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Cintra HA, Rocha DN, da Costa ACC, Tyszler LS, Freitas S, de Araujo LA, Crozoe LI, de Paula LR, Correia PS, Gomes LHF, da Cunha Guida L. Investigating the correlation between genotype and phenotype in Prader-Willi syndrome: a study of 45 cases from Brazil. Orphanet J Rare Dis 2024; 19:240. [PMID: 38902749 PMCID: PMC11188222 DOI: 10.1186/s13023-024-03157-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/28/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a genetic disorder characterized by abnormalities in the 15q11-q13 region. Understanding the correlation between genotype and phenotype in PWS is crucial for improved genetic counseling and prognosis. In this study, we aimed to investigate the correlation between genotype and phenotype in 45 PWS patients who previously underwent methylation-sensitive high-resolution melting (MS-HRM) for diagnosis. RESULTS We employed methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and Sanger sequencing, along with collecting phenotypic data from the patients for comparison. Among the 45 patients, 29 (64%) exhibited a deletion of 15q11-q13, while the remaining 16 (36%) had uniparental disomy. No statistically significant differences were found in the main signs and symptoms of PWS. However, three clinical features showed significant differences between the groups. Deletion patients had a higher prevalence of myopia than those with uniparental disomy, as well as obstructive sleep apnea and an unusual skill with puzzles. CONCLUSIONS The diagnostic tests (MS-HRM, MS-MLPA, and Sanger sequencing) yielded positive results, supporting their applicability in PWS diagnosis. The study's findings indicate a general similarity in the genotype-phenotype correlation across genetic subtypes of PWS.
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Affiliation(s)
- Hiago Azevedo Cintra
- Laboratório de Alta Complexidade, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil
| | - Danielle Nascimento Rocha
- Laboratório de Alta Complexidade, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil
| | - Ana Carolina Carioca da Costa
- Unidade de Pesquisa Clínica, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil
| | - Latife Salomão Tyszler
- Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione, Rio de Janeiro, RJ, Brazil
| | - Silvia Freitas
- Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione, Rio de Janeiro, RJ, Brazil
| | | | - Lisanne Incoutto Crozoe
- Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione, Rio de Janeiro, RJ, Brazil
| | - Luísa Ribeiro de Paula
- Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione, Rio de Janeiro, RJ, Brazil
| | - Patricia Santana Correia
- Centro de Genética Médica, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil
| | - Leonardo Henrique Ferreira Gomes
- Laboratório de Alta Complexidade, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil
| | - Letícia da Cunha Guida
- Laboratório de Alta Complexidade, Instituto Nacional da Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Fiocruz, Rio de Janeiro, Brazil.
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2
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Alba R, Omidvarnia S, Bies JJ, Carlson T, Alfaori Q, Htay T. Complex Cardiovascular Morbidities in Prader-Willi Syndrome: A Multidisciplinary Approach. Cureus 2024; 16:e56591. [PMID: 38646247 PMCID: PMC11031429 DOI: 10.7759/cureus.56591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2024] [Indexed: 04/23/2024] Open
Abstract
This case emphasizes the complexity of Prader-Willi syndrome (PWS), the need for a collaborative approach from specialists, and a closer look at the various cardiovascular complexities associated with this syndrome. While current treatments focus on managing symptoms, ongoing genetic research offers hope for more favorable outcomes. Further studies are crucial to gauge the effectiveness of these treatments for PWS patients. We detail a patient with a complex medical history of PWS, further complicated by congenital heart disease with Eisenmenger's syndrome, diabetes mellitus, pulmonary hypertension, venous insufficiency, hypothyroidism, and hyperlipidemia. Reported in this study is a compilation of clinical data as well as suggestions from several medical specialists in applying a multifaceted approach to treatment, significantly emphasizing the need for interdisciplinary care and management of patients experiencing a combination of various medical issues with an emphasis on cardiovascular complications.
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Affiliation(s)
- Raul Alba
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, USA
| | - Soroush Omidvarnia
- Medicine, Texas Tech University Health Science Center El Paso, El Paso, USA
| | - Jared J Bies
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, USA
| | - Tim Carlson
- Internal Medicine, Texas Tech University Health Science Center El Paso, El Paso, USA
| | - Qusay Alfaori
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, USA
| | - Thwe Htay
- Medical Education, Texas Tech University Health Sciences Center El Paso, El Paso, USA
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3
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Camerino C. The Pivotal Role of Oxytocin's Mechanism of Thermoregulation in Prader-Willi Syndrome, Schaaf-Yang Syndrome, and Autism Spectrum Disorder. Int J Mol Sci 2024; 25:2066. [PMID: 38396741 PMCID: PMC10888953 DOI: 10.3390/ijms25042066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/01/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Oxytocin (Oxt) regulates thermogenesis, and altered thermoregulation results in Prader-Willi syndrome (PWS), Schaaf-Yang syndrome (SYS), and Autism spectrum disorder (ASD). PWS is a genetic disorder caused by the deletion of the paternal allele of 15q11-q13, the maternal uniparental disomy of chromosome 15, or defects in the imprinting center of chromosome 15. PWS is characterized by hyperphagia, obesity, low skeletal muscle tone, and autism spectrum disorder (ASD). Oxt also increases muscle tonicity and decreases proteolysis while PWS infants are hypotonic and require assisted feeding in early infancy. This evidence inspired us to merge the results of almost 20 years of studies and formulate a new hypothesis according to which the disruption of Oxt's mechanism of thermoregulation manifests in PWS, SYS, and ASD through thermosensory abnormalities and skeletal muscle tone. This review will integrate the current literature with new updates on PWS, SYS, and ASD and the recent discoveries on Oxt's regulation of thermogenesis to advance the knowledge on these diseases.
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Affiliation(s)
- Claudia Camerino
- Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, P.za G. Cesare 11, 70100 Bari, Italy;
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
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Kioutchoukova IP, Foster DT, Thakkar RN, Foreman MA, Burgess BJ, Toms RM, Molina Valero EE, Lucke-Wold B. Neurologic orphan diseases: Emerging innovations and role for genetic treatments. World J Exp Med 2023; 13:59-74. [PMID: 37767543 PMCID: PMC10520757 DOI: 10.5493/wjem.v13.i4.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/16/2023] [Accepted: 08/11/2023] [Indexed: 09/15/2023] Open
Abstract
Orphan diseases are rare diseases that affect less than 200000 individuals within the United States. Most orphan diseases are of neurologic and genetic origin. With the current advances in technology, more funding has been devoted to developing therapeutic agents for patients with these conditions. In our review, we highlight emerging options for patients with neurologic orphan diseases, specifically including diseases resulting in muscular deterioration, epilepsy, seizures, neurodegenerative movement disorders, inhibited cognitive development, neuron deterioration, and tumors. After extensive literature review, gene therapy offers a promising route for the treatment of neurologic orphan diseases. The use of clustered regularly interspaced palindromic repeats/Cas9 has demonstrated positive results in experiments investigating its role in several diseases. Additionally, the use of adeno-associated viral vectors has shown improvement in survival, motor function, and developmental milestones, while also demonstrating reversal of sensory ataxia and cardiomyopathy in Friedreich ataxia patients. Antisense oligonucleotides have also been used in some neurologic orphan diseases with positive outcomes. Mammalian target of rapamycin inhibitors are currently being investigated and have reduced abnormal cell growth, proliferation, and angiogenesis. Emerging innovations and the role of genetic treatments open a new window of opportunity for the treatment of neurologic orphan diseases.
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Affiliation(s)
| | - Devon T Foster
- Florida International University Herbert Wertheim College of Medicine, Florida International University Herbert Wertheim College of Medicine, Miami, FL 33199, United States
| | - Rajvi N Thakkar
- College of Medicine, University of Florida, Gainesville, FL 32611, United States
| | - Marco A Foreman
- College of Medicine, University of Florida, Gainesville, FL 32611, United States
| | - Brandon J Burgess
- College of Medicine, University of Florida, Gainesville, FL 32611, United States
| | - Rebecca M Toms
- College of Medicine, University of Florida, Gainesville, FL 32611, United States
| | | | - Brandon Lucke-Wold
- Department of Neurosurgery, University of Florida, Gainesville, FL 32611, United States
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5
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Wang SE, Jiang YH. Novel epigenetic molecular therapies for imprinting disorders. Mol Psychiatry 2023; 28:3182-3193. [PMID: 37626134 PMCID: PMC10618104 DOI: 10.1038/s41380-023-02208-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 07/21/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023]
Abstract
Genomic imprinting disorders are caused by the disruption of genomic imprinting processes leading to a deficit or increase of an active allele. Their unique molecular mechanisms underlying imprinted genes offer an opportunity to investigate epigenetic-based therapy for reactivation of an inactive allele or reduction of an active allele. Current treatments are based on managing symptoms, not targeting the molecular mechanisms underlying imprinting disorders. Here, we highlight molecular approaches of therapeutic candidates in preclinical and clinical studies for individual imprinting disorders. These include the significant progress of discovery and testing of small molecules, antisense oligonucleotides, and CRISPR mediated genome editing approaches as new therapeutic strategies. We discuss the significant challenges of translating these promising therapies from the preclinical stage to the clinic, especially for genome editing based approaches.
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Affiliation(s)
- Sung Eun Wang
- Department of Genetics, Yale University School of Medicine, 333 Cedar street, New Haven, CT, 06520, USA
| | - Yong-Hui Jiang
- Department of Genetics, Yale University School of Medicine, 333 Cedar street, New Haven, CT, 06520, USA.
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar street, New Haven, CT, 06520, USA.
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar street, New Haven, CT, 06520, USA.
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Du F, Zhang Y, Ji X, Zhang N, Xu J, Ning T, Xie SA, Liu S, Li P, Zhu S. IL-8-mediated overexpression of ZNF274 promotes the proliferation and migration of colorectal cancer cells through the transactivation of MRPL40. Heliyon 2023; 9:e19046. [PMID: 37636370 PMCID: PMC10450991 DOI: 10.1016/j.heliyon.2023.e19046] [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: 05/18/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/29/2023] Open
Abstract
Background Colorectal cancer (CRC) is one of the most prevalent malignant tumors with high morbidity and mortality rates worldwide. ZNF274, a member of the zinc-finger-protein family of transcription factors, is critical in chromosomal remodelling and tumorigenesis. However, the role of ZNF274 in CRC and the underlying molecular mechanisms remain unclear. Methods Immunohistochemical analysis was performed to quantify the expression of ZNF274 in human CRC tissues. The Kaplan‒Meier method was used to analyse the relationship between ZNF274 expression and CRC prognosis. The correlation between ZNF274 expression and clinical features was analyzed using Cox regression analysis. Cell proliferation and migration were evaluated by CCK-8, colony formation, and Transwell assays. The limma R package was used to analyse IL-8-related differentially expressed genes in the GSE30364 dataset. The DAVID method was used to screen significantly enriched pathways. Chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter assays were performed to determine the transcriptional regulation of MRPL40 by ZNF274. Results ZNF274 was overexpressed in CRC tissues and indicated poor prognosis. High ZNF274 expression was linked to larger tumor size, invasion, lymph node metastasis, and AJCC stage. Ectopic expression promoted CRC cell proliferation and migration. Mechanistically, MRPL40 was identified as the direct target gene that transactivates the expression of ZNF274. Moreover, IL-8 upregulated ZNF274 expression in a dose-dependent manner. Downregulation of either ZNF274 or MRPL40 expression abrogated the effect of IL-8 on promoting the proliferation and migration of CRC. Conclusion This study revealed an oncogenic role of ZNF274 and the mechanism by which ZNF274 participated in IL-8-induced promotion of CRC progression. These findings demonstrate that ZNF274 could be used as a prognostic factor and potential therapeutic target for CRC treatment.
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Affiliation(s)
- Feng Du
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Yijun Zhang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, 100730, China
| | - Xu Ji
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Nan Zhang
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Junxuan Xu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Tingting Ning
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Si-an Xie
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Si Liu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Peng Li
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
| | - Shengtao Zhu
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical, University, National Clinical Research Centre for Digestive Disease, Beijing, Digestive Disease Centre, Beijing Key Laboratory for Precancerous Lesion of Digestive Disease, 100050 Beijing, PR China
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7
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Soeda S, Ito D, Ogushi T, Sano Y, Negoro R, Fujita T, Saito R, Taniura H. Defects in early synaptic formation and neuronal function in Prader-Willi syndrome. Sci Rep 2023; 13:12053. [PMID: 37491450 PMCID: PMC10368700 DOI: 10.1038/s41598-023-39065-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/19/2023] [Indexed: 07/27/2023] Open
Abstract
Prader-Willi syndrome (PWS), which is a complex epigenetic disorder caused by the deficiency of paternally expressed genes in chromosome 15q11-q13, is associated with several psychiatric dimensions, including autism spectrum disorder. We have previously reported that iPS cells derived from PWS patients exhibited aberrant differentiation and transcriptomic dysregulation in differentiated neural stem cells (NSCs) and neurons. Here, we identified SLITRK1 as a downregulated gene in NSCs differentiated from PWS patient iPS cells by RNA sequencing analysis. Because SLITRK1 is involved in synaptogenesis, we focused on the synaptic formation and function of neurons differentiated from PWS patient iPS cells and NDN or MAGEL2 single gene defect mutant iPS cells. Although βIII tubulin expression levels in all the neurons were comparable to the level of differentiation in the control, pre- and postsynaptic markers were significantly lower in PWS and mutant neurons than in control neurons. PSD-95 puncta along βIII tubulin neurites were also decreased. Membrane potential responses were measured while exposed to high K+ stimulation. The neuronal excitabilities in PWS and mutant neurons showed significantly lower intensity than that of control neurons. These functional defects in PWS neurons may reflect phenotypes of neurodevelopmental disorders in PWS.
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Affiliation(s)
- Shuhei Soeda
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Daiki Ito
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Tomoe Ogushi
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Yui Sano
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Ryosuke Negoro
- Laboratory of Molecular Pharmacokinetics, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Takuya Fujita
- Laboratory of Molecular Pharmacokinetics, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Ryo Saito
- Mitsubishi Tanabe Pharma Corporation, Kamoshida, Aoba, Yokohama, 227-0033, Japan
| | - Hideo Taniura
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
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8
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Nicoară DM, Scutca AC, Mang N, Juganaru I, Munteanu AI, Vitan L, Mărginean O. Central precocious puberty in Prader-Willi syndrome: a narrative review. Front Endocrinol (Lausanne) 2023; 14:1150323. [PMID: 37251677 PMCID: PMC10214499 DOI: 10.3389/fendo.2023.1150323] [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: 01/24/2023] [Accepted: 04/17/2023] [Indexed: 05/31/2023] Open
Abstract
Prader-Willi syndrome (PWS, OMIM176270) is a rare genetic disorder with recognizable dysmorphic features and multisystemic consequences such as endocrine, neurocognitive and metabolic ones. Although most patients with Prader-Willi syndrome exhibit hypogonadotropic hypogonadism, there is variability regarding sexual maturation, with precocious puberty occurring in rare cases. Our aim is to elaborate a thorough review of Prader-Willi patients with central precocious puberty, in order to raise awareness of such cases and to enhance our knowledge regarding the diagnosis and prompt treatment of this particular PWS patients.
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Affiliation(s)
- Delia-Maria Nicoară
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
| | - Alexandra-Cristina Scutca
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
- Department of Pediatrics I, Children’s Emergency Hospital “Louis Turcanu”, Timisoara, Romania
| | - Niculina Mang
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
| | - Iulius Juganaru
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
- Department of Pediatrics I, Children’s Emergency Hospital “Louis Turcanu”, Timisoara, Romania
- Research Center in Pediatrics - Disturbances of Growth and Development in Children – BELIVE, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
| | - Andrei-Ioan Munteanu
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
- Department of Pediatrics I, Children’s Emergency Hospital “Louis Turcanu”, Timisoara, Romania
| | - Luiza Vitan
- Department of Endocrinology, Railway Hospital 2 Bucharest, Timisoara, Romania
| | - Otilia Mărginean
- Department of Pediatrics, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
- Department of Pediatrics I, Children’s Emergency Hospital “Louis Turcanu”, Timisoara, Romania
- Research Center in Pediatrics - Disturbances of Growth and Development in Children – BELIVE, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
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Progress in Brain Magnetic Resonance Imaging of Individuals with Prader-Willi Syndrome. J Clin Med 2023; 12:jcm12031054. [PMID: 36769704 PMCID: PMC9917938 DOI: 10.3390/jcm12031054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Prader-Willi syndrome (PWS), a rare epigenetic disease mapping the imprinted chromosomal domain of 15q11.2-q13.3, manifests a regular neurodevelopmental trajectory in different phases. The current multimodal magnetic resonance imaging (MRI) approach for PWS focues on morphological MRI (mMRI), diffusion MRI (dMRI) and functional MRI (fMRI) to uncover brain alterations. This technique offers another perspective to understand potential neurodevelopmental and neuropathological processes of PWS, in addition to specific molecular gene expression patterns, various clinical manifestations and metabolic phenotypes. Multimodal MRI studies of PWS patients demonstrated common brain changes in the volume of gray matter, the integrity of the fiber tracts and the activation and connectivity of some networks. These findings mainly showed that brain alterations in the frontal reward circuit and limbic system were related to molecular genetics and clinical manifestations (e.g., overwhelming eating, obsessive compulsive behaviors and skin picking). Further exploration using a large sample size and advanced MRI technologies, combined with artificial intelligence algorithms, will be the main research direction to study the structural and functional changes and potential pathogenesis of PWS.
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10
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Alshammari RA, Alnezari OS, Alhirabi WA, Alaamer SJ, Alsadun AS, Alhmazani AF, Bakrshoom YF, Alharbi AH. Parents' awareness in the Kingdom of Saudi Arabia regarding failure to thrive: A descriptive cross-sectional study. Saudi Med J 2022; 43:1383-1389. [PMID: 36517051 PMCID: PMC9994523 DOI: 10.15537/smj.2022.43.12.20220511] [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: 07/05/2022] [Accepted: 11/17/2022] [Indexed: 12/17/2023] Open
Abstract
OBJECTIVES To assess the level of parental Awareness about growth failure across all of Saudi Arabia and look into the potential influence of covariates (social and demographic) as determinants of the level of knowledge of parents, both mother and father, aged between 18 and 60, and on the national level. METHODS A cross-sectional study involving a survey of 4,404 parents, aged between 18 and 60 years, in all administrative regions within Saudi Arabia was undertaken From March 2022 to May 2022. RESULTS The majority of participants had average awareness of FTT, and differences in region, as well as in educational and professional levels, had an impact on this awareness, with participants from the western region who hold bachelor's degree and employees have a better level of awareness than others. CONCLUSION To raise awareness, the whole public, especially parents, has to be continuously informed on failure to thrive in children and how to deal with it through educational programs and awareness campaigns.
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Affiliation(s)
- Reem A. Alshammari
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Osama S. Alnezari
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Waleed A. Alhirabi
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Salm J. Alaamer
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Abdulmajeed S. Alsadun
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Abdulmalik F. Alhmazani
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Yousef F. Bakrshoom
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
| | - Ali H. Alharbi
- From the Department of Pediatric (Alshammari), University of Hail-Medical College, and from the College of Medicine (Alnezari, Alhirabi, Alaamer, Alsadun, Alhmazani, Bakrshoom, Alharbi), University of Hail, Hail, Kingdom of Saudi Arabia.
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11
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López-Garrido MP, Carrascosa-Romero MC, Montero-Hernández M, Serrano-Martínez CM, Sánchez-Sánchez F. Case Report: Precision genetic diagnosis in a case of Dyggve-Melchior-Clausen syndrome reveals paternal isodisomy and heterodisomy of chromosome 18 with imprinting clinical implications. Front Genet 2022; 13:1005573. [PMID: 36468000 PMCID: PMC9716064 DOI: 10.3389/fgene.2022.1005573] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/02/2022] [Indexed: 02/19/2024] Open
Abstract
A twelve-year-old patient with a previous clinical diagnosis of spondylocostal skeletal dysplasia and moderate intellectual disability was genetically analyzed through next generation sequencing of a targeted gene panel of 179 genes associated to skeletal dysplasia and mucopolysaccharidosis in order to stablish a precision diagnosis. A homozygous nonsense [c.62C>G; p.(Ser21Ter)] mutation in DYM gene was identified in the patient. Null mutations in DYM have been associated to Dyggve-Melchior-Clausen syndrome, which is a rare autosomal-recessive disorder characterized by skeletal dysplasia and mental retardation, compatible with the patient´s phenotype. To confirm the pathogenicity of this mutation, a segregation analysis was carried out, revealing that the mutation p(Ser21Ter) was solely inherited from the father, who is a carrier of the mutation, while the mother does not carry the mutation. With the suspicion that a paternal disomy could be causing the disease, a series of microsatellite markers in chromosome 18, where the DYM gene is harbored, was analyzed in all the members of the family. Haplotype analysis provided strong evidence of paternal isodisomy and heterodisomy in that chromosome, confirming the pathological effect of this mutation. Furthermore, the patient may have a compromised expression of the ELOA3 gene due to modifications in the genomic imprinting that may potentially increase the risk of digestive cancer. All these results highlight the importance of obtaining a precision diagnosis in rare diseases.
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Affiliation(s)
- María-Pilar López-Garrido
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Ciudad Real, Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | | | - Minerva Montero-Hernández
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha (UCLM), Spain
| | - Caridad-María Serrano-Martínez
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha (UCLM), Spain
| | - Francisco Sánchez-Sánchez
- Laboratorio de Genética Médica, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha (UCLM), Spain
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12
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A Review of Prader–Willi Syndrome. ENDOCRINES 2022. [DOI: 10.3390/endocrines3020027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Prader–Willi Syndrome (PWS, OMIM #176270) is a rare complex genetic disorder due to the loss of expression of paternally derived genes in the PWS critical region on chromosome 15q11-q13. It affects multiple neuroendocrine systems and may present failure to thrive in infancy, but then, hyperphagia and morbid obesity starting in early childhood became the hallmark of this condition. Short stature, hypogonadism, sleep abnormalities, intellectual disability, and behavioral disturbances highlight the main features of this syndrome. There have been a significant number of advances in our understanding of the genetic mechanisms underlying the disease, especially discoveries of MAGEL2, NDN, MKRN3, and SNORD116 genes in the pathophysiology of PWS. However, early diagnosis and difficulty in treating some of the disease’s most disabling features remain challenging. As our understanding of PWS continues to grow, so does the availability of new therapies and management strategies available to clinicians and families.
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13
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Langouët M, Gorka D, Orniacki C, Dupont-Thibert CM, Chung MS, Glatt-Deeley HR, Germain N, Crandall LJ, Cotney JL, Stoddard CE, Lalande M, Chamberlain SJ. Specific ZNF274 binding interference at SNORD116 activates the maternal transcripts in Prader-Willi syndrome neurons. Hum Mol Genet 2021; 29:3285-3295. [PMID: 32977341 DOI: 10.1093/hmg/ddaa210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/15/2020] [Accepted: 08/26/2020] [Indexed: 12/27/2022] Open
Abstract
Prader-Willi syndrome (PWS) is characterized by neonatal hypotonia, developmental delay and hyperphagia/obesity. This disorder is caused by the absence of paternally expressed gene products from chromosome 15q11-q13. We previously demonstrated that knocking out ZNF274, a Kruppel-associated box-A-domain zinc finger protein capable of recruiting epigenetic machinery to deposit the H3K9me3 repressive histone modification, can activate expression from the normally silent maternal allele of SNORD116 in neurons derived from PWS induced pluripotent stem cells (iPSCs). However, ZNF274 has many other targets in the genome in addition to SNORD116. Depleting ZNF274 will surely affect the expression of other important genes and disrupt other pathways. Here, we used CRISPR/Cas9 to delete ZNF274 binding sites at the SNORD116 locus to determine whether activation of the maternal copy of SNORD116 could be achieved without altering ZNF274 protein levels. We obtained similar activation of gene expression from the normally silenced maternal allele in neurons derived from PWS iPSCs, compared with ZNF274 knockout, demonstrating that ZNF274 is directly involved in the repression of SNORD116. These results suggest that interfering with ZNF274 binding at the maternal SNORD116 locus is a potential therapeutic strategy for PWS.
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Affiliation(s)
- Maéva Langouët
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Dea Gorka
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Clarisse Orniacki
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Clémence M Dupont-Thibert
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Michael S Chung
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Heather R Glatt-Deeley
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Noelle Germain
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Leann J Crandall
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Justin L Cotney
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA.,Institute for Systems Genomics, University of Connecticut, Farmington, CT 06030, USA
| | - Christopher E Stoddard
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Marc Lalande
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA.,Institute for Systems Genomics, University of Connecticut, Farmington, CT 06030, USA
| | - Stormy J Chamberlain
- Department of Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, CT 06030, USA.,Institute for Systems Genomics, University of Connecticut, Farmington, CT 06030, USA
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14
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Markouli M, Strepkos D, Piperi C. Structure, Activity and Function of the SETDB1 Protein Methyltransferase. Life (Basel) 2021; 11:life11080817. [PMID: 34440561 PMCID: PMC8397983 DOI: 10.3390/life11080817] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022] Open
Abstract
The SET Domain Bifurcated Histone Lysine Methyltransferase 1 (SETDB1) is a prominent member of the Suppressor of Variegation 3–9 (SUV39)-related protein lysine methyltransferases (PKMTs), comprising three isoforms that differ in length and domain composition. SETDB1 is widely expressed in human tissues, methylating Histone 3 lysine 9 (H3K9) residues, promoting chromatin compaction and exerting negative regulation on gene expression. SETDB1 has a central role in normal physiology and nervous system development, having been implicated in the regulation of cell cycle progression, inactivation of the X chromosome, immune cells function, expression of retroelements and formation of promyelocytic leukemia (PML) nuclear bodies (NB). SETDB1 has been frequently deregulated in carcinogenesis, being implicated in the pathogenesis of gliomas, melanomas, as well as in lung, breast, gastrointestinal and ovarian tumors, where it mainly exerts an oncogenic role. Aberrant activity of SETDB1 has also been implicated in several neuropsychiatric, cardiovascular and gastrointestinal diseases, including schizophrenia, Huntington’s disease, congenital heart defects and inflammatory bowel disease. Herein, we provide an update on the unique structural and biochemical features of SETDB1 that contribute to its regulation, as well as its molecular and cellular impact in normal physiology and disease with potential therapeutic options.
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15
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Mian-Ling Z, Yun-Qi C, Chao-Chun Z. Prader-Willi Syndrome: Molecular Mechanism and Epigenetic Therapy. Curr Gene Ther 2021; 20:36-43. [PMID: 32329685 DOI: 10.2174/1566523220666200424085336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/02/2020] [Accepted: 04/09/2020] [Indexed: 01/10/2023]
Abstract
Prader-Willi syndrome (PWS) is an imprinted neurodevelopmental disease characterized by cognitive impairments, developmental delay, hyperphagia, obesity, and sleep abnormalities. It is caused by a lack of expression of the paternally active genes in the PWS imprinting center on chromosome 15 (15q11.2-q13). Owing to the imprinted gene regulation, the same genes in the maternal chromosome, 15q11-q13, are intact in structure but repressed at the transcriptional level because of the epigenetic mechanism. The specific molecular defect underlying PWS provides an opportunity to explore epigenetic therapy to reactivate the expression of repressed PWS genes inherited from the maternal chromosome. The purpose of this review is to summarize the main advances in the molecular study of PWS and discuss current and future perspectives on the development of CRISPR/Cas9- mediated epigenome editing in the epigenetic therapy of PWS. Twelve studies on the molecular mechanism or epigenetic therapy of PWS were included in the review. Although our understanding of the molecular basis of PWS has changed fundamentally, there has been a little progress in the epigenetic therapy of PWS that targets its underlying genetic defects.
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Affiliation(s)
- Zhong Mian-Ling
- Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Zhejiang, China
| | - Chao Yun-Qi
- Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Zhejiang, China
| | - Zou Chao-Chun
- Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Zhejiang, China
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16
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Drugs and Epigenetic Molecular Functions. A Pharmacological Data Scientometric Analysis. Int J Mol Sci 2021; 22:ijms22147250. [PMID: 34298869 PMCID: PMC8311652 DOI: 10.3390/ijms22147250] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/25/2021] [Accepted: 06/30/2021] [Indexed: 12/14/2022] Open
Abstract
Interactions of drugs with the classical epigenetic mechanism of DNA methylation or histone modification are increasingly being elucidated mechanistically and used to develop novel classes of epigenetic therapeutics. A data science approach is used to synthesize current knowledge on the pharmacological implications of epigenetic regulation of gene expression. Computer-aided knowledge discovery for epigenetic implications of current approved or investigational drugs was performed by querying information from multiple publicly available gold-standard sources to (i) identify enzymes involved in classical epigenetic processes, (ii) screen original biomedical scientific publications including bibliometric analyses, (iii) identify drugs that interact with epigenetic enzymes, including their additional non-epigenetic targets, and (iv) analyze computational functional genomics of drugs with epigenetic interactions. PubMed database search yielded 3051 hits on epigenetics and drugs, starting in 1992 and peaking in 2016. Annual citations increased to a plateau in 2000 and show a downward trend since 2008. Approved and investigational drugs in the DrugBank database included 122 compounds that interacted with 68 unique epigenetic enzymes. Additional molecular functions modulated by these drugs included other enzyme interactions, whereas modulation of ion channels or G-protein-coupled receptors were underrepresented. Epigenetic interactions included (i) drug-induced modulation of DNA methylation, (ii) drug-induced modulation of histone conformations, and (iii) epigenetic modulation of drug effects by interference with pharmacokinetics or pharmacodynamics. Interactions of epigenetic molecular functions and drugs are mutual. Recent research activities on the discovery and development of novel epigenetic therapeutics have passed successfully, whereas epigenetic effects of non-epigenetic drugs or epigenetically induced changes in the targets of common drugs have not yet received the necessary systematic attention in the context of pharmacological plasticity.
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17
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Urrutia G, de Assuncao TM, Mathison AJ, Salmonson A, Kerketta R, Zeighami A, Stodola TJ, Adsay V, Pehlivanoglu B, Dwinell MB, Zimmermann MT, Iovanna JL, Urrutia R, Lomberk G. Inactivation of the Euchromatic Histone-Lysine N-Methyltransferase 2 Pathway in Pancreatic Epithelial Cells Antagonizes Cancer Initiation and Pancreatitis-Associated Promotion by Altering Growth and Immune Gene Expression Networks. Front Cell Dev Biol 2021; 9:681153. [PMID: 34249932 PMCID: PMC8261250 DOI: 10.3389/fcell.2021.681153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/27/2021] [Indexed: 12/24/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive, painful disease with a 5-year survival rate of only 9%. Recent evidence indicates that distinct epigenomic landscapes underlie PDAC progression, identifying the H3K9me pathway as important to its pathobiology. Here, we delineate the role of Euchromatic Histone-lysine N-Methyltransferase 2 (EHMT2), the enzyme that generates H3K9me, as a downstream effector of oncogenic KRAS during PDAC initiation and pancreatitis-associated promotion. EHMT2 inactivation in pancreatic cells reduces H3K9me2 and antagonizes Kras G12D -mediated acinar-to-ductal metaplasia (ADM) and Pancreatic Intraepithelial Neoplasia (PanIN) formation in both the Pdx1-Cre and P48 Cre/+ Kras G12D mouse models. Ex vivo acinar explants also show impaired EGFR-KRAS-MAPK pathway-mediated ADM upon EHMT2 deletion. Notably, Kras G12D increases EHMT2 protein levels and EHMT2-EHMT1-WIZ complex formation. Transcriptome analysis reveals that EHMT2 inactivation upregulates a cell cycle inhibitory gene expression network that converges on the Cdkn1a/p21-Chek2 pathway. Congruently, pancreas tissue from Kras G12D animals with EHMT2 inactivation have increased P21 protein levels and enhanced senescence. Furthermore, loss of EHMT2 reduces inflammatory cell infiltration typically induced during Kras G12D -mediated initiation. The inhibitory effect on Kras G12D -induced growth is maintained in the pancreatitis-accelerated model, while simultaneously modifying immunoregulatory gene networks that also contribute to carcinogenesis. This study outlines the existence of a novel KRAS-EHMT2 pathway that is critical for mediating the growth-promoting and immunoregulatory effects of this oncogene in vivo, extending human observations to support a pathophysiological role for the H3K9me pathway in PDAC.
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Affiliation(s)
- Guillermo Urrutia
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Thiago Milech de Assuncao
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Angela J. Mathison
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ann Salmonson
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Romica Kerketta
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Atefeh Zeighami
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Timothy J. Stodola
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Volkan Adsay
- Department of Pathology, Koç University Hospital, Istanbul, Turkey
| | - Burcin Pehlivanoglu
- Department of Pathology, Adiyaman University Training and Research Hospital, Adiyaman, Turkey
| | - Michael B. Dwinell
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
- Center for Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michael T. Zimmermann
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, Marseille, France
| | - Raul Urrutia
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Gwen Lomberk
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, United States
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, United States
- LaBahn Pancreatic Cancer Program, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
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18
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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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19
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Tauber M, Hoybye C. Endocrine disorders in Prader-Willi syndrome: a model to understand and treat hypothalamic dysfunction. Lancet Diabetes Endocrinol 2021; 9:235-246. [PMID: 33647242 DOI: 10.1016/s2213-8587(21)00002-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
Prader-Willi syndrome is a rare genetic neurodevelopmental disorder resulting from the loss of expression of maternally imprinted genes located in the paternal chromosomal region, 15q11-13. Impaired hypothalamic development and function is the cause of most of the phenotypes comprising the developmental trajectory of Prader-Willi syndrome: from anorexia at birth to excessive weight gain preceding hyperphagia, and early severe obesity with hormonal deficiencies, behavioural problems, and dysautonomia. Growth hormone deficiency, hypogonadism, hypothyroidism, premature adrenarche, corticotropin deficiency, precocious puberty, and glucose metabolism disorders are the main endocrine dysfunctions observed. Additionally, as a result of hypothalamic dysfunction, oxytocin and ghrelin systems are impaired in most patients. Standard pituitary and gonadal hormone replacement therapies are required. In this Review, we discuss Prader-Willi syndrome as a model of hypothalamic dysfunction, and provide a comprehensive description of the accumulated knowledge on genetics, pathophysiology, and treatment approaches of this rare disorder.
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Affiliation(s)
- Maithé Tauber
- Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants, Toulouse, France; Axe Pédiatrique du CIC 9302/INSERM, Hôpital des Enfants, Toulouse, France; Institut Toulousain des Maladies Infectieuses et Inflammatoires, INSERM UMR1291, CNRS UMR5051, Université Toulouse III, Toulouse, France, France; International Prader-Willi Syndrome Organisation, Cambridge, UK.
| | - Charlotte Hoybye
- International Prader-Willi Syndrome Organisation, Cambridge, UK; Department of Endocrinology, Karolinska University Hospital and Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
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20
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Mendiola AJP, LaSalle JM. Epigenetics in Prader-Willi Syndrome. Front Genet 2021; 12:624581. [PMID: 33659026 PMCID: PMC7917289 DOI: 10.3389/fgene.2021.624581] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder that affects approximately 1 in 20,000 individuals worldwide. Symptom progression in PWS is classically characterized by two nutritional stages. Stage 1 is hypotonia characterized by poor muscle tone that leads to poor feeding behavior causing failure to thrive in early neonatal life. Stage 2 is followed by the development of extreme hyperphagia, also known as insatiable eating and fixation on food that often leads to obesity in early childhood. Other major features of PWS include obsessive-compulsive and hoarding behaviors, intellectual disability, and sleep abnormalities. PWS is genetic disorder mapping to imprinted 15q11.2-q13.3 locus, specifically at the paternally expressed SNORD116 locus of small nucleolar RNAs and noncoding host gene transcripts. SNORD116 is processed into several noncoding components and is hypothesized to orchestrate diurnal changes in metabolism through epigenetics, according to functional studies. Here, we review the current status of epigenetic mechanisms in PWS, with an emphasis on an emerging role for SNORD116 in circadian and sleep phenotypes. We also summarize current ongoing therapeutic strategies, as well as potential implications for more common human metabolic and psychiatric disorders.
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Affiliation(s)
| | - Janine M. LaSalle
- Department of Medical Microbiology and Immunology, Genome Center, MIND Institute, University of California, Davis, Davis, CA, United States
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21
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Bhat KP, Ümit Kaniskan H, Jin J, Gozani O. Epigenetics and beyond: targeting writers of protein lysine methylation to treat disease. Nat Rev Drug Discov 2021; 20:265-286. [PMID: 33469207 DOI: 10.1038/s41573-020-00108-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 02/07/2023]
Abstract
Protein lysine methylation is a crucial post-translational modification that regulates the functions of both histone and non-histone proteins. Deregulation of the enzymes or 'writers' of protein lysine methylation, lysine methyltransferases (KMTs), is implicated in the cause of many diseases, including cancer, mental health disorders and developmental disorders. Over the past decade, significant advances have been made in developing drugs to target KMTs that are involved in histone methylation and epigenetic regulation. The first of these inhibitors, tazemetostat, was recently approved for the treatment of epithelioid sarcoma and follicular lymphoma, and several more are in clinical and preclinical evaluation. Beyond chromatin, the many KMTs that regulate protein synthesis and other fundamental biological processes are emerging as promising new targets for drug development to treat diverse diseases.
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Affiliation(s)
- Kamakoti P Bhat
- Department of Biology, Stanford University, Stanford, CA, USA
| | - H Ümit Kaniskan
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jian Jin
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Or Gozani
- Department of Biology, Stanford University, Stanford, CA, USA.
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22
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Markouli M, Strepkos D, Chlamydas S, Piperi C. Histone lysine methyltransferase SETDB1 as a novel target for central nervous system diseases. Prog Neurobiol 2020; 200:101968. [PMID: 33279625 DOI: 10.1016/j.pneurobio.2020.101968] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/31/2020] [Accepted: 11/29/2020] [Indexed: 12/14/2022]
Abstract
Epigenetic changes that regulate chromatin structure have a major impact in genome stabilization and maintenance of cellular homeostasis, been recently implicated in the pathophysiology of central nervous system (CNS). Aberrant expression and dysregulation of histone modification enzymes has been associated with the development of several CNS disorders, revealing these enzymes as putative targets for drug development and novel therapeutic approaches. SETDB1 is a histone lysine methyltransferase responsible for the di- and tri-methylation of histone 3 (H3) at lysine (K) 9 in euchromatic regions further promoting gene silencing through heterochromatin formation. By this way, SETDB1 has been shown to regulate gene expression and influence normal cellular homeostasis required for nervous system function while it is also implicated in the pathogenesis of CNS disorders. Among them, brain tumors, schizophrenia, Huntington's disease, autism spectrum disorders along with alcohol-induced fetal neurobehavioral deficits and Prader-Willi syndrome are representative examples, indicating the aberrant expression and function of SETDB1 as a common pathogenic factor. In this review, we focus on SETDB1-associated molecular mechanisms implicated in CNS physiology and disease while we further discuss current pharmacological approaches targeting SETDB1 enzymatic activity with beneficial effects.
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Affiliation(s)
- Mariam Markouli
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Dimitrios Strepkos
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Sarantis Chlamydas
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece.
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The RDoC approach for translational psychiatry: Could a genetic disorder with psychiatric symptoms help fill the matrix? the example of Prader-Willi syndrome. Transl Psychiatry 2020; 10:274. [PMID: 32772048 PMCID: PMC7415132 DOI: 10.1038/s41398-020-00964-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022] Open
Abstract
The Research Domain Criteria project (RDoc) proposes a new classification system based on information from several fields in order to encourage translational perspectives. Nevertheless, integrating genetic markers into this classification has remained difficult because of the lack of powerful associations between targeted genes and RDoC domains. We hypothesized that genetic diseases with psychiatric manifestations would be good models for RDoC gene investigations and would thereby extend the translational approach to involve targeted gene pathways. To explore this possibility, we reviewed the current knowledge on Prader-Willi syndrome, a genetic disorder caused by the absence of expression of some of the genes of the chromosome 15q11-13 region inherited from the father. Indeed, we found that the associations between genes of the PW locus and the modification identified in the relevant behavioral, physiological, and brain imaging studies followed the structure of the RDoC matrix and its six domains (positive valence, negative valence, social processing, cognitive systems, arousal/regulatory systems, and sensorimotor systems).
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Alves C, Franco RR. Prader-Willi syndrome: endocrine manifestations and management. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2020; 64:223-234. [PMID: 32555988 PMCID: PMC10522225 DOI: 10.20945/2359-3997000000248] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 02/28/2020] [Indexed: 11/23/2022]
Abstract
Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of gene expression in the 15q11.2-q13 paternal chromosome. Patients with PWS develop hypothalamic dysfunction that can lead to various endocrine changes such as: obesity, growth hormone deficiency, hypogonadism, hypothyroidism, adrenal insufficiency and low bone mineral density. In addition, individuals with PWS have increased risk of developing type 2 diabetes mellitus. This review summarizes and updates the current knowledge about the prevention, diagnosis and treatment of endocrine manifestations associated with Prader Willi syndrome, especially diagnosis of growth hormone deficiency, management and monitoring of adverse effects; diagnosis of central adrenal insufficiency and management in stressful situations; screening for central hypothyroidism; research and treatment of hypogonadism; prevention and treatment of disorders of glucose metabolism. Careful attention to the endocrine aspects of PWS contributes significantly to the health of these individuals. Arch Endocrinol Metab. 2020;64(3):223-34.
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Affiliation(s)
- Crésio Alves
- Hospital Universitário Prof. Edgard SantosFaculdade de MedicinaUniversidade Federal da BahiaSalvadorBABrasil Unidade de Endocrinologia Pediátrica, Hospital Universitário Prof. Edgard Santos, Faculdade de Medicina, Universidade Federal da Bahia (UFBA), Salvador, BA, Brasil
| | - Ruth Rocha Franco
- Hospital das ClínicasFaculdade de MedicinaUniversidade de São PauloSão PauloSPBrasil Ambulatório de Prader-Willi, Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brasil
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25
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Salminen I, Read S, Hurd P, Crespi B. Does SNORD116 mediate aspects of psychosis in Prader-Willi syndrome? Evidence from a non-clinical population. Psychiatry Res 2020; 286:112858. [PMID: 32065983 DOI: 10.1016/j.psychres.2020.112858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 12/27/2022]
Abstract
The paternally expressed gene SNORD116 encodes a set of short nucleolar RNAs that affect the expression of hundreds of other genes via epigenetic interactions. Lack of expression for SNORD116 has been implicated in major phenotypes of Prader-Willi Syndrome (PWS). Rates of psychosis and autism spectrum disorders are greatly increased in PWS, but the genetic and epigenetic causes of these increases remain unknown. We genotyped a large population of typical individuals for five SNPs within SNORD116 and phenotyped them for variation in schizotypal and autism spectrum traits. SNORD116 SNP and haplotype variation mediated variation exclusively in the Schizotypal Personality Questionnaire - Ideas of Reference subscale, which reflects variation in aspects of paranoia. The effect was restricted to females. SNORD116 represents, in addition to UBE3A and NDN-MAGEL2, a third, independent locus in the 15q11-q13 imprinted region that preferentially or exclusively affects levels of paranoia. This convergent pattern may reflect a common neural pathway affected by multiple genes, or an effect of interactions between the imprinted loci.
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Affiliation(s)
- Iiro Salminen
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - Silven Read
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Pete Hurd
- Department of Psychology and Centre for Neuroscience, University of Alberta, Edmonton, Canada
| | - Bernard Crespi
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
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26
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Wang SE, Jiang YH. Potential of Epigenetic Therapy for Prader-Willi Syndrome. Trends Pharmacol Sci 2019; 40:605-608. [DOI: 10.1016/j.tips.2019.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 07/01/2019] [Accepted: 07/01/2019] [Indexed: 01/10/2023]
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Wesseler K, Kraft F, Eggermann T. Molecular and Clinical Opposite Findings in 11p15.5 Associated Imprinting Disorders: Characterization of Basic Mechanisms to Improve Clinical Management. Int J Mol Sci 2019; 20:ijms20174219. [PMID: 31466347 PMCID: PMC6747273 DOI: 10.3390/ijms20174219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 12/14/2022] Open
Abstract
Silver-Russell and Beckwith-Wiedemann syndromes (SRS, BWS) are rare congenital human disorders characterized by opposite growth disturbances. With the increasing knowledge on the molecular basis of SRS and BWS, it has become obvious that the disorders mirror opposite alterations at the same genomic loci in 11p15.5. In fact, these changes directly or indirectly affect the expression of IGF2 and CDKN1C and their associated pathways, and thereby, cause growth disturbances as key features of both diseases. The increase of knowledge has become possible with the development and implementation of new and comprehensive assays. Whereas, in the beginning molecular testing was restricted to single chromosomal loci, many tests now address numerous loci in the same run, and the diagnostic implementation of (epi)genome wide assays is only a question of time. These high-throughput approaches will be complemented by the analysis of other omic datasets (e.g., transcriptome, metabolome, proteome), and it can be expected that the integration of these data will massively improve the understanding of the pathobiology of imprinting disorders and their diagnostics. Especially long-read sequencing methods, e.g., nanopore sequencing, allowing direct detection of native DNA modification, will strongly contribute to a better understanding of genomic imprinting in the near future. Thereby, new genomic loci and types of pathogenic variants will be identified, resulting in more precise discrimination into different molecular subgroups. These subgroups serve as the basis for (epi)genotype-phenotype correlations, allowing a more directed prognosis, counseling, and therapy. By deciphering the pathophysiological consequences of SRS and BWS and their molecular disturbances, future therapies will be available targeting the basic cause of the disease and respective pathomechanisms and will complement conventional therapeutic strategies.
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Affiliation(s)
- Katharina Wesseler
- Institute of Human Genetics, University Hospital, Technical University Aachen (RWTH), 52074 Aachen, Germany
| | - Florian Kraft
- Institute of Human Genetics, University Hospital, Technical University Aachen (RWTH), 52074 Aachen, Germany
| | - Thomas Eggermann
- Institute of Human Genetics, University Hospital, Technical University Aachen (RWTH), 52074 Aachen, Germany.
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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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