - Nobuoki Kohno
- Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan, JST, CREST, Tokyo, Japan
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Yingjun X, Yi Z, Jianzhu W, Yunxia S, Yongzhen C, Liangying Z, Xiangyi J, Qun F. Prader-Willi syndrome with a long-contiguous stretch of homozygosity not covering the critical region. J Child Neurol 2015; 30:371-7. [PMID: 24859787 DOI: 10.1177/0883073814535492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Prader-Willi syndrome is a common and complex disorder affecting multiple systems. Its main manifestations are infantile hypotonia with a poor sucking reflex, a characteristic facial appearance, mild mental retardation, hypogonadism and early-onset obesity. Prader-Willi syndrome is due to the absence of paternally expressed imprinted genes at 15q11.2-13, and 3 main mechanisms are known to be involved in its pathogenesis: paternal microdeletions, maternal uniparental disomy events, and imprinting defects. DNA methylation analysis can detect almost all individuals with Prader-Willi syndrome but is unable to distinguish between the molecular classes of the disease. Thus, additional methods are necessary to identify the molecular classes. Here, we employed chromosomal microarray analysis-single nucleotide polymorphism for diagnosis and detected a long-contiguous stretch of homozygosity on chromosome 15, which is highly predictive of maternal uniparental disomy on chromosome 15. Other methods, including fluorescence in situ hybridization, chromosomal microarray analysis-comparative genomic hybridization, genotyping and family linkage analysis, were performed for further validation. In conclusion, our study highlights the use of long-contiguous stretch of homozygosity detection for the diagnosis of Prader-Willi syndrome.
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Affiliation(s)
- Xie Yingjun
- Fetal Medicine Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zhou Yi
- Fetal Medicine Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Wu Jianzhu
- Fetal Medicine Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Sun Yunxia
- Department of Neonatology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Chen Yongzhen
- Fetal Medicine Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zhong Liangying
- Department of Laboratory Medicine, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jing Xiangyi
- Department of Medical Genetics, Zhongshan School of Medicine and Center for Genome Research, Sun Yat-Sen University, Guangzhou, China
| | - Fang Qun
- Fetal Medicine Center, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Neumann LC, Feiner N, Meyer A, Buiting K, Horsthemke B. The imprinted NPAP1 gene in the Prader-Willi syndrome region belongs to a POM121-related family of retrogenes. Genome Biol Evol 2015; 6:344-51. [PMID: 24482533 PMCID: PMC3942032 DOI: 10.1093/gbe/evu019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We have recently shown that the human Nuclear pore-associated protein (NPAP1)/C15orf2 gene encodes a nuclear pore-associated protein. This gene is one of several paternally expressed imprinted genes in the genomic region 15q11q13. Because the Prader–Willi syndrome is known to be caused by the loss of function of paternally expressed genes in 15q11q13, a phenotypic contribution of NPAP1 cannot be excluded. NPAP1 appears to be under strong positive Darwinian selection in primates, suggesting an important function in primate biology. Interestingly, however, in contrast to all other protein-coding genes in 15q11q13, NPAP1 has no ortholog in the mouse. Our investigation of the evolutionary origin of NPAP1 showed that the gene is specific to primate species and absent from the 15q11q13-orthologous regions in all nonprimate mammals. However, we identified a group of paralogous genes, which we call NPAP1L, in all placental mammals except rodents. Phylogenetic analysis revealed that NPAP1, NPAP1L, and another group of genes (UPF0607), which is also restricted to primates, are closely related to the vertebrate transmembrane nucleoporin gene POM121, although they lack the transmembrane domain. These three newly identified groups of genes all lack conserved introns, and hence, are likely retrogenes. We hypothesize that, in the common ancestor of placentals, the POM121 gene retrotransposed and gave rise to an NPAP1-ancestral retrogene NPAP1L/NPAP1/UPF0607. Our results suggest that the nuclear pore-associated gene NPAP1 originates from the vertebrate nucleoporin gene POM121 and—after several steps of retrotransposition and duplication—has been subjected to genomic imprinting and positive selection after integration into the imprinted SNRPN-UBE3A chromosomal domain.
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Affiliation(s)
- Lisa C Neumann
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Germany
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Angelman syndrome imprinting center encodes a transcriptional promoter. Proc Natl Acad Sci U S A 2014; 112:6871-5. [PMID: 25378697 DOI: 10.1073/pnas.1411261111] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clusters of imprinted genes are often controlled by an imprinting center that is necessary for allele-specific gene expression and to reprogram parent-of-origin information between generations. An imprinted domain at 15q11-q13 is responsible for both Angelman syndrome (AS) and Prader-Willi syndrome (PWS), two clinically distinct neurodevelopmental disorders. Angelman syndrome arises from the lack of maternal contribution from the locus, whereas Prader-Willi syndrome results from the absence of paternally expressed genes. In some rare cases of PWS and AS, small deletions may lead to incorrect parent-of-origin allele identity. DNA sequences common to these deletions define a bipartite imprinting center for the AS-PWS locus. The PWS-smallest region of deletion overlap (SRO) element of the imprinting center activates expression of genes from the paternal allele. The AS-SRO element generates maternal allele identity by epigenetically inactivating the PWS-SRO in oocytes so that paternal genes are silenced on the future maternal allele. Here we have investigated functional activities of the AS-SRO, the element necessary for maternal allele identity. We find that, in humans, the AS-SRO is an oocyte-specific promoter that generates transcripts that transit the PWS-SRO. Similar upstream promoters were detected in bovine oocytes. This result is consistent with a model in which imprinting centers become DNA methylated and acquire maternal allele identity in oocytes in response to transiting transcription.
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Martinez ME, Charalambous M, Saferali A, Fiering S, Naumova AK, St Germain D, Ferguson-Smith AC, Hernandez A. Genomic imprinting variations in the mouse type 3 deiodinase gene between tissues and brain regions. Mol Endocrinol 2014; 28:1875-86. [PMID: 25232934 PMCID: PMC4213365 DOI: 10.1210/me.2014-1210] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Dio3 gene, which encodes for the type 3 deiodinase (D3), controls thyroid hormone (TH) availability. The lack of D3 in mice results in tissue overexposure to TH and a broad neuroendocrine phenotype. Dio3 is an imprinted gene, preferentially expressed from the paternally inherited allele in the mouse fetus. However, heterozygous mice with paternal inheritance of the inactivating Dio3 mutation exhibit an attenuated phenotype when compared with that of Dio3 null mice. To investigate this milder phenotype, the allelic expression of Dio3 was evaluated in different mouse tissues. Preferential allelic expression of Dio3 from the paternal allele was observed in fetal tissues and neonatal brain regions, whereas the biallelic Dio3 expression occurred in the developing eye, testes, and cerebellum and in the postnatal brain neocortex, which expresses a larger Dio3 mRNA transcript. The newborn hypothalamus manifests the highest degree of Dio3 expression from the paternal allele, compared with other brain regions, and preferential allelic expression of Dio3 in the brain relaxed in late neonatal life. A methylation analysis of two regulatory regions of the Dio3 imprinted domain revealed modest but significant differences between tissues, but these did not consistently correlate with the observed patterns of Dio3 allelic expression. Deletion of the Dio3 gene and promoter did not result in significant changes in the tissue-specific patterns of Dio3 allelic expression. These results suggest the existence of unidentified epigenetic determinants of tissue-specific Dio3 imprinting. The resulting variation in the Dio3 allelic expression between tissues likely explains the phenotypic variation that results from paternal Dio3 haploinsufficiency.
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Affiliation(s)
- M Elena Martinez
- Department of Molecular Medicine (M.E.M., D.S.G., A.H.), Maine Medical Center Research Institute, Scarborough, Maine 04074; Centre for Endocrinology (M.C.), William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 1BB, United Kingdom; Department of Obstetrics and Gynecology and Human Genetics (A.S., A.K.N.), McGill University, Montréal, Québec, Canada H9X 3V9; Department of Microbiology and Immunology (S.F.), Dartmouth Medical School, Lebanon, New Hampshire 03756; and Department of Genetics (A.C.F.-S.), University of Cambridge, Cambridge CB2 1TN, United Kingdom
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Epilepsy in Prader-Willi syndrome: clinical, diagnostic and treatment aspects. World J Pediatr 2014; 10:108-13. [PMID: 24801229 DOI: 10.1007/s12519-014-0478-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Epilepsy associated with Prader-Willi syndrome (PWS) represents an early and important complication, often not clearly reported and described in the literature. Consequently, there are controversial data about the clinical characteristics of epilepsy and electroencephalographic (EEG) abnormalities found in these patients. DATA SOURCES Based on recent original publications, we have reviewed the different types of seizures and EEG findings in PWS patients, the response to antiepileptic treatment, and the prognosis of epilepsy. RESULTS The frequency of epilepsy in PWS patients ranges from 4% to 26%. The types of seizure include generalized tonic-clonic seizures, complex partial seizures, atypical absence, staring spells, and myoclonic, tonic and hemiclonic seizures, but the most frequent type is focal epilepsy. Status epilepticus has never been reported. EEG abnormalities are not typical but variable in different patients. However, generalized and focal discharges are the most frequently reported findings. There is no evidence of relationship between the course of epilepsy and frequency, morphology and spread of EEG discharges. However, epilepsy in PWS patients is usually responsive to antiepileptic monotherapy with rapid seizure control and a good outcome. CONCLUSIONS The frequency of epilepsy is higher in PWS patients than in general populations and this complication can be a challenge for the clinicians of these patients. Prospective studies are needed to confirm the good long-term prognosis.
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