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Choufani S, Ko JM, Lou Y, Shuman C, Fishman L, Weksberg R. Paternal Uniparental Disomy of the Entire Chromosome 20 in a Child with Beckwith-Wiedemann Syndrome. Genes (Basel) 2021; 12:genes12020172. [PMID: 33513760 PMCID: PMC7911624 DOI: 10.3390/genes12020172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Epigenetic alterations at imprinted genes on different chromosomes have been linked to several imprinting disorders (IDs) such as Beckwith-Wiedemann syndrome (BWS) and pseudohypoparathyroidism type 1b (PHP1b). Here, we present a male patient with these two distinct IDs caused by two independent mechanisms-loss of methylation (LOM) at chromosome 11p15.5 associated with multi-locus imprinting disturbances (MLID and paternal uniparental disomy of chromosome 20 (patUPD20). A clinical diagnosis of BWS was made based on the clinical features of macrosomia, macroglossia, and umbilical hernia. The diagnosis of PHP1b was supported by the presence of reduced growth velocity and mild learning disability as well as hypocalcemia and hyperphosphatemia at 14 years of age. Molecular analyses, including genome-wide DNA methylation (Illumina 450k array), bisulfite pyrosequencing, single nucleotide polymorphism (SNP) array and microsatellite analysis, demonstrated loss of methylation (LOM) at IC2 on chromosome 11p15.5, and paternal isodisomy of the entire chromosome 20. In addition, imprinting disturbances were noted at the differentially methylated regions (DMRs) associated with DIRAS3 on chromosome 1 and PLAGL1 on chromosome 6. This is the first case report of PHP1b due to patUPD20 diagnosed in a BWS patient with LOM at IC2 demonstrating etiologic heterogeneity for multiple imprinting disorders in a single individual.
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Affiliation(s)
- Sanaa Choufani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
| | - Jung Min Ko
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Youliang Lou
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
| | - Cheryl Shuman
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X8, Canada;
| | - Leona Fishman
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada;
- Department of Pediatrics, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Rosanna Weksberg
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; (S.C.); (J.M.K.); (Y.L.)
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1X8, Canada;
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada;
- Department of Pediatrics, University of Toronto, Toronto, ON M5S 1A1, Canada
- Correspondence:
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Wang Y, Tian H, Chen X. The Distinct Role of the Extra-Large G Protein ɑ-Subunit XLɑs. Calcif Tissue Int 2020; 107:212-219. [PMID: 32596800 DOI: 10.1007/s00223-020-00714-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/17/2020] [Indexed: 02/05/2023]
Abstract
GNAS is one of the most complex gene loci in the human genome and encodes multiple gene products including Gsα, XLαs, NESP55, A/B, and AS transcripts. XLαs, the extra-large G protein ɑ-subunit, is paternally expressed. XLɑs and Gsɑ share the common 2-13 exons with different promoters and first exons. Therefore, XLɑs contains most of the functional domains of Gsα including receptor and effector binding sites. In vitro studies suggest a "Gsɑ"-like function of XLɑs regarding the stimulation of cAMP generation in response to receptor activation with different cellular actions. However, it is unclear whether XLαs has an important physiological function in humans. Pseudopseudohypoparathyroidism (PPHP) and progressive osseous heteroplasia (POH) are caused by paternally inherited mutations of GNAS. Maternal uniparental disomy of chromosome 20 [UPD(20)mat] lacks paternal chromosome 20. Therefore, the phenotypes of these diseases may be secondary to the abnormal functions of XLɑs, at least partly. From the phenotypes of human diseases like PPHP, POH, and UPD(20)mat, as well as some animal models with deficient XLɑs functions, it could be seen that XLɑs is involved in the growth and development of the mammalian fetus, plays a different role in glucose, lipid, and energy metabolism when compared with Gsɑ, and could prevent heterotopic ossification in humans and mice. More in vivo and in vitro studies, especially the development of conditional XLɑs knockout mice, are needed to clarify the physiopathologic roles and related signal pathways of XLɑs.
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Affiliation(s)
- Yan Wang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, West China Hospital, Sichuan University, No. 37 Guoxue Xiang, Chengdu, 610041, China
| | - Haoming Tian
- Department of Endocrinology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiang Chen
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, West China Hospital, Sichuan University, No. 37 Guoxue Xiang, Chengdu, 610041, China.
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Chen X, Meng Y, Tang M, Wang Y, Xie Y, Wan S, Tian H, Yu X. A paternally inherited non-sense variant c.424G>T (p.G142*) in the first exon of XLαs in an adult patient with hypophosphatemia and osteopetrosis. Clin Genet 2020; 97:712-722. [PMID: 32157680 DOI: 10.1111/cge.13734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/05/2023]
Abstract
XLαs, the extra-large isoform of alpha-subunit of the stimulatory guanine nucleotide-binding protein (Gsα), is paternally expressed. The significance of XLαs in humans remains largely unknown. Here, we report a patient who presented with increased bone mass, hypophosphatemia, and elevated parathyroid hormone (PTH) levels. His serum calcium was in the lower limit of the normal range. Whole exome sequencing of this subject found a novel non-sense variant c.424G>T (p. G142*) in the first exon of XLαs, which was inherited from his father and transmitted to his daughter. This variant was predicted to exclusively influence the expression of XLαs, while possibly having no significant effects on other gene products of this locus. Ellsworth-Howard test revealed normal renal response to PTH in proband. Human SaOS2 cells transfected with mutant XLαs failed to generate cyclic adenosine monophosphate under PTH stimulation, indicating skeletal resistance to this hormone. This subject showed higher circulating sclerostin, dickkopf1, and osteoprotegerin (OPG) levels, while lower receptor activator of nuclear factor kappa-B ligand/OPG ratio, leading to reduced bone resorption. Our findings indicate that XLαs plays a critical role in bone metabolism and GNAS locus should be considered as a candidate gene for high bone mass.
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Affiliation(s)
- Xiang Chen
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Meng
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Mengjia Tang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Wang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Ying Xie
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Shan Wan
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Haoming Tian
- Department of Endocrinology, West China Hospital, Sichuan University, Chengdu, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
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Determinants of maximum cup depth in non-glaucoma and primary open-angle glaucoma subjects: a population-based study. Eye (Lond) 2019; 34:892-900. [PMID: 31562382 PMCID: PMC7182556 DOI: 10.1038/s41433-019-0600-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 07/24/2019] [Accepted: 08/22/2019] [Indexed: 11/10/2022] Open
Abstract
Background/objectives To study the associations of intraocular pressure (IOP) and retinal vessel diameters: central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) with the maximum cup depth (MCD) in subjects with and without POAG. Subjects/methods Eligible subjects from the Handan Eye Study. All participants underwent physical and comprehensive eye examinations. Univariable and multivariable linear regression models assessed the association between MCD and other parameters. Results Four thousand one hundred and ninety-four eligible nonglaucoma and 40 POAG subjects were analyzed. On univariable analysis, deeper MCD was significantly associated with younger age, male gender, lower systolic blood pressure (BP), higher IOP, higher estimated cerebro-spinal fluid pressure (ECSFP), lower estimated trans-laminal cribrosa pressure difference (ETLCPD), longer axial length, narrower CRAE, narrower CRVE, larger disc area (DA) and a lower prevalence of hypertension and diabetes. On multivariable analysis, significant independent determinants of MCD were larger DA (P < 0.001; beta: 0.042; B: 0.20; 95% CI: 0.19, 0.22), younger age (P < 0.001; beta: −0.09; B: −0.002; 95% CI: −0.003, −0.001), higher IOP (P < 0.01; beta: 0.040; B: 0.003; 95% CI: 0.001, 0.005), and narrower CRAE (P < 0.001; beta: −0.06; B: −0.001; 95% CI: −0.001, −0.0003). On adding ECSFP and ETLCPD to the model, MCD was associated with IOP but not with estimated CSFP and TLCPD. A 1 μm decrease in CRAE or 1 mmHg increase of IOP was associated with a 1 μm increase of MCD (P < 0.001) and 3 μm increase of MCD respectively (P = 0.009). Conclusions Narrow CRVE and higher IOP are associated with an increase in MCD.
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Colson C, Decamp M, Gruchy N, Coudray N, Ballandonne C, Bracquemart C, Molin A, Mittre H, Takatani R, Jüppner H, Kottler ML, Richard N. High frequency of paternal iso or heterodisomy at chromosome 20 associated with sporadic pseudohypoparathyroidism 1B. Bone 2019; 123:145-152. [PMID: 30905746 PMCID: PMC6637416 DOI: 10.1016/j.bone.2019.03.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/04/2019] [Accepted: 03/18/2019] [Indexed: 12/20/2022]
Abstract
Pseudohypoparathyroidism 1B (PHP1B) is caused by maternal epigenetic defects in the imprinted GNAS cluster. PHP1B can follow an autosomal dominant mode of inheritance or occur sporadically (spor-PHP1B). These latter patients present broad methylation changes of two or more differentially methylated regions (DMR) that, when mimicking the paternal allele, raises the suspicious of the occurrence of paternal uniparental disomy of chromosome 20 (upd(20)pat). A cohort of 33 spor-PHP1B patients was screened for upd(20)pat using comparative genomic hybridization with SNP-chip. Methylation analyses were assessed by methylation specific-multiplex ligation-dependent probe amplification. Upd(20)pat was identified in 6 patients, all exhibiting typical paternal methylation pattern compared to normal controls, namely a complete loss of methylation of GNAS A/B:TSS-DMR, negligible methylation at GNAS-AS1:TSS-DMR and GNAS-XL:Ex1-DMR and complete gain of methylation at GNAS-NESP:TSS-DMR. The overall frequency of upd(20) is 18% in our cohort when searched considering both severe and partial loss of imprinting. However, twenty five patients displayed severe methylation pattern and the upd(20)pat frequency reaches 24% when searching in this group. Consequently, up to day, upd(20)pat is the most common anomaly than other genetic alterations in spor-PHP1B patients. Upd(20)pat occurrence is not linked to the parental age in contrast to upd(20)mat, strongly associated with an advanced maternal childbearing age. This study provides criteria to guide further investigations for upd(20)pat needed for an adequate genetic counseling.
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Affiliation(s)
- Cindy Colson
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Matthieu Decamp
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nicolas Gruchy
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nadia Coudray
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Céline Ballandonne
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Claire Bracquemart
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Arnaud Molin
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Hervé Mittre
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Rieko Takatani
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Marie-Laure Kottler
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France
| | - Nicolas Richard
- Normandie Univ, UNICAEN, CHU de Caen Normandie, Department of Genetics, Reference Center fo Rare Diseases of Calcium and Phosphorus Metabolism, EA7450 BioTARGen, 14000 Caen, France.
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6
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Mantovani G, Bastepe M, Monk D, de Sanctis L, Thiele S, Usardi A, Ahmed SF, Bufo R, Choplin T, De Filippo G, Devernois G, Eggermann T, Elli FM, Freson K, García Ramirez A, Germain-Lee EL, Groussin L, Hamdy N, Hanna P, Hiort O, Jüppner H, Kamenický P, Knight N, Kottler ML, Le Norcy E, Lecumberri B, Levine MA, Mäkitie O, Martin R, Martos-Moreno GÁ, Minagawa M, Murray P, Pereda A, Pignolo R, Rejnmark L, Rodado R, Rothenbuhler A, Saraff V, Shoemaker AH, Shore EM, Silve C, Turan S, Woods P, Zillikens MC, Perez de Nanclares G, Linglart A. Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement. Nat Rev Endocrinol 2018; 14:476-500. [PMID: 29959430 PMCID: PMC6541219 DOI: 10.1038/s41574-018-0042-0] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This Consensus Statement covers recommendations for the diagnosis and management of patients with pseudohypoparathyroidism (PHP) and related disorders, which comprise metabolic disorders characterized by physical findings that variably include short bones, short stature, a stocky build, early-onset obesity and ectopic ossifications, as well as endocrine defects that often include resistance to parathyroid hormone (PTH) and TSH. The presentation and severity of PHP and its related disorders vary between affected individuals with considerable clinical and molecular overlap between the different types. A specific diagnosis is often delayed owing to lack of recognition of the syndrome and associated features. The participants in this Consensus Statement agreed that the diagnosis of PHP should be based on major criteria, including resistance to PTH, ectopic ossifications, brachydactyly and early-onset obesity. The clinical and laboratory diagnosis should be confirmed by a molecular genetic analysis. Patients should be screened at diagnosis and during follow-up for specific features, such as PTH resistance, TSH resistance, growth hormone deficiency, hypogonadism, skeletal deformities, oral health, weight gain, glucose intolerance or type 2 diabetes mellitus, and hypertension, as well as subcutaneous and/or deeper ectopic ossifications and neurocognitive impairment. Overall, a coordinated and multidisciplinary approach from infancy through adulthood, including a transition programme, should help us to improve the care of patients affected by these disorders.
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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, Milan, Italy
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Monk
- Imprinting and Cancer Group, Cancer Epigenetic and Biology Program (PEBC), Institut d'Investigació Biomedica de Bellvitge (IDIBELL), Barcelona, Spain
| | - Luisa de Sanctis
- Pediatric Endocrinology Unit, Department of Public Health and Pediatric Sciences, University of Torino, Turin, Italy
| | - Susanne Thiele
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Lübeck, Lübeck, Germany
| | - Alessia Usardi
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - S Faisal Ahmed
- Developmental Endocrinology Research Group, School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, UK
| | - Roberto Bufo
- IPOHA, Italian Progressive Osseous Heteroplasia Association, Cerignola, Foggia, Italy
| | - Timothée Choplin
- K20, French PHP and related disorders patient association, Jouars Pontchartrain, France
| | - Gianpaolo De Filippo
- APHP, Department of medicine for adolescents, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - Guillemette Devernois
- K20, French PHP and related disorders patient association, Jouars Pontchartrain, France
| | - Thomas Eggermann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Francesca M Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, Gasthuisberg, University of Leuven, Leuven, Belgium
| | - Aurora García Ramirez
- AEPHP, Spanish PHP and related disorders patient association, Huércal-Overa, Almería, Spain
| | - Emily L Germain-Lee
- Albright Center & Center for Rare Bone Disorders, Division of Pediatric Endocrinology & Diabetes, Connecticut Children's Medical Center, Farmington, CT, USA
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Lionel Groussin
- APHP, Department of Endocrinology, Cochin Hospital (HUPC), Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Neveen Hamdy
- Department of Medicine, Division of Endocrinology and Centre for Bone Quality, Leiden University Medical Center, Leiden, Netherlands
| | - Patrick Hanna
- INSERM U1169, Bicêtre Paris Sud, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France
| | - Olaf Hiort
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Lübeck, Lübeck, Germany
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter Kamenický
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- INSERM U1185, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France
| | - Nina Knight
- UK acrodysostosis patients' group, London, UK
| | - Marie-Laure Kottler
- Department of Genetics, Reference Centre for Rare Disorders of Calcium and Phosphate Metabolism, Caen University Hospital, Caen, France
- BIOTARGEN, UNICAEN, Normandie University, Caen, France
| | - Elvire Le Norcy
- University of Paris Descartes, Sorbonne Paris Cité, Paris, France
- APHP, Department of Odontology, Bretonneau Hospital (PNVS), Paris, France
| | - Beatriz Lecumberri
- Department of Endocrinology and Nutrition, La Paz University Hospital, Madrid, Spain
- Department of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain
- Endocrine Diseases Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Michael A Levine
- Division of Endocrinology and Diabetes and Center for Bone Health, Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Regina Martin
- Osteometabolic Disorders Unit, Hormone and Molecular Genetics Laboratory (LIM/42), Endocrinology Division, Hospital das Clínicas HCFMUSP, Faculty of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | - Gabriel Ángel Martos-Moreno
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, CIBERobn, ISCIII, Madrid, Spain
- Department of Pediatrics, Autonomous University of Madrid (UAM), Madrid, Spain
- Endocrine Diseases Research Group, Hospital La Princesa Institute for Health Research (IIS La Princesa), Madrid, Spain
| | | | - Philip Murray
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Arrate Pereda
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Alava, Spain
| | | | - Lars Rejnmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Rebecca Rodado
- AEPHP, Spanish PHP and related disorders patient association, Huércal-Overa, Almería, Spain
| | - Anya Rothenbuhler
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France
| | - Vrinda Saraff
- Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, UK
| | - Ashley H Shoemaker
- Pediatric Endocrinology and Diabetes, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eileen M Shore
- Departments of Orthopaedic Surgery and Genetics, Center for Research in FOP and Related Disorders, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Caroline Silve
- APHP, Service de Biochimie et Génétique Moléculaires, Hôpital Cochin, Paris, France
| | - Serap Turan
- Department of Pediatrics, Division of Endocrinology and Diabetes, Marmara University, Istanbul, Turkey
| | | | - M Carola Zillikens
- Department of Internal Medicine, Bone Center Erasmus MC - University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Guiomar Perez de Nanclares
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, Hospital Universitario Araba-Txagorritxu, Vitoria-Gasteiz, Alava, Spain.
| | - Agnès Linglart
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Platform of Expertise Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France.
- APHP, Endocrinology and diabetes for children, Bicêtre Paris Sud Hospital (HUPS), Le Kremlin-Bicêtre, France.
- INSERM U1169, Bicêtre Paris Sud, Paris Sud - Paris Saclay University, Le Kremlin-Bicêtre, France.
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7
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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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8
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Liu W, Zhang H, Wang J, Yu G, Qiu W, Li Z, Chen M, Choy KW, Sun X. Prenatal diagnosis of complete maternal uniparental isodisomy of chromosome 4 in a fetus without congenital abnormality or inherited disease-associated variations. Mol Cytogenet 2015; 8:85. [PMID: 26539248 PMCID: PMC4632482 DOI: 10.1186/s13039-015-0190-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/28/2015] [Indexed: 11/10/2022] Open
Abstract
Background The prenatal diagnosis of subjects with complete uniparental isodisomy of chromosome 4 (iUPD4) has rarely been reported and poses a great challenge for genetic counseling. In this study, a prenatal case with a high (1 in 58) risk of Down syndrome was diagnosed with iUPD4 by combined chromosomal microarray analysis (CMA), whole exome sequencing (WES) and ultrasound morphology scan. Results By CMA, a pathogenic copy number variant was not detected; however, a complete maternal iUPD4 was identified in this fetus after analyzing the parental genotype results. To detect potentially autosomal recessive variants, WES was performed. Two missense and two frameshift variants were identified but were predicted with uncertain significance; none of the mutations were definitively associated with congenital abnormality or inherited disease. In addition, a detailed ultrasound morphology scan did not identify any structural abnormalities, facial dysmorphisms or intrauterine growth restriction. The family history was unremarkable. The couple was counseled with the prenatal diagnostic results, and they opted to give birth to the child. No phenotypic abnormalities were observed in this child after the first year of life. Conclusion This study provides further evidence that iUPD4 can result in a healthy live birth and demonstrates that the combined use of CMA, WES and ultrasound technology provides additional information for the prenatal diagnosis and clinical management of rare UPD events. Electronic supplementary material The online version of this article (doi:10.1186/s13039-015-0190-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- WeiQiang Liu
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - HuiMin Zhang
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - Jian Wang
- Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127 P. R. China
| | - GuoJiu Yu
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - WenJun Qiu
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - ZhiHua Li
- Department of Prenatal Diagnosis and Fetal Medical, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - Min Chen
- Department of Prenatal Diagnosis and Fetal Medical, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
| | - Kwong Wai Choy
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, P. R. China
| | - XiaoFang Sun
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150 P. R. China
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9
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Liu W, Zhang R, Wei J, Zhang H, Yu G, Li Z, Chen M, Sun X. Rapid Diagnosis of Imprinting Disorders Involving Copy Number Variation and Uniparental Disomy Using Genome-Wide SNP Microarrays. Cytogenet Genome Res 2015; 146:9-18. [PMID: 26184742 DOI: 10.1159/000435847] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2015] [Indexed: 11/19/2022] Open
Abstract
Imprinting disorders, such as Beckwith-Wiedemann syndrome (BWS), Prader-Willi syndrome (PWS) and Angelman syndrome (AS), can be detected via methylation analysis, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA), or other methods. In this study, we applied single nucleotide polymorphism (SNP)-based chromosomal microarray analysis to detect copy number variations (CNVs) and uniparental disomy (UPD) events in patients with suspected imprinting disorders. Of 4 patients, 2 had a 5.25-Mb microdeletion in the 15q11.2q13.2 region, 1 had a 38.4-Mb mosaic UPD in the 11p15.4 region, and 1 had a 60-Mb detectable UPD between regions 14q13.2 and 14q32.13. Although the 14q32.2 region was classified as normal by SNP array for the 14q13 UPD patient, it turned out to be a heterodisomic UPD by short tandem repeat marker analysis. MS-MLPA analysis was performed to validate the variations. In conclusion, SNP-based microarray is an efficient alternative method for quickly and precisely diagnosing PWS, AS, BWS, and other imprinted gene-associated disorders when considering aberrations due to CNVs and most types of UPD.
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Affiliation(s)
- Weiqiang Liu
- Key Laboratory for Reproduction and Genetics of Guangdong Higher Education Institutes, Key Laboratory for Major Obstetric Diseases of Guangdong Province, Guangzhou, PR China
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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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Mantovani G, Elli FM. Pseudohypoparathyroidism type Ib in 2015. ANNALES D'ENDOCRINOLOGIE 2015; 76:101-4. [PMID: 25910998 DOI: 10.1016/j.ando.2015.03.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
Abstract
The term pseudohypoparathryoidism (PHP) refers to a group of rare genetic and epigenetic disorders characterized by resistance to the action of parathyroid hormone (PTH) that activates cAMP signaling in target cells. Together with pseudohypoparathyroidism, Albright hereditary osteodystrophy (AHO) and progressive osseous heteroplasia (POH) represent rare, related and deeply impairing disorders encompassing heterogeneous features, such as brachydactyly, ectopic ossifications, short stature, mental retardation and endocrine deficiencies due to resistance to the action of different hormones. The two main subtypes, PHP-Ia and PHP-Ib, are caused by mutations in GNAS exons 1-13 and methylation defects in the imprinted GNAS cluster respectively, while mutations in the PRKAR1A and PDE4D genes (also involved in mediating cAMP signalling) have been demonstrated in patients with acrodysostosis, a disease of bone formation with characteristics similar to AHO. The molecular overlap among these disorders indicates the need for different classification models and seriously alters our understanding of the mechanisms through which GNAS defects, together with the new recently described defects involving other components of the cAMP signalling cascade, cause AHO-related disorders.
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Affiliation(s)
- Giovanna Mantovani
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy.
| | - Francesca M Elli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Via F. Sforza, 35, 20122 Milan, Italy
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12
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Hasani-Ranjbar S, Jouyandeh Z, Amoli MM, Soltani A, Arzaghi SM. A patient with features of albright hereditory osteodystrophy and unusual neuropsychiatric findings without coding Gsalpha mutations. J Diabetes Metab Disord 2014; 13:56. [PMID: 24959527 PMCID: PMC4067066 DOI: 10.1186/2251-6581-13-56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 04/10/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND Pseudohypoparathyroidism(PHP) is a heterogeneous group of rare metabolic disorders characterized by hypocalcemia and hyperphosphatemia resulting from PTH resistance. Different forms of PHP have been reported based on biochemical and clinical manifestation and genetic findings. Most of these forms are caused by defects in GNAS, an imprinted gene locus with multiple subunits. We reported a 12- year- old girl with unusual clinical manifestations of Pseudopseudohypoparathyroidism(PPHP). METHODS After clinical and biochemical evaluations, the patients' genomic DNA was isolated from peripheral blood leukocytes using salting out method. The whole coding sequences of GNAS gene including 13 exons were amplified by PCR. Quantitative PCR reactions were performed too. FINDINGS We described a 12- year- old girl with Albright Hereditory osteodystrophy (AHO) phenotype, poor school performance, some abnormal movements, TSH resistance with normal serum calcium and phosphorus levels and normal Gsα bioactivity with no mutation in GNAS exons. Unusual neuropsychiatric findings in this patient were compatible with Asperger syndrome. CONCLUSIONS According to our findings this patient could not be categorized in any of PHP subgroups. Identifying of such individuals may be useful to discover different genetic patterns in pseudohypoparathyroidism and pseudopseudohypoparathyroidism. It is important to identify patients in whom PHP is caused by novel GNAS mutations, as careful investigations of these findings will likely further our knowledge of this complex and this unique disorder. In addition this case presented with unusual neuropsychiatric findings which has not been reported up to now.
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Affiliation(s)
- Shirin Hasani-Ranjbar
- Obesity & Eating Habits Research Center, Endocrinology and metabolism Cellular & Molecular Science Institute, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran ; Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran ; Endocrinology & Metabolism Research Institute, 5th Floor, Shariati Hospital, North Kargar Ave., Tehran 14114, Iran
| | - Zahra Jouyandeh
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Mohammad Amoli
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Akbar Soltani
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Masoud Arzaghi
- Endocrinology and Metabolism Research center, Endocrinology & Metabolism research institute, Tehran University of Medical Sciences, Tehran, Iran
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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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14
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Domínguez García A, Castaño González L, Pérez-Nanclares G, Quinteiro González S, Caballero Fernández E. Aspectos clínicos en dos casos de seudohipoparatiroidismo ( i a y i b) y estudio molecular del locus GNAS. An Pediatr (Barc) 2013; 79:319-24. [DOI: 10.1016/j.anpedi.2013.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/08/2013] [Accepted: 03/11/2013] [Indexed: 11/28/2022] Open
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15
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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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Mantovani G, Linglart A, Garin I, Silve C, Elli FM, de Nanclares GP. Clinical utility gene card for: pseudohypoparathyroidism. Eur J Hum Genet 2013; 21:ejhg2012211. [PMID: 22968134 PMCID: PMC3658187 DOI: 10.1038/ejhg.2012.211] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Giovanna Mantovani
- Endocrinology Unit, Deparment of Clinical Sciences and Community Health, University of Milan, Fondazione IRCCS Ca' Granda Policlinico, Milan, Italy.
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17
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Fernández-Rebollo E, Lecumberri B, Gaztambide S, Martinez-Indart L, Perez de Nanclares G, Castaño L. Endocrine profile and phenotype-(epi)genotype correlation in Spanish patients with pseudohypoparathyroidism. J Clin Endocrinol Metab 2013; 98:E996-1006. [PMID: 23533243 DOI: 10.1210/jc.2012-4164] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Recent advances in genetics and epigenetics have revealed an overlap between molecular and clinical features of pseudohypoparathyroidism (PHP) subtypes, broadening the previous spectrum of PHP genotype-phenotype correlations and indicating limitations of the current classification of the disease. OBJECTIVES The aim of the study was to screen patients with clinical diagnoses of PHP type I or pseudo-PHP for underlying molecular defects and explore possible correlations between molecular findings and clinical features. PATIENTS AND METHODS We investigated the GNAS locus at the molecular level in 72 affected patients (46 women and 26 men) from 56 nonrelated families. Clinical data were obtained for 63 of these patients (38 women and 25 men). RESULTS The molecular analysis showed that 35 patients carried structural mutations, 32 had loss of methylation, and 2 had a 2q37 deletion but did not reveal any (epi)mutation for 3 patients. Comparing these results and the clinical data, we observed that a younger age at diagnosis was associated with structural defects at the GNAS gene and epigenetic defects with a diagnosis later in life (9.19 ± 1.64 vs 24.57 ± 2.28 years, P < .0001). CONCLUSIONS This first global review of PHP in Spain highlights the importance of a detailed clinical and genetic study of each patient and the integrated analysis of the findings from the two approaches. It may also help geneticists and clinicians to raise the suspicion of PHP earlier, reach more accurate diagnoses, and provide patients with PHP and their families with useful genetic information and counseling, thereby improving outcomes and quality of life.
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Affiliation(s)
- Eduardo Fernández-Rebollo
- Endocrinology and Diabetes Research Group, Hospital Universitario de Cruces, Universidad del País Vasco-Euskal Herriko Unibertsitatea, 48903 Barakaldo, Spain
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18
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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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Fernández-Rebollo E, Maeda A, Reyes M, Turan S, Fröhlich LF, Plagge A, Kelsey G, Jüppner H, Bastepe M. Loss of XLαs (extra-large αs) imprinting results in early postnatal hypoglycemia and lethality in a mouse model of pseudohypoparathyroidism Ib. Proc Natl Acad Sci U S A 2012; 109:6638-43. [PMID: 22496590 PMCID: PMC3340037 DOI: 10.1073/pnas.1117608109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maternal deletion of the NESP55 differentially methylated region (DMR) (delNESP55/ASdel3-4(m), delNAS(m)) from the GNAS locus in humans causes autosomal dominant pseudohypoparathyroidism type Ib (AD-PHP-Ib(delNASm)), a disorder of proximal tubular parathyroid hormone (PTH) resistance associated with loss of maternal GNAS methylation imprints. Mice carrying a similar, maternally inherited deletion of the Nesp55 DMR (ΔNesp55(m)) replicate these Gnas epigenetic abnormalities and show evidence for PTH resistance, yet these mice demonstrate 100% mortality during the early postnatal period. We investigated whether the loss of extralarge αs (XLαs) imprinting and the resultant biallelic expression of XLαs are responsible for the early postnatal lethality in ΔNesp55(m) mice. First, we found that ΔNesp55(m) mice are hypoglycemic and have reduced stomach-to-body weight ratio. We then generated mice having the same epigenetic abnormalities as the ΔNesp55(m) mice but with normalized XLαs expression due to the paternal disruption of the exon giving rise to this Gnas product. These mice (ΔNesp55(m)/Gnasxl(m+/p-)) showed nearly 100% survival up to postnatal day 10, and a substantial number of them lived to adulthood. The hypoglycemia and reduced stomach-to-body weight ratio observed in 2-d-old ΔNesp55(m) mice were rescued in the ΔNesp55(m)/Gnasxl(m+/p-) mice. Surviving double-mutant animals had significantly reduced Gαs mRNA levels and showed hypocalcemia, hyperphosphatemia, and elevated PTH levels, thus providing a viable model of human AD-PHP-Ib. Our findings show that the hypoglycemia and early postnatal lethality caused by the maternal deletion of the Nesp55 DMR result from biallelic XLαs expression. The double-mutant mice will help elucidate the pathophysiological mechanisms underlying AD-PHP-Ib.
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Affiliation(s)
| | | | | | - Serap Turan
- Endocrine Unit, Department of Medicine, and
- Pediatric Endocrinology, Marmara University School of Medicine, Istanbul 34899, Turkey
| | - Leopold F. Fröhlich
- Endocrine Unit, Department of Medicine, and
- Institute of Pathology, Medical University of Graz, 8036 Graz, Austria
| | - Antonius Plagge
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, United Kingdom; and
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 1TN, United Kingdom
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, and
- Pediatric Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
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Kearney HM, Kearney JB, Conlin LK. Diagnostic Implications of Excessive Homozygosity Detected by SNP-Based Microarrays: Consanguinity, Uniparental Disomy, and Recessive Single-Gene Mutations. Clin Lab Med 2011; 31:595-613, ix. [DOI: 10.1016/j.cll.2011.08.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Abstract
CONTEXT The term pseudohypoparathyroidism (PHP) indicates a group of heterogeneous disorders whose common feature is represented by impaired signaling of various hormones (primarily PTH) that activate cAMP-dependent pathways via Gsα protein. The two main subtypes of PHP, PHP type Ia, and Ib (PHP-Ia, PHP-Ib) are caused by molecular alterations within or upstream of the imprinted GNAS gene, which encodes Gsα and other translated and untranslated products. EVIDENCE ACQUISITION A PubMed search was used to identify the available studies (main query terms: pseudohypoparathyroidism; Albright hereditary osteodystrophy; GNAS; GNAS1; progressive osseous heteroplasia). The most relevant studies until February 2011 have been included in the review. EVIDENCE SYNTHESIS AND CONCLUSIONS Despite the first description of this disorder dates back to 1942, recent findings indicating complex epigenetic alterations beside classical mutations at the GNAS complex gene, pointed out the limitation of the actual classification of the disease, resulting in incorrect genetic counselling and diagnostic procedures, as well as the gap in our actual knowledge of the pathogenesis of these disorders. This review will focus on PHP type I, in particular its diagnosis, classification, treatment, and underlying molecular alterations.
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Affiliation(s)
- Giovanna Mantovani
- Endocrinology and Diabetology Unit, Department of Medical Sciences, Università degli Studi di Milano, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy.
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Fernández-Rebollo E, Pérez de Nanclares G, Lecumberri B, Turan S, Anda E, Pérez-Nanclares G, Feig D, Nik-Zainal S, Bastepe M, Jüppner H. Exclusion of the GNAS locus in PHP-Ib patients with broad GNAS methylation changes: evidence for an autosomal recessive form of PHP-Ib? J Bone Miner Res 2011; 26:1854-63. [PMID: 21523828 PMCID: PMC3814169 DOI: 10.1002/jbmr.408] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Most patients with autosomal dominant pseudohypoparathyroidism type Ib (AD-PHP-Ib) carry maternally inherited microdeletions upstream of GNAS that are associated with loss of methylation restricted to GNAS exon A/B. Only few AD-PHP-Ib patients carry microdeletions within GNAS that are associated with loss of all maternal methylation imprints. These epigenetic changes are often indistinguishable from those observed in patients affected by an apparently sporadic PHP-Ib form that has not yet been defined genetically. We have now investigated six female patients affected by PHP-Ib (four unrelated and two sisters) with complete or almost complete loss of GNAS methylation, whose healthy children (11 in total) showed no epigenetic changes at this locus. Analysis of several microsatellite markers throughout the 20q13 region made it unlikely that PHP-Ib is caused in these patients by large deletions involving GNAS or by paternal uniparental isodisomy or heterodisomy of chromosome 20 (patUPD20). Microsatellite and single-nucleotide variation (SNV) data revealed that the two affected sisters share their maternally inherited GNAS alleles with unaffected relatives that lack evidence for abnormal GNAS methylation, thus excluding linkage to this locus. Consistent with these findings, healthy children of two unrelated sporadic PHP-Ib patients had inherited different maternal GNAS alleles, also arguing against linkage to this locus. Based on our data, it appears plausible that some forms of PHP-Ib are caused by homozygous or compound heterozygous mutation(s) in an unknown gene involved in establishing or maintaining GNAS methylation.
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Affiliation(s)
- Eduardo Fernández-Rebollo
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Jin HY, Lee BH, Choi JH, Kim GH, Kim JK, Lee JH, Yu J, Yoo JH, Ko CW, Lim HH, Chung HR, Yoo HW. Clinical characterization and identification of two novel mutations of the GNAS gene in patients with pseudohypoparathyroidism and pseudopseudohypoparathyroidism. Clin Endocrinol (Oxf) 2011; 75:207-13. [PMID: 21521295 DOI: 10.1111/j.1365-2265.2011.04026.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) are rare disorders resulting from genetic and epigenetic aberrations in the GNAS locus. DESIGN Investigation of clinical characteristics and molecular analysis in PHP and PPHP. PATIENTS Fourteen subjects from 13 unrelated families including subjects with PPHP (n = 1), PHP-Ia (n = 6) and PHP-Ib (n = 7) were enrolled. MEASUREMENTS Clinical data, including age at presentation, presenting symptom, auxological findings, family history, presence of Albright hereditary osteodystrophy (AHO) features and hormonal and biochemical findings, were analysed. The GNAS locus was subjected to direct sequencing and methylation analysis using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). RESULTS Of the 13 PHP subjects, 10 (three PHP-Ia and seven PHP-Ib) presented with hypocalcemic tetany at ages ranging from 7 to 14·8 years. Subcutaneous calcification was observed as an early manifestation of AHO in one PHP-Ia patient (age, 2·9 years) and one PPHP patient (age, 7 months). Six PHP-Ia and one PPHP harboured four different heterozygous mutations within the coding region of GNAS, p.Asp189_Tyr190delinsMetfxX14, p.Val117fsX23, p.Tyr190CysfsX19, and a splicing mutation (c.659 + 1G>A), of which the latter two were novel. Five subjects with PHP-Ib exhibited complete loss of the maternal-specific methylation pattern. The remaining two PHP-Ib showed a loss of methylation of exon 1A on the maternal allele as a consequence of heterozygous 3-kb microdeletions within the STX16 gene. CONCLUSIONS GNAS mutation analyses and MS-MLPA assays are useful molecular tools for understanding the molecular bases and confirming the diagnosis of PHP and PPHP.
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Affiliation(s)
- Hye Young Jin
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
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Zazo C, Thiele S, Martín C, Fernandez-Rebollo E, Martinez-Indart L, Werner R, Garin I, Hiort O, Perez de Nanclares G. Gsα activity is reduced in erythrocyte membranes of patients with psedohypoparathyroidism due to epigenetic alterations at the GNAS locus. J Bone Miner Res 2011; 26:1864-70. [PMID: 21351142 DOI: 10.1002/jbmr.369] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In pseudohypoparathyroidism (PHP), PTH resistance results from impairment of signal transduction of G protein-coupled receptors caused by a deficiency of the Gsα-cAMP signaling cascade due to diminished Gsα activity in maternally imprinted tissues. In PHP-Ia, inactivating mutations of the GNAS gene lead to haploinsufficiency in some tissues with biallelic expression, so in addition to PHP, Albright's hereditary osteodystrophy (AHO) is also present. In PHP-Ib, caused by methylation defects at the GNAS locus, diminished Gsα activity was thought to be limited to maternally imprinted tissues, such as the renal proximal tubule and the thyroid, leading to a lack of AHO. Recently, we demonstrated methylation defects in patients with AHO signs, indicating a connection between epigenetic changes and AHO. Our objective was to determine Gsα activity in erythrocyte membranes in patients with epigenetic defects at the GNAS locus compared to normal controls and patients with inactivating GNAS mutations. Gsα activity and expression, mutation of the GNAS locus, and methylation status were studied in patients with PHP and mild signs of AHO (PHP-Ia: 12; PHP-Ib: 17, of which 8 had some features of AHO). Then, we statistically compared the Gsα activity of the different PHP subtypes. Patients with methylation defects at the GNAS locus show a significant decrease in erythrocyte Gsα activity compared to normal controls (PHP-Ib versus controls, p < .001). This was significantly lower in patients with AHO signs (PHP-Ib + mild-AHO versus PHP-Ib, p < .05). Our research shows that PHP-Ia and PHP-Ib classification is not only overlapped genetically, as reported, but also in terms of Gsα activity. Reduced expression of GNAS due to methylation defects could downregulate Gsα activity in other tissues beyond those described and could also be causative of AHO.
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Affiliation(s)
- Celia Zazo
- Molecular Genetics Laboratory, Research Unit, Hospital Txagorritxu, Vitoria-Gasteiz, Spain
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Bastepe M, Altug-Teber Ö, Agarwal C, Oberfield SE, Bonin M, Jüppner H. Paternal uniparental isodisomy of the entire chromosome 20 as a molecular cause of pseudohypoparathyroidism type Ib (PHP-Ib). Bone 2011; 48:659-62. [PMID: 20965295 PMCID: PMC3039090 DOI: 10.1016/j.bone.2010.10.168] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 11/30/2022]
Abstract
Pseudohypoparathyoridism type Ib (PHP-Ib) typically defines the presence of end-organ resistance to parathyroid hormone in the absence of Albright's hereditary osteodystrophy. Patients affected by this disorder present with imprinting defects in the complex GNAS locus. Microdeletions within STX16 or GNAS have been identified in familial cases with PHP-Ib, but the molecular cause of the GNAS imprinting defects in sporadic PHP-Ib cases remains poorly defined. We now report a case with sporadic PHP-Ib for whom a SNPlex analysis revealed loss of the maternal GNAS allele. Further analysis of the entire genome with a 100K SNP chip identified a paternal uniparental isodisomy affecting the entire chromosome 20 without evidence for another chromosomal abnormality. Our findings explain the observed GNAS methylation changes and the patient's hormone resistance, and furthermore suggest that chromosome 20 harbors, besides GNAS, no additional imprinted region that contributes to the clinical and laboratory phenotype.
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Affiliation(s)
- Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Özge Altug-Teber
- Department of Medical Genetics, University Clinics of Tübingen, Tübingen, Germany
| | - Chhavi Agarwal
- Pediatric Endocrinology, Diabetes and Metabolism Department of Pediatric Endocrinology, Columbia University Medical Center, New York, NY,USA
| | - Sharon E. Oberfield
- Pediatric Endocrinology, Diabetes and Metabolism Department of Pediatric Endocrinology, Columbia University Medical Center, New York, NY,USA
| | - Michael Bonin
- Department of Medical Genetics, University Clinics of Tübingen, Tübingen, Germany
| | - Harald Jüppner
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Fernández-Rebollo E, Lecumberri B, Garin I, Arroyo J, Bernal-Chico A, Goñi F, Orduña R, Castaño L, de Nanclares GP. New mechanisms involved in paternal 20q disomy associated with pseudohypoparathyroidism. Eur J Endocrinol 2010; 163:953-62. [PMID: 20837711 DOI: 10.1530/eje-10-0435] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
PURPOSE Type I pseudohypoparathyroidism (PHP-I) can be subclassified into Ia and Ib, depending on the presence or absence of Albright's hereditary osteodystrophy's phenotype, diminished α-subunit of the stimulatory G protein (G(s)α) activity and multihormonal resistance. Whereas PHP-Ia is mainly associated with heterozygous inactivating mutations in G(s)α-coding exons of GNAS, PHP-Ib is caused by imprinting defects of GNAS. To date, just one patient with PHP and complete paternal uniparental disomy (UPD) has been described. We sought to identify the underlining molecular defect in twenty patients with parathyroid hormone resistance, hypocalcemia and hyperphosphatemia, and abnormal methylation pattern at GNAS locus. METHODS Microsatellite typing and comparative genome hybridization were performed for proband and parents. RESULTS We describe four patients with partial paternal UPD of chromosome 20 involving pat20qUPD in one case, from 20q13.13-qter in two cases, and pat20p heterodisomy plus interstitial 20q isodisomy in one patient. CONCLUSIONS These observations demonstrate that mitotic recombination of chromosome 20 can also give rise to UPD and PHP, a situation similar to other imprinting disorders, such as Beckwith-Wiedemann syndrome or neonatal diabetes.
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Affiliation(s)
- Eduardo Fernández-Rebollo
- Endocrinology and Diabetes Research Group, Molecular Genetics Laboratory, Hospital de Cruces, 48903 Barakaldo, Bizkaia, Spain
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Shoemaker R, Wang W, Zhang K. Mediators and dynamics of DNA methylation. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 3:281-98. [PMID: 20878927 DOI: 10.1002/wsbm.124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
As an inherited epigenetic marker occurring mainly on cytosines at CpG dinucleotides, DNA methylation occurs across many higher eukaryotic organisms. Looking at methylation patterns genome-wide classifies cell types uniquely and in several cases discriminates between healthy and cancerous cell types. DNA methylation can occur allele-specifically, which allows the cellular regulatory machinery to recognize each allele separately. Although only a small number of allele specifically methylated (ASM) regions are known, genome-wide experiments show that ASM is prevalent throughout the human genome. These DNA methylation patterns can be modified via DNA demethylation, which is important for induced pluripotent stem reprogramming and primordial germ cells. Recent evidence shows that the protein activation-induced cytidine deaminase plays a critical role in these demethylation events. Many transcription factors mediate DNA methylation patterns. Some transcription factors bind specifically to methylated or unmethylated sequences and other transcription factors protect genomic regions (e.g., promoter regions) from nearby DNA methylation encroachment. Possibly acting as another epigenetic regulatory layer, methylated cytosines are also converted to 5-hydroxyethylcyotines, which is a new modification type whose biological significance has yet been defined.
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Affiliation(s)
- Robert Shoemaker
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA, USA
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