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Endo K, Shimizu T, Muto Y, Kimishima Y, Abe S, Oikawa M, Kobayashi A, Yamaki T, Nakazato K, Ishida T, Takeishi Y. Acute coronary syndrome with severe coronary calcification in a patient with pseudo-pseudohypoparathyroidism. J Cardiol Cases 2023; 28:172-175. [PMID: 37818432 PMCID: PMC10562121 DOI: 10.1016/j.jccase.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 10/12/2023] Open
Abstract
A 40-year-old female with a history of steroid therapy for juvenile rheumatoid arthritis was brought to our hospital because of chest pain. A diagnosis of non-ST elevation myocardial infarction was made, and emergency coronary angiography revealed stenotic lesions with severe calcification in the left anterior descending artery and the right coronary artery. Percutaneous coronary intervention with rotational atherectomy followed by a drug-coated balloon was performed to the lesion in the left anterior descending artery. The patient had characteristic physical findings including short stature, a round face, and 'knuckle-dimple sign'. Whole-body computed tomography showed many ectopic calcifications, indicating Albright's hereditary osteodystrophy. Ellsworth-Howard test revealed that urinary cyclic adenosine monophosphate response was positive, thus a diagnosis of pseudo-pseudohypoparathyroidism (PPHP) was made. Here, we describe a rare case of PPHP complicated by acute coronary syndrome with severely calcified coronary arteries. Learning objective Pseudo-pseudohypoparathyroidism (PPHP) presents with several characteristic physical findings and ectopic calcifications. Since PPHP involves coronary artery calcification as in the present case, it may be considered as a cause of coronary artery disease.
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Affiliation(s)
- Keiichiro Endo
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Takeshi Shimizu
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yuki Muto
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yusuke Kimishima
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Satoshi Abe
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Masayoshi Oikawa
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Atsushi Kobayashi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Takayoshi Yamaki
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Kazuhiko Nakazato
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Takafumi Ishida
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
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Piedra M, Berja A, Ramos L, García-Unzueta MT, Morán JM, Ruiz D, Amado JA. Analysis of the influence of the T393C polymorphism of the GNAS gene on the clinical expression of primary hyperparathyroidism. ACTA ACUST UNITED AC 2017; 64:524-530. [PMID: 29179855 DOI: 10.1016/j.endinu.2017.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/06/2017] [Accepted: 08/10/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND The receptor of parathyroid hormone and parathyroid hormone-related-protein (PTH/PTHrp) is located in the cell membrane of target tissues - kidney and osteoblasts. It is a G protein-coupled-receptor whose Gsα subunit is encoded by the GNAS gene. Our aim was to study whether the single nucleotide polymorphism (SNP) T393C of the GNAS gene is associated with renal stones, bone mineral density (BMD), or bone remodelling markers in primary hyperparathyroidism (PHPT). METHODS An analysis was made of clinical and biochemical parameters and densitometric values in three areas and their relationship with the T393C SNP of the GNAS gene in 261 patients with primary hyperparathyroidism and in 328 healthy controls. Genotyping was performed using the Custom Taqman® SNP Genotyping assay. RESULTS The genotype frequencies of GNAS T/C 393 were similar in the control and PHPT groups. No association was found between genotypes and clinical expression of PHPT (renal stones and bone fractures). A nonstatistically significant trend was seen to lower BMD in the lumbar spine, femoral neck, and total hip in both PHPT and control C homozygote subjects. CONCLUSION Genetic susceptibility to PHPT related to the GNAS T393C polymorphism or a major influence in its development and clinical expression were found. A C allele-related susceptibility to lower BMD in trabecular bone in both PHPT and control subjects is not sufficient to suggest a more severe clinical expression of PHPT. This trend may be considered as a basis for further studies with larger sample sizes and complementary functional evaluation.
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Affiliation(s)
- María Piedra
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain.
| | - Ana Berja
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
| | - Laura Ramos
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
| | - María Teresa García-Unzueta
- Servicio de Bioquímica, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
| | - Jesús Manuel Morán
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
| | - David Ruiz
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
| | - José Antonio Amado
- Servicio de Endocrinología, Hospital Universitario "Marqués de Valdecilla", Instituto de Investigación "Marqués de Valdecilla" (IDIVAL), Universidad de Cantabria, Avda. de Valdecilla s/n, Santander 39008, Cantabria, Spain
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Işıkay S, Akdemir İ, Yılmaz K. Pseudohypoparathyroidism presenting with ventricular arrhythmia: a case report. J Clin Res Pediatr Endocrinol 2012; 4:42-4. [PMID: 22394705 PMCID: PMC3316463 DOI: 10.4274/jcrpe.476] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Pseudohypoparathyroidism (PHP) is a rare disorder characterized by varying degrees of unresponsiveness to parathyroid hormone. Patients usually present with hypocalcemia-induced seizures or tetany, whereas no case of hypocalcemia-induced cardiac arrhythmia in PHP has been described to date. In this paper, we report the case of a male adolescent with PHP type 1a who presented with hypocalcemia-induced ventricular extrasystoles (bigeminy, trigeminy) and mild corrected QT interval prolongation. The patient had brachydactyly and his second fingers and toes were longer than the others, a finding consistent with PHP. Laboratory tests detected hypomagnesemia, as well as elevated levels of creatine kinase and lactate dehydrogenase. Ventricular arrhythmia and abnormal laboratory tests improved with calcium supplementation and vitamin D treatment. The findings in this patient suggest that hypomagnesemia may make patients with PHP more susceptible to hypocalcemia and may thus prompt a state of hypocalcemia-induced arrhythmia or other cardiac complications.
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Affiliation(s)
- Sedat Işıkay
- Gaziantep University Faculty of Medicine, Department of Pediatrics, Gaziantep, Turkey.
| | | | - Kutluhan Yılmaz
- Gaziantep University Faculty of Medicine, Department of Pediatrics, Gaziantep, Turkey
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Miao ZM, Wang C, Wang BB, Meng DM, Su DM, Cheng Z, Wen QL, Han L, Yu Q, Ma X, Li CG. Identification of a novel mutation in a pseudohypoparathyroidism family. Int J Endocrinol 2011; 2011:509549. [PMID: 21822432 PMCID: PMC3142776 DOI: 10.1155/2011/509549] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 05/23/2011] [Indexed: 12/17/2022] Open
Abstract
Pseudohypoparathyroidism type Ia (PHP Ia) is defined as a series of disorders characterized by multihormone resistance in end-organs and Albright hereditary osteodystrophy (AHO) phenotype. PHP Ia is caused by heterozygous inactivating mutations in GNAS, which encodes the stimulatory G-protein alpha subunit (Gsa). A patient with typical clinical manifestations of pseudohypoparathyroidism (PHP) (round face, short stature, centripetal obesity, brachydactyly, and multi-hormone resistance: parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), and gonadotropins) presented at our center. The sequence of the GNAS gene from the patient and her families revealed a novel missense mutation (Y318H) in the proband and her mother. An in vitro Gsa functional study showed that Gsa function was significantly impaired. These results stress the importance of GNAS gene investigation.
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Affiliation(s)
- Zhi-Min Miao
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
| | - Can Wang
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
| | - Bin-Bin Wang
- Graduate School, Peking Union Medical College, Beijing 100081, China
- Center of Genetics, National Research Institute for Family Planning, Beijing 100081, China
| | - Dong-Mei Meng
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
| | - Dong-Mei Su
- Graduate School, Peking Union Medical College, Beijing 100081, China
- Center of Genetics, National Research Institute for Family Planning, Beijing 100081, China
| | - Zhi Cheng
- Graduate School, Peking Union Medical College, Beijing 100081, China
- Center of Genetics, National Research Institute for Family Planning, Beijing 100081, China
| | - Qiao-Lian Wen
- Graduate School, Peking Union Medical College, Beijing 100081, China
- Center of Genetics, National Research Institute for Family Planning, Beijing 100081, China
| | - Lin Han
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
| | - Qing Yu
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
| | - Xu Ma
- Graduate School, Peking Union Medical College, Beijing 100081, China
- Center of Genetics, National Research Institute for Family Planning, Beijing 100081, China
- Center of Genetics, World Health Organization Collaborating Centre for Research in Human Reproduction, Beijing 100081, China
| | - Chang-Gui Li
- Gout Laboratory, The Affiliated Hospital of Qingdao University Medical College, 16 Jiangsu Road, Qingdao 266003, China
- *Chang-Gui Li:
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Liu S. Increasing alternative promoter repertories is positively associated with differential expression and disease susceptibility. PLoS One 2010; 5:e9482. [PMID: 20208995 PMCID: PMC2830428 DOI: 10.1371/journal.pone.0009482] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Accepted: 01/07/2010] [Indexed: 12/03/2022] Open
Abstract
Background Alternative Promoter (AP) usages have been shown to enable diversified transcriptional regulation of individual gene in a context-specific (e.g., pathway, cell lineage, tissue type, and development stage et. ac.) way. Aberrant uses of APs have been directly linked to mechanism of certain human diseases. However, whether or not there exists a general link between a gene's AP repertoire and its expression diversity is currently unknown. The general relation between a gene's AP repertoire and its disease susceptibility also remains largely unexplored. Methodology/Principal Findings Based on the differential expression ratio inferred from all human microarray data in NCBI GEO and the list of disease genes curated in public repositories, we systemically analyzed the general relation of AP repertoire with expression diversity and disease susceptibility. We found that genes with APs are more likely to be differentially expressed and/or disease associated than those with Single Promoter (SP), and genes with more APs are more likely differentially expressed and disease susceptible than those with less APs. Further analysis showed that genes with increased number of APs tend to have increased length in all aspects of gene structure including 3′ UTR, be associated with increased duplicability, and have increased connectivity in protein-protein interaction network. Conclusions Our genome-wide analysis provided evidences that increasing alternative promoter repertories is positively associated with differential expression and disease susceptibility.
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Affiliation(s)
- Song Liu
- Department of Biostatistics, Roswell Park Cancer Institute, Buffalo, New York, United States of America.
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6
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Abstract
Common DNA sequence variants inadequately explain variability in fat mass among individuals. Abnormal body weights are characteristic of specific imprinted-gene disorders. However, the relevance of imprinted genes to our understanding of obesity among the general population is uncertain. Hitherto unidentified imprinted genes and epigenetic mosaicism are two of the challenges for this emerging field of epigenetics. Subtle epigenetic differences in imprinted genes and gene networks are likely to be present among cells, tissues and individuals. In order to advance obesity research it will be necessary to use genome-wide, next-generation sequencing approaches that allow the detection of such epigenetic differences.
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Affiliation(s)
- Reinhard Stöger
- Department of Biology, University of Washington, 156 Kincaid Hall, Box 351800, Seattle, WA, 98195-1800, USA.
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7
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Maeda SS, Fortes EM, Oliveira UM, Borba VCZ, Lazaretti-Castro M. Hypoparathyroidism and pseudohypoparathyroidism. ACTA ACUST UNITED AC 2007; 50:664-73. [PMID: 17117292 DOI: 10.1590/s0004-27302006000400012] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2006] [Accepted: 04/20/2006] [Indexed: 01/30/2023]
Abstract
The principal function of the parathyroid hormone (PTH) is maintenance of calcium plasmatic levels, withdrawing the calcium from bone tissue, reabsorbing it from the glomerular filtrate, and indirectly increasing its intestinal absorption by stimulating active vitamin D (calcitriol) production. Additionally, the PTH prompts an increase in urinary excretion of phosphorus and bicarbonate, seeking a larger quantity of free calcium available in circulation. Two mechanisms may alter its function, limiting its control on calcium: insufficient PTH production by the parathyroids (hypoparathyroidism), or a resistance against its action in target tissues (pseudohypoparathyroidism). In both cases, there are significantly reduced levels of plasmatic calcium associated with hyperphosphatemia. Clinical cases are characterized by nervous hyperexcitability, with paresthesia, cramps, tetany, hyperreflexia, convulsions, and tetanic crisis. Abnormalities such as cataracts and basal ganglia calcification are also typical of these diseases. Treatment consists of oral calcium supplementation associated with increased doses of vitamin D derivatives.
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Affiliation(s)
- Sergio S Maeda
- Division of Endocrinology, EPM, UNIFESP, São Paulo, SP, Brazil
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8
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Abstract
It is becoming clear that epigenetic changes are involved in human disease as well as during normal development. A unifying theme of disease epigenetics is defects in phenotypic plasticity--cells' ability to change their behaviour in response to internal or external environmental cues. This model proposes that hereditary disorders of the epigenetic apparatus lead to developmental defects, that cancer epigenetics involves disruption of the stem-cell programme, and that common diseases with late-onset phenotypes involve interactions between the epigenome, the genome and the environment. Increased understanding of epigenetic-disease mechanisms could lead to disease-risk stratification for targeted intervention and to targeted therapies.
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Affiliation(s)
- Andrew P Feinberg
- Department of Medicine and Center for Epigenetics, Institute for Basic Biomedical Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, Maryland 21205, USA.
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9
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Masi L, Del Monte F, Gozzini A, De Feo ML, Gionata Gheri R, Neri A, Falchetti A, Amedei A, Imbriaco R, Mavilia C, Tanini A, Brandi ML. A novel polymorphism at the GNAS1 gene associated with low circulating calcium levels. CLINICAL CASES IN MINERAL AND BONE METABOLISM : THE OFFICIAL JOURNAL OF THE ITALIAN SOCIETY OF OSTEOPOROSIS, MINERAL METABOLISM, AND SKELETAL DISEASES 2007; 4:139-145. [PMID: 22461214 PMCID: PMC2781238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The concentration of calcium in the extracellular fluid is crucial for several physiological functions in humans and in normal conditions its circulating levels are maintained between 8.5-10.5 mg/dl. Among the regulators of calcium homeostasis parathyroid hormone (PTH) acts though the G-protein coupled PTH receptor and a hormone-sensitive adenylate cyclase, with Gsα subunit (stimulatory guanine nucleotide-binding protein alpha-subunit) being responsible for the stimulation of the catalytic complex. Mutations of the Gsα encoding gene, GNAS1, are causal for some forms of congenital hypocalcemia. In the present study genetic variability in the GNAS1 gene was analyzed in a group of hypocalcemic patients collected through the Italian Register of Primary Hypoparathyroidism (RIIP). We identified a new intronic variant of the GNAS1 gene, consisting of a T>C polymorphism. This polymorphism was studied in a group of unrelated healthy subjects for a possible association with bone turnover biomarkers and bone mineral density. The T>C polymorphism was found in 18% of the studied populations, with 15% heterozygous TC and 3% homozygous CC (Pearson χ(2)analysis: p=0.04). A significant association with low serum calcium levels was found in healthy subjects carrying the T > C polymorphism (ANCOVA analysis: p=0.04). These results support segregation of a novel GNAS1 gene intronic variant with low calcium levels in primary hypoparathyroidism, pseudo-hypoparathyroidism and in the general population.
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11
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Abstract
DNA methylation is a crucial epigenetic modification of the genome that is involved in regulating many cellular processes. These include embryonic development, transcription, chromatin structure, X chromosome inactivation, genomic imprinting and chromosome stability. Consistent with these important roles, a growing number of human diseases have been found to be associated with aberrant DNA methylation. The study of these diseases has provided new and fundamental insights into the roles that DNA methylation and other epigenetic modifications have in development and normal cellular homeostasis.
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Affiliation(s)
- Keith D Robertson
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, University of Florida, Gainesville, Florida 32610, USA.
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12
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Dong C, Li WD, Geller F, Lei L, Li D, Gorlova OY, Hebebrand J, Amos CI, Nicholls RD, Price RA. Possible genomic imprinting of three human obesity-related genetic loci. Am J Hum Genet 2005; 76:427-37. [PMID: 15647995 PMCID: PMC1196395 DOI: 10.1086/428438] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Accepted: 12/28/2004] [Indexed: 11/03/2022] Open
Abstract
To detect potentially imprinted, obesity-related genetic loci, we performed genomewide parent-of-origin linkage analyses under an allele-sharing model for discrete traits and under a family regression model for obesity-related quantitative traits, using a European American sample of 1,297 individuals from 260 families, with 391 microsatellite markers. We also used two smaller, independent samples for replication (a sample of 370 German individuals from 89 families and a sample of 277 African American individuals from 52 families). For discrete-trait analysis, we found evidence for a maternal effect in chromosome region 10p12 across the three samples, with LOD scores of 5.69 (single-point) and 4.52 (multipoint) for the pooled sample. For quantitative-trait analysis, we found the strongest evidence for a maternal effect (single-point LOD of 2.85; multipoint LOD of 4.01 for body mass index [BMI] and 3.69 for waist circumference) in region 12q24 and for a paternal effect (single-point LOD of 4.79; multipoint LOD of 3.72 for BMI) in region 13q32, in the European American sample. The results suggest that parent-of-origin effects, perhaps including genomic imprinting, may play a role in human obesity.
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Affiliation(s)
- Chuanhui Dong
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Wei-Dong Li
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Frank Geller
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Lei Lei
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Ding Li
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Olga Y. Gorlova
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Johannes Hebebrand
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Christopher I. Amos
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - Robert D. Nicholls
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
| | - R. Arlen Price
- Center for Neurobiology and Behavior, Department of Psychiatry, and Department of Genetics, University of Pennsylvania, Philadelphia; Institute of Medical Biometry and Epidemiology and Clinical Research Group, Department of Child and Adolescent Psychiatry, Philipps-University of Marburg, Marburg, Germany; and Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston
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Abstract
Genomic imprinting in gametogenesis marks a subset of mammalian genes for parent-of-origin-dependent monoallelic expression in the offspring. Embryological and classical genetic experiments in mice that uncovered the existence of genomic imprinting nearly two decades ago produced abnormalities of growth or behavior, without severe developmental malformations. Since then, the identification and manipulation of individual imprinted genes has continued to suggest that the diverse products of these genes are largely devoted to controlling pre- and post-natal growth, as well as brain function and behavior. Here, we review this evidence, and link our discussion to a website (http://www.otago.ac.nz/IGC) containing a comprehensive database of imprinted genes. Ultimately, these data will answer the long-debated question of whether there is a coherent biological rationale for imprinting.
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Affiliation(s)
- Benjamin Tycko
- Institute for Cancer Genetics, Columbia University, New York, New York, USA.
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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: 136] [Impact Index Per Article: 5.9] [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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