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Tajima T, Nakamura A, Oguma M, Yamazaki M. Recent advances in research on isolated congenital central hypothyroidism. Clin Pediatr Endocrinol 2019; 28:69-79. [PMID: 31384098 PMCID: PMC6646241 DOI: 10.1297/cpe.28.69] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 04/21/2019] [Indexed: 12/14/2022] Open
Abstract
Congenital central hypothyroidism (C-CH) is caused by defects in the secretion of
thyrotropin-releasing hormone (TRH) and/or TSH, leading to an impairment in the release of
hormones from the thyroid. The causes of C-CH include congenital anomalies of the
hypothalamic-pituitary regions and several genetic defects. In terms of endocrinology,
C-CH is divided into two categories: (1) accompanied
by another pituitary hormone deficiency and called combined pituitary hormone deficiency,
and (2) isolated C-CH, showing mainly TSH
deficiency. For isolated C-CH, a mutation in the TSH gene (TSHB) encoding
the β-subunit of the protein was first found in 1990 by Japanese researchers, and
thereafter several mutations in TSHB have been reported. Mutations in the
thyrotropin-releasing hormone receptor gene (TRHR), as well as genetic
defects in immunoglobulin superfamily 1 (IGSF1), have also been
identified. It was recently found that isolated C-CH is caused by mutations in transducin
β-like 1 X-linked and insulin receptor substrate 4. It is noted that all patients with
TSHB deficiency and some with IGSF1 deficiency show severe hypothyroidism soon after
birth. Among the causes of C-CH, high frequency of mutations in IGSF1 is
the most prevalent. This review focuses on recent findings on isolated C-CH.
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Affiliation(s)
- Toshihiro Tajima
- Jichi Medical University Children's Medical Center Tochigi, Shimotsuke, Japan
| | - Akie Nakamura
- Department of Pediatrics Hokkaido University School of Medicine, Sapporo, Japan
| | - Makiko Oguma
- Jichi Medical University Children's Medical Center Tochigi, Shimotsuke, Japan
| | - Masayo Yamazaki
- Jichi Medical University Children's Medical Center Tochigi, Shimotsuke, Japan
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Brigante G, Spaggiari G, Santi D, Cioni K, Gnarini V, Diazzi C, Pignatti E, Casarini L, Marino M, Tüttelmann F, Carani C, Simoni M. The TRHR Gene Is Associated with Hypothalamo-Pituitary Sensitivity to Levothyroxine. Eur Thyroid J 2014; 3:101-8. [PMID: 25114873 PMCID: PMC4109513 DOI: 10.1159/000358590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/13/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Thyroidectomized patients need variable doses of levothyroxine (LT4) to obtain target thyroid-stimulating hormone (TSH) levels. Individual feedback set-points have been hypothesized and the influence of several genes in the regulation of the pituitary-thyroid axis has been demonstrated. OBJECTIVES We hypothesized that genetic variants of the TRHR gene could be associated with a different hypothalamo-pituitary sensitivity to thyroid hormone feedback. METHODS We retrospectively analyzed 84 thyroidectomized patients with no residual thyroid function and undetectable thyroglobulin levels. Patients were evaluated under LT4 resulting in TSH levels detectable but <0.5 μIU/ml. The two SNPs rs3134105 and rs3110040 were identified as informative markers of the TRHR gene. Genotyping was performed using high-resolution melting technology. Genotype distribution was compared between the patients and 99 euthyroid controls. RESULTS The selected SNPs were in linkage disequilibrium and only rs3134105 was further considered. A significant difference between the three possible genotypes for rs3134105 was found for TSH (p = 0.04) and free thyroxine (fT4)/TSH ratio (p = 0.02). Moreover, despite similar serum concentrations of free triiodothyronine (fT3) and fT4, carriers of at least one A allele of rs3134105 had significantly lower serum TSH levels (p = 0.01) as well as higher fT3/TSH (p = 0.01) and fT4/TSH ratios (p < 0.01). CONCLUSIONS We demonstrated an association between serum TSH levels and discrete alleles of the TRHR gene in totally thyroidectomized patients under LT4 therapy. Therefore, the TRHR gene seems to be a determinant of hypothalamo-pituitary sensitivity to LT4.
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Affiliation(s)
- Giulia Brigante
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Giorgia Spaggiari
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Daniele Santi
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Katia Cioni
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Valentina Gnarini
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Chiara Diazzi
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Elisa Pignatti
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Center of Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Livio Casarini
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Center of Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Marco Marino
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Center of Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Frank Tüttelmann
- Institute of Human Genetics, University of Munster, Munster, Germany
| | - Cesare Carani
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Azienda USL, Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, Modena, Italy
- Center of Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
- Azienda USL, Modena, Italy
- *Manuela Simoni, MD, PhD, Unit of Endocrinology and Metabolism, Nuovo Ospedale S. Agostino Estense, Via Giardini 1355, IT-41125 Modena (Italy), E-Mail
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Zhao K, Ao Y, Harper RM, Go VLW, Yang H. Food-intake dysregulation in type 2 diabetic Goto-Kakizaki rats: hypothesized role of dysfunctional brainstem thyrotropin-releasing hormone and impaired vagal output. Neuroscience 2013; 247:43-54. [PMID: 23701881 DOI: 10.1016/j.neuroscience.2013.05.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 04/25/2013] [Accepted: 05/02/2013] [Indexed: 12/11/2022]
Abstract
Thyrotropin-releasing hormone (TRH), a neuropeptide contained in neural terminals innervating brainstem vagal motor neurons, enhances vagal outflow to modify multisystemic visceral functions and food intake. Type 2 diabetes (T2D) and obesity are accompanied by impaired vagal functioning. We examined the possibility that impaired brainstem TRH action may contribute to the vagal dysregulation of food intake in Goto-Kakizaki (GK) rats, a T2D model with hyperglycemia and impaired central vagal activation by TRH. Food intake induced by intracisternal injection of TRH analog was reduced significantly by 50% in GK rats, compared to Wistar rats. Similarly, natural food intake in the dark phase or food intake after an overnight fast was reduced by 56-81% in GK rats. Fasting (48h) and refeeding (2h)-associated changes in serum ghrelin, insulin, peptide YY, pancreatic polypeptide and leptin, and the concomitant changes in orexigenic or anorexigenic peptide expression in the brainstem and hypothalamus, all apparent in Wistar rats, were absent or markedly reduced in GK rats, with hormone release stimulated by vagal activation, such as ghrelin and pancreatic polypeptide, decreased substantially. Fasting-induced Fos expression accompanying endogenous brainstem TRH action decreased by 66% and 91%, respectively, in the nucleus tractus solitarius (NTS) and the dorsal motor nucleus of the vagus (DMV) in GK rats, compared to Wistar rats. Refeeding abolished fasting-induced Fos-expression in the NTS, while that in the DMV remained in Wistar but not GK rats. These findings indicate that dysfunctional brainstem TRH-elicited vagal impairment contributes to the disturbed food intake in T2D GK rats, and may provide a pathophysiological mechanism which prevents further weight gain in T2D and obesity.
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Affiliation(s)
- K Zhao
- Research & Development, Department of Veterans Affairs, Greater Los Angeles Health Care System, Los Angeles, CA 90073, USA
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