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Ware AD, Brewer N, Meyers C, Morris C, McCarthy E, Shore EM, James AW. Differential Vascularity in Genetic and Nonhereditary Heterotopic Ossification. Int J Surg Pathol 2019; 27:859-867. [PMID: 31250694 DOI: 10.1177/1066896919857135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Introduction. Nonhereditary heterotopic ossification (NHO) is a common complication of trauma. Progressive osseous heteroplasia (POH) and fibrodysplasia ossificans progressiva (FOP) are rare genetic causes of heterotopic bone. In this article, we detail the vascular patterning associated with genetic versus NHO. Methods. Vascular histomorphometric analysis was performed on patient samples from POH, FOP, and NHO. Endpoints for analysis included blood vessel (BV) number, area, density, size, and wall thickness. Results. Results demonstrated conserved temporal dynamic changes in vascularity across all heterotopic ossification lesions. Immature areas had the highest BV number, while the more mature foci had the highest BV area. Most vascular parameters were significantly increased in genetic as compared with NHO. Discussion. In sum, both genetic and NHO show temporospatial variation in vascularity. These findings suggest that angiogenic pathways are potential therapeutic targets in both genetic and nonhereditary forms of heterotopic ossification.
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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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Abstract
GNAS is a complex imprinted gene encoding the alpha-subunit of the stimulatory heterotrimeric G protein (Gsα). GNAS gives rise to additional gene products that exhibit exclusively maternal or paternal expression, such as XLαs, a large variant of Gsα that shows exclusively paternal expression and is partly identical to the latter. Gsα itself is expressed biallelically in most tissues, although the expression occurs predominantly from the maternal allele in a small set of tissues, such as renal proximal tubules. Inactivating mutations in Gsα-coding GNAS exons are responsible for Albright's hereditary osteodystrophy (AHO), which refers to a constellation of physical and developmental disorders including obesity, short stature, brachydactyly, cognitive impairment, and heterotopic ossification. Patients with Gsα mutations can present with AHO in the presence or absence of end-organ resistance to multiple hormones including parathyroid hormone. Maternal Gsα mutations lead to AHO with hormone resistance (i.e. pseudohypoparathyroidism type-Ia), whereas paternal mutations cause AHO alone (i.e. pseudo-pseudohypoparathyroidism). Heterotopic ossification associated with AHO develops through intramembranous bone formation and is limited to dermis and subcutis. In rare cases carrying Gsα mutations, however, ossifications progress into deep connective tissue and skeletal muscle, a disorder termed progressive osseous heteroplasia (POH). Here I briefly review the genetic, clinical, and molecular aspects of these disorders caused by inactivating GNAS mutations, with particular emphasis on heterotopic ossification.
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Affiliation(s)
- Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, United States.
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4
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Happle R. The concept of type 2 segmental mosaicism, expanding from dermatology to general medicine. J Eur Acad Dermatol Venereol 2018; 32:1075-1088. [PMID: 29405433 DOI: 10.1111/jdv.14838] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/19/2017] [Indexed: 12/11/2022]
Abstract
In autosomal dominant skin disorders, the well-known type 1 segmental mosaicism reflects heterozygosity for a postzygotic new mutation. By contrast, type 2 segmental mosaicism originates in a heterozygous embryo from an early postzygotic mutational event giving rise to loss of the corresponding wild-type allele, which results in a pronounced segmental involvement being superimposed on the ordinary, non-segmental phenotype. Today, this concept has been proven by molecular analysis in many cutaneous traits. The purpose of this review was to seek publications of cases suggesting an extracutaneous manifestation of type 2 segmental mosaicism. Case reports documenting a pronounced extracutaneous segmental involvement were collected from the literature available in PubMed and from personal communications to the author. Pertinent cases are compared to the description of cutaneous segmental mosaicism of type 1 or type 2 as reported in a given trait. In total, reports suggesting extracutaneous type 2 segmental mosaicism were found in 14 different autosomal dominant skin disorders. In this way, clinical evidence is accumulated that extracutaneous type 2 segmental mosaicism does likewise occur in many autosomal dominant skin disorders. So far, however, molecular proof of this particular form of mosaicism is lacking. The present review may stimulate readers to inform colleagues of other specialties on this new concept, in order to initiate further research in this particular field of knowledge that has important implications for diagnosis, treatment and genetic counselling.
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Affiliation(s)
- R Happle
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
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5
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Salemi P, Skalamera Olson JM, Dickson LE, Germain-Lee EL. Ossifications in Albright Hereditary Osteodystrophy: Role of Genotype, Inheritance, Sex, Age, Hormonal Status, and BMI. J Clin Endocrinol Metab 2018; 103:158-168. [PMID: 29059381 PMCID: PMC5761497 DOI: 10.1210/jc.2017-00860] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 10/16/2017] [Indexed: 12/14/2022]
Abstract
CONTEXT Albright hereditary osteodystrophy (AHO) is caused by heterozygous inactivating mutations in GNAS. Depending on the parental origin of the mutated allele, patients develop either pseudohypoparathyroidism type 1A (PHP1A), with multihormone resistance and severe obesity, or pseudopseudohypoparathyroidism (PPHP), without hormonal abnormalities or marked obesity. Subcutaneous ossifications (SCOs) are a source of substantial morbidity in both PHP1A and PPHP. OBJECTIVE This study investigated the previously undetermined prevalence of SCO formation in PHP1A vs PPHP as well as possible correlations with genotype, sex, age, hormonal resistance, and body mass index (BMI). DESIGN This study evaluated patients with AHO for SCOs by physical examination performed by one consistent physician over 16 years. SETTING Albright Clinic, Kennedy Krieger Institute; Institute for Clinical and Translational Research, Johns Hopkins Hospital; Albright Center, Connecticut Children's Medical Center. PATIENTS We evaluated 67 patients with AHO (49 with PHP1A, 18 with PPHP) with documented mutations in GNAS. MAIN OUTCOME MEASURES Relationships of SCOs to genotype, sex, age, hormonal resistance, and BMI. RESULTS Forty-seven of 67 participants (70.1%) had SCOs. Patients with PHP1A and PPHP had similar prevalences and degrees of ossification formation. Patients with frameshift and nonsense mutations had much more extensive SCOs than those with missense mutations. Males were affected more than females. There was no correlation with hormonal status or BMI. CONCLUSIONS There is a similar prevalence of SCOs in PHP1A and PPHP, and the extent of SCO formation correlates with the severity of the mutation. Males are affected more extensively than females, and the SCOs tend to worsen with age.
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Affiliation(s)
- Parissa Salemi
- Department of Pediatrics, Division of Pediatric Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Lauren E Dickson
- Albright Center and Center for Rare Bone Disorders, Division of Pediatric Endocrinology & Diabetes, Connecticut Children's Medical Center, Farmington, Connecticut
| | - Emily L Germain-Lee
- Department of Pediatrics, Division of Pediatric Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Albright Clinic, Kennedy Krieger Institute, Baltimore, Maryland
- Albright Center and Center for Rare Bone Disorders, Division of Pediatric Endocrinology & Diabetes, Connecticut Children's Medical Center, Farmington, Connecticut
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut
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6
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Elli FM, Boldrin V, Pirelli A, Spada A, Mantovani G. The Complex GNAS Imprinted Locus and Mesenchymal Stem Cells Differentiation. Horm Metab Res 2017; 49:250-258. [PMID: 27756094 DOI: 10.1055/s-0042-115305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
All tissues and organs derive from stem cells, which are undifferentiated cells able to differentiate into specialized cells and self-renewal. In mammals, there are embryonic stem cells that generate germ layers, and adult stem cells, which act as a repair system for the body and maintain the normal turnover of regenerative organs. Mesenchymal stem cells (MSCs) are nonhematopoietic adult multipotent cells, which reside in virtually all postnatal organs and tissues, and, under appropriate in vitro conditions, are capable to differentiate into osteogenic, adipogenic, chondrogenic, myogenic, and neurogenic lineages. Their commitment and differentiation depend on several interacting signaling pathways and transcription factors. Most GNAS-based disorders have the common feature of episodic de novo formation of islands of extraskeletal, qualitatively normal, bone in skin and subcutaneous fat. The tissue distribution of these lesions suggests that pathogenesis involves abnormal differentiation of MSCs and/or more committed precursor cells that are present in subcutaneous tissues. Data coming from transgenic mice support the concept that GNAS is a key factor in the regulation of lineage switching between osteoblast and adipocyte fates, and that its role may be to prevent bone formation in tissues where bone should not form. Despite the growing knowledge about the process of heterotopic ossification in rare genetic disorders, the pathophysiological mechanisms by which alterations of cAMP signaling lead to ectopic bone formation in the context of mesenchymal tissues is not fully understood.
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Affiliation(s)
- F M Elli
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - V Boldrin
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Pirelli
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Spada
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - G Mantovani
- Department of Clinical Sciences and Community Health, Endocrinology and Diabetology Unit, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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Happle R. Progressive osseous heteroplasia is not a Mendelian trait but a type 2 segmental manifestation of GNAS inactivation disorders: A hypothesis. Eur J Med Genet 2016; 59:290-4. [PMID: 27058263 DOI: 10.1016/j.ejmg.2016.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 12/30/2022]
Abstract
Progressive osseous heteroplasia (POH) is a segmental disorder characterized by progressive heterotopic ossification that extends from dermal and subcutaneous tissues to deeper structures. So far, it has been taken as a rarely occurring bone disease with autosomal dominant inheritance. Here, arguments are presented in favor of the alternative concept that the disorder is merely a type 2 segmental manifestation of autosomal dominant GNAS inactivation disorders. Type 2 segmental mosaicism arises, in a heterozygous embryo, from a somatic mutational event that occurs at an early developmental stage, resulting in loss of the corresponding wild-type allele and giving rise to a homozygous or hemizygous cell clone. As a characteristic feature, such type 2 segmental involvement is far more pronounced than the type 1 segmental mosaicism as noted in otherwise healthy individuals. The concept of type 2 segmental mosaicism has been proven at the molecular level in six human traits including neurofibromatosis 1, Hailey-Hailey disease, and Gorlin syndrome. In POH, molecular proof of principle is so far lacking. The following lines of reasoning, however, support the hypothesis that POH can be explained by a similar mechanism. Firstly, POH has been found to be associated with different phenotypes caused by inactivating GNAS mutations, which is why it cannot be categorized as one distinct Mendelian trait. Secondly, POH occurs as a rather rare complication of these autosomal dominant traits, which is not compatible with the assumption of a separate Mendelian disorder. Thirdly, in a case of plate-like osteoma that represents a more superficial variant of POH, molecular proof of the concept of type 2 segmental manifestation has already been provided, and the available literature suggests that POH can be best explained by a similar mechanism. Moreover, findings obtained in animal experiments support the assumption that human POH represents such superimposed segmental manifestation of GNAS inactivation disorders.
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Affiliation(s)
- Rudolf Happle
- Department of Dermatology, Freiburg University Medical Center, Freiburg, Germany.
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8
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Lin MH, Numbenjapon N, Germain-Lee EL, Pitukcheewanont P. Progressive osseous heteroplasia, as an isolated entity or overlapping with Albright hereditary osteodystrophy. J Pediatr Endocrinol Metab 2015; 28:911-8. [PMID: 25894639 DOI: 10.1515/jpem-2014-0435] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/11/2015] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Progressive osseous heteroplasia (POH) is a condition of invasive heterotopic ossification. Reports of patients with mild POH with Albright hereditary osteodystrophy (AHO), specifically pseudohypoparathyroidism type Ia (PHP Ia) with hormonal resistance, suggest the possibility of a common molecular basis. GNAS has been implicated to account for overlapping features of POH and PHP Ia. Case 1: A 4-year-old boy with obesity, speech delay, and expanding subcutaneous masses on buttock/forearm. Physical exam revealed round facies and brachydactyly. Blood tests showed normal Ca, P, Mg, 25-OH vitamin D levels but elevated parathyroid hormone (PTH) and thyroid-stimulating hormone (TSH). Abdominal computed tomography (CT) showed areas with calcifications in the subcutaneous tissue, fat, and muscle. Pathology of excised tissue revealed ossifications. Genomic study revealed no GNAS mutation. He had POH and PHP Ia. Case 2: A 3-year-old boy with painful ossifications in the left lower extremity. Lab tests were notable for elevated PTH and high-normal TSH. The CT-scan showed subcutaneous/intramuscular calcifications. Genetic testing showed GNAS mutation in exon 12 [c.1024C>T (R342X)]. Patient had POH and PHP Ia. Case 3: A 9-year-old boy with knee pain and subcutaneous ossifications in back and upper/lower extremity, causing significantly limited joint mobility. Lab tests were normal. The CT-scan showed areas corresponding to subcutaneous/intramuscular ossifications throughout torso and extremities, consistent with POH. There was no GNAS mutation. CONCLUSIONS Patients with heterotopic ossifications present with a wide spectrum of disease. Although GNAS-based mutations have been postulated to account for overlapping features of AHO and POH, normal DNA studies in certain patients with POH/AHO suggest that there may exist other molecular/epigenetic mechanisms explaining their overlapping features.
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MESH Headings
- Bone Diseases, Metabolic/complications
- Bone Diseases, Metabolic/genetics
- Bone Diseases, Metabolic/pathology
- Child
- Child, Preschool
- Chromogranins
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Humans
- Male
- Mutation/genetics
- Ossification, Heterotopic/complications
- Ossification, Heterotopic/genetics
- Ossification, Heterotopic/pathology
- Prognosis
- Pseudohypoparathyroidism/complications
- Pseudohypoparathyroidism/genetics
- Pseudohypoparathyroidism/pathology
- Skin Diseases, Genetic/complications
- Skin Diseases, Genetic/genetics
- Skin Diseases, Genetic/pathology
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9
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Pignolo RJ, Ramaswamy G, Fong JT, Shore EM, Kaplan FS. Progressive osseous heteroplasia: diagnosis, treatment, and prognosis. APPLICATION OF CLINICAL GENETICS 2015; 8:37-48. [PMID: 25674011 PMCID: PMC4321643 DOI: 10.2147/tacg.s51064] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Progressive osseous heteroplasia (POH) is an ultrarare genetic condition of progressive ectopic ossification. Most cases of POH are caused by heterozygous inactivating mutations of GNAS, the gene encoding the alpha subunit of the G-stimulatory protein of adenylyl cyclase. POH is part of a spectrum of related genetic disorders, including Albright hereditary osteodystrophy, pseudohypoparathyroidism, and primary osteoma cutis, that share common features of superficial ossification and association with inactivating mutations of GNAS. The genetics, diagnostic criteria, supporting clinical features, current management, and prognosis of POH are reviewed here, and emerging therapeutic strategies are discussed.
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Affiliation(s)
- Robert J Pignolo
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; Department of Orthopaedic Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; The Center for Research in FOP and Related Disorders, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Girish Ramaswamy
- Department of Orthopaedic Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; The Center for Research in FOP and Related Disorders, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - John T Fong
- Department of Orthopaedic Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; The Center for Research in FOP and Related Disorders, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Eileen M Shore
- Department of Orthopaedic Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; The Center for Research in FOP and Related Disorders, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Frederick S Kaplan
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; Department of Orthopaedic Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA ; The Center for Research in FOP and Related Disorders, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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10
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Coutinho I, Teixeira V, Cardoso JC, Reis JP. Plate-like osteoma cutis: nothing but skin and bone? BMJ Case Rep 2014; 2014:bcr-2013-202901. [PMID: 24798356 DOI: 10.1136/bcr-2013-202901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Osteoma cutis encompasses a group of cutaneous ossifying disorders, more commonly secondary to trauma, inflammation or neoplasms. Fourteen per cent, however, are primary, and these may be syndromatic (associated to Albright's hereditary osteodystrophy) or occur in isolation. We report a case of a 10-year-old girl who presented with a stone-hard plate on the scalp, with no relevant personal or family history, nor changes in calcium-phosphate metabolism, parathyroid hormone or thyroid function. Skin biopsy confirmed osteoma cutis. Plate-like osteoma cutis is rare, and believed to be a non-progressive form of heterotopic ossification, included in the spectrum of progressive osseus heteroplasia and Albright hereditary osteodystrophy, due to GNAS gene mutations. This recently clarified association should remind us of the possible unfavourable evolution of a seemingly innocent clinical picture, emphasising the need for appropriate evaluation, management and follow-up.
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Affiliation(s)
- Inês Coutinho
- Department of Dermatology, Coimbra University Hospital, Coimbra, Portugal
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11
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Elli FM, Barbieri AM, Bordogna P, Ferrari P, Bufo R, Ferrante E, Giardino E, Beck-Peccoz P, Spada A, Mantovani G. Screening for GNAS genetic and epigenetic alterations in progressive osseous heteroplasia: first Italian series. Bone 2013; 56:276-80. [PMID: 23796510 DOI: 10.1016/j.bone.2013.06.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 01/16/2023]
Abstract
Progressive osseous heteroplasia (POH) is a rare autosomal dominant disorder of mesenchymal differentiation characterized by progressive heterotopic ossification (HO) of dermis, deep connective tissues and skeletal muscle. Usually, initial bone formation occurs during infancy as primary osteoma cutis (OC) then progressively extending into deep connective tissues and skeletal muscle over childhood. Most cases of POH are caused by paternally inherited inactivating mutations of GNAS gene. Maternally inherited mutations as well as epigenetic defects of the same gene lead to pseudohypoparathyroidism (PHP) and Albright's hereditary osteodystrophy (AHO). During the last decade, some reports documented the existence of patients with POH showing additional features characteristic of AHO such as short stature and brachydactyly, previously thought to occur only in other GNAS-associated disorders. Thus, POH can now be considered as part of a wide spectrum of ectopic bone formation disorders caused by inactivating GNAS mutations. Here, we report genetic and epigenetic analyses of GNAS locus in 10 patients affected with POH or primary OC, further expanding the spectrum of mutations associated with this rare disease and indicating that, unlike PHP, methylation alterations at the same locus are absent or uncommon in this disorder.
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Affiliation(s)
- F M Elli
- Department of Clinical Sciences and Community Health, University of Milan, Endocrinology and Diabetology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20122 Milano, Italy
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12
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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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13
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Huso DL, Edie S, Levine MA, Schwindinger W, Wang Y, Jüppner H, Germain-Lee EL. Heterotopic ossifications in a mouse model of albright hereditary osteodystrophy. PLoS One 2011; 6:e21755. [PMID: 21747923 PMCID: PMC3126840 DOI: 10.1371/journal.pone.0021755] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 06/06/2011] [Indexed: 11/22/2022] Open
Abstract
Albright hereditary osteodystrophy (AHO) is characterized by short stature, brachydactyly, and often heterotopic ossifications that are typically subcutaneous. Subcutaneous ossifications (SCO) cause considerable morbidity in AHO with no effective treatment. AHO is caused by heterozygous inactivating mutations in those GNAS exons encoding the α-subunit of the stimulatory G protein (Gα(s)). When inherited maternally, these mutations are associated with obesity, cognitive impairment, and resistance to certain hormones that mediate their actions through G protein-coupled receptors, a condition termed pseudohypoparathyroidism type 1a (PHP1a). When inherited paternally, GNAS mutations cause only AHO but not hormonal resistance, termed pseudopseudohypoparathyroidism (PPHP). Mice with targeted disruption of exon 1 of Gnas (Gnas(E1-/+)) replicate human PHP1a or PPHP phenotypically and hormonally. However, SCO have not yet been reported in Gnas(E1+/-) mice, at least not those that had been analyzed by us up to 3 months of age. Here we now show that Gnas(E1-/+) animals develop SCO over time. The ossified lesions increase in number and size and are uniformly detected in adult mice by one year of age. They are located in both the dermis, often in perifollicular areas, and the subcutis. These lesions are particularly prominent in skin prone to injury or pressure. The SCO comprise mature bone with evidence of mineral deposition and bone marrow elements. Superficial localization was confirmed by radiographic and computerized tomographic imaging. In situ hybridization of SCO lesions were positive for both osteonectin and osteopontin. Notably, the ossifications were much more extensive in males than females. Because Gnas(E1-/+) mice develop SCO features that are similar to those observed in AHO patients, these animals provide a model system suitable for investigating pathogenic mechanisms involved in SCO formation and for developing novel therapeutics for heterotopic bone formation. Moreover, these mice provide a model with which to investigate the regulatory mechanisms of bone formation.
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Affiliation(s)
- David L. Huso
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sarah Edie
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michael A. Levine
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - William Schwindinger
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, United States of America
| | - Yingli Wang
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Harald Jüppner
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Pediatric Nephrology Unit, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Emily L. Germain-Lee
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Albright Clinic, Kennedy Krieger Institute, Baltimore, Maryland, United States of America
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States of America
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Myllylä RM, Haapasaari KM, Palatsi R, Germain-Lee EL, Hägg PM, Ignatius J, Tuukkanen J. Multiple miliary osteoma cutis is a distinct disease entity: four case reports and review of the literature. Br J Dermatol 2011; 164:544-52. [PMID: 21062265 DOI: 10.1111/j.1365-2133.2010.10121.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Multiple miliary osteoma cutis (MMOC) is a rare nodular skin disease characterized by tiny bone nodules which usually form on the facial skin, typically in middle age. The aetiology of this phenomenon is poorly understood. OBJECTIVES To search for possible bone formation progenitors and to look for a possible association with mutations in the GNAS gene (encoding the G-protein α-stimulatory subunit) and related hormonal parameters in patients with MMOC. We also reviewed the literature and discuss the aetiology and pathogenesis of adult-onset primary osteomas. METHODS We report four cases of MMOC. Histological samples were analysed for bone morphogenetic protein (BMP)-2, BMP-4 and oestrogen receptor-α known to be involved in bone formation. Endocrinological laboratory investigations and hand X-rays were performed to exclude a systemic disease. The GNAS gene was sequenced from DNA extracted from peripheral blood in all four patients and from a skin sample in one patient to exclude somatic mutations. RESULTS Histological analyses revealed intramembranous cutaneous bone formation resembling the findings seen in GNAS gene-based osteoma cutis disorders. However, we did not find any germline or somatic GNAS gene mutations in our patients and all laboratory investigations gave normal results. BMP-2 and -4 were expressed normally in MMOC samples, but oestrogen receptor-α was not expressed. Altogether 47 MMOC cases, 41 female and six male, have been published between 1928 and 2009. Of these cases, 55% had a history of pre-existing acne and only 15% had extrafacial osteomas. CONCLUSIONS MMOC is a rare but distinct disease entity of unknown aetiology. Histologically, the tiny nodular osteomas show intramembranous superficial ossification but the aetiology appears to be different from GNAS-related disorders. The osteomas seem to increase slowly in number after appearing in middle age.
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Affiliation(s)
- R M Myllylä
- Department of Anatomy and Cell Biology, University of Oulu, Finland.
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15
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Talsania N, Jolliffe V, O'Toole EA, Cerio R. Platelike osteoma cutis. J Am Acad Dermatol 2011; 64:613-5. [PMID: 21315967 DOI: 10.1016/j.jaad.2009.07.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 07/09/2009] [Accepted: 07/30/2009] [Indexed: 12/01/2022]
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16
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Shore EM, Kaplan FS. Inherited human diseases of heterotopic bone formation. Nat Rev Rheumatol 2010; 6:518-27. [PMID: 20703219 DOI: 10.1038/nrrheum.2010.122] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human disorders of hereditary and nonhereditary heterotopic ossification are conditions in which osteogenesis occurs outside of the skeleton, within soft tissues of the body. The resulting extraskeletal bone is normal. The aberration lies within the mechanisms that regulate cell-fate determination, directing the inappropriate formation of cartilage or bone, or both, in tissues such as skeletal muscle and adipose tissue. Specific gene mutations have been identified in two rare inherited disorders that are clinically characterized by extensive and progressive extraskeletal bone formation-fibrodysplasia ossificans progressiva and progressive osseous heteroplasia. In fibrodysplasia ossificans progressiva, activating mutations in activin receptor type-1, a bone morphogenetic protein type I receptor, induce heterotopic endochondral ossification, which results in the development of a functional bone organ system that includes skeletal-like bone and bone marrow. In progressive osseous heteroplasia, the heterotopic ossification leads to the formation of mainly intramembranous bone tissue in response to inactivating mutations in the GNAS gene. Patients with these diseases variably show malformation of normal skeletal elements, identifying the causative genes and their associated signaling pathways as key mediators of skeletal development in addition to regulating cell-fate decisions by adult stem cells.
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Affiliation(s)
- Eileen M Shore
- Department of Orthopedic Surgery, University of Pennsylvania School of Medicine, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081, USA.
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17
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Abstract
Plate-like osteoma cutis is widely thought to be present at birth, but it has never been illustrated in early infancy until now. We report on an infant that presented with congenital plate-like osteoma cutis, showing the earliest clinical aspect of the lesion and its initial morphologic changes.
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18
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Haro R, Revelles JM, Angulo J, Fariña MDC, Martín L, Requena L. Plaque-like osteoma cutis with transepidermal elimination. J Cutan Pathol 2009; 36:591-3. [PMID: 19476531 DOI: 10.1111/j.1600-0560.2008.01081.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Osteoma cutis is a rare lesion that consists of the presence of bone tissue within the dermis and/or hypodermis. It may be classified as primary osteoma cutis, when bone tissue develops in the skin without any pre-existing lesion and secondary osteoma cutis, which is more frequent and occurs when osseous tissue develops on a pre-existing lesion. We present a case of primary plaque-like osteoma cutis involving the scalp, left forehead and left cheek, which appeared in an adult male. Histopathological study showed several islands of mature osseous tissue involving the full thickness of the dermis. In some areas, there was also transepidermal elimination of bone spicules. We review the literature about previously reported similar cases.
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Affiliation(s)
- Rosario Haro
- Department of Dermatology, Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain
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19
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20
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Adegbite NS, Xu M, Kaplan FS, Shore EM, Pignolo RJ. Diagnostic and mutational spectrum of progressive osseous heteroplasia (POH) and other forms of GNAS-based heterotopic ossification. Am J Med Genet A 2008; 146A:1788-96. [PMID: 18553568 DOI: 10.1002/ajmg.a.32346] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Progressive osseous heteroplasia (POH) is a rare, disabling disease of heterotopic ossification (HO) that progresses from skin and subcutaneous tissues into deep skeletal muscle. POH occurs in the absence of multiple developmental features of Albright hereditary osteodystrophy (AHO) or hormone resistance, clinical manifestations that are also associated with GNAS inactivation. However, occasional patients with AHO and pseudohypoparathyroidism 1a/c (PHP1a/c; AHO features plus hormone resistance) have also been described who have progressive HO. This study was undertaken to define the diagnostic and mutational spectrum of POH and progressive disorders of HO, and to distinguish them from related disorders in which HO remains confined to the skin and subcutaneous tissues. We reviewed the charts of 111 individuals who had cutaneous and subcutaneous ossification. All patients were assessed for eight characteristics: age of onset of HO, presence and location of HO, depth of HO, type of HO, progression of HO, features of AHO, PTH resistance, and GNAS mutation analysis. We found, based on clinical criteria, that POH and progressive HO syndromes are at the severe end of a phenotypic spectrum of GNAS-inactivating conditions associated with extra-skeletal ossification. While most individuals with superficial or progressive ossification had mutations in GNAS, there were no specific genotype-phenotype correlations that distinguished the more progressive forms of HO (e.g., POH) from the non-progressive forms (osteoma cutis, AHO, and PHP1a/c).
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Affiliation(s)
- N S Adegbite
- Department of Orthopaedic Surgery, University of Pennsylvania, School of Medicine, Philadelphia, Pennsylvania 19104, USA
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21
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Kumagai K, Motomura K, Egashira M, Tomita M, Suzuki M, Uetani M, Shindo H. A case of progressive osseous heteroplasia: a first case in Japan. Skeletal Radiol 2008; 37:563-7. [PMID: 18309480 DOI: 10.1007/s00256-008-0469-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 12/06/2007] [Accepted: 01/21/2008] [Indexed: 02/02/2023]
Abstract
Progressive osseous heteroplasia (POH) is a rare, hereditary, disorder (number 166350 in Mendelian Inheritance in Man), which was first identified in 1994 and is characterized by dermal ossification beginning in infancy as a result of increasing and extensive bone formation in deep muscle and fascia. We describe a boy with typical clinical, radiographic, and genetic features of POH. A nonsense mutation in exon 7 of the GNAS1 gene was identified in genomic DNA from the patient. No such case has been reported in East Asia or Japan before this patient.
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Affiliation(s)
- Kenji Kumagai
- Department of Orthopedic Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki City, Japan.
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22
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Weinstein LS, Xie T, Zhang QH, Chen M. Studies of the regulation and function of the Gs alpha gene Gnas using gene targeting technology. Pharmacol Ther 2007; 115:271-91. [PMID: 17588669 PMCID: PMC2031856 DOI: 10.1016/j.pharmthera.2007.03.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 03/27/2007] [Indexed: 01/14/2023]
Abstract
The heterotrimeric G protein alpha-subunit G(s)alpha is ubiquitously expressed and mediates receptor-stimulated intracellular cAMP generation. Its gene Gnas is a complex imprinted gene which uses alternative promoters and first exons to generate other gene products, including the G(s)alpha isoform XL alpha s and the chromogranin-like protein NESP55, which are specifically expressed from the paternal and maternal alleles, respectively. G(s)alpha itself is imprinted in a tissue-specific manner, being biallelically expressed in most tissues but paternally silenced in a few tissues. Gene targeting of specific Gnas transcripts demonstrates that heterozygous mutation of G(s)alpha on the maternal (but not the paternal) allele leads to early lethality, perinatal subcutaneous edema, severe obesity, and multihormone resistance, while the paternal mutation leads to only mild obesity and insulin resistance. These parent-of-origin differences are the consequence of tissue-specific G(s)alpha imprinting. XL alpha s deficiency leads to a perinatal suckling defect and a lean phenotype with increased insulin sensitivity. The opposite metabolic effects of G(s)alpha and XL alpha s deficiency are associated with decreased and increased sympathetic nervous system activity, respectively. NESP55 deficiency has no metabolic consequences. Other gene targeting experiments have shown Gnas to have 2 independent imprinting domains controlled by 2 different imprinting control regions. Tissue-specific G(s)alpha knockout models have identified important roles for G(s)alpha signaling pathways in skeletal development, renal function, and glucose and lipid metabolism. Our present knowledge gleaned from various Gnas gene targeting models are discussed in relation to the pathogenesis of human disorders with mutation or abnormal imprinting of the human orthologue GNAS.
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Affiliation(s)
- Lee S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20854, USA.
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23
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Abstract
The emerging field of regenerative medicine will require a reliable source of stem cells in addition to biomaterial scaffolds and cytokine growth factors. Adipose tissue represents an abundant and accessible source of adult stem cells with the ability to differentiate along multiple lineage pathways. The isolation, characterization, and preclinical and clinical application of adipose-derived stem cells (ASCs) are reviewed in this article.
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Affiliation(s)
- Jeffrey M Gimble
- Stem Cell Biology Laboratory and Clinical Nutrition Research Unit, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
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24
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Heike CL, Cunningham ML, Steiner RD, Wenkert D, Hornung RL, Gruss JS, Gannon FH, McAlister WH, Mumm S, Whyte MP. Skeletal changes in epidermal nevus syndrome: does focal bone disease harbor clues concerning pathogenesis? Am J Med Genet A 2006; 139A:67-77. [PMID: 16222671 DOI: 10.1002/ajmg.a.30915] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epidermal nevus syndrome (ENS) is a rare, sporadic, congenital disorder of unknown etiology featuring a complex and highly variable phenotype that can include focal or generalized skeletal disease. We describe a young man with ENS manifesting right-sided linear skin lesions, generalized weakness, diffuse osteopenia associated with hypophosphatemic rickets, and distinctive focal bone lesions ipsilateral to the skin findings. Review of the literature concerning ENS-associated skeletal disease suggested such focal bone defects are fibrous dysplasia, but our patient did not have the typical radiographic or histopathologic findings of fibrous dysplasia. Nevertheless, his circulating fibroblast growth factor 23 (FGF-23) level was elevated, likely functioning as a "phosphatonin," yet no activating mutations in GNAS previously reported in fibrous dysplasia or McCune-Albright syndrome were detected in his leukocytes or affected skin. We postulate that the focal skeletal disease, although different than fibrous dysplasia, may be a source of FGF-23 in ENS.
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Affiliation(s)
- Carrie L Heike
- Department of Pediatrics, Children's Craniofacial Center, University of Washington and Children's Hospital and Regional Medical Center, Seattle, Washington 98105-5371, USA.
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25
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Abstract
Bone and cartilage and their disorders are addressed under the following headings: functions of bone; normal and abnormal bone remodeling; osteopetrosis and osteoporosis; epithelial-mesenchymal interaction, condensation and differentiation; osteoblasts, markers of bone formation, osteoclasts, components of bone, and pathology of bone; chondroblasts, markers of cartilage formation, secondary cartilage, components of cartilage, and pathology of cartilage; intramembranous and endochondral bone formation; RUNX genes and cleidocranial dysplasia (CCD); osterix; histone deacetylase 4 and Runx2; Ligand to receptor activator of NFkappaB (RANKL), RANK, osteoprotegerin, and osteoimmunology; WNT signaling, LRP5 mutations, and beta-catenin; the role of leptin in bone remodeling; collagens, collagenopathies, and osteogenesis imperfecta; FGFs/FGFRs, FGFR3 skeletal dysplasias, craniosynostosis, and other disorders; short limb chondrodysplasias; molecular control of the growth plate in endochondral bone formation and genetic disorders of IHH and PTHR1; ANKH, craniometaphyseal dysplasia, and chondrocalcinosis; transforming growth factor beta, Camurati-Engelmann disease (CED), and Marfan syndrome, types I and II; an ACVR1 mutation and fibrodysplasia ossificans progressiva; MSX1 and MSX2: biology, mutations, and associated disorders; G protein, activation of adenylyl cyclase, GNAS1 mutations, McCune-Albright syndrome, fibrous dysplasia, and Albright hereditary osteodystrophy; FLNA and associated disorders; and morphological development of teeth and their genetic mutations.
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Affiliation(s)
- M Michael Cohen
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada.
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26
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Lietman SA, Ding C, Cooke DW, Levine MA. Reduction in Gsalpha induces osteogenic differentiation in human mesenchymal stem cells. Clin Orthop Relat Res 2005:231-8. [PMID: 15864058 DOI: 10.1097/01.blo.0000153279.90512.38] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We hypothesized that a decrease in Gsalpha expression occurs with osteogenic differentiation and that when Gsalpha expression was decreased by antisense oligonucleotides or direct inhibition of protein kinase A there was a concomitant increase in Runx2/Cbfa1. We also investigated the mechanism involved in the change in Runx2/Cbfa1 levels and whether the expression of other genes known to be involved in bone formation was altered. There was a decrease in Gsalpha expression with osteogenic differentiation and antisense oligonucleotides, and protein kinase A inhibition led to increased expression and DNA binding of the osteoblast-specific Runx2/Cbfa1. Additionally, with decreased Gsalpha expression or protein kinase A inhibition, Runx2/Cbfa1 protein was serine phosphorylated and ubiquitinated less. Microarray analysis, after the addition of antisense Gsalpha, showed a more than 10-fold increase in collagen Type I Alpha 2 mRNA (a target of Runx2/Cbfa1). These data show that reduced expression of Gsalpha can induce an osteoblast-like phenotype. The results also indicate a potential pathophysiologic role in patients with heterozygous inactivating mutations in GNAS1, the gene for the alpha chain (Gsalpha) of the heterotrimeric G protein, present in three disorders with ectopic intramembranous bone: Albright's hereditary osteodystrophy, progressive osseous heteroplasia, and osteoma cutis.
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Affiliation(s)
- Steven A Lietman
- Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH, USA.
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27
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Gennero I, Moulin P, Edouard T, Conte-Auriol F, Tauber MT, Salles JP. Métabolisme minéral osseux: données récentes et perspectives relatives à l’ostéogenèse. Arch Pediatr 2004; 11:1473-83. [PMID: 15596338 DOI: 10.1016/j.arcped.2004.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 08/30/2004] [Indexed: 10/26/2022]
Abstract
Important data have recently been added to our knowledge of bone mineral metabolism in children. Molecular pathophysiology of several pediatric syndromes has been clarified. Specially, the components of endocrine and metabolic regulations are tightly related with regard to the trophicity of bone. On another hand, the impact of several therapeutics of bone diseases like biphosphonates, parathormone (PTH) or growth hormone on bone anabolism is now strongly emphasized. All these points are important for the becoming of bone pediatric diseases in the adult life. Here we analyze the essential components of mineral metabolism and of its regulation in view of the recent biological data, like PTH/PTHrP (PTH-related peptide)-evoked cell signaling, the role of FGF 23 (Fibroblast growth factor 23) in hypophosphatemia and the regulation of vitamin D metabolism by 1alpha-hydroxylase. Inter-relation of these regulating elements is present in several genetic diseases and in the Mc Cune Albright syndrome. Relationships between metabolic and endocrine factors are analyzed considering their impact on PTH secretion and osteogenesis.
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Affiliation(s)
- I Gennero
- Laboratoire de biochimie, hôpital La Grave, TSA 60033, 31059 Toulouse 9, France
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28
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Abstract
GNAS is a complex imprinted gene that uses multiple promoters to generate several gene products, including the G protein alpha-subunit (G(s)alpha) that couples seven-transmembrane receptors to the cAMP-generating enzyme adenylyl cyclase. Somatic activating G(s)alpha mutations, which alter key residues required for the GTPase turn-off reaction, are present in various endocrine tumors and fibrous dysplasia of bone, and in a more widespread distribution in patients with McCune- Albright syndrome. Heterozygous inactivating G(s)alpha mutations lead to Albright hereditary osteodystrophy. G(s)alpha is imprinted in a tissue-specific manner, being primarily expressed from the maternal allele in renal proximal tubules, thyroid, pituitary, and ovary. Maternally inherited mutations lead to Albright hereditary osteodystrophy (AHO) plus PTH, TSH, and gonadotropin resistance (pseudohypoparathyroidism type 1A), whereas paternally inherited mutations lead to AHO alone. Pseudohypoparathyroidism type 1B, in which patients develop PTH resistance without AHO, is almost always associated with a GNAS imprinting defect in which both alleles have a paternal-specific imprinting pattern on both parental alleles. Familial forms of the disease are associated with a mutation within a closely linked gene that deletes a region that is presumably required for establishing the maternal imprint, and therefore maternal inheritance of the mutation results in the GNAS imprinting defect. Imprinting of one differentially methylated region within GNAS is virtually always lost in pseudohypoparathyroidism type 1B, and this region is probably responsible for tissue-specific G(s)alpha imprinting. Mouse knockout models show that G(s)alpha and the alternative G(s)alpha isoform XLalphas that is expressed from the paternal GNAS allele may have opposite effects on energy metabolism in mice.
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Affiliation(s)
- Lee S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Abstract
Heterotopic ossification, the formation of bone in soft tissue, requires inductive signaling pathways, inducible osteoprogenitor cells, and a heterotopic environment conducive to osteogenesis. Little is known about the molecular pathogenesis of this condition. Research into two rare heritable and developmental forms, fibrodysplasia ossificans progressiva and progressive osseous heteroplasia, has provided clinical, pathologic, and genetic insights. In fibrodysplasia ossificans progressiva, overexpression of bone morphogenetic protein 4 and underexpression of multiple antagonists of this protein highlight the potential role of a potent morphogenetic gradient. Research on fibrodysplasia ossificans progressiva also has led to the identification of the genetic cause of progressive osseous heteroplasia: inactivating mutations in the alpha subunit of the gene coding for the stimulatory G protein of adenylyl cyclase. Better understanding of the complex developmental and molecular pathology of these disorders may lead to more effective strategies to prevent and treat other, more common forms of heterotopic ossification.
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Affiliation(s)
- Frederick S Kaplan
- Departments of Orthopaedic Surgery and Medicine, The University of Pennsylvania School of Medicine, Silverstein 2, 3400 Spruce Street, Philadelphia, PA 19104-5283, USA
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Faust RA, Shore EM, Stevens CE, Xu M, Shah S, Phillips CD, Kaplan FS. Progressive osseous heteroplasia in the face of a child. Am J Med Genet A 2003; 118A:71-5. [PMID: 12605446 DOI: 10.1002/ajmg.a.10170] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We describe a rare case of progressive osseous heteroplasia of the face in a child. Biopsy showed osteoma cutis superficially with ectopic bone formation in the deeper tissues including skeletal muscle. Analysis of DNA from peripheral blood leukocytes showed mutations in the gene encoding the alpha subunit of the stimulatory G protein of adenylyl cyclase (GNAS1), confirming the diagnosis of progressive osseous heteroplasia.
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Affiliation(s)
- Russell A Faust
- Department of Otolaryngology and Pediatrics, Children's Hospital of Michigan, Detroit, 48201, USA.
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Davis MDP, Pittelkow MR, Lindor NM, Lundstrom CE, Fitzpatrick LA. Progressive extensive osteoma cutis associated with dysmorphic features: a new syndrome? Case report and review of the literature. Br J Dermatol 2002; 146:1075-80. [PMID: 12072082 DOI: 10.1046/j.1365-2133.2002.04674.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Osteoma cutis, also called cutaneous ossification, refers to the rare occurrence of bone in the skin. It may be primary, occurring in normal skin, or secondary, occurring in disrupted skin tissue. A 42-year-old white woman presented with long-standing progressive primary osteoma cutis involving her head and neck, trunk and extremities. She had craniofacial dysmorphism with mid-face hypoplasia, including saddle nose deformity, mild to moderate generalized joint hypermobility, extensive paravertebral ossification, and disc space calcification. The differential diagnosis for this entity is presented. This phenotype may be a previously undescribed syndrome.
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Affiliation(s)
- M D P Davis
- Department of Dermatology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Abstract
Gs is the ubiquitously expressed heterotrimeric G protein that couples receptors to the effector enzyme adenylyl cyclase and is required for receptor-stimulated intracellular cAMP generation. Activated receptors promote the exchange of GTP for GDP on the Gs alpha-subunit (Gs(alpha)), resulting in Gs activation; an intrinsic GTPase activity of Gs(alpha) deactivates Gs by hydrolyzing bound GTP to GDP. Mutations of Gs(alpha) residues involved in the GTPase reaction that lead to constitutive activation are present in endocrine tumors, fibrous dysplasia of bone, and McCune-Albright syndrome. Heterozygous loss-of-function mutations lead to Albright hereditary osteodystrophy (AHO), a disease characterized by short stature, obesity, and skeletal defects, and are sometimes associated with progressive osseous heteroplasia. Maternal transmission of Gs(alpha) mutations leads to AHO plus resistance to several hormones (e.g., parathyroid hormone) that activate Gs in their target tissues (pseudohypoparathyroidism type IA), while paternal transmission leads only to the AHO phenotype (pseudopseudohypoparathyroidism). Studies in both mice and humans demonstrate that Gs(alpha) is imprinted in a tissue-specific manner, being expressed primarily from the maternal allele in some tissues and biallelically expressed in most other tissues. This likely explains why multihormone resistance occurs only when Gs(alpha) mutations are inherited maternally. The Gs(alpha) gene GNAS1 has at least four alternative promoters and first exons, leading to the production of alternative gene products including Gs(alpha), XL alphas (a novel Gs(alpha) isoform expressed only from the paternal allele), and NESP55 (a chromogranin-like protein expressed only from the maternal allele). The fourth alternative promoter and first exon (exon 1A) located just upstream of the Gs(alpha) promoter is normally methylated on the maternal allele and is transcriptionally active on the paternal allele. In patients with parathyroid hormone resistance but without AHO (pseudohypoparathyroidism type IB), the exon 1A promoter region is unmethylated and transcriptionally active on both alleles. This GNAS1 imprinting defect is predicted to decrease Gs(alpha) expression in tissues where Gs(alpha) is normally imprinted and therefore to lead to renal parathyroid hormone resistance.
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Affiliation(s)
- Lee S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Shore EM, Ahn J, Jan de Beur S, Li M, Xu M, Gardner RJM, Zasloff MA, Whyte MP, Levine MA, Kaplan FS. Paternally inherited inactivating mutations of the GNAS1 gene in progressive osseous heteroplasia. N Engl J Med 2002; 346:99-106. [PMID: 11784876 DOI: 10.1056/nejmoa011262] [Citation(s) in RCA: 237] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Progressive osseous heteroplasia (POH), an autosomal dominant disorder, is characterized by extensive dermal ossification during childhood, followed by disabling and widespread heterotopic ossification of skeletal muscle and deep connective tissue. Occasional reports of mild heterotopic ossification in Albright's hereditary osteodystrophy (AHO) and a recent report of two patients with AHO who had atypically extensive heterotopic ossification suggested a common genetic basis for the two disorders. AHO is caused by heterozygous inactivating mutations in the GNAS1 gene that result in decreased expression or function of the alpha subunit of the stimulatory G protein (Gsalpha) of adenylyl cyclase. METHODS We tested the hypothesis that GNAS1 mutations cause POH, using the polymerase chain reaction to amplify GNAS1 exons and exon-intron boundaries in 18 patients with sporadic or familial POH. RESULTS Heterozygous inactivating GNAS1 mutations were identified in 13 of the 18 probands with POH. The defective allele in POH is inherited exclusively from fathers, a result consistent with a model of imprinting for GNAS1. Direct evidence that the same mutation can cause either POH or AHO was observed within a single family, in which the phenotype correlated with the parental origin of the mutant allele. CONCLUSIONS Paternally inherited inactivating GNAS1 mutations cause POH. This finding extends the range of phenotypes derived from haplo insufficiency of GNAS1, provides evidence that imprinting is a regulatory mechanism for GNAS1 expression, and suggests that Gsalpha is a critical negative regulator of osteogenic commitment in nonosseous connective tissues.
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Affiliation(s)
- Eileen M Shore
- Department of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia 19104-6018, USA.
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Ing EB, Heathcote JG. Congenital isolated osteoma cutis of the lateral canthus. CANADIAN JOURNAL OF OPHTHALMOLOGY 2001; 36:408-10. [PMID: 11794391 DOI: 10.1016/s0008-4182(01)80086-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Weinstein LS, Yu S, Warner DR, Liu J. Endocrine manifestations of stimulatory G protein alpha-subunit mutations and the role of genomic imprinting. Endocr Rev 2001; 22:675-705. [PMID: 11588148 DOI: 10.1210/edrv.22.5.0439] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The heterotrimeric G protein G(s) couples hormone receptors (as well as other receptors) to the effector enzyme adenylyl cyclase and is therefore required for hormone-stimulated intracellular cAMP generation. Receptors activate G(s) by promoting exchange of GTP for GDP on the G(s) alpha-subunit (G(s)alpha) while an intrinsic GTPase activity of G(s)alpha that hydrolyzes bound GTP to GDP leads to deactivation. Mutations of specific G(s)alpha residues (Arg(201) or Gln(227)) that are critical for the GTPase reaction lead to constitutive activation of G(s)-coupled signaling pathways, and such somatic mutations are found in endocrine tumors, fibrous dysplasia of bone, and the McCune-Albright syndrome. Conversely, heterozygous loss-of-function mutations may lead to Albright hereditary osteodystrophy (AHO), a disease characterized by short stature, obesity, brachydactyly, sc ossifications, and mental deficits. Similar mutations are also associated with progressive osseous heteroplasia. Interestingly, paternal transmission of GNAS1 mutations leads to the AHO phenotype alone (pseudopseudohypoparathyroidism), while maternal transmission leads to AHO plus resistance to several hormones (e.g., PTH, TSH) that activate G(s) in their target tissues (pseudohypoparathyroidism type IA). Studies in G(s)alpha knockout mice demonstrate that G(s)alpha is imprinted in a tissue-specific manner, being expressed primarily from the maternal allele in some tissues (e.g., renal proximal tubule, the major site of renal PTH action), while being biallelically expressed in most other tissues. Disrupting mutations in the maternal allele lead to loss of G(s)alpha expression in proximal tubules and therefore loss of PTH action in the kidney, while mutations in the paternal allele have little effect on G(s)alpha expression or PTH action. G(s)alpha has recently been shown to be also imprinted in human pituitary glands. The G(s)alpha gene GNAS1 (as well as its murine ortholog Gnas) has at least four alternative promoters and first exons, leading to the production of alternative gene products including G(s)alpha, XLalphas (a novel G(s)alpha isoform that is expressed only from the paternal allele), and NESP55 (a chromogranin-like protein that is expressed only from the maternal allele). A fourth alternative promoter and first exon (exon 1A) located approximately 2.5 kb upstream of the G(s)alpha promoter is normally methylated on the maternal allele and transcriptionally active on the paternal allele. In patients with isolated renal resistance to PTH (pseudohypoparathyroidism type IB), the exon 1A promoter region has a paternal-specific imprinting pattern on both alleles (unmethylated, transcriptionally active), suggesting that this region is critical for the tissue-specific imprinting of G(s)alpha. The GNAS1 imprinting defect in pseudohypoparathyroidism type IB is predicted to decrease G(s)alpha expression in renal proximal tubules. Studies in G(s)alpha knockout mice also demonstrate that this gene is critical in the regulation of lipid and glucose metabolism.
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Affiliation(s)
- L S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Abstract
Progressive osseous heteroplasia (POH) is a recently described genetic disorder of mesenchymal differentiation characterized by dermal ossification during infancy and progressive heterotopic ossification of cutaneous, subcutaneous, and deep connective tissues during childhood. The disorder can be distinguished from fibrodysplasia ossificans progressiva (FOP) by the presence of cutaneous ossification, the absence of congenital malformations of the skeleton, the absence of inflammatory tumorlike swellings, the asymmetric mosaic distribution of lesions, the absence of predictable regional patterns of heterotopic ossification, and the predominance of intramembranous rather than endochondral ossification. POH can be distinguished from Albright hereditary osteodystrophy (AHO) by the progression of heterotopic ossification from skin and subcutaneous tissue into skeletal muscle, the presence of normal endocrine function, and the absence of a distinctive habitus associated with AHO. Although the genetic basis of POH is unknown, inactivating mutations of the GNAS1 gene are associated with AHO. The report in this issue of the JBMR of 2 patients with combined features of POH and AHO--one with classic AHO, severe POH-like features, and reduced levels of Gsalpha protein and one with mild AHO, severe POH-like features, reduced levels of Gsalpha protein, and a mutation in GNAS1--suggests that classic POH also could be caused by GNAS1 mutations. This possibility is further supported by the identification of a patient with atypical but severe platelike osteoma cutis (POC) and a mutation in GNAS1, indicating that inactivating mutations in GNAS1 may lead to severe progressive heterotopic ossification of skeletal muscle and deep connective tissue independently of AHO characteristics. These observations suggest that POH may lie at one end of a clinical spectrum of ossification disorders mediated by abnormalities in GNAS1 expression and impaired activation of adenylyl cyclase. Analysis of patients with classic POH (with no AHO features) is necessary to determine whether the molecular basis of POH is caused by inactivating mutations in the GNAS1 gene.
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Affiliation(s)
- F S Kaplan
- Department of Orthopaedic Surgery, The University of Pennsylvania School of Medicine, Philadelphia, USA
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