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Abbas A, Hammad AS, Al-Shafai M. The role of genetic and epigenetic GNAS alterations in the development of early-onset obesity. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2024; 793:108487. [PMID: 38103632 DOI: 10.1016/j.mrrev.2023.108487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND GNAS (guanine nucleotide-binding protein, alpha stimulating) is an imprinted gene that encodes Gsα, the α subunit of the heterotrimeric stimulatory G protein. This subunit mediates the signalling of a diverse array of G protein-coupled receptors (GPCRs), including the melanocortin 4 receptor (MC4R) that serves a pivotal role in regulating food intake, energy homoeostasis, and body weight. Genetic or epigenetic alterations in GNAS are known to cause pseudohypoparathyroidism in its different subtypes and have been recently associated with isolated, early-onset, severe obesity. Given the diverse biological functions that Gsα serves, multiple molecular mechanisms involving various GPCRs, such as MC4R, β2- and β3-adrenoceptors, and corticotropin-releasing hormone receptor, have been implicated in the pathophysiology of severe, early-onset obesity that results from genetic or epigenetic GNAS changes. SCOPE OF REVIEW This review examines the structure and function of GNAS and provides an overview of the disorders that are caused by defects in this gene and may feature early-onset obesity. Moreover, it elucidates the potential molecular mechanisms underlying Gsα deficiency-induced early-onset obesity, highlighting some of their implications for the diagnosis, management, and treatment of this complex condition. MAJOR CONCLUSIONS Gsα deficiency is an underappreciated cause of early-onset, severe obesity. Therefore, screening children with unexplained, severe obesity for GNAS defects is recommended, to enhance the molecular diagnosis and management of this condition.
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Affiliation(s)
- Alaa Abbas
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Ayat S Hammad
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, P.O. Box 2713, Doha, Qatar; Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Mashael Al-Shafai
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, P.O. Box 2713, Doha, Qatar; Biomedical Research Center, Qatar University, P.O. Box 2713, Doha, Qatar.
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Yang W, Zuo Y, Zhang N, Wang K, Zhang R, Chen Z, He Q. GNAS locus: bone related diseases and mouse models. Front Endocrinol (Lausanne) 2023; 14:1255864. [PMID: 37920253 PMCID: PMC10619756 DOI: 10.3389/fendo.2023.1255864] [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: 07/10/2023] [Accepted: 09/29/2023] [Indexed: 11/04/2023] Open
Abstract
GNASis a complex locus characterized by multiple transcripts and an imprinting effect. It orchestrates a variety of physiological processes via numerous signaling pathways. Human diseases associated with the GNAS gene encompass fibrous dysplasia (FD), Albright's Hereditary Osteodystrophy (AHO), parathyroid hormone(PTH) resistance, and Progressive Osseous Heteroplasia (POH), among others. To facilitate the study of the GNAS locus and its associated diseases, researchers have developed a range of mouse models. In this review, we will systematically explore the GNAS locus, its related signaling pathways, the bone diseases associated with it, and the mouse models pertinent to these bone diseases.
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Affiliation(s)
- Wan Yang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yiyi Zuo
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Nuo Zhang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Kangning Wang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Runze Zhang
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Ziyi Chen
- School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Qing He
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
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Miller DE, Hanna P, Galey M, Reyes M, Linglart A, Eichler EE, Jüppner H. Targeted Long-Read Sequencing Identifies a Retrotransposon Insertion as a Cause of Altered GNAS Exon A/B Methylation in a Family With Autosomal Dominant Pseudohypoparathyroidism Type 1b (PHP1B). J Bone Miner Res 2022; 37:1711-1719. [PMID: 35811283 PMCID: PMC9474630 DOI: 10.1002/jbmr.4647] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/14/2022] [Accepted: 07/01/2022] [Indexed: 11/09/2022]
Abstract
Pseudohypoparathyroidism type Ib (PHP1B) is characterized predominantly by resistance to parathyroid hormone (PTH) leading to hypocalcemia and hyperphosphatemia. These laboratory abnormalities are caused by maternal loss-of-methylation (LOM) at GNAS exon A/B, which reduces in cis expression of the stimulatory G protein α-subunit (Gsα). Paternal Gsα expression in proximal renal tubules is silenced through unknown mechanisms, hence LOM at exon A/B reduces further Gsα protein in this kidney portion, leading to PTH resistance. In a previously reported PHP1B family, affected members showed variable LOM at exon A/B, yet no genetic defect was found by whole-genome sequencing despite linkage to GNAS. Using targeted long-read sequencing (T-LRS), we discovered an approximately 2800-bp maternally inherited retrotransposon insertion nearly 1200 bp downstream of exon XL not found in public databases or in 13,675 DNA samples analyzed by short-read whole-genome sequencing. T-LRS data furthermore confirmed normal methylation at exons XL, AS, and NESP and showed that LOM comprising exon A/B is broader than previously thought. The retrotransposon most likely causes the observed epigenetic defect by impairing function of a maternally derived NESP transcript, consistent with findings in mice lacking full-length NESP mRNA and in PHP1B patients with deletion of exon NESP and adjacent intronic sequences. In addition to demonstrating that T-LRS is an effective strategy for identifying a small disease-causing variant that abolishes or severely reduces exon A/B methylation, our data demonstrate that this sequencing technology has major advantages for simultaneously identifying structural defects and altered methylation. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Danny E. Miller
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children’s Hospital, Seattle, WA
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
| | - Patrick Hanna
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Miranda Galey
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Agnès Linglart
- Université Paris-Saclay, Inserm, Physiologie et physiopathologie endocrinienne; AP-HP, Department of molecular genetics, Bicêtre Paris-Saclay hospital, Le Kremlin Bicêtre, France
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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4
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Kottler ML. Pseudo-hypoparathyroïdie et ses variants. Med Sci (Paris) 2022; 38:655-662. [DOI: 10.1051/medsci/2022103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Les pseudohypoparathyroïdies (PHP) sont des maladies rares, caractérisées par une résistance à l’action rénale de la parathormone. Le défaut génétique est localisé au locus GNAS, qui code la sous-unité alpha stimulatrice des protéines G (Gαs). Ce locus est le siège de régulations complexes, épissage alternatif et empreinte parentale éteigant de façon tissu-spécifique l’expression de l’allèle paternel. Des mutations hétérozygotes perte de fonction, des épimutations responsables d’une perte d’expression sont associées à un large spectre pathologique : PHP1A, PHP1B, ossification hétérotopique, ostéodystophie, obésité, retard de croissance in utero, etc., dont les mécanismes restent encore incomplètement connus.
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Xu Z, Shi J, Zhang Y, Liu Y, Zhao J, Chen Q, Song C, Geng S, Xie W, Wu F, Bai Y, Yang Y, Li X. Zfp57 Exerts Maternal and Sexually Dimorphic Effects on Genomic Imprinting. Front Cell Dev Biol 2022; 10:784128. [PMID: 35252168 PMCID: PMC8895500 DOI: 10.3389/fcell.2022.784128] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/04/2022] [Indexed: 12/05/2022] Open
Abstract
Zfp57 has both maternal and zygotic functions in mouse. It maintains genomic imprinting at most known imprinted regions and controls allelic expression of the target imprinted genes in mouse embryos. The DNA methylation imprint at many imprinting control regions (ICRs) is lost when both maternal and zygotic Zfp57 are absent in Zfp57 maternal–zygotic mutant mouse embryos. Interestingly, we found that DNA methylation at a few ICRs was partially lost without maternal Zfp57 in Zfp57 heterozygous mouse embryos derived from Zfp57 homozygous female mice. This suggests that maternal Zfp57 is essential for the maintenance of DNA methylation at a small subset of imprinted regions in mouse embryos. This maternal effect of Zfp57 was applied to allelic expression switch as well as expression levels of the corresponding imprinted genes. It is rather surprising that DNA methylation imprint was affected differently at Rasgrf1 and AK008011 imprinted regions in the female or male Zfp57 maternal–zygotic mutant embryos, with more significant loss of DNA methylation observed in the male mutant embryos. Loss of ZFP57 resulted in gender-specific differences in allelic expression switch and expression level changes of some imprinted genes in female or male mutant embryos. These results indicate maternal and sexually dimorphic effects of ZFP57 on genomic imprinting in mouse.
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Affiliation(s)
- Zhen Xu
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Jiajia Shi
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Yu Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuhan Liu
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Junzheng Zhao
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Qian Chen
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Chenglin Song
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Shuhui Geng
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Feizhen Wu
- Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yun Bai
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Xiajun Li
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
- *Correspondence: Xiajun Li,
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Kiuchi Z, Reyes M, Hanna P, Sharma A, DeClue T, Olney RC, Tebben P, Jüppner H. Progression of PTH Resistance in Autosomal Dominant Pseudohypoparathyroidism Type Ib Due to Maternal STX16 Deletions. J Clin Endocrinol Metab 2022; 107:e681-e687. [PMID: 34477200 PMCID: PMC8899049 DOI: 10.1210/clinem/dgab660] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/04/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Maternally inherited STX16 deletions that cause loss of methylation at GNAS exon A/B and thereby reduce Gsα expression are the most frequent cause of autosomal dominant pseudohypoparathyroidism type Ib (AD-PHP1B). Early identification of these disease-causing variants in the children of affected and unaffected female carriers would prompt treatment with calcium and calcitriol once parathyroid hormone (PTH) levels increase, thereby preventing hypocalcemia and associated complications. OBJECTIVE This study aimed to determine when PTH and calcium abnormalities develop after birth if a STX16 deletion is inherited maternally. METHODS Forty-four children of affected (n = 7) or unaffected (n = 7) females with a STX16 deletion were investigated for the presence of these variants. If a deletion was identified, measurement of PTH, calcium, phosphate, and thyrotropin (TSH) was advised. RESULTS The STX16 deletion that causes AD-PHP1B was identified in 25 children. Pretreatment laboratory results were available for 19 of those cases. Elevated PTH levels were detected by 2 years of age, and these were progressively higher if laboratory testing was first performed after establishing the genetic defect later in life. Total serum calcium levels remained within normal limits until about 5 years of age. TSH levels showed no consistent rise over time. CONCLUSION Establishing whether a STX16 deletion is inherited from a female carrier of a disease-causing variant rapidly establishes the diagnosis of AD-PHP1B. Several years before overt hypocalcemia developed, PTH levels increased, thereby establishing the onset of PTH resistance. Our findings provide diagnostic guidance and when treatment with calcium and calcitriol should be considered in order to prevent hypocalcemia and associated sequelae.
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Affiliation(s)
- Zentaro Kiuchi
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Patrick Hanna
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Anu Sharma
- Division of Diabetes, Endocrinology and Metabolism, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Terry DeClue
- St Joseph’s Children’s Hospital, Tampa, FL 33607, USA
| | - Robert C Olney
- Nemours Children’s Specialty Care, Jacksonville, FL 32207, USA
| | - Peter Tebben
- Departments of Internal Medicine and Pediatrics, Divisions of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Danzig J, Li D, Jan de Beur S, Levine MA. High-throughput Molecular Analysis of Pseudohypoparathyroidism 1b Patients Reveals Novel Genetic and Epigenetic Defects. J Clin Endocrinol Metab 2021; 106:e4603-e4620. [PMID: 34157100 PMCID: PMC8677598 DOI: 10.1210/clinem/dgab460] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Patients with pseudohypoparathyroidism type 1b (PHP1b) show disordered imprinting of the maternal GNAS allele or paternal uniparental disomy (UPD). Genetic deletions in STX16 or in upstream exons of GNAS are present in many familial but not sporadic cases. OBJECTIVE Characterization of epigenetic and genetic defects in patients with PHP1b. DESIGN AND PATIENTS DNA from 84 subjects, including 26 subjects with sporadic PHP1b, 27 affected subjects and 17 unaffected and/or obligate gene carriers from 12 PHP1b families, 11 healthy individuals, and 3 subjects with PHP1a was subjected to quantitative pyrosequencing of GNAS differentially methylated regions (DMRs), microarray analysis, and microsatellite haplotype analysis. SETTING Academic medical center. MAIN OUTCOME MEASUREMENTS Molecular pathology of PHP1b. RESULTS Healthy subjects, unaffected family members and obligate carriers of paternal PHP1b alleles, and subjects with PHP1a showed normal methylation of all DMRs. All PHP1b subjects showed loss of methylation (LOM) at the exon A/B DMR. Affected members of 9 PHP1b kindreds showed LOM only at the exon A/B DMR, which was associated with a 3-kb deletion of STX16 exons 4 through 6 in 7 families and a novel deletion of STX16 and adjacent NEPEPL1 in 1 family. A novel NESP deletion was found in 1 of 2 other families with more extensive methylation defects. One sporadic PHP1b had UPD of 20q, 2 had 3-kb STX16 deletions, and 5 had apparent epigenetic mosaicism. CONCLUSIONS We found diverse patterns of defective methylation and identified novel or previously known mutations in 9 of 12 PHP1b families.
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Affiliation(s)
- Jennifer Danzig
- Division of Endocrinology and Diabetes, and The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Dong Li
- Center for Applied Genomics, The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Suzanne Jan de Beur
- Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael A Levine
- Division of Endocrinology and Diabetes, and The Children’s Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Romanet P, Galluso J, Kamenicky P, Hage M, Theodoropoulou M, Roche C, Graillon T, Etchevers HC, De Murat D, Mougel G, Figarella-Branger D, Dufour H, Cuny T, Assié G, Barlier A. Somatotroph Tumors and the Epigenetic Status of the GNAS Locus. Int J Mol Sci 2021; 22:ijms22147570. [PMID: 34299200 PMCID: PMC8306130 DOI: 10.3390/ijms22147570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/09/2021] [Accepted: 07/10/2021] [Indexed: 11/16/2022] Open
Abstract
Forty percent of somatotroph tumors harbor recurrent activating GNAS mutations, historically called the gsp oncogene. In gsp-negative somatotroph tumors, GNAS expression itself is highly variable; those with GNAS overexpression most resemble phenotypically those carrying the gsp oncogene. GNAS is monoallelically expressed in the normal pituitary due to methylation-based imprinting. We hypothesize that changes in GNAS imprinting of gsp-negative tumors affect GNAS expression levels and tumorigenesis. We characterized the GNAS locus in two independent somatotroph tumor cohorts: one of 23 tumors previously published (PMID: 31883967) and classified by pan-genomic analysis, and a second with 82 tumors. Multi-omics analysis of the first cohort identified a significant difference between gsp-negative and gsp-positive tumors in the methylation index at the known differentially methylated region (DMR) of the GNAS A/B transcript promoter, which was confirmed in the larger series of 82 tumors. GNAS allelic expression was analyzed using a polymorphic Fok1 cleavage site in 32 heterozygous gsp-negative tumors. GNAS expression was significantly reduced in the 14 tumors with relaxed GNAS imprinting and biallelic expression, compared to 18 tumors with monoallelic expression. Tumors with relaxed GNAS imprinting showed significantly lower SSTR2 and AIP expression levels. Altered A/B DMR methylation was found exclusively in gsp-negative somatotroph tumors. 43% of gsp-negative tumors showed GNAS imprinting relaxation, which correlated with lower GNAS, SSTR2 and AIP expression, indicating lower sensitivity to somatostatin analogues and potentially aggressive behavior.
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Affiliation(s)
- Pauline Romanet
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Conception, Hospital Laboratory of Molecular Biology, 13385 Marseille, France; (P.R.); (J.G.); (G.M.)
| | - Justine Galluso
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Conception, Hospital Laboratory of Molecular Biology, 13385 Marseille, France; (P.R.); (J.G.); (G.M.)
| | - Peter Kamenicky
- Université Paris-Saclay, Inserm, Physiologie et Physiopathologie Endocriniennes, Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Service d’Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Rares de l’Hypophyse, 94270 Le Kremlin-Bicêtre, Île-de-France, France; (P.K.); (M.H.)
| | - Mirella Hage
- Université Paris-Saclay, Inserm, Physiologie et Physiopathologie Endocriniennes, Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Service d’Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Rares de l’Hypophyse, 94270 Le Kremlin-Bicêtre, Île-de-France, France; (P.K.); (M.H.)
| | - Marily Theodoropoulou
- Medizinische Klinik und Poliklinik IV, LMU Klinikum, Ludwig Maximilian University Munich, 80336 Munich, Germany;
| | - Catherine Roche
- APHM, La Conception Hospital, Laboratory of Molecular Biology, 13385 Marseille, France;
| | - Thomas Graillon
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Timone Hospital Department of Neurosurgery, 13385 Marseille, France; (T.G.); (H.D.)
| | - Heather C. Etchevers
- Aix Marseille Univ, INSERM, MMG, UMR1251, Marmara Institute, 13385 Marseille, France;
| | - Daniel De Murat
- Université de Paris, Institut Cochin, Inserm U1016, CNRS UMR8104, F-75014 Paris, France; (D.D.M.); (G.A.)
| | - Grégory Mougel
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Conception, Hospital Laboratory of Molecular Biology, 13385 Marseille, France; (P.R.); (J.G.); (G.M.)
| | - Dominique Figarella-Branger
- Aix-Marseille Univ, APHM, CNRS, INP, Inst Neurophysiopathol, CHU Timone, Service d’Anatomie Pathologique et de Neuropathologie, 13385 Marseille, France;
| | - Henry Dufour
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Timone Hospital Department of Neurosurgery, 13385 Marseille, France; (T.G.); (H.D.)
| | - Thomas Cuny
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, Department of Endocrinology, Hospital La Conception, 13385 Marseille, France;
| | - Guillaume Assié
- Université de Paris, Institut Cochin, Inserm U1016, CNRS UMR8104, F-75014 Paris, France; (D.D.M.); (G.A.)
- Department of Endocrinology, Center for Rare Adrenal Diseases, Assistance Publique—Hôpitaux de Paris, Hôpital Cochin, 75014 Paris, France
| | - Anne Barlier
- Aix Marseille Univ, INSERM, APHM, MMG, UMR1251, Marmara Institute, La Conception, Hospital Laboratory of Molecular Biology, 13385 Marseille, France; (P.R.); (J.G.); (G.M.)
- Correspondence:
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Abstract
Pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) are caused by mutations and/or epigenetic changes at the complex GNAS locus on chromosome 20q13.3 that undergoes parent-specific methylation changes at several differentially methylated regions (DMRs). GNAS encodes the alpha-subunit of the stimulatory G protein (Gsα) and several splice variants thereof. PHP type Ia (PHP1A) is caused by heterozygous inactivating mutations involving the maternal exons 1-13. Heterozygosity of these maternal GNAS mutations cause PTH-resistant hypocalcemia and hyperphosphatemia because paternal Gsα expression is suppressed in certain organs thus leading to little or no Gsα protein in the proximal renal tubules and other tissues. Besides biochemical abnormalities, PHP1A patients show developmental abnormalities, referred to as Albright's hereditary osteodystrophy (AHO). Some, but not all of these AHO features are encountered also in patients affected by PPHP, who carry paternal Gsα-specific mutations and typically show no laboratory abnormalities. Autosomal dominant PHP type Ib (AD-PHP1B) is caused by heterozygous maternal deletions within GNAS or STX16, which are associated with loss of methylation at the A/B DMR alone or at all maternally methylated GNAS exons. Loss of methylation of exon A/B and the resulting biallelic expression of A/B transcript reduces Gsα expression thus leading to hormonal resistance. Epigenetic changes at all differentially methylated GNAS regions are also observed in sporadic PHP1B, which is the most frequent PHP1B variant. However, this disease variant remains unresolved at the molecular level, except for rare cases with paternal uniparental isodisomy or heterodisomy of chromosome 20q (patUPD20q).
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Affiliation(s)
- Harald Jüppner
- Endocrine Unit, Department of Medicine and Pediatric Nephrology Unit, Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Correspondence: Harald Jüppner, MD, Endocrine Unit, Thier 10, 50 Blossom Street, Massachusetts General Hospital, Boston, MA 02114, USA.
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10
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Luo D, Qi X, Liu L, Su Y, Fang L, Guan Q. Genetic and Epigenetic Characteristics of Autosomal Dominant Pseudohypoparathyroidism Type 1B: Case Reports and Literature Review. Horm Metab Res 2021; 53:225-235. [PMID: 33513624 DOI: 10.1055/a-1341-9891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Autosomal dominant pseudohypoparathyroidism 1B (AD-PHP1B) is a rare endocrine and imprinted disorder. The objective of this study is to clarify the imprinted regulation of the guanine nucleotide binding-protein α-stimulating activity polypeptide 1 (GNAS) cluster in the occurrence and development of AD-PHP1B based on animal and clinical patient studies. The methylation-specific multiples ligation-dependent probe amplification (MS-MLPA) was conducted to detect the copy number variation in syntaxin-16 (STX16) gene and methylation status of the GNAS differentially methylated regions (DMRs). Long-range PCR was used to confirm deletion at STX16 gene. In the first family, DNA analysis of the proband and proband's mother revealed an isolated loss of methylation (LOM) at exon A/B and a 3.0 kb STX16 deletion. The patient's healthy grandmother had the 3.0 kb STX16 deletion but no epigenetic abnormality. The patient's healthy maternal aunt showed no genetic or epigenetic abnormality. In the second family, the analysis of long-range PCR revealed the 3.0 kb STX16 deletion for the proband but not her children. In this study, 3.0 kb STX16 deletion causes isolated LOM at exon A/B in two families, which is the most common genetic mutation of AD-PHP1B. The deletion involving NESP55 or AS or genomic rearrangements of GNAS can also result in AD-PHP1B, but it's rare. LOM at exon A/B DMR is prerequisite methylation defect of AD-PHP1B. STX16 and NESP55 directly control the imprinting at exon A/B, while AS controls the imprinting at exon A/B by regulating the transcriptional level of NESP55.
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Affiliation(s)
- Dandan Luo
- Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, China
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
| | - Xiangyu Qi
- Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, China
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
| | - Luna Liu
- Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, China
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
| | - Yu Su
- Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, China
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
| | - Li Fang
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
| | - Qingbo Guan
- Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, China
- Shandong Provincial Key Laboratory of Endocrinology and Lipid Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, China
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
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11
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Yang Y, Chu X, Nie M, Song A, Jiang Y, Li M, Xia W, Xing X, Wang O. A novel long-range deletion spanning STX16 and NPEPL1 causing imprinting defects of the GNAS locus discovered in a patient with autosomal-dominant pseudohypoparathyroidism type 1B. Endocrine 2020; 69:212-219. [PMID: 32337648 DOI: 10.1007/s12020-020-02304-6] [Citation(s) in RCA: 8] [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: 01/04/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Pseudohypoparathyroidism (PHP) is a rare disorder characterized by hypocalcemia, hyperphosphatemia, and resistance to parathyroid hormone (PTH). According to different GNAS mutations, PHP is divided into several subtypes, among which autosomal-dominant PHP1B (AD-PHP1B) is caused by STX16 deletion and epigenetic alteration of GNAS. Although the deletion of STX16 exons 2-6 is commonly observed, other mutations involving STX16 can also result in AD-PHP1B. MATERIALS AND METHODS The clinical information of a 38-year-old male PHP patient was collected. The genomic DNA from peripheral blood cells was extracted for genetic analysis of GNAS and upstream STX16 by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and whole-exome sequencing (WES). Sanger sequencing was performed to verify the break point of the novel long-range deletion. RESULTS The patient's medical history of tetany and seizure as well as laboratory examination showing hypocalcemia and elevated PTH levels indicated the diagnosis of PHP. The results of MS-MLPA showed loss of methylation of GNAS A/B:TSS-DMR and half-reduced copy number of STX16 exon 1-9, which revealed the subtype of AD-PHP1B. Furthermore, the WES study displayed a 87.5 kb missing upstream of GNAS. A 87.5 kb deletion spanning STX16 and NPEPL1 together with an insertion of 28 bp of unknown origin was verified by PCR along with Sanger sequencing. CONCLUSIONS A novel deletion of 87.5 kb spanning STX16 and NPEPL1 was discovered in an AD-PHP1B patient, which provides new information on molecular defects leading to AD-PHP1B.
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Affiliation(s)
- Yi Yang
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Xueying Chu
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Min Nie
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - An Song
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Yan Jiang
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Mei Li
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Weibo Xia
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Xiaoping Xing
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China
| | - Ou Wang
- Key Laboratory of Endocrinology of the Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China.
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12
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Ahn J, Wu H, Lee J, Hwang IS, Yu D, Ahn JS, Lee JW, Hwang S, Lee K. Identification of a Novel Imprinted Transcript in the Porcine GNAS Complex Locus Using Methylome and Transcriptome of Parthenogenetic Fetuses. Genes (Basel) 2020; 11:genes11010096. [PMID: 31947640 PMCID: PMC7017182 DOI: 10.3390/genes11010096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 12/27/2022] Open
Abstract
Genomic imprinting in domestic animals contributes to the variance of performance traits. However, research remains to be done on large-scale detection of epigenetic landscape of porcine imprinted loci including the GNAS complex locus. The purpose of this study was to generate porcine parthenogenetic fetuses and comprehensively identify imprinting patterns of the GNAS locus in transcript levels. To this end, both normally fertilized and bimaternal (uniparental) parthenogenetic porcine fetuses were generated, and whole genome bisulfite sequencing (WGBS) and RNA sequencing (RNA-seq) were performed to construct methylome and transcriptome, respectively. Differentially methylated regions (DMRs) between the fetuses were identified through methylome analysis, and parental-origin-specific expression patterns of transcripts were examined with transcriptome. As a result, three major DMRs were identified: paternally methylated Nesp DMR, maternally methylated Nespas-Gnasxl DMR, and maternally methylated Exon1B–Exon1A DMR. Parental-origin-specific expressions of those five DMR-affected transcripts were found, including a novel imprinted transcript, Exon1B, in pigs. In conclusion, using parthenotes, parental-origin-specific imprinting patterns in the porcine GNAS locus was comprehensively identified, and our approach paves the way for the discovery of novel imprinted genes and loci in a genomic context across species.
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Affiliation(s)
- Jinsoo Ahn
- Functional Genomics Laboratory, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA; (J.A.); (H.W.); (J.L.); (D.Y.)
| | - Huiguang Wu
- Functional Genomics Laboratory, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA; (J.A.); (H.W.); (J.L.); (D.Y.)
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Joonbum Lee
- Functional Genomics Laboratory, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA; (J.A.); (H.W.); (J.L.); (D.Y.)
| | - In-Sul Hwang
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Jeonbuk 55365, Korea;
| | - Debing Yu
- Functional Genomics Laboratory, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA; (J.A.); (H.W.); (J.L.); (D.Y.)
- Department of Animal Breeding & Genetics, College of Animal Science & Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jin-Seop Ahn
- Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea; (J.-S.A.)
| | - Jeong-Woong Lee
- Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea; (J.-S.A.)
| | - Seongsoo Hwang
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Jeonbuk 55365, Korea;
- Correspondence: (S.H.); (K.L.)
| | - Kichoon Lee
- Functional Genomics Laboratory, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA; (J.A.); (H.W.); (J.L.); (D.Y.)
- Correspondence: (S.H.); (K.L.)
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13
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Taneera J, Dhaiban S, Mohammed AK, Mukhopadhyay D, Aljaibeji H, Sulaiman N, Fadista J, Salehi A. GNAS gene is an important regulator of insulin secretory capacity in pancreatic β-cells. Gene 2019; 715:144028. [PMID: 31374326 DOI: 10.1016/j.gene.2019.144028] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/27/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Type 2 diabetes (T2D) is a complex polygenic disease with unclear mechanism. In an attempt to identify novel genes involved in β-cell function, we harness a bioinformatics method called Loss-of-function tool (LoFtool) gene score. METHODS RNA-sequencing data from human islets were used to cross-reference genes within the 1st quartile of most intolerant LoFtool score with the 100th most expressed genes in human islets. Out of these genes, GNAS and EEF1A1 genes were selected for further investigation in diabetic islets, metabolic tissues along with their correlation with diabetic phenotypes. The influence of GNAS and EEF1A1 on insulin secretion and β-cell function were validated in INS-1 cells. RESULTS A comparatively higher expression level of GNAS and EEF1A1 was observed in human islets than fat, liver and muscle tissues. Furthermore, diabetic islets displayed a reduced expression of GNAS, but not of EEF1A, compared to non-diabetic islets. The expression of GNAS was positively correlated with insulin secretory index, GLP1R, GIPR and inversely correlated with HbA1c. Diabetic human islets displayed a reduced cAMP generation and insulin secretory capacity in response to glucose. Moreover, siRNA silencing of GNAS in INS-1 cells reduced insulin secretion, insulin content, and cAMP production. In addition, the expression of Insulin, PDX1, and MAFA was significantly down-regulated in GNAS-silenced cells. However, cell viability and apoptosis rate were unaffected. CONCLUSION LoFtool is a powerful tool to identify genes associated with pancreatic islets dysfunction. GNAS is a crucial gene for the β-cell insulin secretory capacity.
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Affiliation(s)
- Jalal Taneera
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates.
| | - Sarah Dhaiban
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Abdul Khader Mohammed
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Debasmita Mukhopadhyay
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Hayat Aljaibeji
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Nabil Sulaiman
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Joao Fadista
- Department of Epidemiology Research, Statens Serum Institute, Copenhagen, Denmark; Lund University Diabetes Centre (LUDC), Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Albert Salehi
- Lund University Diabetes Centre (LUDC), Department of Clinical Sciences, Lund University, Malmö, Sweden
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14
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Saito T, Hara S, Kato T, Tamano M, Muramatsu A, Asahara H, Takada S. A tandem repeat array in IG-DMR is essential for imprinting of paternal allele at the Dlk1-Dio3 domain during embryonic development. Hum Mol Genet 2019; 27:3283-3292. [PMID: 29931170 DOI: 10.1093/hmg/ddy235] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/18/2018] [Indexed: 12/27/2022] Open
Abstract
Genomic imprinting is a phenomenon that causes parent-origin-specific monoallelic expression of a small subset of genes, known as imprinted genes, by parentally inherited epigenetic marks. Imprinted genes at the delta-like homolog 1 gene (Dlk1)-type III iodothyronine deiodinase gene (Dio3) imprinted domain, regulated by intergenic differentially methylated region (IG-DMR), are essential for normal development of late embryonic stages. Although the functions of IG-DMR have been reported by generating knockout mice, molecular details of the regulatory mechanisms are not fully understood as the specific sequence(s) of IG-DMR have not been identified. Here, we generated mutant mice by deleting a 216 bp tandem repeated sequence in IG-DMR, which comprised seven repeats of 24 bp motifs, by genome editing technologies. The mutant mice showed that paternal transmission of the deletion allele, but not maternal transmission, induces severe growth retardation and perinatal lethality, possibly due to placental defects. Embryos with a paternally transmitted deletion allele showed biallelic expression of maternally expressed genes and repression of paternally expressed genes. DNA methylation status also showed loss of methylation at IG-DMR and Gtl2-DMR, indicating that the tandem repeat sequence of IG-DMR is one of the functional sequences of IG-DMR, which is required for maintaining DNA methylation imprints of paternal allele at IG-DMR.
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Affiliation(s)
- Takeshi Saito
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan.,Department of Systems BioMedicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Hara
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tomoko Kato
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan.,Regenerative Medicine Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Moe Tamano
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Akari Muramatsu
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Hiroshi Asahara
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan.,Department of Systems BioMedicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Shuji Takada
- Department of Systems BioMedicine, National Research Institute for Child Health and Development, Tokyo, Japan
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15
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Elli FM, Bordogna P, Arosio M, Spada A, Mantovani G. Mosaicism for GNAS methylation defects associated with pseudohypoparathyroidism type 1B arose in early post-zygotic phases. Clin Epigenetics 2018; 10:16. [PMID: 29445425 PMCID: PMC5801752 DOI: 10.1186/s13148-018-0449-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 01/30/2018] [Indexed: 11/10/2022] Open
Abstract
Background Pseudohypoparathyroidism type 1B (PHP1B; MIM#603233) is a rare imprinting disorder (ID), associated with the GNAS locus, characterized by parathyroid hormone (PTH) resistance in the absence of other endocrine or physical abnormalities. Sporadic PHP1B cases, with no known underlying primary genetic lesions, could represent true stochastic errors in early embryonic maintenance of methylation. Previous data confirmed the existence of different degrees of methylation defects associated with PHP1B and suggested the presence of mosaicism, a phenomenon already described in the context of other IDs. Results With respect to mosaic conditions, the study of multiple tissues is a necessary approach; thus, we investigated somatic cell lines (peripheral blood and buccal epithelium and cells from the urine sediment) descending from different germ layers from 19 PHP patients (11 spor-PHP1B, 4 GNAS mutated PHP1A, and 4 PHP with no GNAS (epi)genetic defects) and 5 healthy controls. We identified 11 patients with epigenetic defects, further subdivided in groups with complete or partial methylation defects. The recurrence of specific patterns of partial methylation defects limited to specific CpGs was confirmed by checking methylation profiles of spor-PHP1B patients diagnosed in our lab (n = 56). Underlying primary genetic defects, such as uniparental disomy or deletion, potentially causative for the detected partial methylation were excluded in all samples. Conclusions Our data showed no differences of methylation levels between organs and tissues from the same patient, so we concluded that the epimutation occurred in early post-zygotic phases and that the partial defects were mosaics. The number of patients with no detectable (epi)genetic GNAS defects was too small to exclude epimutations occurring in later post-zygotic phases, affecting only selected tissues different from blood, thus leading to underdiagnosis during routine molecular diagnosis. Finally, we found no correlation between methylation ratios, representing the proportion of epimutated cells, and the clinical presentation, further confirming the hypothesis of a threshold effect of the GNAS loss of imprinting leading to an "all-or-none" phenotype.
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Affiliation(s)
- Francesca Marta Elli
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
| | - Paolo Bordogna
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maura Arosio
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Anna Spada
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giovanna Mantovani
- Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza, 35-20122 Milan, Italy
- Endocrinology and Metabolic Diseases Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
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16
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Alisch RS, Van Hulle C, Chopra P, Bhattacharyya A, Zhang SC, Davidson RJ, Kalin NH, Goldsmith HH. A multi-dimensional characterization of anxiety in monozygotic twin pairs reveals susceptibility loci in humans. Transl Psychiatry 2017; 7:1282. [PMID: 29225348 PMCID: PMC5802687 DOI: 10.1038/s41398-017-0047-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 09/13/2017] [Indexed: 02/06/2023] Open
Abstract
The etiology of individual differences in human anxiousness is complex and includes contributions from genetic, epigenetic (i.e., DNA methylation) and environmental factors. Past genomic approaches have been limited in their ability to detect human anxiety-related differences in these factors. To overcome these limitations, we employed both a multi-dimensional characterization method, to select monozygotic twin pairs discordant for anxiety, and whole genome DNA methylation sequencing. This approach revealed 230 anxiety-related differentially methylated loci that were annotated to 183 genes, including several known stress-related genes such as NAV1, IGF2, GNAS, and CRTC1. As an initial validation of these findings, we tested the significance of an overlap of these data with anxiety-related differentially methylated loci that we previously reported from a key neural circuit of anxiety (i.e., the central nucleus of the amygdala) in young monkeys and found a significant overlap (P-value < 0.05) of anxiety-related differentially methylated genes, including GNAS, SYN3, and JAG2. Finally, sequence motif predictions of all the human differentially methylated regions indicated an enrichment of five transcription factor binding motifs, suggesting that DNA methylation may regulate gene expression by mediating transcription factor binding of these transcripts. Together, these data demonstrate environmentally sensitive factors that may underlie the development of human anxiety.
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Affiliation(s)
- Reid S. Alisch
- 0000 0001 0701 8607grid.28803.31Departments of Psychiatry, University of Wisconsin, Madison, WI USA ,0000 0001 2167 3675grid.14003.36Neuroscience Training Program, University of Wisconsin, Madison, WI USA
| | - Carol Van Hulle
- 0000 0001 2167 3675grid.14003.36Waisman Center, University of Wisconsin, Madison, WI USA
| | - Pankaj Chopra
- 0000 0001 0941 6502grid.189967.8Department of Human Genetics, Emory University School of Medicine, Atlanta, GA USA
| | - Anita Bhattacharyya
- 0000 0001 2167 3675grid.14003.36Waisman Center, University of Wisconsin, Madison, WI USA
| | - Su-Chun Zhang
- 0000 0001 2167 3675grid.14003.36Neuroscience Training Program, University of Wisconsin, Madison, WI USA ,0000 0001 2167 3675grid.14003.36Waisman Center, University of Wisconsin, Madison, WI USA ,0000 0001 0701 8607grid.28803.31Departments of Neuroscience, University of Wisconsin, Madison, WI USA ,0000 0001 0701 8607grid.28803.31Departments of Neurology, University of Wisconsin, Madison, WI USA
| | - Richard J. Davidson
- 0000 0001 0701 8607grid.28803.31Departments of Psychiatry, University of Wisconsin, Madison, WI USA ,0000 0001 2167 3675grid.14003.36Neuroscience Training Program, University of Wisconsin, Madison, WI USA ,0000 0001 2167 3675grid.14003.36Waisman Center, University of Wisconsin, Madison, WI USA ,0000 0001 0701 8607grid.28803.31Departments of Psychology, University of Wisconsin, Madison, WI USA ,Center for Healthy Minds, Madison, WI USA
| | - Ned H. Kalin
- 0000 0001 0701 8607grid.28803.31Departments of Psychiatry, University of Wisconsin, Madison, WI USA ,0000 0001 2167 3675grid.14003.36Neuroscience Training Program, University of Wisconsin, Madison, WI USA
| | - H. Hill Goldsmith
- 0000 0001 2167 3675grid.14003.36Waisman Center, University of Wisconsin, Madison, WI USA ,0000 0001 0701 8607grid.28803.31Departments of Psychology, University of Wisconsin, Madison, WI USA
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17
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Turan S. Current Nomenclature of Pseudohypoparathyroidism: Inactivating Parathyroid Hormone/Parathyroid Hormone-Related Protein Signaling Disorder. J Clin Res Pediatr Endocrinol 2017; 9:58-68. [PMID: 29280743 PMCID: PMC5790322 DOI: 10.4274/jcrpe.2017.s006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Disorders related to parathyroid hormone (PTH) resistance and PTH signaling pathway impairment are historically classified under the term of pseudohypoparathyroidism (PHP). The disease was first described and named by Fuller Albright and colleagues in 1942. Albright hereditary osteodystrophy (AHO) is described as an associated clinical entity with PHP, characterized by brachydactyly, subcutaneous ossifications, round face, short stature and a stocky build. The classification of PHP is further divided into PHP-Ia, pseudo-PHP (pPHP), PHP-Ib, PHP-Ic and PHP-II according to the presence or absence of AHO, together with an in vivo response to exogenous PTH and the measurement of Gsα protein activity in peripheral erythrocyte membranes in vitro. However, PHP classification fails to differentiate all patients with different clinical and molecular findings for PHP subtypes and classification become more complicated with more recent molecular characterization and new forms having been identified. So far, new classifications have been established by the EuroPHP network to cover all disorders of the PTH receptor and its signaling pathway. Inactivating PTH/PTH-related protein signaling disorder (iPPSD) is the new name proposed for a group of these disorders and which can be further divided into subtypes - iPPSD1 to iPPSD6. These are termed, starting from PTH receptor inactivation mutation (Eiken and Blomstrand dysplasia) as iPPSD1, inactivating Gsα mutations (PHP-Ia, PHP-Ic and pPHP) as iPPSD2, loss of methylation of GNAS DMRs (PHP-Ib) as iPPSD3, PRKAR1A mutations (acrodysostosis type 1) as iPPSD4, PDE4D mutations (acrodysostosis type 2) as iPPSD5 and PDE3A mutations (autosomal dominant hypertension with brachydactyly) as iPPSD6. iPPSDx is reserved for unknown molecular defects and iPPSDn+1 for new molecular defects which are yet to be described. With these new classifications, the aim is to clarify the borders of each different subtype of disease and make the classification according to molecular pathology. The iPPSD group is designed to be expandable and new classifications will readily fit into it as necessary.
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Affiliation(s)
- Serap Turan
- Marmara University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
,* Address for Correspondence: Marmara University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey Phone: +90 216 625 45 45 E-mail:
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18
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Wang L, Chang S, Wang Z, Wang S, Huo J, Ding G, Li R, Liu C, Shangguan S, Lu X, Zhang T, Qiu Z, Wu J. Altered GNAS imprinting due to folic acid deficiency contributes to poor embryo development and may lead to neural tube defects. Oncotarget 2017; 8:110797-110810. [PMID: 29340017 PMCID: PMC5762285 DOI: 10.18632/oncotarget.22731] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/29/2017] [Indexed: 01/28/2023] Open
Abstract
Disturbed epigenetic modifications have been linked to the pathogenesis of Neural Tube Defects (NTDs) in those with folate deficiency during pregnancy. However, evidence is lacking to delineate the critical region in epigenome regulated by parental folic acid and mechanisms by which folate deficiency affects normal embryogenesis. Our data from clinical samples revealed the presence of aberrant DNA methylation in GNAS imprinting cluster in NTD samples with low folate concentrations. Results from mouse models indicated that the establishment of GNAS imprinting was influenced by both maternal and paternal folate-deficient diets. Such aberrant GNAS imprinting was present prior to the gametogenesis period. Imprinting in Exon1A/GNAS gDMR was abolished in both spermatozoa and oocytes upon treating with a parental folate-deficient diet (3.6% in spermatozoa, 9.8% in oocytes). Interestingly, loss of imprinting in the GNAS gene cluster altered chromatin structure to an overwhelmingly open structure (58.48% in the folate-free medium group vs. 39.51% in the folate-normal medium group; P < 0.05), and led to a disturbed expression of genes in this region. Furthermore, an elevated cyclic AMP levels was observed in folate acid deficiency group. Our results imply that GNAS imprinting plays major roles in folic acid metabolism regulation during embryogenesis. Aberrant GNAS imprinting is an attribute to NTDs, providing a new perspective for explaining the molecular mechanisms by which folate supplementation in human pregnancy provides protection from NTDs.
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Affiliation(s)
- Li Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Shaoyan Chang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Zhen Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Shan Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Junsheng Huo
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, P.R. China
| | - Gangqiang Ding
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, P.R. China
| | - Rui Li
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Chi Liu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Shaofang Shangguan
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Xiaolin Lu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Zhiyong Qiu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
| | - Jianxin Wu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, P.R. China
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Tafaj O, Hann S, Ayturk U, Warman ML, Jüppner H. Mice maintain predominantly maternal Gαs expression throughout life in brown fat tissue (BAT), but not other tissues. Bone 2017; 103:177-187. [PMID: 28694163 PMCID: PMC5943706 DOI: 10.1016/j.bone.2017.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/14/2017] [Accepted: 07/01/2017] [Indexed: 11/20/2022]
Abstract
The murine Gnas (human GNAS) locus gives rise to Gαs and different splice variants thereof. The Gαs promoter is not methylated thus allowing biallelic expression in most tissues. In contrast, the alternative first Gnas/GNAS exons and their promoters undergo parent specific methylation, which limits transcription to the non-methylated allele. Pseudohypoparathyroidism type Ia (PHP1A) or type Ib (PHP1B) are caused by heterozygous maternal GNAS mutations suggesting that little or no Gαs is derived in some tissues from the non-mutated paternal GNAS thereby causing hormonal resistance. Previous data had indicated that Gαs is mainly derived from the maternal Gnas allele in brown adipose tissue (BAT) of newborn mice, yet it is biallelically expressed in adult BAT. This suggested that paternal Gαs expression is regulated by an unknown factor(s) that varies considerably with age. To extend these findings, we now used a strain-specific SNP in Gnas exon 11 (rs13460569) for evaluation of parent-specific Gαs expression through the densitometric quantification of BanII-digested RT-PCR products and digital droplet PCR (ddPCR). At all investigated ages, Gαs transcripts were derived in BAT predominantly from the maternal Gnas allele, while kidney and liver showed largely biallelic Gαs expression. Only low or undetectable levels of other paternally Gnas-derived transcripts were observed, making it unlikely that these are involved in regulating paternal Gαs expression. Our findings suggest that a cis-acting factor could be implicated in reducing paternal Gαs expression in BAT and presumably in proximal renal tubules, thereby causing PTH-resistance if the maternal GNAS/Gnas allele is mutated.
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Affiliation(s)
- Olta Tafaj
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Steven Hann
- Department of Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ugur Ayturk
- Department of Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Matthew L Warman
- Department of Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Pediatric Nephrology Unit, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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20
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Grüters-Kieslich A, Reyes M, Sharma A, Demirci C, DeClue TJ, Lankes E, Tiosano D, Schnabel D, Jüppner H. Early-Onset Obesity: Unrecognized First Evidence for GNAS Mutations and Methylation Changes. J Clin Endocrinol Metab 2017; 102:2670-2677. [PMID: 28453643 PMCID: PMC5546863 DOI: 10.1210/jc.2017-00395] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 04/17/2017] [Indexed: 12/16/2022]
Abstract
Context Early-onset obesity, characteristic for disorders affecting the leptin-melanocortin pathway, is also observed in pseudohypoparathyroidism type 1A (PHP1A), a disorder caused by maternal GNAS mutations that disrupt expression or function of the stimulatory G protein α-subunit (Gsα). Mutations and/or epigenetic abnormalities at the same genetic locus are also the cause of pseudohypoparathyroidism type 1B (PHP1B). However, although equivalent biochemical and radiographic findings can be encountered in these related disorders caused by GNAS abnormalities, they are considered distinct clinical entities. Objectives To further emphasize the overlapping features between both disorders, we report the cases of several children, initially brought to medical attention because of unexplained early-onset obesity, in whom PHP1B or PHP1A was eventually diagnosed. Patients and Methods Search for GNAS methylation changes or mutations in cohorts of patients with early-onset obesity. Results Severe obesity had been noted in five infants, with a later diagnosis of PHP1B due to STX16 deletions and/or abnormal GNAS methylation. These findings prompted analysis of 24 unselected obese patients, leading to the discovery of inherited STX16 deletions in 2 individuals. Similarly, impressive early weight gains were noted in five patients, who initially lacked additional Albright hereditary osteodystrophy features but in whom PHP1A due to GNAS mutations involving exons encoding Gsα was diagnosed. Conclusions Obesity during the first year of life can be the first clinical evidence for PHP1B, expanding the spectrum of phenotypic overlap between PHP1A and PHP1B. Importantly, GNAS methylation abnormalities escape detection by targeted or genome-wide sequencing strategies, raising the question of whether epigenetic GNAS analyses should be considered for unexplained obesity.
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Affiliation(s)
- Annette Grüters-Kieslich
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
- Department of Pediatric Endocrinology and Diabetes, Charité-Universitätsmedizin, Berlin 10117, Germany
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Amita Sharma
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Cem Demirci
- Pediatric Endocrinology, Connecticut Children’s Medical Center, University of Connecticut School of Medicine, Farmington, Connecticut 06030
| | | | - Erwin Lankes
- Department of Pediatric Endocrinology and Diabetes, Charité-Universitätsmedizin, Berlin 10117, Germany
- Center for Chronically Sick Children, Charité-Universitätsmedizin, Berlin 10117, Germany
| | - Dov Tiosano
- Division of Pediatric Endocrinology, Meyer Children's Hospital, Rambam Health Care Campus, Haifa 31096, Israel
| | - Dirk Schnabel
- Department of Pediatric Endocrinology and Diabetes, Charité-Universitätsmedizin, Berlin 10117, Germany
- Center for Chronically Sick Children, Charité-Universitätsmedizin, Berlin 10117, Germany
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
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21
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Grigelioniene G, Nevalainen PI, Reyes M, Thiele S, Tafaj O, Molinaro A, Takatani R, Ala-Houhala M, Nilsson D, Eisfeldt J, Lindstrand A, Kottler ML, Mäkitie O, Jüppner H. A Large Inversion Involving GNAS Exon A/B and All Exons Encoding Gsα Is Associated With Autosomal Dominant Pseudohypoparathyroidism Type Ib (PHP1B). J Bone Miner Res 2017; 32:776-783. [PMID: 28084650 PMCID: PMC5395346 DOI: 10.1002/jbmr.3083] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/31/2016] [Accepted: 01/11/2017] [Indexed: 01/08/2023]
Abstract
Pseudohypoparathyroidism type Ib (PHP1B) is characterized primarily by resistance to parathyroid hormone (PTH) and thus hypocalcemia and hyperphosphatemia, in most cases without evidence for Albright hereditary osteodystrophy (AHO). PHP1B is associated with epigenetic changes at one or several differentially-methylated regions (DMRs) within GNAS, which encodes the α-subunit of the stimulatory G protein (Gsα) and splice variants thereof. Heterozygous, maternally inherited STX16 or GNAS deletions leading to isolated loss-of-methylation (LOM) at exon A/B alone or at all maternal DMRs are the cause of autosomal dominant PHP1B (AD-PHP1B). In this study, we analyzed three affected individuals, the female proband and her two sons. All three revealed isolated LOM at GNAS exon A/B, whereas the proband's healthy maternal grandmother and uncle showed normal methylation at this locus. Haplotype analysis was consistent with linkage to the STX16/GNAS region, yet no deletion could be identified. Whole-genome sequencing of one of the patients revealed a large heterozygous inversion (1,882,433 bp). The centromeric breakpoint of the inversion is located 7,225 bp downstream of GNAS exon XL, but its DMR showed no methylation abnormality, raising the possibility that the inversion disrupts a regulatory element required only for establishing or maintaining exon A/B methylation. Because our three patients presented phenotypes consistent with PHP1B, and not with PHP1A, the Gsα promoter is probably unaffected by the inversion. Our findings expand the spectrum of genetic mutations that lead to LOM at exon A/B alone and thus biallelic expression of the transcript derived from this alternative first GNAS exon. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Giedre Grigelioniene
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
| | - Pasi I Nevalainen
- Endocrine Unit, Department of Internal Medicine, Tampere University Hospital, Tampere, Finland
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Susanne Thiele
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Olta Tafaj
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Marja Ala-Houhala
- Department of Pediatrics, Tampere University Hospital, Tampere, Finland
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Jesper Eisfeldt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital Stockholm, Stockholm, Sweden
| | - Marie-Laure Kottler
- Centre Hospitalier Universitaire de Caen, Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphorus Metabolism, Caen, France
| | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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22
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Mantovani G, Spada A, Elli FM. Pseudohypoparathyroidism and Gsα-cAMP-linked disorders: current view and open issues. Nat Rev Endocrinol 2016; 12:347-56. [PMID: 27109785 DOI: 10.1038/nrendo.2016.52] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pseudohypoparathyroidism exemplifies an unusual form of hormone resistance as the underlying molecular defect is a partial deficiency of the α subunit of the stimulatory G protein (Gsα), a key regulator of the cAMP signalling pathway, rather than of the parathyroid hormone (PTH) receptor itself. Despite the first description of this disorder dating back to 1942, later findings have unveiled complex epigenetic alterations in addition to classic mutations in GNAS underpining the molecular basis of the main subtypes of pseudohypoparathyroidism. Moreover, mutations in PRKAR1A and PDE4D, which encode proteins crucial for Gsα-cAMP-mediated signalling, have been found in patients with acrodysostosis. As acrodysostosis, a disease characterized by skeletal malformations and endocrine disturbances, shares clinical and molecular characteristics with pseudohypoparathyroidism, making a differential diagnosis and providing genetic counselling to patients and families is a challenge for endocrinologists. Accumulating data on the genetic and clinical aspects of this group of diseases highlight the limitation of the current classification system and prompt the need for a new definition as well as for new diagnostic and/or therapeutic algorithms. This Review discusses both the current understanding and future challenges for the clinical and molecular diagnosis, classification and treatment of pseudohypoparathyroidism.
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MESH Headings
- Bone Diseases, Metabolic/diagnosis
- Bone Diseases, Metabolic/genetics
- Chromogranins/genetics
- Chromosome Deletion
- Chromosomes, Human, Pair 2/genetics
- Cyclic AMP
- Cyclic AMP-Dependent Protein Kinase RIalpha Subunit/genetics
- Cyclic Nucleotide Phosphodiesterases, Type 4/genetics
- Diagnosis, Differential
- Dysostoses/diagnosis
- Dysostoses/genetics
- Epigenesis, Genetic/genetics
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Humans
- Intellectual Disability/diagnosis
- Intellectual Disability/genetics
- Ossification, Heterotopic/diagnosis
- Ossification, Heterotopic/genetics
- Osteochondrodysplasias/diagnosis
- Osteochondrodysplasias/genetics
- Pseudohypoparathyroidism/classification
- Pseudohypoparathyroidism/diagnosis
- Pseudohypoparathyroidism/genetics
- Signal Transduction
- Skin Diseases, Genetic/diagnosis
- Skin Diseases, Genetic/genetics
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Affiliation(s)
- Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy
| | - Anna Spada
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy
| | - Francesca Marta Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via Francesco Sforza 35, Milan 20122, Italy
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23
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Takatani R, Molinaro A, Grigelioniene G, Tafaj O, Watanabe T, Reyes M, Sharma A, Singhal V, Raymond FL, Linglart A, Jüppner H. Analysis of Multiple Families With Single Individuals Affected by Pseudohypoparathyroidism Type Ib (PHP1B) Reveals Only One Novel Maternally Inherited GNAS Deletion. J Bone Miner Res 2016; 31:796-805. [PMID: 26479409 PMCID: PMC4826817 DOI: 10.1002/jbmr.2731] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/05/2015] [Accepted: 10/12/2015] [Indexed: 01/22/2023]
Abstract
Proximal tubular resistance to parathyroid hormone (PTH) resulting in hypocalcemia and hyperphosphatemia are preeminent abnormalities in pseudohypoparathyroidism type Ib (PHP1B), but resistance toward other hormones as well as variable features of Albright's Hereditary Osteodystrophy (AHO) can occur also. Genomic DNA from PHP1B patients shows epigenetic changes at one or multiple differentially methylated regions (DMRs) within GNAS, the gene encoding Gαs and splice variants thereof. In the autosomal dominant disease variant, these methylation abnormalities are caused by deletions in STX16 or GNAS on the maternal allele. The molecular defect(s) leading to sporadic PHP1B (sporPHP1B) remains in most cases unknown and we therefore analyzed 60 sporPHP1B patients and available family members by microsatellite markers, single nucleotide polymorphisms (SNPs), multiplex ligation-dependent probe amplification (MLPA), and methylation-specific MLPA (MS-MLPA). All investigated cases revealed broad GNAS methylation changes, but no evidence for inheritance of two paternal chromosome 20q alleles. Some patients with partial epigenetic modifications in DNA from peripheral blood cells showed more complete GNAS methylation changes when testing their immortalized lymphoblastoid cells. Analysis of siblings and children of sporPHP1B patients provided no evidence for an abnormal mineral ion regulation and no changes in GNAS methylation. Only one patient revealed, based on MLPA and microsatellite analyses, evidence for an allelic loss, which resulted in the discovery of two adjacent, maternally inherited deletions (37,597 and 1427 bp, respectively) that remove the area between GNAS antisense exons 3 and 5, including exon NESP. Our findings thus emphasize that the region comprising antisense exons 3 and 4 is required for establishing all maternal GNAS methylation imprints. The genetic defect(s) leading in sporPHP1B to epigenetic GNAS changes and thus PTH-resistance remains unknown, but it seems unlikely that this disease variant is caused by heterozygous inherited or de novo mutations involving GNAS.
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Affiliation(s)
- Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Giedre Grigelioniene
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Olta Tafaj
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tomoyuki Watanabe
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Monica Reyes
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Amita Sharma
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Vibha Singhal
- Pediatric Endocrinology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - F Lucy Raymond
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Agnès Linglart
- Paediatric Endocrinology and Diabetology, French National Reference Centre for Rare Disorders of Mineral Metabolism, AP-HP Hôpital Bicêtre Paris Sud, le Kremlin-Bicêtre, France
- Faculté de Médecine, Université Paris Sud, le Kremlin-Bicêtre, France
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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24
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Picard C, Decrequy A, Guenet D, Bursztejn AC, Toledano D, Richard N, Kottler ML. Diagnosis and management of congenital hypothyroidism associated with pseudohypoparathyroidism. Horm Res Paediatr 2015; 83:111-7. [PMID: 25591844 DOI: 10.1159/000369492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/29/2014] [Indexed: 11/19/2022] Open
Abstract
UNLABELLED Hypothyroidism is a particular condition observed in pseudohypoparathyroidism (PHP), a rare disorder characterized by parathyroid (PTH) resistance leading to hypocalcemia and hyperphosphatemia associated with a GNAS (guanine nucleotide-binding protein α-subunit) mutation (PHP1A) or epimutation (PHP1B). To determine the presence of hypothyroidism at birth we conducted a retrospective study in our cohort of patients presenting with either PHP1A (n = 116) or PHP1B (n = 99). We also investigated patients presenting at birth with congenital hypothyroidism (CH) and a eutopic thyroid gland for phosphocalcium abnormalities suggesting PTH resistance and PHP. Our study reveals CH as the earliest diagnostic clue for PHP1A, but not for PHP1B. We estimated the frequency of CH at birth to be between 8 and 34% in patients presenting with PHP1A. The elevation of phosphatemia and PTH concentration precedes hypocalcemia in PHP1A. Conversely, the frequency of PHP1A in patients presenting CH is dramatically low. This may be due to the low prevalence of PHP1A which remains unknown. CONCLUSIONS Subclinical and overt hypothyroidism can occur in PHP1A patients at birth many years before PTH resistance becomes clinically apparent. Although such cases appear to be rare, some pediatric patients with unexplained CH are likely to benefit from measuring calcium, phosphorus, and PTH for extended periods of time.
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Affiliation(s)
- Charlotte Picard
- Service de Génétique, Centre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphore, CHU de Caen, Caen, France
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25
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Tibbit CJ, Williamson CM, Mehta S, Ball ST, Chotalia M, Nottingham WT, Eaton SA, Quwailid MM, Teboul L, Kelsey G, Peters J. Antisense Activity across the Nesp Promoter is Required for Nespas-Mediated Silencing in the Imprinted Gnas Cluster. Noncoding RNA 2015; 1:246-265. [PMID: 29861426 PMCID: PMC5932550 DOI: 10.3390/ncrna1030246] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/17/2015] [Accepted: 11/17/2015] [Indexed: 12/03/2022] Open
Abstract
Macro long non-coding RNAs (lncRNAs) play major roles in gene silencing in inprinted gene clusters. Within the imprinted Gnas cluster, the paternally expressed Nespas lncRNA downregulates its sense counterpart Nesp. To explore the mechanism of action of Nespas, we generated two new knock-in alleles to truncate Nespas upstream and downstream of the Nesp promoter. We show that Nespas is essential for methylation of the Nesp differentially methylated region (DMR), but higher levels of Nespas are required for methylation than are needed for downregulation of Nesp. Although Nespas is transcribed for over 27 kb, only Nespas transcript/transcription across a 2.6 kb region that includes the Nesp promoter is necessary for methylation of the Nesp DMR. In both mutants, the levels of Nespas were extraordinarily high, due at least in part to increased stability, an effect not seen with other imprinted lncRNAs. However, even when levels were greatly raised, Nespas remained exclusively cis-acting. We propose Nespas regulates Nesp methylation and expression to ensure appropriate levels of expression of the protein coding transcripts Gnasxl and Gnas on the paternal chromosome. Thus, Nespas mediates paternal gene expression over the entire Gnas cluster via a single gene, Nesp.
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Affiliation(s)
- Charlotte J Tibbit
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current address: MRC Functional Genomics Unit, Department of Physiology Anatomy & Genetics, Le Gros Clark Building, University of Oxford, South Parks Road, Oxford OX13QX, UK.
| | - Christine M Williamson
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current Address: MRC Harwell, Harwell Campus, Oxfordshire OX110RD, UK.
| | - Stuti Mehta
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current address: GI Division, Their 340, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Simon T Ball
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current address: Mary Lyon Centre, MRC Harwell, Harwell Campus, Oxfordshire OX110RD, UK.
| | - Mita Chotalia
- Epigenetics Programme, The Babraham Institute, Cambridge CB223AT, UK.
- Current address: Genome Function Group, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, London W120NN, UK.
| | - Wade T Nottingham
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current address: West London Free School, 2 Bridge Avenue, Hammersmith, London W69JP, UK.
| | - Sally A Eaton
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
- Current address: Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Mohamed M Quwailid
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
| | - Lydia Teboul
- Mary Lyon Centre, MRC Harwell, Harwell Campus, Oxfordshire OX110RD, UK.
| | - Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge CB223AT, UK.
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB23EG, UK.
| | - Jo Peters
- MRC Harwell, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX110RD, UK.
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26
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Abstract
The GNAS complex locus encodes the alpha-subunit of the stimulatory G protein (Gsα), a ubiquitous signaling protein mediating the actions of many hormones, neurotransmitters, and paracrine/autocrine factors via generation of the second messenger cAMP. GNAS gives rise to other gene products, most of which exhibit exclusively monoallelic expression. In contrast, Gsα is expressed biallelically in most tissues; however, paternal Gsα expression is silenced in a small number of tissues through as-yet-poorly understood mechanisms that involve differential methylation within GNAS. Gsα-coding GNAS mutations that lead to diminished Gsα expression and/or function result in Albright's hereditary osteodystrophy (AHO) with or without hormone resistance, i.e., pseudohypoparathyroidism type-Ia/Ic and pseudo-pseudohypoparathyroidism, respectively. Microdeletions that alter GNAS methylation and, thereby, diminish Gsα expression in tissues in which the paternal Gsα allele is normally silenced also cause hormone resistance, which occurs typically in the absence of AHO, a disorder termed pseudohypoparathyroidism type-Ib. Mutations of GNAS that cause constitutive Gsα signaling are found in patients with McCune-Albright syndrome, fibrous dysplasia of bone, and different endocrine and non-endocrine tumors. Clinical features of these diseases depend significantly on the parental allelic origin of the GNAS mutation, reflecting the tissue-specific paternal Gsα silencing. In this article, we review the pathogenesis and the phenotypes of these human diseases.
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Affiliation(s)
- Serap Turan
- Pediatric Endocrinology, Marmara University School of Medicine Hospital, Istanbul, Turkey;
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114;
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27
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Molinaro A, Tiosano D, Takatani R, Chrysis D, Russell W, Koscielniak N, Kottler ML, Agretti P, De Marco G, Ahtiainen P, Christov M, Mäkitie O, Tonacchera M, Jüppner H. TSH elevations as the first laboratory evidence for pseudohypoparathyroidism type Ib (PHP-Ib). J Bone Miner Res 2015; 30:906-12. [PMID: 25403028 PMCID: PMC4401615 DOI: 10.1002/jbmr.2408] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/05/2014] [Accepted: 11/10/2014] [Indexed: 01/21/2023]
Abstract
Hypocalcemia and hyperphosphatemia because of resistance toward parathyroid hormone (PTH) in the proximal renal tubules are the most prominent abnormalities in patients affected by pseudohypoparathyroidism type Ib (PHP-Ib). In this rare disorder, which is caused by GNAS methylation changes, resistance can occur toward other hormones, such as thyroid-stimulating hormone (TSH), that mediate their actions through G protein-coupled receptors. However, these additional laboratory abnormalities are usually not recognized until PTH-resistant hypocalcemia becomes clinically apparent. We now describe four pediatric patients, first diagnosed with subclinical or overt hypothyroidism between the ages of 0.2 and 15 years, who developed overt PTH-resistance 3 to 20 years later. Although anti-thyroperoxidase (anti-TPO) antibodies provided a plausible explanation for hypothyroidism in one of these patients, this and two other patients revealed broad epigenetic GNAS abnormalities, which included loss of methylation (LOM) at exons AS, XL, and A/B, and gain of methylation at exon NESP55; ie, findings consistent with PHP-Ib. LOM at GNAS exon A/B alone led in the fourth patient to the identification of a maternally inherited 3-kb STX16 deletion, a well-established cause of autosomal dominant PHP-Ib. Although GNAS methylation changes were not detected in additional pediatric and adult patients with subclinical hypothyroidism (23 pediatric and 39 adult cases), hypothyroidism can obviously be the initial finding in PHP-Ib patients. One should therefore consider measuring PTH, along with calcium and phosphate, in patients with unexplained hypothyroidism for extended periods of time to avoid hypocalcemia and associated clinical complications.
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Affiliation(s)
- Angelo Molinaro
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Dov Tiosano
- Division of Pediatric Endocrinology, Meyer Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Rieko Takatani
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dionisios Chrysis
- Department of Pediatrics, Medical School, University of Patras, Patras, Greece
| | - William Russell
- Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nikolas Koscielniak
- Program in Occupational Therapy, Washington University School of Medicine, St. Louis, MO, USA
| | - Marie-Laure Kottler
- Centre Hospitalier Universitaire de Caen, Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphorus Metabolism, F-14000 Caen, France
| | - Patrizia Agretti
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Giuseppina De Marco
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Petteri Ahtiainen
- Central Finland Central Hospital, Jyväskylä, and Kuopio University Hospital, Kuopio, Finland
| | - Marta Christov
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Outi Mäkitie
- Hospital for Children and Adolescents, University of Helsinki, and Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Massimo Tonacchera
- Endocrinology Unit, Department of Clinical and Experimental Medicine, University of Pisa, University Hospital of Pisa, Pisa, Italy
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Jüppner H. Genetic and epigenetic defects at the GNAS locus cause different forms of pseudohypoparathyroidism. ANNALES D'ENDOCRINOLOGIE 2015; 76:92-7. [PMID: 25882888 DOI: 10.1016/j.ando.2015.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 01/07/2023]
Affiliation(s)
- Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, 02114 Boston, United States.
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29
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Mehta S, Williamson CM, Ball S, Tibbit C, Beechey C, Fray M, Peters J. Transcription driven somatic DNA methylation within the imprinted Gnas cluster. PLoS One 2015; 10:e0117378. [PMID: 25659103 PMCID: PMC4319783 DOI: 10.1371/journal.pone.0117378] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 12/25/2014] [Indexed: 12/14/2022] Open
Abstract
Differential marking of genes in female and male gametes by DNA methylation is essential to genomic imprinting. In female gametes transcription traversing differentially methylated regions (DMRs) is a common requirement for de novo methylation at DMRs. At the imprinted Gnas cluster oocyte specific transcription of a protein-coding transcript, Nesp, is needed for methylation of two DMRs intragenic to Nesp, namely the Nespas-Gnasxl DMR and the Exon1A DMR, thereby enabling expression of the Gnas transcript and repression of the Gnasxl transcript. On the paternal allele, Nesp is repressed, the germline DMRs are unmethylated, Gnas is repressed and Gnasxl is expressed. Using mutant mouse models, we show that on the paternal allele, ectopic transcription of Nesp traversing the intragenic Exon1A DMR (which regulates Gnas expression) results in de novo methylation of the Exon1A DMR and de-repression of Gnas just as on the maternal allele. However, unlike the maternal allele, methylation on the mutant paternal allele occurs post-fertilisation, i.e. in somatic cells. This, to our knowledge is the first example of transcript/transcription driven DNA methylation of an intragenic CpG island, in somatic tissues, suggesting that transcription driven de novo methylation is not restricted to the germline in the mouse. Additionally, Gnasxl is repressed on a paternal chromosome on which Nesp is ectopically expressed. Thus, a paternally inherited Gnas cluster showing ectopic expression of Nesp is “maternalised” in terms of Gnasxl and Gnas expression. We show that these mice have a phenotype similar to mutants with two expressed doses of Gnas and none of Gnasxl.
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Affiliation(s)
- Stuti Mehta
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
- * E-mail:
| | - Christine M. Williamson
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
| | - Simon Ball
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
| | - Charlotte Tibbit
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
| | - Colin Beechey
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
| | - Martin Fray
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
| | - Jo Peters
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, United Kingdom
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Lemos MC, Thakker RV. GNAS mutations in Pseudohypoparathyroidism type 1a and related disorders. Hum Mutat 2014; 36:11-9. [PMID: 25219572 PMCID: PMC4309471 DOI: 10.1002/humu.22696] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 09/02/2014] [Indexed: 12/13/2022]
Abstract
Pseudohypoparathyroidism type 1a (PHP1a) is characterized by hypocalcaemia and hyperphosphatemia due to parathyroid hormone resistance, in association with the features of Albright's hereditary osteodystrophy (AHO). PHP1a is caused by maternally inherited inactivating mutations of Gs-alpha, which is encoded by a complex imprinted locus termed GNAS. Paternally inherited mutations can lead either to pseudopseudohypoparathyroidism (PPHP) characterized by AHO alone, or to progressive osseous heteroplasia (POH), characterized by severe heterotopic ossification. The clinical aspects and molecular genetics of PHP1a and its related disorders are reviewed together with the 343 kindreds with Gs-alpha germline mutations reported so far in the literature. These 343 (176 different) mutations are scattered throughout the 13 exons that encode Gs-alpha and consist of 44.9% frameshift, 28.0% missense, 14.0% nonsense, and 9.0% splice-site mutations, 3.2% in-frame deletions or insertions, and 0.9% whole or partial gene deletions. Frameshift and other highly disruptive mutations were more frequent in the reported 37 POH kindreds than in PHP1a/PPHP kindreds (97.3% vs. 68.7%, P < 0.0001). This mutation update and respective genotype-phenotype data may be of use for diagnostic and research purposes and contribute to a better understanding of these complex disorders.
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Affiliation(s)
- Manuel C Lemos
- CICS-UBI, Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Covilhã 6200-506, Portugal
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31
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Congras A, Yerle-Bouissou M, Pinton A, Vignoles F, Liaubet L, Ferchaud S, Acloque H. Sperm DNA methylation analysis in swine reveals conserved and species-specific methylation patterns and highlights an altered methylation at the GNAS locus in infertile boars. Biol Reprod 2014; 91:137. [PMID: 25320151 DOI: 10.1095/biolreprod.114.119610] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Male infertility is an increasing health issue in today's society for both human and livestock populations. In livestock, male infertility slows the improvement of animal selection programs and agricultural productivity. There is increasing evidence that epigenetic marks play an important role in the production of good-quality sperm. We therefore screened for specific or common epigenetic signatures of livestock infertility. To do so, we compared DNA methylation level in sperm DNA from fertile and infertile boars. We evaluated first the global level of sperm DNA methylation and found no difference between the two groups of boars. We then selected 42 loci of interest, most of them known to be imprinted in human or mice, and assessed the imprinting status of five of them not previously described in swine tissues: WT1, CNTN3, IMPACT, QPCT, and GRB10. DNA methylation level was then quantified in fertile and infertile boars at these 42 loci. Results from fertile boars indicated that the methylation level of the selected loci is highly conserved between pig, human, and mice, with a few exceptions, including the POU5F1 (OCT4) promoter and RTL1. Comparison between fertile and infertile boars revealed that one imprinted region, the GNAS locus, shows an increase in sperm DNA methylation in three out of eight infertile boars with low semen quality. This increase in DNA methylation is associated with an altered expression of the genes belonging to the GNAS locus, suggesting a new role for GNAS in the proper formation of functional gametes.
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Affiliation(s)
- Annabelle Congras
- INRA, UMR1388 Génétique, Physiologie et Systèmes d'Elevage, GenPhySE, Castanet-Tolosan, France
| | - Martine Yerle-Bouissou
- INRA, UMR1388 Génétique, Physiologie et Systèmes d'Elevage, GenPhySE, Castanet-Tolosan, France
| | - Alain Pinton
- Université de Toulouse INPT ENVT, UMR1388 Génétique Physiologie et Systèmes d'Elevage GenPhySE, Toulouse, France
| | - Florence Vignoles
- INRA, UMR1388 Génétique, Physiologie et Systèmes d'Elevage, GenPhySE, Castanet-Tolosan, France
| | - Laurence Liaubet
- INRA, UMR1388 Génétique, Physiologie et Systèmes d'Elevage, GenPhySE, Castanet-Tolosan, France
| | - Stéphane Ferchaud
- UE1372 GenESI Génétique, Expérimentation et Système Innovants, Surgères, France
| | - Hervé Acloque
- INRA, UMR1388 Génétique, Physiologie et Systèmes d'Elevage, GenPhySE, Castanet-Tolosan, France
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Chen D, Zhang A, Fang M, Fang R, Ge J, Jiang Y, Zhang H, Han C, Ye X, Huang H, Liu Y, Dong M. Increased methylation at differentially methylated region of GNAS in infants born to gestational diabetes. BMC MEDICAL GENETICS 2014; 15:108. [PMID: 25269528 PMCID: PMC4411875 DOI: 10.1186/s12881-014-0108-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 09/24/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Offspring of pregnancy complicated with gestational diabetes (GDM) are at high risk for metabolic diseases. The mechanisms behind the association of intrauterine exposure to GDM and high risk of health problems in later life remain largely unknown. The aim of this study was to clarify the alteration in methylation levels at differentially methylated regions (DMRs) of GNAS and IGF2 in fetuses of GDM women and to explore the possible mechanisms linking maternal GDM with high risk of metabolic diseases in later life of GDM offspring. METHODS Lymphocytes were isolated from umbilical cord blood of infants born to 87 women with GDM and 81 women with normal pregnancy. Genomic DNA was extracted and DNA methylation levels of GNAS and IGF2 DMRs were determined by Massarray quantitative methylation analysis. RESULTS The methylation levels were detected in 7 CpG sites of GNAS DMRs and 6 sites of IGF2 DMRs. Methylation levels were significantly higher at sites 4, 5 and 7 of GNAS DMR in GDM compared to normal pregnancy (P = 0.007, 0.008 and 0.008, respectively). The methylation level at site 4 of GNAS was significantly correlated with the presence of GDM (P = 0.003), the methylation levels at site 5 and 7 were significantly correlated with the presence of GDM (P = 0.002 for both) and gestational age (P = 0.027 for both). There was no significant difference in any sites of IGF2 DMR (P > 0.05 for all). CONCLUSIONS We concluded maternal GDM-induced hypermethylation at GNAS DMR and this condition may be among the mechanisms associating maternal GDM with increased risk of metabolic diseases in later life of offspring.
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Affiliation(s)
- Danqing Chen
- Women's Hospital, School of Medicine, Zhejiang University, 1 Xueshi Road, Hangzhou, 310006, Zhejiang Province, China.
| | - Aiping Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China.
| | - Min Fang
- Shaoxing Women and Children's Hospital, Shaoxing, China.
| | - Rong Fang
- Huzhou Maternity and Child Care Hospital, Huzhou, China.
| | - Jiamei Ge
- Jiaxing Maternity and Child Care Hospital, Jiaxing, China.
| | - Yuan Jiang
- Ningbo Women and Children's Hospital, Ningbo, China.
| | - Hong Zhang
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
| | - Cong Han
- Women's Hospital, School of Medicine, Zhejiang University, 1 Xueshi Road, Hangzhou, 310006, Zhejiang Province, China.
| | - Xiaoqun Ye
- Women's Hospital, School of Medicine, Zhejiang University, 1 Xueshi Road, Hangzhou, 310006, Zhejiang Province, China.
| | - Hefeng Huang
- Women's Hospital, School of Medicine, Zhejiang University, 1 Xueshi Road, Hangzhou, 310006, Zhejiang Province, China. .,Key Laboratory of Reproductive Genetics, Ministry of Education, Zhejiang University, Hangzhou, China.
| | - Yun Liu
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China. .,Department of Biochemistry and Molecular Biology, Key Laboratory of Molecular Medicine, The Ministry of Education, Fudan University Shanghai Medical College, 303 Mingdao Building, 138 Yixueyuan Road, Shanghai, 200032, PR China.
| | - Minyue Dong
- Women's Hospital, School of Medicine, Zhejiang University, 1 Xueshi Road, Hangzhou, 310006, Zhejiang Province, China. .,Key Laboratory of Reproductive Genetics, Ministry of Education, Zhejiang University, Hangzhou, China. .,Key Laboratory of Women's Reproductive Health of Zhejiang Province, Hangzhou, China.
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Cleaton MA, Edwards CA, Ferguson-Smith AC. Phenotypic Outcomes of Imprinted Gene Models in Mice: Elucidation of Pre- and Postnatal Functions of Imprinted Genes. Annu Rev Genomics Hum Genet 2014; 15:93-126. [DOI: 10.1146/annurev-genom-091212-153441] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Carol A. Edwards
- Department of Genetics, University of Cambridge, Cambridge CB2 3EG, United Kingdom;
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Grybek V, Aubry L, Maupetit-Méhouas S, Le Stunff C, Denis C, Girard M, Linglart A, Silve C. Methylation and transcripts expression at the imprinted GNAS locus in human embryonic and induced pluripotent stem cells and their derivatives. Stem Cell Reports 2014; 3:432-43. [PMID: 25241742 PMCID: PMC4266011 DOI: 10.1016/j.stemcr.2014.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 02/06/2023] Open
Abstract
Data from the literature indicate that genomic imprint marks are disturbed in human pluripotent stem cells (PSCs). GNAS is an imprinted locus that produces one biallelic (Gsα) and four monoallelic (NESP55, GNAS-AS1, XLsα, and A/B) transcripts due to differential methylation of their promoters (DMR). To document imprinting at the GNAS locus in PSCs, we studied GNAS locus DMR methylation and transcript (NESP55, XLsα, and A/B) expression in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) derived from two human fibroblasts and their progenies. Results showed that (1) methylation at the GNAS locus DMRs is DMR and cell line specific, (2) changes in allelic transcript expression can be independent of a change in allele-specific DNA methylation, and (3) interestingly, methylation at A/B DMR is correlated with A/B transcript expression. These results indicate that these models are valuable to study the mechanisms controlling GNAS methylation, factors involved in transcript expression, and possibly mechanisms involved in the pathophysiology of pseudohypoparathyroidism type 1B. GNAS locus methylation is DMR and cell line specific in human pluripotent stem cells Allelic transcript expression can be independent of allele-specific DNA methylation A/B transcript expression, a key for PHP1B, is correlated with A/B DMR methylation
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Affiliation(s)
- Virginie Grybek
- INSERM U986, Hôpital Bicêtre, Le Kremlin Bicêtre 94276, France
| | - Laetitia Aubry
- UEVE UMR 861, I-Stem, AFM, Evry 91030, France; INSERM UMR 861, I-Stem, AFM, Evry 91030, France
| | | | | | - Cécile Denis
- CECS, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, Evry 91030, France
| | - Mathilde Girard
- CECS, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, Evry 91030, France
| | - Agnès Linglart
- INSERM U986, Hôpital Bicêtre, Le Kremlin Bicêtre 94276, France; Service d'Endocrinologie Pédiatrique, Hôpital Bicêtre-AP-HP, Le Kremlin Bicêtre 94276, France; Centre de Référence des Maladies Rares du Métabolisme Phospho-Calcique Hôpital Bicêtre, Le Kremlin Bicêtre 94276, France
| | - Caroline Silve
- INSERM U986, Hôpital Bicêtre, Le Kremlin Bicêtre 94276, France; Centre de Référence des Maladies Rares du Métabolisme Phospho-Calcique Hôpital Bicêtre, Le Kremlin Bicêtre 94276, France; Laboratoire de Biochimie Hormonale et Génétique, Hôpital Bichat Claude Bernard-AP-HP, Paris 75018, France.
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35
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Peters J. The role of genomic imprinting in biology and disease: an expanding view. Nat Rev Genet 2014; 15:517-30. [PMID: 24958438 DOI: 10.1038/nrg3766] [Citation(s) in RCA: 288] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression according to parental origin. It has long been established that imprinted genes have major effects on development and placental biology before birth. More recently, it has become evident that imprinted genes also have important roles after birth. In this Review, I bring together studies of the effects of imprinted genes from the prenatal period onwards. Recent work on postnatal stages shows that imprinted genes influence an extraordinarily wide-ranging array of biological processes, the effects of which extend into adulthood, and play important parts in common diseases that range from obesity to psychiatric disorders.
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Affiliation(s)
- Jo Peters
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Oxfordshire OX11 0RD, UK
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36
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Elli FM, de Sanctis L, Bollati V, Tarantini L, Filopanti M, Barbieri AM, Peverelli E, Beck-Peccoz P, Spada A, Mantovani G. Quantitative analysis of methylation defects and correlation with clinical characteristics in patients with pseudohypoparathyroidism type I and GNAS epigenetic alterations. J Clin Endocrinol Metab 2014; 99:E508-17. [PMID: 24423294 DOI: 10.1210/jc.2013-3086] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
CONTEXT Pseudohypoparathyroidism type I (PHP-I) includes two main subtypes, PHP-Ia and -Ib. About 70% of PHP-Ia patients, who show Albright hereditary osteodystrophy (AHO) associated with resistance toward multiple hormones (PTH/TSH/GHRH/gonadotropins), carry heterozygous mutations in the α-subunit of the stimulatory G protein (Gsα) exons 1-13, encoded by the guanine nucleotide binding-protein α-stimulating activity polypeptide 1 (GNAS), whereas the majority of PHP-Ib patients, who classically display hormone resistance limited to PTH and TSH with no AHO sign, have methylation defects in the imprinted GNAS cluster. Recently methylation defects have been detected also in patients with PHP and different degrees of AHO, indicating a molecular overlap between the two forms. OBJECTIVES The objectives of the study were to collect patients with the following characteristics: clinical PHP-I (with or without AHO), no mutation in Gsα coding sequence, but the presence of GNAS methylation alterations and to investigate the existence of correlations between the degree of the epigenetic defect and the severity of the disease. PATIENTS AND METHODS We quantified GNAS methylation alterations by both PCR-pyrosequencing and methylation specific-multiplex ligation-dependent probe amplification assay in genomic DNA from 63 patients with PHP-I and correlated these findings with clinical parameters (age at diagnosis; calcium, phosphorus, PTH, TSH levels; presence or absence of each AHO sign). RESULTS By both approaches, the degree of the imprinting defect did not correlate with the onset of the disease, the severity of endocrine resistances, or with the presence/absence of specific AHO signs. CONCLUSIONS Similar molecular alterations may lead to a broad spectrum of diseases, from isolated PTH resistance to complete PHP-Ia, and the degree of methylation alterations does not reflect or anticipate the severity and the type of different PHP/AHO manifestations.
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Affiliation(s)
- Francesca M Elli
- Department of Clinical Sciences and Community Health (F.M.E., M.F., A.M.B., E.P., P.B.-P., A.S., G.M.), Endocrinology and Diabetology Unit, University of Milan, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico, Ca' Granda Ospedale Maggiore Policlinico, and Center of Molecular and Genetic Epidemiology (V.B., L.T.), Department of Clinical Sciences and Community Health, Università di Milano and Fondazione Cà Granda Istituto di Ricovero e Cura a Carattere Scientifico, Ospedale Maggiore Policlinico, 20122 Milan, Italy; and Department of Public Health and Pediatrics (L.d.S.), University of Turin, and Regina Margherita Children's Hospital, 10126 Turin, Italy
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Turan S, Fernandez-Rebollo E, Aydin C, Zoto T, Reyes M, Bounoutas G, Chen M, Weinstein LS, Erben RG, Marshansky V, Bastepe M. Postnatal establishment of allelic Gαs silencing as a plausible explanation for delayed onset of parathyroid hormone resistance owing to heterozygous Gαs disruption. J Bone Miner Res 2014; 29:749-60. [PMID: 23956044 PMCID: PMC3926912 DOI: 10.1002/jbmr.2070] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 07/26/2013] [Accepted: 08/02/2013] [Indexed: 12/16/2022]
Abstract
Pseudohypoparathyroidism type-Ia (PHP-Ia), characterized by renal proximal tubular resistance to parathyroid hormone (PTH), results from maternal mutations of GNAS that lead to loss of α-subunit of the stimulatory G protein (Gαs) activity. Gαs expression is paternally silenced in the renal proximal tubule, and this genomic event is critical for the development of PTH resistance, as patients display impaired hormone action only if the mutation is inherited maternally. The primary clinical finding of PHP-Ia is hypocalcemia, which can lead to various neuromuscular defects including seizures. PHP-Ia patients frequently do not present with hypocalcemia until after infancy, but it has remained uncertain whether PTH resistance occurs in a delayed fashion. Analyzing reported cases of PHP-Ia with documented GNAS mutations and mice heterozygous for disruption of Gnas, we herein determined that the manifestation of PTH resistance caused by the maternal loss of Gαs, ie, hypocalcemia and elevated serum PTH, occurs after early postnatal life. To investigate whether this delay could reflect gradual development of paternal Gαs silencing, we then analyzed renal proximal tubules isolated by laser capture microdissection from mice with either maternal or paternal disruption of Gnas. Our results revealed that, whereas expression of Gαs mRNA in this tissue is predominantly from the maternal Gnas allele at weaning (3 weeks postnatal) and in adulthood, the contributions of the maternal and paternal Gnas alleles to Gαs mRNA expression are equal at postnatal day 3. In contrast, we found that paternal Gαs expression is already markedly repressed in brown adipose tissue at birth. Thus, the mechanisms silencing the paternal Gαs allele in renal proximal tubules are not operational during early postnatal development, and this finding correlates well with the latency of PTH resistance in patients with PHP-Ia.
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Affiliation(s)
- Serap Turan
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Pediatric Endocrinology, Marmara University School of Medicine Hospital, Istanbul, Turkey
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Auclair G, Guibert S, Bender A, Weber M. Ontogeny of CpG island methylation and specificity of DNMT3 methyltransferases during embryonic development in the mouse. Genome Biol 2014; 15:545. [PMID: 25476147 PMCID: PMC4295324 DOI: 10.1186/s13059-014-0545-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 11/14/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the mouse, the patterns of DNA methylation are established during early embryonic development in the epiblast. We quantified the targets and kinetics of DNA methylation acquisition in epiblast cells, and determined the contribution of the de novo methyltransferases DNMT3A and DNMT3B to this process. RESULTS We generated single-base maps of DNA methylation from the blastocyst to post-implantation stages and in embryos lacking DNMT3A or DNMT3B activity. DNA methylation is established within two days of implantation between embryonic days 4.5 and 6.5. The kinetics of de novo methylation are uniform throughout the genome, suggesting a random mechanism of deposition. In contrast, many CpG islands acquire methylation slowly in late epiblast cells. Five percent of CpG islands gain methylation and are found in the promoters of germline genes and in exons of important developmental genes. The onset of global methylation correlates with the upregulation of Dnmt3a/b genes in the early epiblast. DNMT3A and DNMT3B act redundantly to methylate the bulk genome and repetitive elements, whereas DNMT3B has a prominent role in the methylation of CpG islands on autosomes and the X chromosome. Reduced CpG island methylation in Dnmt3b-deficient embryos correlates with gene reactivation in promoters but reduced transcript abundance in gene bodies. Finally, DNMT3B establishes secondary methylation marks at imprinted loci, which distinguishes bona fide germline from somatic methylation imprints. CONCLUSIONS We reveal that the DNMT3 de novo methyltransferases play both redundant and specific functions in the establishment of DNA methylation in the mouse embryo.
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Affiliation(s)
- Ghislain Auclair
- CNRS, University of Strasbourg, UMR 7242 Biotechnology and Cell Signaling, 300 Bd Sébastien Brant, BP 10413, 67412 Illkirch, France
| | - Sylvain Guibert
- CNRS, University of Strasbourg, UMR 7242 Biotechnology and Cell Signaling, 300 Bd Sébastien Brant, BP 10413, 67412 Illkirch, France
| | - Ambre Bender
- CNRS, University of Strasbourg, UMR 7242 Biotechnology and Cell Signaling, 300 Bd Sébastien Brant, BP 10413, 67412 Illkirch, France
| | - Michael Weber
- CNRS, University of Strasbourg, UMR 7242 Biotechnology and Cell Signaling, 300 Bd Sébastien Brant, BP 10413, 67412 Illkirch, France
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39
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MacDonald WA, Mann MRW. Epigenetic regulation of genomic imprinting from germ line to preimplantation. Mol Reprod Dev 2013; 81:126-40. [PMID: 23893518 DOI: 10.1002/mrd.22220] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 07/20/2013] [Indexed: 01/25/2023]
Abstract
Genomic imprinting is an epigenetic process that distinguishes parental alleles, resulting in parent-specific expression of a gene or cluster of genes. Imprints are acquired during gametogenesis when genome-wide epigenetic remodeling occurs. These imprints must then be maintained during preimplantation development, when another wave of genome-wide epigenetic remodeling takes place. Thus, for imprints to persist as parent-specific epigenetic marks, coordinated factors and processes must be involved to both recognize an imprint and protect it from genome-wide remodeling. Parent-specific DNA methylation has long been recognized as a primary epigenetic mark demarcating a genomic imprint. Recent work has advanced our understanding of how and when parent-specific DNA methylation is erased and acquired in the germ line as well as maintained during preimplantation development. Epigenetic factors have also been identified that are recruited to imprinted regions to protect them from genome-wide DNA demethylation during preimplantation development. Intriguingly, asynchrony in epigenetic reprogramming appears to be a recurrent theme with asynchronous acquisition between male and female germ lines, between different imprinted genes, and between the two parental alleles of a gene. Here, we review recent advancements and discuss how they impact our current understanding of the epigenetic regulation of genomic imprinting.
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Affiliation(s)
- William A MacDonald
- Departments of Obstetrics & Gynecology, and Biochemistry, University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada; Children's Health Research Institute, London, Ontario, Canada
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He J, Zhang A, Fang M, Fang R, Ge J, Jiang Y, Zhang H, Han C, Ye X, Yu D, Huang H, Liu Y, Dong M. Methylation levels at IGF2 and GNAS DMRs in infants born to preeclamptic pregnancies. BMC Genomics 2013; 14:472. [PMID: 23844573 PMCID: PMC3723441 DOI: 10.1186/1471-2164-14-472] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 07/09/2013] [Indexed: 11/23/2022] Open
Abstract
Background Offspring of pregnancy complicated with preeclampsia are at high risk for hypertension, stroke and possibly obesity. The mechanisms behind the association of intrauterine exposure to preeclampsia and high risk of health problems in the later life remain largely unknown. The aims of the current investigation were to determine the changes in DNA methylation at IGF2 and GNAS DMR in offspring of preeclamptic pregnancy and to explore the possible mechanisms underlying the association between maternal preeclampsia and high risk for health problems in the later life of their offspring. Results Umbilical cord blood was taken from infants born to women of preeclampsia (n=56), gestational hypertension (n=23) and normal pregnancy (n=81). DNA methylation levels of IGF2 and GNAS DMR were determined by Massarray quantitative methylation analysis. Methylation levels at IGF2 DMR were significantly lower in preeclampsia than normal pregnancy. The average methylation level at IGF2 DMR was significantly correlated with preeclampsia even after birth weight, maternal age, gestational age at delivery and fetal gender were adjusted. The difference in methylation level was not significantly different between mild and severe preeclampsia. The methylation level at GNAS DMR was not significantly correlated with birth weight, maternal age, gestational age at delivery, fetal gender, preeclampsia or gestational hypertension. Conclusions We concluded preeclampsia induced a decrease in methylation level at IGF 2 DMR, and this might be among the mechanisms behind the association between intrauterine exposure to preeclampsia and high risk for metabolic diseases in the later life of the infants.
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Affiliation(s)
- Jing He
- Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province 310006, China
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Eaton SA, Hough T, Fischer-Colbrie R, Peters J. Maternal inheritance of the Gnas cluster mutation Ex1A-T affects size, implicating NESP55 in growth. Mamm Genome 2013; 24:276-85. [PMID: 23839232 PMCID: PMC3745623 DOI: 10.1007/s00335-013-9462-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 06/10/2013] [Indexed: 02/07/2023]
Abstract
Genes subjected to genomic imprinting are often associated with prenatal and postnatal growth. Furthermore, it has been observed that maternally silenced/paternally expressed genes tend to favour offspring growth, whilst paternally silenced/maternally expressed genes will restrict growth. One imprinted cluster in which this has been shown to hold true is the Gnas cluster; of the three proteins expressed from this cluster, two, Gsα and XLαs, have been found to affect postnatal growth in a number of different mouse models. The remaining protein in this cluster, NESP55, has not yet been shown to be involved in growth. We previously described a new mutation, Ex1A-T, which upon paternal transmission resulted in postnatal growth retardation due to loss of imprinting of Gsα and loss of expression of the paternally expressed XLαs. Here we describe maternal inheritance of Ex1A-T which gives rise to a small but highly significant overgrowth phenotype which we attribute to reduction of maternally expressed NESP55.
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Affiliation(s)
- Sally A Eaton
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK.
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Ball ST, Kelly ML, Robson JE, Turner MD, Harrison J, Jones L, Napper D, Beechey CV, Hough T, Plagge A, Cattanach BM, Cox RD, Peters J. Gene Dosage Effects at the Imprinted Gnas Cluster. PLoS One 2013; 8:e65639. [PMID: 23822972 PMCID: PMC3688811 DOI: 10.1371/journal.pone.0065639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 04/25/2013] [Indexed: 01/27/2023] Open
Abstract
Genomic imprinting results in parent-of-origin-dependent monoallelic gene expression. Early work showed that distal mouse chromosome 2 is imprinted, as maternal and paternal duplications of the region (with corresponding paternal and maternal deficiencies) give rise to different anomalous phenotypes with early postnatal lethalities. Newborns with maternal duplication (MatDp(dist2)) are long, thin and hypoactive whereas those with paternal duplication (PatDp(dist2)) are chunky, oedematous, and hyperactive. Here we focus on PatDp(dist2). Loss of expression of the maternally expressed Gnas transcript at the Gnas cluster has been thought to account for the PatDp(dist2) phenotype. But PatDp(dist2) also have two expressed doses of the paternally expressed Gnasxl transcript. Through the use of targeted mutations, we have generated PatDp(dist2) mice predicted to have 1 or 2 expressed doses of Gnasxl, and 0, 1 or 2 expressed doses of Gnas. We confirm that oedema is due to lack of expression of imprinted Gnas alone. We show that it is the combination of a double dose of Gnasxl, with no dose of imprinted Gnas, that gives rise to the characteristic hyperactive, chunky, oedematous, lethal PatDp(dist2) phenotype, which is also hypoglycaemic. However PatDp(dist2) mice in which the dosage of the Gnasxl and Gnas is balanced (either 2∶2 or 1∶1) are neither dysmorphic nor hyperactive, have normal glucose levels, and are fully viable. But PatDp(dist2) with biallelic expression of both Gnasxl and Gnas show a marked postnatal growth retardation. Our results show that most of the PatDp(dist2) phenotype is due to overexpression of Gnasxl combined with loss of expression of Gnas, and suggest that Gnasxl and Gnas may act antagonistically in a number of tissues and to cause a wide range of phenotypic effects. It can be concluded that monoallelic expression of both Gnasxl and Gnas is a requirement for normal postnatal growth and development.
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Affiliation(s)
- Simon T. Ball
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Michelle L. Kelly
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Joan E. Robson
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Martin D. Turner
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Jackie Harrison
- Medical Research Council Mary Lyon Centre, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Lynn Jones
- Medical Research Council Mary Lyon Centre, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Diane Napper
- Medical Research Council Mary Lyon Centre, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Colin V. Beechey
- Medical Research Council Mary Lyon Centre, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Tertius Hough
- Medical Research Council Mary Lyon Centre, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Bruce M. Cattanach
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Roger D. Cox
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
| | - Jo Peters
- Medical Research Council Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxfordshire, United Kingdom
- * E-mail:
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Turan S, Bastepe M. The GNAS complex locus and human diseases associated with loss-of-function mutations or epimutations within this imprinted gene. Horm Res Paediatr 2013; 80:229-41. [PMID: 24107509 PMCID: PMC3874326 DOI: 10.1159/000355384] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 08/29/2013] [Indexed: 12/14/2022] Open
Abstract
GNAS is a complex imprinted locus leading to several different gene products that show exclusive monoallelic expression. GNAS also encodes the α-subunit of the stimulatory G protein (Gsα), a ubiquitously expressed signaling protein that is essential for the actions of many hormones and other endogenous molecules. Gsα is expressed biallelically in most tissues but its expression is silenced from the paternal allele in a small number of tissues. The tissue-specific paternal silencing of Gsα results in different parent-of-origin-specific phenotypes in patients who carry inactivating GNAS mutations. In this paper, we review the GNAS complex locus and discuss how disruption of Gsα expression and the expression of other GNAS products shape the phenotypes of human disorders caused by mutations in this gene.
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Affiliation(s)
- Serap Turan
- Pediatric Endocrinology, Marmara University School of Medicine Hospital, Istanbul, Turkey
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA
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Cheeseman MT, Vowell K, Hough TA, Jones L, Pathak P, Tyrer HE, Kelly M, Cox R, Warren MV, Peters J. A mouse model for osseous heteroplasia. PLoS One 2012; 7:e51835. [PMID: 23284784 PMCID: PMC3526487 DOI: 10.1371/journal.pone.0051835] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 11/07/2012] [Indexed: 11/29/2022] Open
Abstract
GNAS/Gnas encodes Gsα that is mainly biallelically expressed but shows imprinted expression in some tissues. In Albright Hereditary Osteodystrophy (AHO) heterozygous loss of function mutations of GNAS can result in ectopic ossification that tends to be superficial and attributable to haploinsufficiency of biallelically expressed Gsα. Oed-Sml is a point missense mutation in exon 6 of the orthologous mouse locus Gnas. We report here both the late onset ossification and occurrence of benign cutaneous fibroepithelial polyps in Oed-Sml. These phenotypes are seen on both maternal and paternal inheritance of the mutant allele and are therefore due to an effect on biallelically expressed Gsα. The ossification is confined to subcutaneous tissues and so resembles the ossification observed with AHO. Our mouse model is the first with both subcutaneous ossification and fibroepithelial polyps related to Gsα deficiency. It is also the first mouse model described with a clinically relevant phenotype associated with a point mutation in Gsα and may be useful in investigations of the mechanisms of heterotopic bone formation. Together with earlier results, our findings indicate that Gsα signalling pathways play a vital role in repressing ectopic bone formation.
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Affiliation(s)
- Michael T Cheeseman
- Medical Research Council Mammalian Genetics Unit, Medical Research Council Harwell, Oxfordshire, UK.
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Turan S, Ignatius J, Moilanen JS, Kuismin O, Stewart H, Mann NP, Linglart A, Bastepe M, Jüppner H. De novo STX16 deletions: an infrequent cause of pseudohypoparathyroidism type Ib that should be excluded in sporadic cases. J Clin Endocrinol Metab 2012; 97:E2314-9. [PMID: 23087324 PMCID: PMC3513531 DOI: 10.1210/jc.2012-2920] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 09/24/2012] [Indexed: 01/18/2023]
Abstract
CONTEXT Maternally inherited 3-kb STX16 deletions cause autosomal dominant pseudohypoparathyroidism type Ib (PHP-Ib) characterized by PTH resistance with loss of methylation restricted to the GNAS exon A/B. OBJECTIVE The objective of the study was to search for the 3-kb STX16 deletion and to establish haplotypes for the GNAS region for two PHP-Ib patients and their families. SETTING The study was conducted at a research laboratory and tertiary care hospitals. PATIENTS The index cases presented at the ages 8 and 9.5 yr, respectively, with hypocalcemia, hyperphosphatemia, and elevated PTH. INTERVENTIONS There were no interventions. RESULTS DNA analyses of the index cases revealed an isolated loss of the GNAS exon A/B methylation and the 3-kb STX16 deletion. In the first family, the patient's healthy mother and sister showed no genetic or epigenetic abnormality, yet microsatellite analysis of the GNAS region indicated that both siblings share the same maternal allele, with the exception of an allelic loss for marker 261P9-CA1 (located within STX16), leading to the conclusion that a de novo mutation had occurred on the maternal allele. In the second family, three siblings of the index case are also affected, and an analysis of their DNA revealed the 3-kb STX16 deletion, which was also found in the healthy mother and a maternal uncle. Analysis of the siblings of the deceased maternal grandfather and some of their descendants excluded the 3-kb STX16 deletion, but haplotype analysis of the GNAS region suggested that he had acquired the mutation de novo. CONCLUSIONS De novo 3-kb STX16 deletions, reported only once previously, are infrequent but should be excluded in all cases of PHP-Ib, even when the family history is negative for an inherited form of this disorder.
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Affiliation(s)
- Serap Turan
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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Plagge A. Non-Coding RNAs at the Gnas and Snrpn-Ube3a Imprinted Gene Loci and Their Involvement in Hereditary Disorders. Front Genet 2012; 3:264. [PMID: 23226156 PMCID: PMC3509947 DOI: 10.3389/fgene.2012.00264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/05/2012] [Indexed: 12/02/2022] Open
Abstract
Non-coding RNAs (ncRNAs) have long been recognized at imprinted gene loci and provided early paradigms to investigate their functions and molecular mechanisms of action. The characteristic feature of imprinted genes, their monoallelic, parental-origin-dependent expression, is achieved through complex epigenetic regulation, which is modulated by ncRNAs. This minireview focuses on two imprinted gene clusters, in which changes in ncRNA expression contribute to human disorders. At the GNAS locus loss of NESP RNA can cause autosomal dominant Pseudohypoparathyroidism type 1b (AD-PHP-Ib), while at the SNRPN-UBE3A locus a long ncRNA and processed snoRNAs play a role in Angelman-Syndrome (AS) and Prader–Willi-Syndrome (PWS). The ncRNAs silence overlapping protein-coding transcripts in sense or anti-sense orientation through changes in histone modifications as well as DNA methylation at CpG-rich sequence motifs. Their epigenetic modulatory functions are required in early development in the pre-implantation embryo or already in the parental germ cells. However, it remains unclear whether the sequence homology-carrying ncRNA itself is required, or whether the process of its transcription through other promoters causes the silencing effect.
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Affiliation(s)
- Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool Liverpool, UK
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Ivanova E, Chen JH, Segonds-Pichon A, Ozanne SE, Kelsey G. DNA methylation at differentially methylated regions of imprinted genes is resistant to developmental programming by maternal nutrition. Epigenetics 2012; 7:1200-10. [PMID: 22968513 PMCID: PMC3469461 DOI: 10.4161/epi.22141] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The nutritional environment in which the mammalian fetus or infant develop is recognized as influencing the risk of chronic diseases, such as type 2 diabetes and hypertension, in a phenomenon that has become known as developmental programming. The late onset of such diseases in response to earlier transient experiences has led to the suggestion that developmental programming may have an epigenetic component, because epigenetic marks such as DNA methylation or histone tail modifications could provide a persistent memory of earlier nutritional states. One class of genes that has been considered a potential target or mediator of programming events is imprinted genes, because these genes critically depend upon epigenetic modifications for correct expression and because many imprinted genes have roles in controlling fetal growth as well as neonatal and adult metabolism. In this study, we have used an established model of developmental programming-isocaloric protein restriction to female mice during gestation or lactation-to examine whether there are effects on expression and DNA methylation of imprinted genes in the offspring. We find that although expression of some imprinted genes in liver of offspring is robustly and sustainably changed, methylation of the differentially methylated regions (DMRs) that control their monoallelic expression remains largely unaltered. We conclude that deregulation of imprinting through a general effect on DMR methylation is unlikely to be a common factor in developmental programming.
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Affiliation(s)
- Elena Ivanova
- Epigenetics Programme; The Babraham Institute; Cambridge, UK
| | - Jian-Hua Chen
- Metabolic Research Laboratories; Institute of Metabolic Science; University of Cambridge; Cambridge UK
| | | | - Susan E. Ozanne
- Metabolic Research Laboratories; Institute of Metabolic Science; University of Cambridge; Cambridge UK
- MRC Centre for Obesity and Related Metabolic Diseases; Cambridge, UK
| | - Gavin Kelsey
- Epigenetics Programme; The Babraham Institute; Cambridge, UK
- Centre for Trophoblast Research; University of Cambridge; Cambridge, UK
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A survey of tissue-specific genomic imprinting in mammals. Mol Genet Genomics 2012; 287:621-30. [PMID: 22821278 DOI: 10.1007/s00438-012-0708-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/03/2012] [Indexed: 01/20/2023]
Abstract
In mammals, most somatic cells contain two copies of each autosomal gene, one inherited from each parent. When a gene is expressed, both parental alleles are usually transcribed. However, a subset of genes is subject to the epigenetic silencing of one of the parental copies by genomic imprinting. In this review, we explore the evidence for variability in genomic imprinting between different tissue and cell types. We also consider why the imprinting of particular genes may be restricted to, or lost in, specific tissues and discuss the potential for high-throughput sequencing technologies in facilitating the characterisation of tissue-specific imprinting and assaying the potentially functional variations in epigenetic marks.
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Lassi G, Ball ST, Maggi S, Colonna G, Nieus T, Cero C, Bartolomucci A, Peters J, Tucci V. Loss of Gnas imprinting differentially affects REM/NREM sleep and cognition in mice. PLoS Genet 2012; 8:e1002706. [PMID: 22589743 PMCID: PMC3349741 DOI: 10.1371/journal.pgen.1002706] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/27/2012] [Indexed: 12/17/2022] Open
Abstract
It has been suggested that imprinted genes are important in the regulation of sleep. However, the fundamental question of whether genomic imprinting has a role in sleep has remained elusive up to now. In this work we show that REM and NREM sleep states are differentially modulated by the maternally expressed imprinted gene Gnas. In particular, in mice with loss of imprinting of Gnas, NREM and complex cognitive processes are enhanced while REM and REM-linked behaviors are inhibited. This is the first demonstration that a specific overexpression of an imprinted gene affects sleep states and related complex behavioral traits. Furthermore, in parallel to the Gnas overexpression, we have observed an overexpression of Ucp1 in interscapular brown adipose tissue (BAT) and a significant increase in thermoregulation that may account for the REM/NREM sleep phenotypes. We conclude that there must be significant evolutionary advantages in the monoallelic expression of Gnas for REM sleep and for the consolidation of REM-dependent memories. Conversely, biallelic expression of Gnas reinforces slow wave activity in NREM sleep, and this results in a reduction of uncertainty in temporal decision-making processes.
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Affiliation(s)
- Glenda Lassi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Simon T. Ball
- Medical Research Council Mammalian Genetics Unit, Harwell, United Kingdom
| | - Silvia Maggi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Giovanni Colonna
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Thierry Nieus
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Cheryl Cero
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Alessandro Bartolomucci
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jo Peters
- Medical Research Council Mammalian Genetics Unit, Harwell, United Kingdom
| | - Valter Tucci
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
- * E-mail:
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Kobayashi H, Sakurai T, Sato S, Nakabayashi K, Hata K, Kono T. Imprinted DNA methylation reprogramming during early mouse embryogenesis at the Gpr1-Zdbf2 locus is linked to long cis-intergenic transcription. FEBS Lett 2012; 586:827-33. [PMID: 22449967 DOI: 10.1016/j.febslet.2012.01.059] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 01/27/2012] [Accepted: 01/31/2012] [Indexed: 11/25/2022]
Abstract
The paternally-expressed imprinted genes Gpr1 and Zdbf2 form a gene cluster wherein the imprinted-methylated regions of these two genes differ. We identified a novel, paternally expressed, long intergenic non-coding Zdbf2 variant (Zdbf2linc) transcribed from maternally methylated Gpr1 DMR during early embryogenesis in the mouse. While the Gpr1 DMR displayed biallelic hypermethylation, Zdbf2linc expression was rarely observed in the post-gastrulation, despite a positive correlation between the methylation of Zdbf2 DMRs and the mono-allelic transcription of the original Zdbf2 coding variant. Furthermore, lack of the maternal methylation imprint resulted in the biallelic expression of both coding and non-coding Zdbf2 transcripts as well as complete methylation of Zdbf2 DMRs. Globally, our findings suggest the role of Zdbf2linc in the establishment of secondary epigenetic modifications after implantation.
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Affiliation(s)
- Hisato Kobayashi
- Department of BioScience, Tokyo University of Agriculture, Setagaya-ku, Tokyo, Japan
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