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Bagga AD, Johnson BP, Zhang Q. Spatially Dependent Tissue Distribution of Thyroid Hormones by Plasma Thyroid Hormone Binding Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572629. [PMID: 38187691 PMCID: PMC10769377 DOI: 10.1101/2023.12.20.572629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Plasma thyroid hormone (TH) binding proteins (THBPs), including thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin (ALB), carry THs to extrathyroidal sites, where THs are unloaded locally and then taken up via membrane transporters into the tissue proper. The respective roles of THBPs in supplying THs for tissue uptake are not completely understood. To investigate this, we developed a spatial human physiologically based kinetic (PBK) model of THs, which produces several novel findings. (1) Contrary to postulations that TTR and/or ALB are the major local T4 contributors, the three THBPs may unload comparable amounts of T4 in Liver, a rapidly perfused organ; however, their contributions in slowly perfused tissues follow the order of abundances of T4TBG, T4TTR, and T4ALB. The T3 amounts unloaded from or loaded onto THBPs in a tissue acting as a T3 sink or source respectively follow the order of abundance of T3TBG, T3ALB, and T3TTR regardless of perfusion rate. (2) Any THBP alone is sufficient to maintain spatially uniform TH tissue distributions. (3) The TH amounts unloaded by each THBP species are spatially dependent and nonlinear in a tissue, with ALB being the dominant contributor near the arterial end but conceding to TBG near the venous end. (4) Spatial gradients of TH transporters and metabolic enzymes may modulate these contributions, producing spatially invariant or heterogeneous TH tissue concentrations depending on whether the blood-tissue TH exchange operates in near-equilibrium mode. In summary, our modeling provides novel insights into the differential roles of THBPs in local TH tissue distribution.
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Affiliation(s)
- Anish D. Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Brian P. Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA 30322, USA
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2
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Wolff F, Fery F, Désir J, Gadisseur R, Cavalier E, Cotton F. Familial dysalbuminemic hyperthyroxinemia coexisting with a Grave's disease: a Belgian case report. Clin Chem Lab Med 2024; 0:cclm-2024-0204. [PMID: 38557642 DOI: 10.1515/cclm-2024-0204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 03/21/2024] [Indexed: 04/04/2024]
Affiliation(s)
- Fleur Wolff
- Department of Clinical Chemistry, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Françoise Fery
- Department of Endocrinology, Centre Hospitalier Interrégional Edith Cavell (CHIREC), Brussels, Belgium
| | - Julie Désir
- Human Genetics Center, Institute of Pathology and Genetics, Gosselies, Belgium
| | - Romy Gadisseur
- Department of Clinical Chemistry, CHU de Liège, CIRM, University of Liège (ULiège), Liège, Belgium
| | - Etienne Cavalier
- Department of Clinical Chemistry, CHU de Liège, CIRM, University of Liège (ULiège), Liège, Belgium
| | - Frédéric Cotton
- Department of Clinical Chemistry, Laboratoire Hospitalier Universitaire de Bruxelles (LHUB-ULB), Université Libre de Bruxelles (ULB), Brussels, Belgium
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3
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Brown A, Hofman P, Li B, Heron C, Heather N. A Positive Newborn Screen for Congenital Hypothyroidism in a Clinically Euthyroid Neonate-Avoiding Unnecessary Treatment. Int J Neonatal Screen 2023; 9:ijns9020016. [PMID: 37092510 PMCID: PMC10123723 DOI: 10.3390/ijns9020016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Newborn screening for congenital hypothyroidism (CH) has dramatically improved the neurocognitive outcomes for newborns with a confirmed positive screening test result. However, screening yields a small number of false positive and false negative results. This report describes the first known case of familial dysalbuminaemic hyperthyroxinaemia presenting with a positive newborn thyroid stimulating hormone screen. This condition is characterized by artefactually elevated free tetraiodothyronine (T4) and triiodothyronine (T3) levels due to increased albumin binding and subsequent dissociation during laboratory assays but normal true free thyroid hormone and thyroid stimulating hormone (TSH) levels in a clinically euthyroid subject. This highlights the need to take care when attributing clinical significance to discordant results.
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Affiliation(s)
- Ashleigh Brown
- Starship Child Health, Te Whatu Ora Te Toka Tumai Auckland, Auckland 1023, New Zealand
| | - Paul Hofman
- Starship Child Health, Te Whatu Ora Te Toka Tumai Auckland, Auckland 1023, New Zealand
- Liggins Institute, University of Auckland, Auckland 1023, New Zealand
| | - Bobby Li
- Canterbury Health Laboratories, Te Whatu Ora Waitaha Canterbury, Christchurch 8011, New Zealand
| | - Campbell Heron
- LabPlus, Te Whatu Ora Te Toka Tumai Auckland, Auckland 1148, New Zealand
| | - Natasha Heather
- Liggins Institute, University of Auckland, Auckland 1023, New Zealand
- LabPlus, Te Whatu Ora Te Toka Tumai Auckland, Auckland 1148, New Zealand
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D'Aurizio F, Kratzsch J, Gruson D, Petranović Ovčariček P, Giovanella L. Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization. Crit Rev Clin Lab Sci 2023; 60:101-140. [PMID: 36227760 DOI: 10.1080/10408363.2022.2121960] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Thyroid dysfunctions are among the most common endocrine disorders and accurate biochemical testing is needed to confirm or rule out a diagnosis. Notably, true hyperthyroidism and hypothyroidism in the setting of a normal thyroid-stimulating hormone level are highly unlikely, making the assessment of free thyroxine (FT4) inappropriate in most new cases. However, FT4 measurement is integral in both the diagnosis and management of relevant central dysfunctions (central hypothyroidism and central hyperthyroidism) as well as for monitoring therapy in hyperthyroid patients treated with anti-thyroid drugs or radioiodine. In such settings, accurate FT4 quantification is required. Global standardization will improve the comparability of the results across laboratories and allow the development of common clinical decision limits in evidence-based guidelines. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. However, technical and implementation challenges, including the establishment of different clinical decision limits for distinct patient groups, still remain. Accordingly, different assays and reference values cannot be interchanged. Two-way communication between the laboratory and clinical specialists is pivotal to properly select a reliable FT4 assay, establish reference intervals, investigate discordant results, and monitor the analytical and clinical performance of the method over time.
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Affiliation(s)
- Federica D'Aurizio
- Department of Laboratory Medicine, University Hospital of Udine, Udine, Italy
| | - Jürgen Kratzsch
- Institute for Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital, University of Leipzig, Leipzig, Germany
| | - Damien Gruson
- Department of Clinical Biochemistry, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium
| | - Petra Petranović Ovčariček
- Department of Oncology and Nuclear Medicine, University Hospital Center Sestre milosrdnice, Zagreb, Croatia
| | - Luca Giovanella
- Clinic for Nuclear Medicine and Competence Center for Thyroid Diseases, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Bellinzona, Switzerland.,Clinic for Nuclear Medicine and Thyroid Center, University and University Hospital of Zurich, Zurich, Switzerland
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5
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Narinx N, David K, Walravens J, Vermeersch P, Claessens F, Fiers T, Lapauw B, Antonio L, Vanderschueren D. Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology. Cell Mol Life Sci 2022; 79:543. [PMID: 36205798 DOI: 10.1007/s00018-022-04562-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/12/2022] [Accepted: 09/17/2022] [Indexed: 11/03/2022]
Abstract
According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.
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Affiliation(s)
- N Narinx
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Herestraat 49, ON1bis box 902, 3000, Leuven, Belgium.,Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - K David
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Herestraat 49, ON1bis box 902, 3000, Leuven, Belgium.,Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium
| | - J Walravens
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - P Vermeersch
- Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - F Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - T Fiers
- Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - B Lapauw
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium.,Department of Endocrinology, Ghent University Hospital, Ghent, Belgium
| | - L Antonio
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Herestraat 49, ON1bis box 902, 3000, Leuven, Belgium.,Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium
| | - D Vanderschueren
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases and Metabolism, KU Leuven, Herestraat 49, ON1bis box 902, 3000, Leuven, Belgium. .,Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.
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Yadav P, Sarode LP, Gaddam RR, Kumar P, Bhatti JS, Khurana A, Navik U. Zebrafish as an emerging tool for drug discovery and development for thyroid diseases. FISH & SHELLFISH IMMUNOLOGY 2022; 130:53-60. [PMID: 36084888 DOI: 10.1016/j.fsi.2022.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 12/06/2022]
Abstract
Zebrafish is a useful model for understanding human genetics and diseases and has evolved into a prominent scientific research model. The genetic structure of zebrafish is 70% identical to that of humans. Its small size, low cost, and transparent embryo make it a valuable tool in experimentation. Zebrafish and mammals possess the same molecular mechanism of thyroid organogenesis and development. Thus, thyroid hormone signaling, embryonic development, thyroid-related disorders, and novel genes involved in early thyroid development can all be studied using zebrafish as a model. Here in this review, we emphasize the evolving role of zebrafish as a possible tool for studying the thyroid gland in the context of physiology and pathology. The transcription factors nkx2.1a, pax2a, and hhex which contribute a pivotal role in the differentiation of thyroid primordium are discussed. Further, we have described the role of zebrafish as a model for thyroid cancer, evaluation of defects in thyroid hormone transport, thyroid hormone (TH) metabolism, and as a screening tool to study thyrotoxins. Hence, the present review highlights the role of zebrafish as a novel approach to understand thyroid development and organogenesis.
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Affiliation(s)
- Poonam Yadav
- Department of Pharmacology, Central University of Punjab, Ghudda, Bathinda, Punjab, India
| | - Lopmudra P Sarode
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur, 440033, Maharashtra, India
| | - Ravinder Reddy Gaddam
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, IA, USA
| | - Puneet Kumar
- Department of Pharmacology, Central University of Punjab, Ghudda, Bathinda, Punjab, India
| | - Jasvinder Singh Bhatti
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Ghudda, Bathinda, Punjab, India
| | - Amit Khurana
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Pauwelsstr. 30, D-52074, Aachen, Germany.
| | - Umashanker Navik
- Department of Pharmacology, Central University of Punjab, Ghudda, Bathinda, Punjab, India.
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7
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Jensen RC, Glintborg D, Timmermann CAG, Nielsen F, Boye H, Madsen JB, Bilenberg N, Grandjean P, Jensen TK, Andersen MS. Higher free thyroxine associated with PFAS exposure in first trimester. The Odense Child Cohort. ENVIRONMENTAL RESEARCH 2022; 212:113492. [PMID: 35597289 DOI: 10.1016/j.envres.2022.113492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/18/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Perfluoroalkyl substances (PFAS) are endocrine disrupting chemicals with elimination half-lives ranging from four to eight years. Experimental studies found PFAS able to interfere with thyroid hormone-binding proteins. During the first 20 weeks of gestation (GW), the fetus is reliant on placental transfer of maternal thyroid hormones, mainly free thyroxine (FT4). However, previous studies investigating associations between exposure to PFAS and thyroid hormone status mainly focused on blood samples from late pregnancy or umbilical cord with mixed findings. OBJECTIVES To investigate associations between serum-PFAS concentrations and thyroid hormone status in early pregnancy as reflected by FT4 and thyroid-stimulating hormone (TSH). METHODS In the Odense Child Cohort, a single-center study, we measured maternal pregnancy serum concentrations of five PFAS: perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA); and FT4 and TSH in 1048 pregnant women at median GW 12 (25th, 75th percentile: 10, 15). Multivariate linear regression models were performed to estimate associations between PFAS exposure and thyroid hormone status. RESULTS A doubling in PFOS, PFOA, and PFNA concentrations was associated with an increment in FT4 concentration by 1.85% (95% CI: 0.66%, 3.05%), 1.29% (95% CI: 0.21%, 2.39%), and 1.70% (95% CI: 0.48%, 2.94%), respectively, in adjusted analyses. A statistically significant dose-response relationship was observed across exposure quartiles for PFOS, PFOA, and PFNA in the association with FT4. No association was found between concentrations of PFAS and TSH in adjusted analyses. CONCLUSION Exposure to PFOS, PFOA, and PFNA was associated with higher FT4 concentrations in women during early pregnancy. The potential clinical implications of these findings remain to be clarified.
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Affiliation(s)
- Richard Christian Jensen
- Department of Endocrinology, Odense University Hospital, Søndre Blvd. 29, 5000, Odense C, Denmark; Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, J.B. Winsløws Vej 17A, 5000, Odense C, Denmark.
| | - Dorte Glintborg
- Department of Endocrinology, Odense University Hospital, Søndre Blvd. 29, 5000, Odense C, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, 5000, Odense, Denmark
| | - Clara Amalie Gade Timmermann
- Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, J.B. Winsløws Vej 17A, 5000, Odense C, Denmark; National Institute of Public Health, University of Southern Denmark, Studiestræde 6, 1455, København K, Denmark
| | - Flemming Nielsen
- Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, J.B. Winsløws Vej 17A, 5000, Odense C, Denmark
| | - Henriette Boye
- Odense Child Cohort, Hans Christian Andersen Children's Hospital, Odense University Hospital, Kløvervænget 23C, 5000, Odense C, Denmark
| | - Jeppe Buur Madsen
- Department of Biochemistry and Immunology, Lillebaelt Hospital, Kabbeltoft 25, University Hospital of Southern Denmark, 7100, Vejle, Denmark
| | - Niels Bilenberg
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, 5000, Odense, Denmark; Odense Child Cohort, Hans Christian Andersen Children's Hospital, Odense University Hospital, Kløvervænget 23C, 5000, Odense C, Denmark; Department of Child and Adolescent Mental Health Odense, Mental Health Services in the Region of Southern Denmark, J. B. Winsløws Vej 16, 5000, Odense, Denmark
| | - Philippe Grandjean
- Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, J.B. Winsløws Vej 17A, 5000, Odense C, Denmark; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, 677 Huntington Avenue Boston, MA, 02115, USA
| | - Tina Kold Jensen
- Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, J.B. Winsløws Vej 17A, 5000, Odense C, Denmark; Odense Child Cohort, Hans Christian Andersen Children's Hospital, Odense University Hospital, Kløvervænget 23C, 5000, Odense C, Denmark; OPEN, University of Southern Denmark, J. B. Winsløws Vej 9a, 5000, Odense C, Denmark
| | - Marianne S Andersen
- Department of Endocrinology, Odense University Hospital, Søndre Blvd. 29, 5000, Odense C, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, 5000, Odense, Denmark
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Gawandi S, Jothivel K, Kulkarni S. Identification of a novel mutation in thyroxine-binding globulin (TBG) gene associated with TBG-deficiency and its effect on the thyroid function. J Endocrinol Invest 2022; 45:731-739. [PMID: 34761328 DOI: 10.1007/s40618-021-01697-z] [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: 05/13/2021] [Accepted: 10/23/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE This study presents a case of familial transmission of thyroxine-binding globulin (TBG) deficiency. The SERPINA7-gene which codes for TBG is located on the X-chromosome (Xq21-22). More than 45 mutations have been reported to cause TBG- deficiency from various countries, but none from India so far. Genetic analysis of SERPINA7 gene was carried out to determine the cause of low TBG levels in one family. METHODS DNA samples of the propositus and the family members were subjected to Polymerase Chain Reaction (PCR) followed by direct sequencing. Allele-specific PCR and Next-gen sequencing (NGS) were employed to confirm the site of the mutation. Thyroid function tests were estimated by Radioimmunoassay (RIA) and Immunoradiometric assay (IRMA) kits. X-chromosomal inactivation status was analyzed in the female members harboring the mutation. RESULTS A mutational screening in this family revealed a novel frame-shift mutation S353Q, 354fs3X in the exon 4 of the SERPINA7 gene which will be referred to as TBG-complete deficiency-India (TBG-CD-Ind). One out of four female family members harboring the mutation showed selective X-chromosomal inactivation. The affected family members were clinically euthyroid initially, showed changes in the thyroid function when tested after a long time span. However, the changes in the thyroid function in the affected family members had an autoimmune etiology. CONCLUSION This study presents the first report of TBG-CD from India wherein a novel frameshift mutation referred to as TBG-CD-Ind (S353Q, 354fs3X) in the SERPINA7 gene was detected. No apparent association was identified between thyroid function and the TBG-mutation in the affected subjects. A detailed biochemical and genomic testing to determine the exact cause of discordant TFT in the patients would certainly aid in the unequivocal diagnosis of the thyroid function and for the precise individualized treatment.
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Affiliation(s)
- S Gawandi
- Radiation Medicine Centre, Bhabha Atomic Research Centre, TMH Annexe Building, Parel, Mumbai, 400012, India
| | - K Jothivel
- Radiation Medicine Centre, Bhabha Atomic Research Centre, TMH Annexe Building, Parel, Mumbai, 400012, India
| | - S Kulkarni
- Radiation Medicine Centre, Bhabha Atomic Research Centre, TMH Annexe Building, Parel, Mumbai, 400012, India.
- Homi Bhabha National Institute , Bhabha Atomic Research Centre, Mumbai, India.
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9
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Hengeveld RCC, Albersen M, Hadders MAH, Hellinga I, Bikker H, Heijboer AC, Paul van Trotsenburg AS, Hillebrand JJ, Boelen A, Zwaveling-Soonawala N. A Newborn Falsely Suspected of Congenital Hypothyroidism due to Mutated Thyroxine-Binding Globulin with Low Binding Affinity. Horm Res Paediatr 2021; 94:76-80. [PMID: 34126618 DOI: 10.1159/000516691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/15/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Neonatal screening programs for congenital hypothyroidism (CH) have been implemented worldwide to facilitate early diagnosis and treatment. The Dutch neonatal CH screening is primarily based on the measurement of thyroxine (T4). When T4 is low, an additional thyroxine-binding globulin (TBG) measurement is performed to reduce the number of false-positive screening results due to harmless TBG deficiency. Here, we present a case of a rare functional TBG deficiency leading to a false suspicion of CH. CASE PRESENTATION Neonatal screening in this patient revealed a decreased T4, normal TSH, and normal TBG concentration, suggesting central CH. However, free T4 was normal. DNA sequencing analysis revealed a novel, hemizygous mutation (c.139G>A) in SERPINA7, the gene encoding TBG, resulting in the substitution of the conserved amino acid alanine to threonine at position 27. Crystal structure analyses showed that this substitution has a detrimental effect on binding of T4 to TBG. CONCLUSIONS The novel SERPINA7 variant in this patient led to a false suspicion of central hypothyroidism in the Dutch T4-based neonatal screening program. It is important to recognize patients with such TBG defects to prevent unnecessary additional testing and treatment.
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Affiliation(s)
- Rutger C C Hengeveld
- Department of Clinical Chemistry, Amsterdam UMC, Central Diagnostic Laboratory, University of Amsterdam, Amsterdam, The Netherlands
| | - Monique Albersen
- Department of Clinical Chemistry, Amsterdam UMC, Endocrine Laboratory, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Michael A H Hadders
- Department of Molecular Cancer Research, Oncode Institute, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
| | - Ilse Hellinga
- Department of Pediatric Endocrinology, Amsterdam UMC, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Hennie Bikker
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Annemieke C Heijboer
- Department of Clinical Chemistry, Amsterdam UMC, Central Diagnostic Laboratory, University of Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Chemistry, Amsterdam UMC, Endocrine Laboratory, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - A S Paul van Trotsenburg
- Department of Pediatric Endocrinology, Amsterdam UMC, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Jacquelien J Hillebrand
- Department of Clinical Chemistry, Amsterdam UMC, Central Diagnostic Laboratory, University of Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Chemistry, Amsterdam UMC, Endocrine Laboratory, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Clinical Chemistry, Amsterdam UMC, Central Diagnostic Laboratory, University of Amsterdam, Amsterdam, The Netherlands
| | - Nitash Zwaveling-Soonawala
- Department of Pediatric Endocrinology, Amsterdam UMC, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
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10
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Growth Performance, Serum Biochemical Indices, Duodenal Histomorphology, and Cecal Microbiota of Broiler Chickens Fed on Diets Supplemented with Cinnamon Bark Powder at Prestarter and Starter Phases. Animals (Basel) 2021; 11:ani11010094. [PMID: 33419092 PMCID: PMC7825433 DOI: 10.3390/ani11010094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 12/12/2022] Open
Abstract
Ross 308 broiler chicks (n = 240) aged 1 day were assigned to five groups for eight replicates (six chicks for each) (3♂ and 3♀). Basal dietary groups were supplemented by 2000, 4000, and 6000 mg/kg cinnamon (CN) for 21 days. Basal diet alone was used as a negative control, and basal antibiotic diet (Colimox) was used as a positive control. At 10, 14, and 21 days of age, chicks that received 2000 mg CN and Colimox had a higher body weight, resulting in an increase in body weight gain. CN also resulted in the maximum improvement in the feed conversion ratio and feed efficiency over 1-21 days at the level of 2000 mg/kg. At days 10, the maximum relative breast weight was 2000 mg/kg of CN. Mean serum albumin concentrations, duodenal villus height, and goblet cell density increased (p < 0.05) by 2000 mg/kg of CN, and mean serum globulin and total protein concentrations and crypt depth increased (p < 0.05) by 6000 mg/kg of CN compared with control. Increased cecal Escherichia coli number was CN dose-dependent. In conclusion, dietary inclusion of 2000 mg/kg CN can be applied as an alternative to in-feed antibiotics for broiler starter diet.
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11
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Kratzsch J, Baumann NA, Ceriotti F, Lu ZX, Schott M, van Herwaarden AE, Henriques Vieira JG, Kasapic D, Giovanella L. Global FT4 immunoassay standardization: an expert opinion review. Clin Chem Lab Med 2020; 59:1013-1023. [PMID: 33554525 DOI: 10.1515/cclm-2020-1696] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/13/2020] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Results can vary between different free thyroxine (FT4) assays; global standardization would improve comparability of results between laboratories, allowing development of common clinical decision limits in evidence-based guidelines. CONTENT We summarize the path to standardization of FT4 assays, and challenges associated with FT4 testing in special populations, including the need for collaborative efforts toward establishing population-specific reference intervals. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. Further studies are needed to establish common reference intervals/clinical decision limits. Standardization of FT4 assays will change test results substantially; therefore, a major education program will be required to ensure stakeholders are aware of the benefits of FT4 standardization, planned transition procedure, and potential clinical impact of the changes. Assay recalibration by manufacturers and approval process simplification by regulatory authorities will help minimize the clinical impact of standardization. SUMMARY Significant progress has been made toward standardization of FT4 testing, but technical and logistical challenges remain. OUTLOOK Collaborative efforts by manufacturers, laboratories, and clinicians are required to achieve successful global standardization of the FT4 assays.
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Affiliation(s)
- Juergen Kratzsch
- Institute for Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital, University of Leipzig, Leipzig, Germany
| | - Nikola A Baumann
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ferruccio Ceriotti
- Clinical Laboratory, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Zhong X Lu
- Department of Medicine, Monash University, Victoria, Australia
| | - Matthias Schott
- Division for Specific Endocrinology, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany
| | | | | | | | - Luca Giovanella
- Clinic for Nuclear Medicine and Competence Centre for Thyroid Diseases, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- University Hospital and University of Zurich, Zurich, Switzerland
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12
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Chen LD, Lu HJ, Gan YL, Pang SW, Zheng Q, Ye DM, Huang XY, Qi HN, Xu WB, Wen XZ, Li LH, Li L. Partial thyroxine-binding globulin deficiency in a family with coding region mutations in the TBG gene. J Endocrinol Invest 2020; 43:1703-1710. [PMID: 32266677 DOI: 10.1007/s40618-020-01245-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 03/30/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE T4-binding globulin (TBG) is the main thyroid hormone (TH) transporter present in human serum. Inherited thyroxine-binding globulin (TBG) deficiency is caused by mutations in the TBG (SERPINA7) gene, which is located on the X chromosome. This study was performed to report and evaluate coding region mutations in TBG gene for partial thyroxine-binding globulin deficiency. METHODS A pedigree spanning four generations is described in this study. The proband is a female with partial TBG deficiency. All members of this pedigree underwent thyroid function tests, while Sanger sequencing was used to identify the TBG gene mutations. Bioinformatics databases were used to evaluate the deleterious effects of the mutation(s). Two hundred and seven unrelated individuals were used to evaluate the thyroid function of individuals with different TBG mutations. A one-way ANOVA was used to analyze the impact of the TBG mutations on thyroid function. RESULTS TBG gene sequencing results revealed that the proband had a novel mutation in codon 27 leading to alanine to valine substitution (p.A27V). This mutation was associated with lower serum T4 levels (p < 0.0001) when compared to the groups that did not carry the mutation. The previously reported p.L283F mutation was also found in the proband. The hemizygous p.L283F individuals presenting with lower T4 serum and TBG levels (p < 0.001) when compared to wildtype males and females. Both mutations were deleterious upon SIFT and PolyPhen-2 evaluation. CONCLUSION Associated with partial thyroxine-binding globulin deficiency, this study reports a novel p.A27V mutation in the TBG gene.
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Affiliation(s)
- L-D Chen
- Department of Laboratory Medicine, General Hospital of Southern Theater Command of PLA, Guangzhou, 510010, Guangdong, China
| | - H-J Lu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - Y-L Gan
- Department of Laboratory Medicine, General Hospital of Southern Theater Command of PLA, Guangzhou, 510010, Guangdong, China
| | - S-W Pang
- Zhengzhou Yihe Hospital, Zhengzhou, 450000, Henan, China
| | - Q Zheng
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - D-M Ye
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - X-Y Huang
- Department of Laboratory Medicine, General Hospital of Southern Theater Command of PLA, Guangzhou, 510010, Guangdong, China
| | - H-N Qi
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - W-B Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - X-Z Wen
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China
| | - L-H Li
- Department of Laboratory Medicine, General Hospital of Southern Theater Command of PLA, Guangzhou, 510010, Guangdong, China.
| | - L Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Shatai Road 1023, Guangzhou, 510515, Guangdong, China.
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13
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Bikle DD. The Free Hormone Hypothesis: When, Why, and How to Measure the Free Hormone Levels to Assess Vitamin D, Thyroid, Sex Hormone, and Cortisol Status. JBMR Plus 2020; 5:e10418. [PMID: 33553985 PMCID: PMC7839820 DOI: 10.1002/jbm4.10418] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/29/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The free hormone hypothesis postulates that only the nonbound fraction (the free fraction) of hormones that otherwise circulate in blood bound to their carrier proteins is able to enter cells and exert biologic effects. In this review, I will examine four hormone groups-vitamin D metabolites (especially 25OHD), thyroid hormones (especially thyroxine [T4]), sex steroids (especially testosterone), and glucocorticoids (especially cortisol)-that are bound to various degrees to their respective binding proteins-vitamin D-binding protein (DBP), thyroid-binding globulin (TBG), sex hormone-binding globulin (SHBG), and cortisol-binding globulin (CBG)-for which a strong case can be made that measurement of the free hormone level provides a better assessment of hormonal status than the measurement of total hormonal levels under conditions in which the binding proteins are affected in levels or affinities for the hormones to which they bind. I will discuss the rationale for this argument based on the free hormone hypothesis, discuss potential exceptions to the free hormone hypothesis, and review functions of the binding proteins that may be independent of their transport role. I will then review the complications involved with measuring the free hormone levels and the efforts to calculate those levels based on estimates of binding constants and levels of both total hormone and total binding protein. In this review, the major focus will be on DBP and free 25OHD, but the parallels and differences with the other binding proteins and hormones will be highlighted. Vitamin D and its metabolites, thyroid hormones, sex steroids, and glucocorticoids are transported in blood bound to serum proteins. The tightness of binding varies depending on the hormone and the binding protein such that the percent free varies from 0.03% for T4 and 25OHD to 4% for cortisol with testosterone at 2%. Although the major function of the primary carrier proteins (DBP, TBG, SHBG, and CBG) may be to transport their respective lipophilic hormones within the aqueous media that is plasma, these proteins may have other functions independent of their transport function. For most tissues, these hormones enter the cell as the free hormone presumably by diffusion (the free hormone hypothesis), although a few tissues such as the kidney and reproductive tissues express megalin/cubilin enabling by endocytosis protein-bound hormone to enter the cell. Measuring the free levels of these protein-bound hormones is likely to provide a better measure of the true hormone status than measuring the total levels in situations where the levels and/or affinities of the binding proteins are altered. Methods to measure free hormone levels are problematic as the free levels can be quite low, the methods require separation of bound and free that could disturb the steady state, and the means of separating bound and free are prone to error. Calculation of free levels using existing data for association constants between the hormone and its binding protein are likewise prone to error because of assumptions of linear binding models and invariant association constants, both of which are invalid. © 2020 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine University of California San Francisco USA.,Department of Medicine San Francisco VA Medical Center San Francisco CA USA
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