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Zhang HY, Wu FY, Li XS, Tu PH, Zhang CX, Yang RM, Cui RJ, Wu CY, Fang Y, Yang L, Song HD, Zhao SX. TSHR Variant Screening and Phenotype Analysis in 367 Chinese Patients With Congenital Hypothyroidism. Ann Lab Med 2024; 44:343-353. [PMID: 38433572 PMCID: PMC10961619 DOI: 10.3343/alm.2023.0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/29/2023] [Accepted: 02/12/2024] [Indexed: 03/05/2024] Open
Abstract
Background Genetic defects in the human thyroid-stimulating hormone (TSH) receptor (TSHR) gene can cause congenital hypothyroidism (CH). However, the biological functions and comprehensive genotype-phenotype relationships for most TSHR variants associated with CH remain unexplored. We aimed to identify TSHR variants in Chinese patients with CH, analyze the functions of the variants, and explore the relationships between TSHR genotypes and clinical phenotypes. Methods In total, 367 patients with CH were recruited for TSHR variant screening using whole-exome sequencing. The effects of the variants were evaluated by in-silico programs such as SIFT and polyphen2. Furthermore, these variants were transfected into 293T cells to detect their Gs/cyclic AMP and Gq/11 signaling activity. Results Among the 367 patients with CH, 17 TSHR variants, including three novel variants, were identified in 45 patients, and 18 patients carried biallelic TSHR variants. In vitro experiments showed that 10 variants were associated with Gs/cyclic AMP and Gq/11 signaling pathway impairment to varying degrees. Patients with TSHR biallelic variants had lower serum TSH levels and higher free triiodothyronine and thyroxine levels at diagnosis than those with DUOX2 biallelic variants. Conclusions We found a high frequency of TSHR variants in Chinese patients with CH (12.3%), and 4.9% of cases were caused by TSHR biallelic variants. Ten variants were identified as loss-of-function variants. The data suggest that the clinical phenotype of CH patients caused by TSHR biallelic variants is relatively mild. Our study expands the TSHR variant spectrum and provides further evidence for the elucidation of the genetic etiology of CH.
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Affiliation(s)
- Hai-Yang Zhang
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Feng-Yao Wu
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xue-Song Li
- Department of Endocrine Metabolism, Minhang Hospital, Fudan University, Shanghai, China
| | - Ping-Hui Tu
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cao-Xu Zhang
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rui-Meng Yang
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ren-Jie Cui
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen-Yang Wu
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ya Fang
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liu Yang
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huai-Dong Song
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuang-Xia Zhao
- The Core Laboratory in Medical Center of Clinical Research, Department of Molecular Diagnostics & Endocrinology, Shanghai Ninth People’s Hospital, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Grasberger H, Dumitrescu AM, Liao XH, Swanson EG, Weiss RE, Srichomkwun P, Pappa T, Chen J, Yoshimura T, Hoffmann P, França MM, Tagett R, Onigata K, Costagliola S, Ranchalis J, Vollger MR, Stergachis AB, Chong JX, Bamshad MJ, Smits G, Vassart G, Refetoff S. STR mutations on chromosome 15q cause thyrotropin resistance by activating a primate-specific enhancer of MIR7-2/MIR1179. Nat Genet 2024; 56:877-888. [PMID: 38714869 DOI: 10.1038/s41588-024-01717-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 03/14/2024] [Indexed: 05/22/2024]
Abstract
Thyrotropin (TSH) is the master regulator of thyroid gland growth and function. Resistance to TSH (RTSH) describes conditions with reduced sensitivity to TSH. Dominantly inherited RTSH has been linked to a locus on chromosome 15q, but its genetic basis has remained elusive. Here we show that non-coding mutations in a (TTTG)4 short tandem repeat (STR) underlie dominantly inherited RTSH in all 82 affected participants from 12 unrelated families. The STR is contained in a primate-specific Alu retrotransposon with thyroid-specific cis-regulatory chromatin features. Fiber-seq and RNA-seq studies revealed that the mutant STR activates a thyroid-specific enhancer cluster, leading to haplotype-specific upregulation of the bicistronic MIR7-2/MIR1179 locus 35 kb downstream and overexpression of its microRNA products in the participants' thyrocytes. An imbalance in signaling pathways targeted by these micro-RNAs provides a working model for this cause of RTSH. This finding broadens our current knowledge of genetic defects altering pituitary-thyroid feedback regulation.
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Affiliation(s)
- Helmut Grasberger
- Department of Internal Medicine, Medical School, University of Michigan, Ann Arbor, MI, USA
| | - Alexandra M Dumitrescu
- Department of Medicine, The University of Chicago, Chicago, IL, USA
- Committee on Molecular Metabolism and Nutrition, The University of Chicago, Chicago, IL, USA
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Elliott G Swanson
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Roy E Weiss
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Theodora Pappa
- Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Junfeng Chen
- Institute of Transformative Bio-Molecules (WPI-ITbM) and Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Takashi Yoshimura
- Institute of Transformative Bio-Molecules (WPI-ITbM) and Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Phillip Hoffmann
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles-Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Rebecca Tagett
- Michigan Medicine BRCF Bioinformatics Core, University of Michigan, Ann Arbor, MI, USA
| | | | - Sabine Costagliola
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Jane Ranchalis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Mitchell R Vollger
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Andrew B Stergachis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Jessica X Chong
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Michael J Bamshad
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Guillaume Smits
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles-Vrije Universiteit Brussel, Brussels, Belgium
- Center of Human Genetics, Hôpital Erasme, Hôpital Universitaire de Bruxelles, and Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Gilbert Vassart
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles, Brussels, Belgium
| | - Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, IL, USA.
- Committee on Genetics, The University of Chicago, Chicago, IL, USA.
- Department of Pediatrics, The University of Chicago, Chicago, IL, USA.
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3
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Piva I, Censi S, Manso J, Barollo S, Bertazza L, Scaroni C, Mian C, Barbot M. A Novel TSH Receptor Gene Variant Associated with Non-Autoimmune Hyperthyrotropinemia: A Case Report. Endocr Metab Immune Disord Drug Targets 2024; 24:273-276. [PMID: 37622708 DOI: 10.2174/1871530323666230824153915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/26/2023]
Abstract
BACKGROUND Resistance to TSH is defined as reduced sensitivity to normal, biologicallyactive TSH, and abnormally high levels of TSH are needed to achieve normal levels of thyroid hormones. CASE PRESENTATION A 15-year-old female patient, having been treated since childhood with levothyroxine for hyperthyrotropinemia was referred to our institution complaining of tachycardia after the levothyroxine therapy had been increased. Thyroid ultrasound features were normal, and thyroid antibodies were negative. The therapy was gradually tapered in light of the symptoms, although subclinical hypothyroidism was evident at thyroid function tests. First-degree relatives were tested for thyroid function, and the father was also found to have a previously-unknown subclinical hypothyroidism. The patient underwent genetic testing for TSH receptor (TSHR) gene mutations, which revealed a gene variant hitherto not described: p.C598R (c.1792T>C). The father was also tested and was found to carry the same mutation, while other first-degree relatives were wild-type for the TSHR gene. An in-silico analysis was performed, which revealed a loss-of-function phenotype corresponding to the described variant, suggesting a novel loss-of-function TSH receptor gene mutation. CONCLUSION In this case report, we present a novel loss-of-function gene mutation in the TSH receptor gene associated with a TSH resistance phenotype.
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Affiliation(s)
- Ilaria Piva
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Simona Censi
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Jacopo Manso
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
- Department of Woman's and Child 's Health, Pediatric Endocrinology and Adolescence Unit, University Hospital of Padova, Padova, Italy
| | - Susi Barollo
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Loris Bertazza
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Carla Scaroni
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Caterina Mian
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Mattia Barbot
- Endocrinology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
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Abstract
Genetic factors are involved in the etiology of most diseases, but prior to 2000, the methods for identifying such factors were very limited. Genome-wide association study (GWAS), developed in the 2000s, is an analytical method that can be applied to most diseases, including endocrine disorders. GWAS has provided a wealth of information on disease risks and the molecular pathogenesis of many human diseases. This review summarizes key findings from GWAS for thyroid physiology and diseases, and illustrates how GWAS is a powerful research tool to elucidate the molecular mechanisms of the diseases.
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Affiliation(s)
- Satoshi Narumi
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
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5
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Zhang W, Jin F, Guo R, Qi Z, Wang Y, Li X, Wu Y, Li W, Hu X, Hao C. Newborn Genetic Screening Revealed Increased Levels of Biochemical Indicators in Carriers of Heterozygous Variants. Genet Test Mol Biomarkers 2022; 26:573-581. [PMID: 36577126 DOI: 10.1089/gtmb.2022.0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background: Conventional newborn screening (NBS) is usually based on biochemical methods to predict the risk of inborn errors of metabolism. Recent studies have applied next-generation sequencing in NBS and revealed much more information, including carrier status. Whether these carriers of variants differ from other individuals was not fully determined. Objective: This research investigated the effect of heterozygous carrier status of pathogenic variants on biochemical indicators during NBS. Methods: We enrolled newborns participating in both conventional NBS and our previous Newborn Screening with Targeted Sequencing (NESTS) program from January 2021 to December 2021 in the Shunyi Maternal and Children's Hospital of Beijing Children's Hospital. Newborn levels of phenylalanine (Phe), thyroid stimulating hormone (TSH), and 17-hydroxyprogesterone (17-OHP) were measured to be analyzed together with associated sequencing results. Results: A total of 2351 newborns in the NESTS program was examined in the study. None had biallelic variants in genes related to congenital hypothyroidism (CH), hyperphenylalaninemia (HPA) or congenital adrenal hyperplasia. Forty-nine heterozygous carriers with phenylalanine hydroxylase (PAH) variants had significantly higher levels of Phe (p < 0.0001), and 11 heterozygous carriers of thyroid-stimulating hormone receptor (TSHR) variants had significantly higher levels of TSH (p < 0.05). Although heterozygous carriers had higher biochemical levels, they were below the diagnostic threshold of HPA and CH. Conclusions: Carriers of heterozygous variants in PAH or TSHR had significantly increased biochemical levels of associated factors in NBS. For individuals with higher Phe or TSH levels within the normal reference intervals, attention should be paid to the possibility of heterozygous carrier status.
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Affiliation(s)
- Wenyan Zhang
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Feng Jin
- Shunyi Maternal and Children's Hospital of Beijing Children's Hospital, Beijing, China
| | - Ruolan Guo
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Henan Key Laboratory of Pediatric Inherited and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's Hospital, Zhengzhou, China
| | - Zhan Qi
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Henan Key Laboratory of Pediatric Inherited and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's Hospital, Zhengzhou, China
| | - Yaling Wang
- Shunyi Maternal and Children's Hospital of Beijing Children's Hospital, Beijing, China
| | - Xueling Li
- Shunyi Maternal and Children's Hospital of Beijing Children's Hospital, Beijing, China
| | - Yali Wu
- Shunyi Maternal and Children's Hospital of Beijing Children's Hospital, Beijing, China
| | - Wei Li
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Henan Key Laboratory of Pediatric Inherited and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's Hospital, Zhengzhou, China
| | - Xuyun Hu
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Henan Key Laboratory of Pediatric Inherited and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's Hospital, Zhengzhou, China
| | - Chanjuan Hao
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.,Henan Key Laboratory of Pediatric Inherited and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's Hospital, Zhengzhou, China
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6
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AlRasheed MM. TSH-β gene polymorphism in Saudi patients with thyroid cancer; a case-control study. Saudi Pharm J 2022; 30:1538-1542. [DOI: 10.1016/j.jsps.2022.07.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 07/23/2022] [Indexed: 10/16/2022] Open
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7
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Peters C, Schoenmakers N. MECHANISMS IN ENDOCRINOLOGY: The pathophysiology of transient congenital hypothyroidism. Eur J Endocrinol 2022; 187:R1-R16. [PMID: 35588090 PMCID: PMC9254299 DOI: 10.1530/eje-21-1278] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 05/19/2022] [Indexed: 11/08/2022]
Abstract
Transient congenital hypothyroidism (TCH) refers to congenital hypothyroidism which spontaneously resolves in the first few months or years of life. Currently, there is a paucity of reliable markers predicting TCH at diagnosis, and the diagnosis is established following the withdrawal of levothyroxine therapy around 3 years of age. The incidence of TCH is increasing, and it is a major contributor to the overall increase in the incidence of CH in recent studies. Both genetic factors, in particular mutations affecting DUOX2 and DUOXA2, and environmental factors, for example, iodine deficiency and excess, anti- TSHR antibodies and exposure to antithyroid or iodine-rich medications, may cause TCH. Resolution of TCH in childhood may reflect both normal thyroid physiology (decreased thyroid hormone biosynthesis requirements after the neonatal period) and clearance or cessation of environmental precipitants. The relative contributions and interactions of genetic and environmental factors to TCH, and the extent to which TCH may be prevented, require evaluation in future population-based studies.
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Affiliation(s)
- Catherine Peters
- Department of Endocrinology, Great Ormond Street Hospital for Children, London, UK
| | - Nadia Schoenmakers
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- Correspondence should be addressed to N Schoenmakers;
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8
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Abstract
Thyroid diseases in children and adolescents include acquired or congenital conditions, including genetic disorders either isolated or part of a syndrome. Briefly, we will review the physiology and pathophysiology of the thyroid gland and its disorders. The aim of this chapter is to describe genetic abnormalities of the thyroid gland.
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9
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Xue P, Yang Y, Yun Q, Cui Y, Yu B, Long W. Variant of TSHR is Not a Frequent Cause of Congenital Hypothyroidism in Chinese Han Patients. Int J Gen Med 2021; 14:4135-4143. [PMID: 34377013 PMCID: PMC8349214 DOI: 10.2147/ijgm.s322726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/16/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To screen variants of the thyroid stimulating hormone receptor (TSHR) gene among congenital hypothyroidism (CH) patients. PATIENTS AND METHODS We conducted a genetic screening of the TSHR gene in a cohort of 125 Chinese CH patients. Variants were detected by customized targeted next-generation sequencing. RESULTS A total of 11 TSHR missense heterozygous variants were identified in 14 CH patients. Six variants were in the transmembrane domains, four variants were in the leucine-rich repeats and one variant was located in the hinge region of the TSHR protein. p.F525S was the most prevalent variant with an allele frequency of 0.016, followed by p.R450H with an allele frequency of 0.012. The allele frequency of most variants was higher in our cohort than those of other populations. CONCLUSION The prevalence of TSHR variants was 11.2%. Variant p.F525S was the most prevalent variant with an allele frequency of 0.016. The prevalence of TSHR variants was different from other populations.
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Affiliation(s)
- Peng Xue
- Department of Pediatrics, Changzhou Children’s Hospital, Changzhou, People’s Republic of China
| | - Yuqi Yang
- Department of Medical Genetics, Affiliated Changzhou Women and Children’s Hospital, Nanjing Medical University, Changzhou, People’s Republic of China
| | - Qi Yun
- Department of Pediatrics, Changzhou Children’s Hospital, Changzhou, People’s Republic of China
| | - Yue Cui
- Department of Pediatrics, Changzhou Children’s Hospital, Changzhou, People’s Republic of China
| | - Bin Yu
- Department of Medical Genetics, Affiliated Changzhou Women and Children’s Hospital, Nanjing Medical University, Changzhou, People’s Republic of China
| | - Wei Long
- Department of Medical Genetics, Affiliated Changzhou Women and Children’s Hospital, Nanjing Medical University, Changzhou, People’s Republic of China
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10
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Kostopoulou E, Miliordos K, Spiliotis B. Genetics of primary congenital hypothyroidism-a review. Hormones (Athens) 2021; 20:225-236. [PMID: 33400193 DOI: 10.1007/s42000-020-00267-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE Congenital primary hypothyroidism (CH) is a state of inadequate thyroid hormone production detected at birth, caused either by absent, underdeveloped or ectopic thyroid gland (dysgenesis), or by defected thyroid hormone biosynthesis (dyshormonogenesis). A genetic component has been identified in many cases of CH. This review summarizes the clinical and biochemical features of the genetic causes of primary CH. METHODS A literature review was conducted of gene defects causing congenital hypothyroidism. RESULTS Mutations in five genes have predominantly been implicated in thyroid dysgenesis (TSHR, FOXE1, NKX2-1, PAX8, and NKX2-5), the primary cause of CH (85%), and mutations in seven genes in thyroid dyshormonogenesis (SLC5A5, TPO, DUOX2, DUOXA2, SLC6A4, Tg, and DEHAL1). These genes encode for proteins that regulate genes expressed during the differentiation of the thyroid, such as TPO and Tg genes, or genes that regulate iodide organification, thyroglobulin synthesis, iodide transport, and iodotyrosine deiodination. Besides thyroid dysgenesis and dyshormonogenesis, additional causes of congenital hypothyroidism, such as iodothyronine transporter defects and resistance to thyroid hormones, have also been associated with genetic mutations. CONCLUSION The identification of the underlying genetic defects of CH is important for genetic counseling of families with an affected member, for identifying additional clinical characteristics or the risk for thyroid neoplasia and for diagnostic and management purposes.
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Affiliation(s)
- Eirini Kostopoulou
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece.
| | - Konstantinos Miliordos
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece
| | - Bessie Spiliotis
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics|, University of Patras School of Medicine, Patras, Greece
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11
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Sugisawa C, Ono M, Kashimada K, Hasegawa T, Narumi S. Inactivation of a Frameshift TSH Receptor Variant Val711Phefs*18 is Due to Acquisition of a Hydrophobic Degron. J Clin Endocrinol Metab 2021; 106:e265-e272. [PMID: 33108452 DOI: 10.1210/clinem/dgaa772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Inactivating variants of thyrotropin (thyroid-stimulating hormone; TSH) receptor (TSHR) cause congenital hypothyroidism. More than 60 such variants have been reported so far, most of which were located in the extracellular or transmembrane domain. OBJECTIVE We report the identification and characterization of a frameshift TSHR variant in the intracytoplasmic C-tail region. METHODS Sequencing of TSHR was performed in a patient with congenital hypothyroidism. The functionality of the identified variants was assessed by expressing TSHR in HEK293 cells and measuring TSH-dependent activation of the cAMP-response element-luciferase reporter. A series of systematic mutagenesis experiments were performed to characterize the frameshifted amino acid sequence. RESULTS The proband was heterozygous for a known TSHR variant (p.Arg519His) and a novel frameshift TSHR variant (p.Val711Phefs*18), which removed 54 C-terminal residues and added a 17-amino acid frameshifted sequence. The loss of function of Val711Phefs*18-TSHR was confirmed in vitro, but the function of Val711*-TSHR was found to be normal. Western blotting showed the low protein expression of Val711Phefs*18-TSHR. Fusion of the frameshift sequence to green fluorescent protein or luciferase induced inactivation of them, indicating that the sequence acted as a degron. A systematic mutagenesis study revealed that the density of hydrophobic residues in the frameshift sequence determined the stability. Eight additional frameshift TSHR variants that covered all possible shifted frames in C-tail were created, and another frameshift variant (Thr748Profs*27) with similar effect was found. CONCLUSIONS We characterized a naturally occurring frameshift TSHR variant located in C-tail, and provided a unique evidence that hydrophobicity in the C-terminal region of the receptor affects protein stability.
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Affiliation(s)
- Chiho Sugisawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Showa University Fujigaoka Hospital, Kanagawa, Japan
| | - Makoto Ono
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Pediatrics, Tokyo Bay Urayasu Ichikawa Medical Center, Chiba, Japan
| | - Kenichi Kashimada
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tomonobu Hasegawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Satoshi Narumi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
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12
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Schöneberg T, Liebscher I. Mutations in G Protein-Coupled Receptors: Mechanisms, Pathophysiology and Potential Therapeutic Approaches. Pharmacol Rev 2020; 73:89-119. [PMID: 33219147 DOI: 10.1124/pharmrev.120.000011] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
There are approximately 800 annotated G protein-coupled receptor (GPCR) genes, making these membrane receptors members of the most abundant gene family in the human genome. Besides being involved in manifold physiologic functions and serving as important pharmacotherapeutic targets, mutations in 55 GPCR genes cause about 66 inherited monogenic diseases in humans. Alterations of nine GPCR genes are causatively involved in inherited digenic diseases. In addition to classic gain- and loss-of-function variants, other aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, pseudogenes, gene fusion, and gene dosage, contribute to the repertoire of GPCR dysfunctions. However, the spectrum of alterations and GPCR involvement is probably much larger because an additional 91 GPCR genes contain homozygous or hemizygous loss-of-function mutations in human individuals with currently unidentified phenotypes. This review highlights the complexity of genomic alteration of GPCR genes as well as their functional consequences and discusses derived therapeutic approaches. SIGNIFICANCE STATEMENT: With the advent of new transgenic and sequencing technologies, the number of monogenic diseases related to G protein-coupled receptor (GPCR) mutants has significantly increased, and our understanding of the functional impact of certain kinds of mutations has substantially improved. Besides the classical gain- and loss-of-function alterations, additional aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, uniparental disomy, pseudogenes, gene fusion, and gene dosage, need to be elaborated in light of GPCR dysfunctions and possible therapeutic strategies.
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Affiliation(s)
- Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
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13
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Matsushima N, Takatsuka S, Miyashita H, Kretsinger RH. Leucine Rich Repeat Proteins: Sequences, Mutations, Structures and Diseases. Protein Pept Lett 2019; 26:108-131. [PMID: 30526451 DOI: 10.2174/0929866526666181208170027] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the genes encoding Leucine Rich Repeat (LRR) containing proteins are associated with over sixty human diseases; these include high myopia, mitochondrial encephalomyopathy, and Crohn's disease. These mutations occur frequently within the LRR domains and within the regions that shield the hydrophobic core of the LRR domain. The amino acid sequences of fifty-five LRR proteins have been published. They include Nod-Like Receptors (NLRs) such as NLRP1, NLRP3, NLRP14, and Nod-2, Small Leucine Rich Repeat Proteoglycans (SLRPs) such as keratocan, lumican, fibromodulin, PRELP, biglycan, and nyctalopin, and F-box/LRR-repeat proteins such as FBXL2, FBXL4, and FBXL12. For example, 363 missense mutations have been identified. Replacement of arginine, proline, or cysteine by another amino acid, or the reverse, is frequently observed. The diverse effects of the mutations are discussed based on the known structures of LRR proteins. These mutations influence protein folding, aggregation, oligomerization, stability, protein-ligand interactions, disulfide bond formation, and glycosylation. Most of the mutations cause loss of function and a few, gain of function.
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Affiliation(s)
- Norio Matsushima
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan.,Institute of Tandem Repeats, Noboribetsu 059-0464, Japan
| | - Shintaro Takatsuka
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroki Miyashita
- Institute of Tandem Repeats, Noboribetsu 059-0464, Japan.,Hokubu Rinsho Co., Ltd, Sapporo 060-0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
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14
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Peters C, van Trotsenburg ASP, Schoenmakers N. DIAGNOSIS OF ENDOCRINE DISEASE: Congenital hypothyroidism: update and perspectives. Eur J Endocrinol 2018; 179:R297-R317. [PMID: 30324792 DOI: 10.1530/eje-18-0383] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Congenital hypothyroidism (CH) may be primary, due to a defect affecting the thyroid gland itself, or central, due to impaired thyroid-stimulating hormone (TSH)-mediated stimulation of the thyroid gland as a result of hypothalamic or pituitary pathology. Primary CH is the most common neonatal endocrine disorder, traditionally subdivided into thyroid dysgenesis (TD), referring to a spectrum of thyroid developmental abnormalities, and dyshormonogenesis, where a defective molecular pathway for thyroid hormonogenesis results in failure of hormone production by a structurally intact gland. Delayed treatment of neonatal hypothyroidism may result in profound neurodevelopmental delay; therefore, CH is screened for in developed countries to facilitate prompt diagnosis. Central congenital hypothyroidism (CCH) is a rarer entity which may occur in isolation, or (more frequently) in association with additional pituitary hormone deficits. CCH is most commonly defined biochemically by failure of appropriate TSH elevation despite subnormal thyroid hormone levels and will therefore evade diagnosis in primary, TSH-based CH-screening programmes. This review will discuss recent genetic aetiological advances in CH and summarize epidemiological data and clinical diagnostic challenges, focussing on primary CH and isolated CCH.
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Affiliation(s)
- C Peters
- Department of Endocrinology, Great Ormond Street Hospital for Children, London, UK
| | - A S P van Trotsenburg
- Department of Paediatric Endocrinology, Emma Children’s Hospital Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - N Schoenmakers
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-Medical Research
Council Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, UK
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15
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Makretskaya N, Bezlepkina O, Kolodkina A, Kiyaev A, Vasilyev EV, Petrov V, Kalinenkova S, Malievsky O, Dedov II, Tiulpakov A. High frequency of mutations in 'dyshormonogenesis genes' in severe congenital hypothyroidism. PLoS One 2018; 13:e0204323. [PMID: 30240412 PMCID: PMC6150524 DOI: 10.1371/journal.pone.0204323] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 09/06/2018] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Results of the screening of disease causative mutations in congenital hypothyroidism (CH) vary significantly, depending on the sequence strategy, patients' inclusion criteria and bioinformatics. The objective was to study the molecular basis of severe congenital hypothyroidism, using the next generation sequencing (NGS) and the recent guidelines for assessment of sequence variants. DESIGN 243 patients with CH (TSH levels at neonatal screening or retesting greater than 90 mU/l) and 56 control subjects were included in the study. METHODS A custom NGS panel targeting 12 CH causative genes was used for sequencing. The sequence variants were rated according to American College of Medical Genetics and Genomics (ACMG) guidelines. RESULTS In total, 48 pathogenic, 7 likely pathogenic and 57 variants of uncertain significance were identified in 92/243 patients (37.9%), while 4 variants of uncertain significance were found in 4/56 control subjects (7.1%). 13.1% (12/92) of the cases showed variants in 'thyroid dysgenesis' (TD) genes: TSHR, n = 6; NKX2-1, n = 2; NKX2-5, n = 1; PAX8, n = 3. The variants in 'dyshormonogenesis' (DH) genes were found in 84.8% (78/92) of cases: TPO, n = 30; DUOX2, n = 24; TG, n = 8; SLC5A5, n = 3; SLC26A4, n = 6; IYD, n = 1. 8 patients showed oligonenic variants. The majority of variants identified in DH genes were monoallelic. CONCLUSIONS In contrast to earlier studies demonstrating the predominance of TD in severe CH, the majority of variants identified in our study were in DH genes. A large proportion of monoallelic variants detected among DH genes suggests that non-mendelian mechanisms may play a role in the development of CH.
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Affiliation(s)
- Nina Makretskaya
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Olga Bezlepkina
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Anna Kolodkina
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Alexey Kiyaev
- Department of Polyclinic Pediatrics, Ural State Medical University, Ekaterinburg, Russian Federation
| | - Evgeny V. Vasilyev
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Vasily Petrov
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Svetlana Kalinenkova
- Genetics Laboratory, Moscow Regional Research and Clinical Institute, Moscow, Russian Federation
| | - Oleg Malievsky
- Department of Hospital Pediatrics, Republican Children’s Clinical Hospital, Ufa, Russian Federation
| | - Ivan I. Dedov
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
| | - Anatoly Tiulpakov
- Department and Laboratory of Inherited Endocrine Disorders, Endocrinology Research Centre, Moscow, Russian Federation
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16
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Sugisawa C, Abe K, Sunaga Y, Taniyama M, Hasegawa T, Narumi S. Identification of compound heterozygous TSHR mutations (R109Q and R450H) in a patient with nonclassic TSH resistance and functional characterization of the mutant receptors. Clin Pediatr Endocrinol 2018; 27:123-130. [PMID: 30083029 PMCID: PMC6073063 DOI: 10.1297/cpe.27.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 02/08/2018] [Indexed: 11/05/2022] Open
Abstract
Genetic defects of the TSH receptor (TSHR) signaling pathway cause a form of congenital
hypothyroidism (CH) known as TSH resistance. Consistent with the physiological
understanding that thyroidal iodine uptake is up-regulated by TSHR signaling, most
patients with TSH resistance have low to normal thyroidal 123I uptake
representing the classic TSH resistance. However, paradoxically high 123I
uptake was reported in four molecularly-confirmed patients indicating nonclassic TSH
resistance. Here, we report the fifth patient with the nonclassic phenotype. He was a
12-yr-old CH patient and treated with levothyroxine. At the age 11 yr, he showed slightly
small thyroid gland and elevated thyroidal 123I uptake. Genetic analysis showed
that he was compound heterozygous for two known missense mutations (Arg109Gln and
Arg450His) in the TSHR gene. Further, the signal transduction of Arg109Gln-TSHR was
defective in both Gs- and Gq-coupled pathways, while Arg450His-TSHR showed Gq-dominant
defect. 123I uptake was evaluated earlier in 16 patients with TSH resistance,
and a correlation between TSH levels and 123I uptake was shown in patients with
specific genotypes (Arg450His or Leu653Val). Collectively, we have re-confirmed that the
emergence of the nonclassic phenotype requires two factors: mutant TSHR with Gq-dominant
coupling defect and relatively high levels of serum TSH.
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Affiliation(s)
- Chiho Sugisawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.,Department of Internal Medicine, Showa University Fujigaoka Hospital, Kanagawa, Japan
| | - Kiyomi Abe
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | | | - Matsuo Taniyama
- Department of Internal Medicine, Showa University Fujigaoka Hospital, Kanagawa, Japan.,Tokyo Health Service Association, Tokyo, Japan
| | - Tomonobu Hasegawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Satoshi Narumi
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
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17
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Briet C, Suteau-Courant V, Munier M, Rodien P. Thyrotropin receptor, still much to be learned from the patients. Best Pract Res Clin Endocrinol Metab 2018; 32:155-164. [PMID: 29678283 DOI: 10.1016/j.beem.2018.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the absence of crystal available for the full-length thyrotropin receptor, knowledge of its structure and functioning has benefitted from the identification and characterization of mutations in patients with various thyroid dysfunctions. The characterization of activating mutations has contributed to the elaboration of a model involving the extracellular domain of the receptor as an inverse tethered agonist which, upon binding of the ligand, relieves the transmembrane domain from an inhibiting interaction and activates it. The models derived from comparisons with other receptors, enriched with the information provided by the study of mutations, have proven useful for the design of small-molecule agonists and antagonists that may be used in the future to treat thyroid dysfunctions. In this review, extrathyroidal expression of the thyrotropin receptor is described, the role of which is still poorly defined.
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Affiliation(s)
- Claire Briet
- Centre de Référence des Maladies Rares de la Thyroïde et des Récepteurs Hormonaux, Centre Hospitalo-Universitaire d'Angers, 4 Rue Larrey, Angers, France; Institut MITOVASC, UMR CNRS 6015, INSERM 1083, Université d'Angers, France.
| | - Valentine Suteau-Courant
- Centre de Référence des Maladies Rares de la Thyroïde et des Récepteurs Hormonaux, Centre Hospitalo-Universitaire d'Angers, 4 Rue Larrey, Angers, France; Institut MITOVASC, UMR CNRS 6015, INSERM 1083, Université d'Angers, France.
| | - Mathilde Munier
- Centre de Référence des Maladies Rares de la Thyroïde et des Récepteurs Hormonaux, Centre Hospitalo-Universitaire d'Angers, 4 Rue Larrey, Angers, France; Institut MITOVASC, UMR CNRS 6015, INSERM 1083, Université d'Angers, France.
| | - Patrice Rodien
- Centre de Référence des Maladies Rares de la Thyroïde et des Récepteurs Hormonaux, Centre Hospitalo-Universitaire d'Angers, 4 Rue Larrey, Angers, France; Institut MITOVASC, UMR CNRS 6015, INSERM 1083, Université d'Angers, France.
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18
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Abe K, Narumi S, Suwanai AS, Adachi M, Muroya K, Asakura Y, Nagasaki K, Abe T, Hasegawa T. Association between monoallelic TSHR mutations and congenital hypothyroidism: a statistical approach. Eur J Endocrinol 2018; 178:137-144. [PMID: 29092890 DOI: 10.1530/eje-16-1049] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 09/30/2017] [Accepted: 11/01/2017] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Biallelic TSHR mutations cause congenital hypothyroidism (CH). Serum TSH levels of monoallelic mutation carriers range from normal to mildly elevated, and thus the size of its effect remains unclear. The objectives were to examine the association between monoallelic TSHR mutations and positivity at newborn screening (NBS) for CH, and to test whether the association was modified by another genetic factor. SUBJECTS AND METHODS We enrolled 395 patients that had a positive result in NBS and sequenced TSHR. Monoallelic TSHR mutation carriers were further sequenced for DUOX2. Molecular functions of the mutations were verified in vitro. The frequency of the mutations in the study subjects was compared with a theoretical value in the Japanese general population. Odds ratio (OR) for NBS positivity associated with the mutation was calculated. Using Bayes' theorem, we estimated a posterior probability of NBS positivity given the mutation. RESULTS Twenty-six monoallelic TSHR mutation carriers were found. Four out of the 26 also had a monoallelic DUOX2 mutation (double heterozygotes). The frequencies of monoallelic TSHR mutation carriers (6.6%) and double heterozygotes (1.0%) were significantly higher than those in the general population (0.58% and 0.0087%, respectively). OR for NBS positivity of having a monoallelic TSHR mutation or being a double heterozygote was 12.0 or 117.9, respectively. Posterior probability of NBS positivity was 0.38% in monoallelic TSHR mutation carriers and 3.8% in double heterozygotes. CONCLUSIONS Monoallelic TSHR mutations are significantly associated with NBS positivity, and the association is further strengthened by the coexistence of monoallelic DUOX2 mutations.
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Affiliation(s)
- Kiyomi Abe
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Satoshi Narumi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Ayuko S Suwanai
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Masanori Adachi
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Koji Muroya
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Yumi Asakura
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Keisuke Nagasaki
- Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medicine and Dental Sciences, Niigata, Japan
| | - Takayuki Abe
- Center for Clinical Research, Keio University School of Medicine, Tokyo, Japan
| | - Tomonobu Hasegawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
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19
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Abstract
Thyroid hormones are essential for skeletal development and are important regulators of bone maintenance in adults. Childhood hypothyroidism causes delayed skeletal development, retarded linear growth and impaired bone mineral accrual. Epiphyseal dysgenesis is evidenced by classic features of stippled epiphyses on X-ray. In severe cases, post-natal growth arrest results in a complex skeletal dysplasia. Thyroid hormone replacement stimulates catch-up growth and bone maturation, but recovery may be incomplete dependent on the duration and severity of hypothyroidism prior to treatment. A severe phenotype characteristic of hypothyroidism occurs in children with resistance to thyroid hormone due to mutations affecting THRA encoding thyroid hormone receptor α (TRα). Discovery of this rare condition recapitulated animal studies demonstrating that TRα mediates thyroid hormone action in the skeleton. In adults, thyrotoxicosis is well known to cause severe osteoporosis and fracture, but cases are rare because of prompt diagnosis and treatment. Recent data, however, indicate that subclinical hyperthyroidism is associated with low bone mineral density (BMD) and an increased risk of fracture. Population studies have also shown that variation in thyroid status within the reference range in post-menopausal women is associated with altered BMD and fracture risk. Thus, thyroid status at the upper end of the euthyroid reference range is associated with low BMD and increased risk of osteoporotic fragility fracture. Overall, extensive data demonstrate that euthyroid status is required for normal post-natal growth and bone mineral accrual, and is fundamental for maintenance of adult bone structure and strength.
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Affiliation(s)
- G. R. Williams
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, 10N5 Commonwealth Building, London, W12 0NN UK
| | - J. H. D. Bassett
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, 10N6 Commonwealth Building, London, W12 0NN UK
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20
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de Filippis T, Gelmini G, Paraboschi E, Vigone MC, Di Frenna M, Marelli F, Bonomi M, Cassio A, Larizza D, Moro M, Radetti G, Salerno M, Ardissino D, Weber G, Gentilini D, Guizzardi F, Duga S, Persani L. A frequent oligogenic involvement in congenital hypothyroidism. Hum Mol Genet 2017; 26:2507-2514. [PMID: 28444304 DOI: 10.1093/hmg/ddx145] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 04/12/2017] [Indexed: 12/16/2022] Open
Abstract
Congenital hypothyroidism (CH), the most frequent form of preventable mental retardation, is predicted to have a relevant genetic origin. However, CH is frequently reported to be sporadic and candidate gene variations were found in <10% of the investigated patients. Here, we characterize the involvement of 11 candidate genes through a systematic Next Generation Sequencing (NGS) analysis. The NGS was performed in 177 unrelated CH patients (94 gland-in-situ; 83 dysgenesis) and in 3,538 control subjects. Non-synonymous or splicing rare variants (MAF < 0.01) were accepted, and their functional impact was predicted by a comprehensive bioinformatic approach and co-segregation studies. The frequency of variations in cases and controls was extended to 18 CH-unrelated genes. At least one rare variant was accepted in 103/177 patients. Monogenic recessive forms of the disease were found in five cases, but oligogenic involvement was detected in 39 patients. The 167 variations were found to affect all genes independently of the CH phenotype. These findings were replicated in an independent cohort of additional 145 CH cases. When compared to 3,538 controls, the CH population was significantly enriched with disrupting variants in the candidate genes (P = 5.5 × 10-7), but not with rare variations in CH-unrelated genes. Co-segregation studies of the hypothyroid phenotype with multiple gene variants in several pedigrees confirmed the potential oligogenic origin of CH. The systematic NGS approach reveals the frequent combination of rare variations in morphogenetic or functional candidate genes in CH patients independently of phenotype. The oligogenic origin represents a suitable explanation for the frequent sporadic CH occurrence.
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Affiliation(s)
- Tiziana de Filippis
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Giulia Gelmini
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Elvezia Paraboschi
- Department of Biomedical Sciences, Humanitas University, 20089 Rozzano, Milan, Italy.,Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | | | | | - Federica Marelli
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Marco Bonomi
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy.,Department of Clinical Sciences and Community Health (DISCCO), University of Milan, Milan, Italy
| | | | - Daniela Larizza
- Department of Pediatrics, IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy
| | - Mirella Moro
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | | | | | - Diego Ardissino
- Cardiology Department, Parma University Hospital, Parma, Italy
| | - Giovanna Weber
- San Raffaele Hospital and Vita-Salute University, Milan, Italy
| | - Davide Gentilini
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Fabiana Guizzardi
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Stefano Duga
- Department of Biomedical Sciences, Humanitas University, 20089 Rozzano, Milan, Italy.,Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Luca Persani
- Division of Endocrine and Metabolic Diseases & Labs of Endocrine and Metabolic Research or Molecular Biology, IRCCS Istituto Auxologico Italiano, Milan, Italy.,Department of Clinical Sciences and Community Health (DISCCO), University of Milan, Milan, Italy
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21
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Wang F, Liu C, Jia X, Liu X, Xu Y, Yan S, Jia X, Huang Z, Liu S, Gu M. Next-generation sequencing of NKX2.1, FOXE1, PAX8, NKX2.5, and TSHR in 100 Chinese patients with congenital hypothyroidism and athyreosis. Clin Chim Acta 2017; 470:36-41. [PMID: 28455095 DOI: 10.1016/j.cca.2017.04.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND The abnormal expression of certain transcription factors (NKX2.1, FOXE1, NKX2.5, and PAX8) and thyroid stimulating hormone receptor (TSHR) genes has been associated with athyreosis, which is a form of thyroid dysgenesis (TD). We aimed to identify candidate gene mutations in CH patients with athyreosis and to establish the genotype-phenotype correlations in a Chinese population. METHODS The exons and flanking sequences of NKX2.1, FOXE1, NKX2.5, PAX8, and TSHR were screened by next-generation sequencing and further confirmed by direct Sanger sequencing. The mutation frequencies were calculated and compared against databases. The relationship between genotype and phenotype was also determined. RESULTS Seven variants were detected in TSHR-p.P52T, p.G132R, p.M164K, p.R450H, p.C700E, p.A522V, and p.R528S. The p. G132R, p. M164K and p. R528S variants were first identified in public databases. Five variants (p.G44D, p.G360V, p.R401Q, p.L418I, and p.E453Q) were found in NKX2.1 and one variant (p.P243T) was detected in FOXE1. In addition, one variant (p.N291I) was found in NKX2.5 and two variants (p.A355V and c.-26G>A) were detected in PAX8. CONCLUSIONS Our study indicated that TSHR mutations have phenotypic variability and has further expanded the mutation spectrum of TSHR. We also revealed that the rate of NKX2.1, FOXE1, NKX2.5, and PAX8 mutations were low in patients with CH and athyreosis, in contrast to the higher rate of TSHR mutations.
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Affiliation(s)
- Fang Wang
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China; Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Chang Liu
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Xiuhua Jia
- Clinic Lab, Linyi Maternal and Children Health's Hospital, Linyi, China
| | - Xiangju Liu
- Genetics Diagnostic Lab, Tai'an Maternity and Child Care Hospital, Tai'an 271000, China
| | - Yinglei Xu
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Shengli Yan
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Xuewen Jia
- Department of Cardiovascular, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Zuzhou Huang
- Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China
| | - Shiguo Liu
- Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
| | - Maosheng Gu
- Genetic Medicine Center, Xuzhou Maternal and Children Health's Hospital, Xuzhou 221009, China.
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22
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Abstract
Developmental anomalies of the thyroid gland, defined as thyroid dysgenesis, underlie the majority of cases of congenital hypothyroidism. Thyroid dysgenesis is predominantly a sporadic disorder although a reported familial enrichment, variation of incidence by ethnicity and the monogenic defects associated mainly with athyreosis or orthotopic thyroid hypoplasia, suggest a genetic contribution. Of note, the most common developmental anomaly, thyroid ectopy, remains unexplained. Ectopy may result from multiple genetic or epigenetic variants in the germline and/or at the somatic level. This review provides a brief overview of the monogenic defects in candidate genes that have been identified so far and of the syndromes which are known to be associated with thyroid dysgenesis.
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Affiliation(s)
- Rasha Abu-Khudir
- Endocrinology Service and Research Center, Sainte-Justine Hospital and Department of Pediatrics, University of Montreal, Montreal, H3T 1C5, Quebec, Canada; Chemistry Department, Biochemistry Division, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
| | - Stéphanie Larrivée-Vanier
- Endocrinology Service and Research Center, Sainte-Justine Hospital and Department of Pediatrics, University of Montreal, Montreal, H3T 1C5, Quebec, Canada.
| | - Jonathan D Wasserman
- Division of Endocrinology, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.
| | - Johnny Deladoëy
- Endocrinology Service and Research Center, Sainte-Justine Hospital and Department of Pediatrics, University of Montreal, Montreal, H3T 1C5, Quebec, Canada.
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23
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Abstract
Resistance to thyrotropin (RTSH) is broadly defined as reduced sensitivity of thyroid follicle cells to stimulation by biologically active TSH due to genetic defects. Affected individuals have elevated serum TSH in the absence of goiter, with the severity ranging from nongoitrous isolated hyperthyrotropinemia to severe congenital hypothyroidism with thyroid hypoplasia. Conceptually, defects leading to RTSH impair both aspects of TSH-mediated action, namely thyroid hormone synthesis and gland growth. These include inactivating mutations in the genes encoding the TSH receptor and the PAX8 transcription factor. A common third cause has been genetically mapped to a locus on chromosome 15, but the underlying pathophysiology has not yet been elucidated. This review provides a succinct overview of currently defined causes of nonsyndromic RTSH, their differential diagnoses (autoimmune; partial iodine organification defects; syndromic forms of RTSH) and implications for the clinical approach to patients with RTSH.
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Affiliation(s)
- Helmut Grasberger
- University of Michigan, 6504 MSRB I, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA.
| | - Samuel Refetoff
- The University of Chicago, MC3090, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
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24
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Zhang HM, Zhou YQ, Dong Y, Su Q. Identification and functional characterization of a novel thyrotropin receptor mutation (V87L) in a Chinese woman with subclinical hypothyroidism. Exp Ther Med 2017; 13:290-294. [PMID: 28123504 DOI: 10.3892/etm.2016.3957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 11/10/2016] [Indexed: 11/05/2022] Open
Abstract
The thyrotropin receptor (TSHR) gene has been defined as a highly mutable gene. Mutations in the TSHR gene result in either gain or loss of the receptor function. Subclinical hypothyroidism (SH) is a clinical condition defined as an elevated serum TSH level associated with normal free thyroxine and free triiodothyronine. Chronic autoimmune thyroiditis is the most frequent cause of subclinical hypothyroidism in adults. In rare cases, a loss-of-function mutation of TSHR is the cause of SH. In the present study, a novel TSHR mutation (V87L; confirmed to be a loss-of-function mutation) was identified in a 59-year-old Chinese woman, as the potential cause of the patient's subclinical hypothyroidism. The case may provide valuable insight into the etiology of SH.
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Affiliation(s)
- Hong-Mei Zhang
- Department of Endocrinology, Xin Hua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200092, P.R. China
| | - Ya-Qin Zhou
- Department of Ultrasonography, Ruijin Hospital, North Branch, Xin Hua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 201801, P.R. China
| | - Yan Dong
- Department of Endocrinology, Xin Hua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200092, P.R. China
| | - Qing Su
- Department of Endocrinology, Xin Hua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200092, P.R. China
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25
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Abstract
Thyroid dysgenesis (TD) is the most common cause of congenital hypothyroidism in iodine-sufficient regions and includes a spectrum of developmental anomalies. The genetic components of TD are complex. Although a sporadic disease, advances in developmental biology have revealed monogenetic forms of TD. Inheritance is not based on a simple Mendelian pattern and additional genetic elements might contribute to the phenotypic spectrum. This article summarizes the key steps of normal thyroid development and provides an update on responsible genes and underlying mechanisms of TD. Up-to-date technologies in genetics and biology will allow us to advance in our knowledge of TD.
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Affiliation(s)
- Athanasia Stoupa
- Pediatric Endocrinology, Diabetology and Gynecology Department, Necker Enfants-Malades University Hospital, Assistance Publique Hôpitaux de Paris, 149 rue de Sèvres, 75015, Paris, France; Imagine Institute, Inserm U1163, 24 boulevard du Montparnasse, 75015, Paris, France
| | - Dulanjalee Kariyawasam
- Pediatric Endocrinology, Diabetology and Gynecology Department, Necker Enfants-Malades University Hospital, Assistance Publique Hôpitaux de Paris, 149 rue de Sèvres, 75015, Paris, France; Imagine Institute, Inserm U1163, 24 boulevard du Montparnasse, 75015, Paris, France; Cochin Institute, Inserm U1016, 22 rue Mechain, 75014, Paris, France
| | - Aurore Carré
- Imagine Institute, Inserm U1163, 24 boulevard du Montparnasse, 75015, Paris, France; Cochin Institute, Inserm U1016, 22 rue Mechain, 75014, Paris, France
| | - Michel Polak
- Pediatric Endocrinology, Diabetology and Gynecology Department, Necker Enfants-Malades University Hospital, Assistance Publique Hôpitaux de Paris, 149 rue de Sèvres, 75015, Paris, France; Imagine Institute, Inserm U1163, 24 boulevard du Montparnasse, 75015, Paris, France; Cochin Institute, Inserm U1016, 22 rue Mechain, 75014, Paris, France; Paris Descartes University, Sorbonne Paris Cité, 12 rue de l'École de Médecine, 75006, Paris, France.
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26
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Abstract
The skeleton is an exquisitely sensitive and archetypal T3-target tissue that demonstrates the critical role for thyroid hormones during development, linear growth, and adult bone turnover and maintenance. Thyrotoxicosis is an established cause of secondary osteoporosis, and abnormal thyroid hormone signaling has recently been identified as a novel risk factor for osteoarthritis. Skeletal phenotypes in genetically modified mice have faithfully reproduced genetic disorders in humans, revealing the complex physiological relationship between centrally regulated thyroid status and the peripheral actions of thyroid hormones. Studies in mutant mice also established the paradigm that T3 exerts anabolic actions during growth and catabolic effects on adult bone. Thus, the skeleton represents an ideal physiological system in which to characterize thyroid hormone transport, metabolism, and action during development and adulthood and in response to injury. Future analysis of T3 action in individual skeletal cell lineages will provide new insights into cell-specific molecular mechanisms and may ultimately identify novel therapeutic targets for chronic degenerative diseases such as osteoporosis and osteoarthritis. This review provides a comprehensive analysis of the current state of the art.
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Affiliation(s)
- J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, London W12 0NN, United Kingdom
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, London W12 0NN, United Kingdom
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27
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Stoy H, Gurevich VV. How genetic errors in GPCRs affect their function: Possible therapeutic strategies. Genes Dis 2015; 2:108-132. [PMID: 26229975 PMCID: PMC4516391 DOI: 10.1016/j.gendis.2015.02.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 02/07/2015] [Indexed: 01/14/2023] Open
Abstract
Activating and inactivating mutations in numerous human G protein-coupled receptors (GPCRs) are associated with a wide range of disease phenotypes. Here we use several class A GPCRs with a particularly large set of identified disease-associated mutations, many of which were biochemically characterized, along with known GPCR structures and current models of GPCR activation, to understand the molecular mechanisms yielding pathological phenotypes. Based on this mechanistic understanding we also propose different therapeutic approaches, both conventional, using small molecule ligands, and novel, involving gene therapy.
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28
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Romanet P, Osei L, Netchine I, Pertuit M, Enjalbert A, Reynaud R, Barlier A. Case report of GNAS epigenetic defect revealed by a congenital hypothyroidism. Pediatrics 2015; 135:e1079-83. [PMID: 25802348 DOI: 10.1542/peds.2014-2806] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Pseudohypoparathyroidism (PHP) is a group of disorders characterized by end-organ resistance to the parathyroid hormone (PTH). PHP type 1A includes multihormone resistance syndrome, Albright's hereditary osteodystrophy, and obesity and is caused by mutations in GNAS exon 1 through 13. PHP type 1B (PHP1B), caused by epigenetic changes in the GNAS locus, was initially described as an isolated resistance to PTH. Epigenetic changes in GNAS have also been reported in patients who display mild Albright's hereditary osteodystrophy or mild thyroid-stimulating hormone (TSH) resistance without mutation of GNAS. Here we report a case of PHP caused by epigenetic changes in GNAS in a patient with congenital hypothyroidism. The patient was referred for a positive newborn screening for hypothyroidism (TSH 50 mIU/L). She exhibited severe clinical features of congenital hypothyroidism. The thyroid was in place, and etiologic explorations were negative. TSH was normalized under L-thyroxin, and the symptoms disappeared, except for a macroglossia. In childhood, PHP was suspected in addition to elevated PTH, obesity, brachydactyly, and a rounded face. Sequencing, methylation analysis, and large deletion research were performed in GNAS. No genetic mutations were found. Methylation analysis revealed a broad epigenetic defect without deletion in GNAS consistent with sporadic PHP1B. The multilocus methylation analysis were negative. This finding expands the known onsets of PHP1B and emphasizes the need for a new PHP classification system. This case report has important consequences for the etiologic diagnosis of congenital hypothyroidism because it adds a new cause of the disease.
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Affiliation(s)
- Pauline Romanet
- Assistance Publique Hôpitaux de Marseille, Hôpital la Conception, Laboratory of Molecular Biology, Marseille, France; Aix Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France
| | - Lindsay Osei
- Assistance Publique Hôpitaux de Marseille, Hôpital La Timone Enfant, Departments of Pediatrics, Marseille, France
| | - Irène Netchine
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche Saint-Antoine, UMR_S 938, Paris, France; and Sorbonne Universités, Paris, France
| | - Morgane Pertuit
- Assistance Publique Hôpitaux de Marseille, Hôpital la Conception, Laboratory of Molecular Biology, Marseille, France
| | - Alain Enjalbert
- Assistance Publique Hôpitaux de Marseille, Hôpital la Conception, Laboratory of Molecular Biology, Marseille, France; Aix Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France
| | - Rachel Reynaud
- Aix Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France; Assistance Publique Hôpitaux de Marseille, Hôpital La Timone Enfant, Departments of Pediatrics, Marseille, France
| | - Anne Barlier
- Assistance Publique Hôpitaux de Marseille, Hôpital la Conception, Laboratory of Molecular Biology, Marseille, France; Aix Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France;
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29
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Tenenbaum-Rakover Y, Almashanu S, Hess O, Admoni O, Hag-Dahood Mahameed A, Schwartz N, Allon-Shalev S, Bercovich D, Refetoff S. Long-term outcome of loss-of-function mutations in thyrotropin receptor gene. Thyroid 2015; 25:292-9. [PMID: 25557138 PMCID: PMC4361004 DOI: 10.1089/thy.2014.0311] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Loss-of-function mutations in the thyrotropin receptor (TSHR) gene lead to resistance to TSH (RTSH) presenting with either congenital hypothyroidism (CH) or subclinical hypothyroidism (SCH). Despite several reports of patients with TSHR mutations, data on the long-term outcome of this condition are limited, and no consensus exists on the need for hormone replacement therapy. The aim of the present study was to assess the long-term outcome in children and adolescents with RTSH due to TSHR mutations. METHODS The TSHR gene was sequenced in 94 subjects (aged 3 days-21 years) with either nonautoimmune SCH or CH with RTSH. RESULTS Twenty-seven subjects (29%) carried mutations in TSHR. Fifteen infants were identified by neonatal screening, and the other 79 patients were detected in the process of testing for various other conditions or because of family occurrence of thyroid test abnormalities. Six different mutations were identified: c.484C>G (p.P162A), c.202C>T (p.P68S), c.790C>T (p.P264S), c.269A>C (p.Q90P), c.1957C>G (p.L653V), and c.1347C>T (p.R450C). Twelve subjects were homozygous, three were compound heterozygous, and 12 were heterozygous. Mean serum TSH levels at diagnosis and at last visit were significantly higher in patients with TSHR mutations than in those without mutations (29.04 vs. 14.15, p=0.002; 31.73 vs. 6.19, p<0.0001, respectively). Homozygous patients had a more severe phenotype (TSH 53.6 vs. 9.24, p<0.0001). Mean serum free thyroxine (fT4) levels at the last visit were significantly lower than at the first visit in the homozygous individuals (p=0.05) for a follow-up period of as long as 11 years. Heterozygous subjects had only mild hyperthyrotropinemia with stable TSH levels. However, homozygous subjects showed a trend toward increased TSH and decreased fT4 with time. CONCLUSION SCH in heterozygotes with TSHR mutations is a stable compensated condition with an appropriately adjusted set point for pituitary-thyroid feedback that does not require replacement therapy. However, homozygous subjects, with incompletely compensated SCH, show reduced fT4 levels over time and may require levothyroxine treatment. Replacement therapy should be considered on an individual basis, and long-term follow up is recommended.
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Affiliation(s)
- Yardena Tenenbaum-Rakover
- Pediatric Endocrine Unit, Ha'Emek Medical Center, Afula, Israel
- Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Shlomo Almashanu
- National Newborn Screening Program, Israeli Ministry of Health, Tel HaShomer Shiba Medical Center, Ramat Gan, Israel
| | - Ora Hess
- Pediatric Endocrine Unit, Ha'Emek Medical Center, Afula, Israel
| | - Osnat Admoni
- Pediatric Endocrine Unit, Ha'Emek Medical Center, Afula, Israel
| | | | - Naama Schwartz
- Clinical Research Unit, Ha'Emek Medical Center, Afula, Israel
| | - Stavit Allon-Shalev
- Rappaport Faculty of Medicine, Technion, Haifa, Israel
- Genetic Institute, Ha'Emek Medical Center, Afula, Israel
| | - Dani Bercovich
- Genetic Institute, Ha'Emek Medical Center, Afula, Israel
- Tel Hai College and GGA—Galilee Genetic Analysis Lab, Kazerin, Israel
| | - Samuell Refetoff
- Departments of Medicine, Pediatrics, and Committee on Genetics, The University of Chicago, Chicago, Illinois
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30
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Marcucci G, Cianferotti L, Beck-Peccoz P, Capezzone M, Cetani F, Colao A, Davì MV, degli Uberti E, Del Prato S, Elisei R, Faggiano A, Ferone D, Foresta C, Fugazzola L, Ghigo E, Giacchetti G, Giorgino F, Lenzi A, Malandrino P, Mannelli M, Marcocci C, Masi L, Pacini F, Opocher G, Radicioni A, Tonacchera M, Vigneri R, Zatelli MC, Brandi ML. Rare diseases in clinical endocrinology: a taxonomic classification system. J Endocrinol Invest 2015; 38:193-259. [PMID: 25376364 DOI: 10.1007/s40618-014-0202-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/17/2014] [Indexed: 02/05/2023]
Abstract
PURPOSE Rare endocrine-metabolic diseases (REMD) represent an important area in the field of medicine and pharmacology. The rare diseases of interest to endocrinologists involve all fields of endocrinology, including rare diseases of the pituitary, thyroid and adrenal glands, paraganglia, ovary and testis, disorders of bone and mineral metabolism, energy and lipid metabolism, water metabolism, and syndromes with possible involvement of multiple endocrine glands, and neuroendocrine tumors. Taking advantage of the constitution of a study group on REMD within the Italian Society of Endocrinology, consisting of basic and clinical scientists, a document on the taxonomy of REMD has been produced. METHODS AND RESULTS This document has been designed to include mainly REMD manifesting or persisting into adulthood. The taxonomy of REMD of the adult comprises a total of 166 main disorders, 338 including all variants and subtypes, described into 11 tables. CONCLUSIONS This report provides a complete taxonomy to classify REMD of the adult. In the future, the creation of registries of rare endocrine diseases to collect data on cohorts of patients and the development of common and standardized diagnostic and therapeutic pathways for each rare endocrine disease is advisable. This will help planning and performing intervention studies in larger groups of patients to prove the efficacy, effectiveness, and safety of a specific treatment.
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Affiliation(s)
- G Marcucci
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
| | - L Cianferotti
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - P Beck-Peccoz
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - M Capezzone
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Endocrinology and Metabolism and Biochemistry, University of Siena, Policlinico Santa Maria alle Scotte, Siena, Italy
| | - F Cetani
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Colao
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - M V Davì
- Section D, Department of Medicine, Clinic of Internal Medicine, University of Verona, Verona, Italy
| | - E degli Uberti
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - S Del Prato
- Section of Metabolic Diseases and Diabetes, Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - R Elisei
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Faggiano
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - D Ferone
- Endocrinology, Department of Internal Medicine and Medical Specialties and Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy
| | - C Foresta
- Department of Medicine and Centre for Human Reproduction Pathology, University of Padova, Padua, Italy
| | - L Fugazzola
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - E Ghigo
- Division of Endocrinology, Diabetology and Metabolism Department of Medical Sciences, University Hospital Città Salute e Scienza, Turin, Italy
| | - G Giacchetti
- Division of Endocrinology, Azienda Ospedaliero-Universitaria, Ospedali Riuniti Umberto I-GM Lancisi-G Salesi, Università Politecnica delle Marche, Ancona, Italy
| | - F Giorgino
- Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - A Lenzi
- Chair of Endocrinology, Section Medical Pathophysiology, Food Science and Endocrinology, Department Exp. Medicine, Sapienza University of Rome, Policlinico Umberto I, Rome, Italy
| | - P Malandrino
- Endocrinology, Department of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - M Mannelli
- Endocrinology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - C Marcocci
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - L Masi
- Department of Orthopedic, Metabolic Bone Diseases Unit AOUC-Careggi Hospital, Largo Palagi, 1, Florence, Italy
| | - F Pacini
- Section of Endocrinology and Metabolism, University of Siena, Siena, Italy
| | - G Opocher
- Familial Cancer Clinic and Oncoendocrinology, Veneto Institute of Oncology, IRCCS, Padua, Italy
- Department of Medicine DIMED, University of Padova, Padova, Italy
| | - A Radicioni
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - M Tonacchera
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - R Vigneri
- Department of Clinical and Molecular Biomedicine, University of Catania, and Humanitas Catania Center of Oncology, Catania, Italy
| | - M C Zatelli
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - M L Brandi
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
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31
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Abstract
Genetic defects of hormone receptors are the most common form of end-organ hormone resistance. One example of such defects is TSH resistance, which is caused by biallelic inactivating mutations in the TSH receptor gene (TSHR). TSH, a master regulator of thyroid functions, affects virtually all cellular processes involving thyroid hormone production, including thyroidal iodine uptake, thyroglobulin iodination, reuptake of iodinated thyroglobulin and thyroid cell growth. Resistance to TSH results in defective thyroid hormone production from the neonatal period, namely congenital hypothyroidism. Classically, clinical phenotypes of TSH resistance due to inactivating TSHR mutations were thought to vary depending on the residual mutant receptor activity. Nonfunctional mutations in the two alleles produce severe thyroid hypoplasia with overt hypothyroidism (uncompensated TSH resistance), while hypomorphic mutations in at least one allele produce normal-sized thyroid gland with preserved hormone-producing capacity (compensated TSH resistance). More recently, a new subgroup of TSH resistance (nonclassic TSH resistance) that is characterized by paradoxically high thyroidal iodine uptake has been reported. In this article, the pathophysiology and clinical features of TSH resistance due to inactivating TSHR mutations are reviewed, with particular attention to the nonclassic form.
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Affiliation(s)
- Satoshi Narumi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
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32
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Noor A, Lionel AC, Cohen-Woods S, Moghimi N, Rucker J, Fennell A, Thiruvahindrapuram B, Kaufman L, Degagne B, Wei J, Parikh SV, Muglia P, Forte J, Scherer SW, Kennedy JL, Xu W, McGuffin P, Farmer A, Strauss J, Vincent JB. Copy number variant study of bipolar disorder in Canadian and UK populations implicates synaptic genes. Am J Med Genet B Neuropsychiatr Genet 2014; 165B:303-13. [PMID: 24700553 DOI: 10.1002/ajmg.b.32232] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 03/10/2014] [Indexed: 01/03/2023]
Abstract
Genome-wide single nucleotide polymorphism (SNP) data from 936 bipolar disorder (BD) individuals and 940 psychiatrically healthy comparison individuals of North European descent were analyzed for copy number variation (CNV). Using multiple CNV calling algorithms, and validating using in vitro molecular analyses, we identified CNVs implicating several candidate genes that encode synaptic proteins, such as DLG1, DLG2, DPP6, NRXN1, NRXN2, NRXN3, SHANK2, and EPHA5, as well as the neuronal splicing regulator RBFOX1 (A2BP1), and neuronal cell adhesion molecule CHL1. We have also identified recurrent CNVs on 15q13.3 and 16p11.2-regions previously reported as risk loci for neuropsychiatric disorders. In addition, we performed CNV analysis of individuals from 215 BD trios and identified de novo CNVs involving the NRXN1 and DRD5 genes. Our study provides further evidence of the occasional involvement of genomic mutations in the etiology of BD, however, there is no evidence of an increased burden of CNVs in BD. Further, the identification of CNVs at multiple members of the neurexin gene family in BD individuals, supports the role of synaptic disruption in the etiology of BD.
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Affiliation(s)
- Abdul Noor
- Molecular Neuropsychiatry & Development Lab, Campbell Family Mental Health Research Institute, The Centre for Addiction & Mental Health, Toronto, Ontario, Canada
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33
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Frequency and clinical implication of the R450H mutation in the thyrotropin receptor gene in the Japanese population detected by Smart Amplification Process 2. BIOMED RESEARCH INTERNATIONAL 2014; 2014:964635. [PMID: 24895636 PMCID: PMC4026960 DOI: 10.1155/2014/964635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/15/2014] [Accepted: 04/15/2014] [Indexed: 12/20/2022]
Abstract
In Japanese pediatric patients with thyrotropin (TSH) resistance, the R450H mutation in TSH receptor gene (TSHR) is occasionally observed. We studied the frequency and clinical implication of the R450H mutation in TSHR in the general population of Japanese adults using smart amplification process 2 (SmartAmp2). We designed SmartAmp2 primer sets to detect this mutation using a drop of whole blood. We analyzed thyroid function, antithyroid antibodies, and this mutation in 429 Japanese participants who had not been found to have thyroid disease. Two cases without antithyroid antibodies were heterozygous for the R450H mutation in TSHR. Thus, the prevalence of this mutation was 0.47% in the general population and 0.63% among those without antithyroid antibodies. Their serum TSH concentrations were higher than the average TSH concentration not only in subjects without antithyroid antibodies but also in those with antithyroid antibodies. The R450H mutation in TSHR is relatively common in the Japanese population and potentially affects thyroid function. The present study demonstrates that the SmartAmp2 method is useful to detect the R450H mutation in TSHR, which is one of the common causes of TSH resistance in the Japanese population.
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34
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Abstract
Advances in prenatal imaging techniques and in fetal hormonology now allow for identification of disorders of thyroid function in the fetus. These can potentially be treated in utero by giving drugs to the mother. This review shows the feasibility of in utero treatment of fetal thyroid disorders, either indirectly by treating the mother or by giving the necessary drugs directly to the fetus. For goitrous fetal hypothyroidism leading to hydramnios, repeated intra-amniotic injections of thyroxine have been reported to decrease the size of the fetal thyroid. Experience with such procedures is limited but positive. The risk that direct in utero treatment of the fetus may provoke premature labor or cause infection should be carefully evaluated. In women with Graves' disease, autoimmune fetal hyperthyroidism can generally be treated in a noninvasive way by optimizing treatment of the mother, such as by increasing the dose of antithyroid drugs. Follow-up of the efficacy and the possible long-term consequences of medical interventions to normalize thyroid function of the fetus are of great importance. Specialized care of the fetus should be provided by skilled teams with extensive experience in prenatal care.
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Affiliation(s)
- Michel Polak
- Pediatric Endocrinology, Gynecology and Diabetology, Necker Enfants-Malades Hospital, AP-HP, Paris, France; INSERM U845, IMAGINE affiliate, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
| | - Dominique Luton
- Obstetrics and Gynecology, AP-HP, GHU Nord, Hôpital Beaujon and Bichat, Paris and Clichy, Université Paris VII, Paris, France.
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35
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Abstract
The most frequent cause of congenital hypothyroidism is thyroid dysgenesis. Thyroid dysgenesis summarizes a spectrum of developmental abnormalities of the embryonic thyroid ranging from complete absence of the thyroid gland (athyreosis), to a normally located but too small thyroid (hypoplasia), or an abnormally located thyroid gland (ectopy). Although considered a sporadic disease, distinct genetic forms of isolated or syndromic thyroid dysgenesis have been described in recent years. However, genetics of thyroid dysgenesis (TD) are mostly not following simple Mendelian patterns, and beside monogenic, multigenic and epigenetic mechanisms need to be considered. The review will highlight the molecular mechanisms of thyroid organogenesis, clinical and genetic features of the different monogenetic forms of thyroid dysgenesis, the aspects relevant for diagnosis and counseling of affected families and current research strategies to get more insight into the non-Medelian mechanisms of normal and abnormal thyroid development.
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Affiliation(s)
- Gabor Szinnai
- Division of Paediatric Endocrinology and Diabetology, University Children's Hospital Basel UKBB, Spitalstrasse 33, CH-4031 Basel, Switzerland; Department of Biomedicine, University Basel, Spitalstrasse 33, CH-4031 Basel, Switzerland.
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Agretti P, De Marco G, Di Cosmo C, Bagattini B, Ferrarini E, Montanelli L, Vitti P, Tonacchera M. Frequency and effect on serum TSH of phosphodiesterase 8B (PDE8B) gene polymorphisms in patients with sporadic nonautoimmune subclinical hypothyroidism. J Endocrinol Invest 2014; 37:189-94. [PMID: 24497218 DOI: 10.1007/s40618-013-0036-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 11/16/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND Nonautoimmune subclinical hypothyroidism (NSH) is characterized by elevated serum TSH in presence of normal thyroid hormone levels and absence of anti-thyroid antibodies. As result of a genomic-wide study, a strong association between three polymorphic variants in intron 1 of human PDE8B gene (rs4704397, rs6885099, rs2046045) and serum TSH has been reported in euthyroid subjects. AIM The aim of this study was to evaluate frequency and effects on serum TSH of PDE8B gene polymorphisms in patients with sporadic NSH and verify if differences in serum TSH levels are associated to these polymorphic variants. SUBJECTS AND METHODS A total of 58 Italian selected patients affected by NSH, with elevated serum TSH, normal FT3 and FT4 and without TSHr gene mutations, were subjected to genotyping for specific single nucleotide polymorphism of PDE8B gene. RESULTS In all patients, the integrity of TSH receptor gene was attested. The ancestral allele associated with increased serum TSH was present in 42/58 patients (72.4 %) for rs4704397, in 42/58 patients (72.4 %) for rs6885099 and in 44/58 patients (75.9 %) for rs2046045. However, similar values of serum TSH were detected in patients with minor or major allele for each polymorphism. CONCLUSIONS A prevalence of the minor allele of PDE8B gene polymorphism associated with elevated serum levels of TSH was demonstrated in patients affected by sporadic NSH; however, significant differences in circulating TSH in patients with minor or major alleles for each polymorphism were not identified demonstrating the lack of association between the polymorphisms and serum TSH levels in these patients.
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Affiliation(s)
- P Agretti
- Dipartimento di Medicina Clinica e Sperimentale, Sezione di Endocrinologia, Università di Pisa, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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Kleinau G, Neumann S, Grüters A, Krude H, Biebermann H. Novel insights on thyroid-stimulating hormone receptor signal transduction. Endocr Rev 2013; 34:691-724. [PMID: 23645907 PMCID: PMC3785642 DOI: 10.1210/er.2012-1072] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The TSH receptor (TSHR) is a member of the glycoprotein hormone receptors, a subfamily of family A G protein-coupled receptors. The TSHR is of great importance for the growth and function of the thyroid gland. The TSHR and its endogenous ligand TSH are pivotal proteins with respect to a variety of physiological functions and malfunctions. The molecular events of TSHR regulation can be summarized as a process of signal transduction, including signal reception, conversion, and amplification. The steps during signal transduction from the extra- to the intracellular sites of the cell are not yet comprehensively understood. However, essential new insights have been achieved in recent years on the interrelated mechanisms at the extracellular region, the transmembrane domain, and intracellular components. This review contains a critical summary of available knowledge of the molecular mechanisms of signal transduction at the TSHR, for example, the key amino acids involved in hormone binding or in the structural conformational changes that lead to G protein activation or signaling regulation. Aspects of TSHR oligomerization, signaling promiscuity, signaling selectivity, phenotypes of genetic variations, and potential extrathyroidal receptor activity are also considered, because these are relevant to an understanding of the overall function of the TSHR, including physiological, pathophysiological, and pharmacological perspectives. Directions for future research are discussed.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Ostring 3, Augustenburger Platz 1, 13353 Berlin, Germany.
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Moia S, Godi M, Walker GE, Roccio M, Agretti P, Tonacchera M, Berardi R, Bellone S, Prodam F, Giordano M, Bona G. The W520X mutation in the TSHR gene brings on subclinical hypothyroidism through an haploinsufficiency mechanism. J Endocrinol Invest 2013; 36:716-21. [PMID: 23563316 DOI: 10.3275/8930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND TSHR is a G-protein-coupled seven transmembrane domain receptor that activates the two major signal transduction pathways: the Gαs/adenylate cyclase and the Gαq/11/phospholipase C pathways. Inactivating mutations in the TSHR gene have been demonstrated to be responsible for subclinical hypothyroidism, a disorder characterized by elevated serum TSH concentrations despite normal thyroid hormones levels. AIM We identified in a child a nonsense mutation (W520X) in the third transmembrane domain of the TSHR that causes the lack of the C-terminus portion of the receptor. The functional significance of this variation was assessed in vitro. MATERIAL/SUBJECT AND METHODS The W520X mutation was introduced into the pSVL vector containing the wild-type sequence of TSHR gene. Wild-type and mutated vectors were expressed in Chinese Hamster Ovary (CHO) cells, and cAMP, inositol phosphate (IP), immunofluorescence and FACS analyses were performed. RESULTS Transfection with pSVL-TSHR vector induced basal cAMP and IP production in the absence of TSH stimulation, indicating a constitutive activity for the TSHR. An impairment of receptor function was demonstrated by the observation that cells expressing the mutant TSHR exhibited a lower second messenger production with respect to the wild-type, despite a normal expression of the receptor at the cell surface. CONCLUSIONS The mechanism through which the W520X mutation exerts its effect is more likely haploinsufficiency rather than a dominant-negative effect. This could explain the phenotype of our patient, who has a hormonal pattern in the range of a mild subclinical hypothyroidism, without an overt disease phenotype.
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Affiliation(s)
- S Moia
- Division of Pediatrics, Department of Health Sciences, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy.
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Raychaudhuri N, Fernando R, Smith TJ. Thyrotropin regulates IL-6 expression in CD34+ fibrocytes: clear delineation of its cAMP-independent actions. PLoS One 2013; 8:e75100. [PMID: 24086448 PMCID: PMC3783445 DOI: 10.1371/journal.pone.0075100] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/11/2013] [Indexed: 11/18/2022] Open
Abstract
IL-6 plays diverse roles in normal and disease-associated immunity such as that associated with Graves’ disease (GD). In that syndrome, the orbit undergoes remodeling during a process known as thyroid-associated ophthalmopathy (TAO). Recently, CD34+ fibrocytes were found to infiltrate the orbit in TAO where they transition into CD34+ orbital fibroblasts. Surprisingly, fibrocytes display high levels of functional thyrotropin receptor (TSHR), the central antigen in GD. We report here that TSH and the pathogenic anti-TSHR antibodies that drive hyperthyroidism in GD induce IL-6 expression in fibrocytes and orbital fibroblasts. Unlike TSHR signaling in thyroid epithelium, that occurring in fibrocytes is completely independent of adenylate cyclase activation and cAMP generation. Instead TSH activates PDK1 and both AKT/PKB and PKC pathways. Expression and use of PKCβII switches to that of PKCµ as fibrocytes transition to TAO orbital fibroblasts. This shift is imposed by CD34− orbital fibroblasts but reverts when CD34+ fibroblasts are isolated. The up-regulation of IL-6 by TSH results from coordinately enhanced IL-6 gene promoter activity and increased IL-6 mRNA stability. TSH-dependent IL-6 expression requires activity at both CREB (−213 to −208 nt) and NF-κB (–78 to −62 nt) binding sites. These results provide novel insights into the molecular action of TSH and signaling downstream for TSHR in non-thyroid cells. Fibrocytes neither express adenylate cyclase nor generate cAMP and thus these findings are free from any influence of cAMP-related signaling. They identify potential therapeutic targets for TAO.
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Affiliation(s)
- Nupur Raychaudhuri
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Roshini Fernando
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Terry J. Smith
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Division of Metabolism, Endocrine, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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Nettore IC, Cacace V, De Fusco C, Colao A, Macchia PE. The molecular causes of thyroid dysgenesis: a systematic review. J Endocrinol Invest 2013; 36:654-64. [PMID: 23698639 DOI: 10.3275/8973] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Congenital hypothyroidism (CH) is a frequent disease occurring with an incidence of about 1/2500 newborns/year. In 80-85% of the cases CH is caused by alterations in thyroid morphogenesis, generally indicated by the term "thyroid dysgenesis" (TD). TD is generally a sporadic disease, but in about 5% of the cases a genetic origin has been demonstrated. In these cases, mutations in genes playing a role during thyroid morphogenesis (NKX2-1, PAX8, FOXE1, NKX2-5, TSHR) have been reported. AIM This work reviews the main steps of thyroid morphogenesis and all the genetic alterations associated with TD and published in the literature.
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Affiliation(s)
- I C Nettore
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", Via S. Pansini, 5 - 80131 Naples, Italy
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Cassio A, Nicoletti A, Rizzello A, Zazzetta E, Bal M, Baldazzi L. Current loss-of-function mutations in the thyrotropin receptor gene: when to investigate, clinical effects, and treatment. J Clin Res Pediatr Endocrinol 2013; 5 Suppl 1:29-39. [PMID: 23154162 PMCID: PMC3608004 DOI: 10.4274/jcrpe.864] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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
Thyroid-stimulating hormone receptor (TSHR) loss-of-function (LOF) mutations lead to a wide spectrum of phenotypes, ranging from severe congenital hypothyroidism (CH) to mild euthyroid hyperthyrotropinemia. The degree of TSH resistance depends on the severity of the impairment of the receptor function caused by the mutation and on the number of mutated alleles In this review data about genotype-phenotype correlation and criteria for clinical work-up will be presented and discussed. Complete TSH resistance due to biallelic LOF TSHR mutations must be suspected in all patients with severe not syndromic CH and severe thyroid hypoplasia diagnosed at birth by neonatal screening. Partial forms of TSH resistance show a more heterogeneous hormonal and clinical pattern . In these cases TSH serum levels are above the upper limit of normal range for the age but with a very variable pattern, free thyroxine (T4) concentrations are within the normal range and thyroid size can be normal or hypoplastic at ultrasound scan. An early substitutive treatment with L-T4 must be mandatory in all patients with severe CH due to complete uncompensated TSH resistance diagnosed at birth by neonatal screening. The usefulness of substitutive treatment appears much more controversial inpatients with subclinical hypothyroidism due to partial TSH resistance in whom the increased TSH concentration should be able to compensate the mild functional impairment of the mutant receptor. Together with standard criteria we recommend also an accurate clinical work-up to select patients who are candidates for a LOF TSHR mutation.
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Affiliation(s)
- Alessandra Cassio
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
| | - Annalisa Nicoletti
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Angela Rizzello
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Emanuela Zazzetta
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Milva Bal
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Lilia Baldazzi
- Department of Gynaecologic, Obstetric and Paediatric Sciences, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
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Cerbone M, Agretti P, De Marco G, Improda N, Pignata C, Santamaria F, Tonacchera M, Salerno M. Non-autoimmune subclinical hypothyroidism due to a mutation in TSH receptor: report on two brothers. Ital J Pediatr 2013; 39:5. [PMID: 23332130 PMCID: PMC3565903 DOI: 10.1186/1824-7288-39-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 01/15/2013] [Indexed: 11/10/2022] Open
Abstract
Subclinical hypothyroidism (SH) is a condition characterized by a mild persistent thyroid failure. The main cause is represented by autoimmune thyroiditis, but mutations in genes encoding proteins involved in TSH pathway are thought to be responsible for SH, particularly in cases arising in familial settings. Patients with the syndrome of TSH unresponsiveness may have compensated or overt hypothyroidism with a wide spectrum of clinical and morphological alterations depending on the degree of impairment of TSH-receptor (TSH-R) function. We describe the case of two brothers with non autoimmune SH carrying the same heterozygous mutation in the extracellular domain of TSH-R and presenting with different clinical, biochemical and morphological features. The first one had only a slight persistent elevation of TSH, a normal thyroid ultrasound and did never require l- thyroxine (L-T4) replacement treatment. The second one had a neonatal persistent moderate TSH levels increase associated with a thyroid gland hypoplasia and was treated with L-T4 since the first months of life. These two cases support the recent association of TSH-R mutations inheritance as an autosomal dominant pattern with variable expressivity and suggest that the decision to start replacement therapy in patients with persistent SH due to TSH resistance should be individualized.
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Affiliation(s)
- Manuela Cerbone
- Department of Pediatrics, University of Naples Federico II, Naples, Italy
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Dietrich JW, Landgrafe G, Fotiadou EH. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis. J Thyroid Res 2012; 2012:351864. [PMID: 23365787 PMCID: PMC3544290 DOI: 10.1155/2012/351864] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/21/2012] [Indexed: 12/11/2022] Open
Abstract
This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range.
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Affiliation(s)
- Johannes W. Dietrich
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
| | - Gabi Landgrafe
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
- Klinik für Allgemein- und Visceralchirurgie, Agaplesion Bethesda Krankenhaus Wuppertal gGmbH, Hainstraße 35, 42109 Wuppertal, NRW, Germany
| | - Elisavet H. Fotiadou
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
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45
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van Engelen K, Mommersteeg MTM, Baars MJH, Lam J, Ilgun A, van Trotsenburg ASP, Smets AMJB, Christoffels VM, Mulder BJM, Postma AV. The ambiguous role of NKX2-5 mutations in thyroid dysgenesis. PLoS One 2012; 7:e52685. [PMID: 23285148 PMCID: PMC3532205 DOI: 10.1371/journal.pone.0052685] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/19/2012] [Indexed: 12/20/2022] Open
Abstract
NKX2-5 is a homeodomain-containing transcription factor implied in both heart and thyroid development. Numerous mutations in NKX2-5 have been reported in individuals with congenital heart disease (CHD), but recently a select few have been associated with thyroid dysgenesis, among which the p.A119S variation. We sequenced NKX2-5 in 303 sporadic CHD patients and 38 families with at least two individuals with CHD. The p.A119S variation was identified in two unrelated patients: one was found in the proband of a family with four affected individuals with CHD and the other in a sporadic CHD patient. Clinical evaluation of heart and thyroid showed that the mutation did not segregate with CHD in the familial case, nor did any of the seven mutation carriers have thyroid abnormalities. We tested the functional consequences of the p.A119S variation in a cellular context by performing transactivation assays with promoters relevant for both heart and thyroid development in rat heart derived H10 cells and HELA cells. There was no difference between wildtype NKX2-5 and p.A119S NKX2-5 in activation of the investigated promoters in both cell lines. Additionally, we reviewed the current literature on the topic, showing that there is no clear evidence for a major pathogenic role of NKX2-5 mutations in thyroid dysgenesis. In conclusion, our study demonstrates that p.A119S does not cause CHD or TD and that it is a rare variation that behaves equal to wildtype NKX2-5. Furthermore, given the wealth of published evidence, we suggest that NKX2-5 mutations do not play a major pathogenic role in thyroid dysgenesis, and that genetic testing of NKX2-5 in TD is not warranted.
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Abstract
INTRODUCTION The thyrotropin receptor (TSHR) is essential for thyroid growth and for the production of thyroid hormones. It is unique among the glycoprotein hormone receptors, in that some of the TSHRs undergo cleavage and shedding of the alpha subunit. AREAS COVERED This review discusses the structure and function of the TSHR, followed by an evaluation of its role in thyroid disease. Possible limitations of the TSHR as a therapeutic target are also discussed. EXPERT OPINION The TSHR is involved in a number of hereditary and acquired disorders of the thyroid making it of potential importance as a therapeutic target in thyroid disease. Expression of the TSHR in several non-thyroidal tissues and the development of systemic manifestations of thyroid disease suggest that the TSHR is also of interest as a therapeutic target outside the thyroid.
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Affiliation(s)
- Samer El-Kaissi
- Specialized Diabetes and Endocrine Centre, King Fahad Medical City, Dabab Street, P.O. Box 59046, Riyadh 11525, Saudi Arabia.
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Chang WC, Liao CY, Chen WC, Fan YC, Chiu SJ, Kuo HC, Woon PY, Chao MC. R450H TSH receptor mutation in congenital hypothyroidism in Taiwanese children. Clin Chim Acta 2012; 413:1004-7. [PMID: 22405933 DOI: 10.1016/j.cca.2012.02.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 02/17/2012] [Accepted: 02/24/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND The most common congenital endocrine disorder, congenital hypothyroidism (CHT), is strongly associated with thyroid hormone deficiency. Previous studies have indicated that mutations of thyroid stimulation hormone receptor (TSHR) are a risk factor for the development of congenital hypothyroidism. One mutation of TSHR, p.R450H, is particularly frequent in Japanese children with CHT. However, the frequency of this TSHR mutation among Taiwanese patients with CHT is unclear. METHODS We enrolled 149 CHT patients and 334 healthy subjects who volunteered to participate in health screening examinations. We characterized the clinical status of CHT patients with the TSHR mutations. RESULTS There was a significant association between the TSHR mutation (p.R450H) and the risk of CHT (P=0.0008 under the dominant model and P=0.0002 under the allelic model). The frequency of homozygous p.R450H in the CHT patients was 1.4% and that of heterozygous p.R450H was 5.6%. All five patients had elevated serum TSH levels. However, there was no difference in TSH levels between those with heterozygous and homozygous p.R450H mutations. CONCLUSION Approximately 7% of the patients in this study with CHT had heterozygous or homozygous TSHR mutations (c.1349G>A, p.R450H). Consistent with previous reports on Japanese populations, this mutation was relatively important in the Taiwanese children with CHT.
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Affiliation(s)
- Wei-Chiao Chang
- Department of Medical Genetics, College of Medicine, Kaohsiung Medical University, Taiwan.
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Shao L, Jiang H, Liang J, Niu X, Teng L, Zhang H. Study on the relationship between TSHR gene and thyroid diseases. Cell Biochem Biophys 2011; 61:377-82. [PMID: 21830127 DOI: 10.1007/s12013-011-9194-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Thyroid stimulating hormone receptor (TSHR) is thought to play a critical role in the pathogenesis of certain thyroid diseases, including Graves' disease (GD), multinodular thyroid goiter (MTG), and Hashimoto's thyroiditis (HT). In order to understand whether single nucleotide polymorphisms in the TSHR gene contribute to thyroid diseases, we have conducted a case-control study in which, we examined 8 TSHR gene single-nucleotide polymorphisms in introns 1, 4, 5, 6 and exons 7 and 8, respectively, among patients with thyroid diseases. These included one family with GD (3 patients and 9 healthy members); 60 patients with familiar thyroid diseases (30 with GD, 20 with MTG, and 10 with HT patients), 48 sporadic patients with GD and 96 healthy control individuals. Direct sequencing of all 10 exons and part of introns of TSHR gene, in these patients as well as healthy controls revealed eight polymorphisms. A novel polymorphism in exon 8 AGA(Arg) → CGA(Arg). However, there were no significant differences between patients and controls in the incidence of these polymorphisms. These results suggest that the polymorphisms (polymorphism in intron 1 at 81 bp upstream of exon 2; polymorphism in intron 4 at 135 bp upstream of exon 5; polymorphism in intron 4 at 365 bp upstream of exon 5; polymorphism in intron 5 at 69 bp upstream of exon 6; means polymorphism in intron 6 at 13 bp downstream of exon 6; polymorphism in intron 6 at 187 bp upstream of exon 7; E7+16: polymorphism in 16 bp of exon 7; polymorphism in 40 bp of exon 8) of the TSHR gene may not contribute to the pathogenesis of thyroid diseases.
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Affiliation(s)
- Li Shao
- Department of Geratology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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49
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Sriphrapradang C, Tenenbaum-Rakover Y, Weiss M, Barkoff MS, Admoni O, Kawthar D, Caltabiano G, Pardo L, Dumitrescu AM, Refetoff S. The coexistence of a novel inactivating mutant thyrotropin receptor allele with two thyroid peroxidase mutations: a genotype-phenotype correlation. J Clin Endocrinol Metab 2011; 96:E1001-6. [PMID: 21490078 PMCID: PMC3100752 DOI: 10.1210/jc.2011-0127] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT TSH receptor (TSHR) and thyroid peroxidase (TPO) gene mutations occur independently. This is the first report of their coexistence in the same individuals. OBJECTIVES The objective of the study was to evaluate the genotype-phenotype correlations when mutations in both genes are present alone or together in the same individual. PATIENTS AND METHODS Thirty subjects from an extended Arab kindred underwent clinical investigation and molecular studies of the mutant TSHRs. RESULTS A novel mutant TSHR was identified, involving four nucleotides at three sites on the same allele, c.267G>T (L89L), c.269/270AG>CT (Q90P), and c.790C>T (P264S). In addition, two known TPO gene mutations, G493S and R540X, were identified. Thirteen heterozygotes for the mutant TSHR allele had mild hyperthyrotropinemia. In nine of theses, the coexistence of a TPO mutation in one allele did not magnify the hyperthyrotropinemia. Homozygotes for the mutant TSHR and a compound heterozygote for the TPO mutations presented frank hypothyroidism. In vitro studies showed increasing loss of function for Q90P less than P264S less than Q90P/P264S TSHR mutants, the latter being that expressed in the subjects under investigation. The two interchangeably used WT TSHR vectors, L87 and V87, although functionally identical, differed in structure and function in the presence of the Q90P mutation. CONCLUSIONS TSHR and TPO gene mutations were identified alone and together in individuals of a consanguineous kindred. Homozygotes for the TSHR and a compound heterozygote for the TPO mutations were hypothyroid. The mild hyperthyrotropinemia of heterozygotes for the mutant TSHR allele was not aggravated by the coexistence of a TPO defect in one allele.
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Persani L, Gelmini G, Marelli F, Beck-Peccoz P, Bonomi M. Syndromes of resistance to TSH. ANNALES D'ENDOCRINOLOGIE 2011; 72:60-3. [PMID: 21513912 DOI: 10.1016/j.ando.2011.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The resistance to TSH action is a genetic disease characterized by molecular defects hampering the adequate transmission of TSH stimulatory signal into thyroid cells. In principle the defect may affect every step along the cascade of events following the binding of TSH to its receptor (TSHR) on thyroid cell membranes. The phenotypic expressivity of TSH resistance is highly variable going from severe congenital hypothyroidism (CH) with thyroid hypoplasia to mild hyperthyrotropinemia (hyperTSH) associated with an apparent euthyroid state. More severe forms follow a recessive pattern of inheritance and occur in patients with biallelic mutations both causing a severe loss of TSHR function. Differential diagnosis in these cases includes the exclusions of other causes of isolated thyroid dysgenesis. Mildest forms may instead occur in patients with monoallelic TSHR defects following a dominant mode of inheritance. In these cases we described the dominant negative effect exerted by some mutants on the activity of the receptor encoded by the wild type allele. In these cases, differential diagnosis involves the exclusion of autoimmune thyroid disease or pseudohypoparathyroidism associated with defects at the GNAS locus. This review will focus on the variable clinical expression of this disease.
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Affiliation(s)
- L Persani
- Department of scienze Mediche, università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milan, Italy.
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