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Context: Clinical course and need for long-term L-thyroxine (LT4) therapy of congenital hypothyroidism (CH) with gland in situ (GIS) remain unclear., Objective: To describe the clinical history of CH with GIS and evaluate the proportion of patients who can suspend therapy during follow-up., Design and Setting: Retrospective evaluation of patients followed at referral regional center for CH of Pisa., Patients: 77 patients with confirmed primary CH and GIS after positive neonatal screening were included. All children started LT4 at CH confirm., Interventions: At 3 years of age, 55 children underwent a clinical re-evaluation after withdrawal of therapy with hormonal examinations, imaging of the thyroid gland with ultrasonography and 123-iodine with perchlorate discharge test. Subsequent periodic controls of thyroid function were executed and, when possible, a new attempt to stop LT4 was performed. Adequate follow-up data (at least 6 months after treatment suspension trial) were available for 49 patients., Results: Among the 55 patients who were reassessed, 18 (32.7%) were euthyroid. Considering subsequent follow-up, 49% of patients were no longer treated and 51% were taking therapy. No differences in neonatal parameters were observed between the two groups; LT4 dose before the last trial off medication was higher in permanent CH (p 0.016)., Conclusion: Monitoring of thyroid function in children with CH and GIS is necessary to evaluate the need for substitution and avoid overtreatment. Even if therapy can be suspended, patients need to be monitored because apparently normal thyroid function may decline several months after withdrawal of LT4., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)

Background: Iodine deficiency is the result of insufficient intake of dietary iodine and as a consequence causes multiple adverse effects. About 2 billion individuals in the world are affected by iodine deficiency. It has been found that the most effective way to control iodine deficiency is through the universal salt iodization. However, salt iodization alone may not be sufficient to assure adequate iodine nutrition. In most industrialized countries, excess consumption of salt has become recognized as a health risk. Therefore, biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake., Aim and Methods: The aim of this study was to test the efficiency of a new model of iodine prophylaxis in a group of 50 healthy volunteers through the intake of vegetables (potatoes, cherry tomatoes, carrots, and green salad) fortified with iodine. Each serving of vegetables consisted of 100 g of potatoes, carrots, tomatoes, or salad containing 45 mg of iodine (30% of the Recommended Daily Allowance), and the volunteers consumed a single serving of vegetables, as preferred, each day for 2 weeks. Urinary iodine (UI) excretion was measured before and after intake of vegetables., Results: The UI concentration measured in volunteers before the intake of vegetables was 98.3 mg/L (basal value), increasing to 117.5 mg/L during the intake of vegetables. Seven days after the discontinuation of vegetable intake, UI was 85 mg/L. UI concentration increment was 19.6% compared with the basal value; therefore, the difference was statistically significant (P = .035)., Conclusions: Biofortification of vegetables with iodine provides a mild but significative increase in UI concentration and, together with the habitual use of iodized salt, may contribute to improve the iodine nutritional status of the population without risks of iodine excess.

Objective: MicroRNAs (miRNAs) are small endogenous noncoding RNAs that pair with target messengers regulating gene expression. Changes in miRNA levels occur in thyroid cancer. Fine-needle aspiration (FNA) with cytological evaluation is the most reliable tool for malignancy prediction in thyroid nodules, but cytological diagnosis remains undetermined for 20% of nodules., Design: In this study, we evaluated the expression of seven miRNAs in benign nodules, papillary thyroid carcinomas (PTCs), and undetermined nodules at FNA., Methods: The prospective study included 141 samples obtained by FNA of thyroid nodules from 138 patients. miRNA expression was evaluated by quantitative RT-PCR and statistical analysis of data was performed. Genetic analysis of codon 600 of BRAF gene was also performed., Results: Using data mining techniques, we obtained a criterion to classify a nodule as benign or malignant on the basis of miRNA expression. The decision model based on the expression of miR-146b, miR-155, and miR-221 was valid for 86/88 nodules with determined cytology (97.73%), and adopting cross-validation techniques we obtained a reliability of 78.41%. The prediction was valid for 31/53 undetermined nodules with 16 false-positive and six false-negative predictions. The mutated form V600E of BRAF gene was demonstrated in 19/43 PTCs and in 1/53 undetermined nodules., Conclusions: The expression profiles of three miRNAs allowed us to distinguish benign from PTC starting from FNA. When the assay was applied to discriminate thyroid nodules with undetermined cytology, a low sensitivity and specificity despite the low number of false-negative predictions was obtained, limiting the practical interest of the method.

Context: Congenital hypothyroidism (CH) associated with goiter or a gland of normal size has been linked to dual oxidase 2 (DUOX2) mutations in the presence of iodide organification defect., Objective: Thirty unrelated children with CH or subclinical hypothyroidism (SH) identified during infancy with a eutopic thyroid gland, coming from our Screening Centre for CH or referred from other regions of Italy, were studied with the perchlorate discharge test to identify organification defects. Eleven children with iodide organification defect were considered for the genetic analysis of TPO, DUOX2, and dual oxidase maturation factor 2 (DUOXA2) genes., Patients: Eight children with CH and three with SH and eutopic thyroid gland were included in the study. After discontinuation of therapy, a partial or complete organification defect was shown after ¹²³I scintigraphy and perchlorate test., Methods: TPO, DUOX2, and DUOXA2 genes were analyzed, and functional activity of DUOX2 variants was studied in HeLa cells., Results: Sequencing of the DUOX2 gene revealed a deletion S965fsX994 in three children; two were euthyroid after 1 month of L-T₄ discontinuation but developed SH after 5 and 18 months, respectively, whereas the other child had SH. One child with SH showed H678R, R701Q, and P982A substitutions, and another child with SH showed only the P982A. One child with SH showed the Y1150C mutation, and another euthyroid child showed the A728T mutation. Functional studies confirmed that S965fsX994, Y1150C, and A728T mutations were responsible for the defect in H₂O₂ production, whereas H678R, R701Q, and P982A did not alter H₂O₂ production in vitro., Conclusions: Genetic analysis of the DUOX2 gene was performed in 11 children with organification defect. Two new mutations (Y1150C and A728T) and the deletion S965FsX994 were responsible for the deficit in the organification process and the phenotypes. Three polymorphisms (H678R, P982A, and R701Q) were identified.

Context: Some cases of congenital hypothyroidism (CH) are associated with a gland of normal size., Objective: To explore the cause of organification defect in one child with CH and a eutopic thyroid gland, genetic analyses of TPO, DUOX2, and DUOXA2 genes were performed., Patient: One child with CH, a eutopic thyroid gland, and a partial organification defect was shown after (123)I scintigraphy and perchlorate test., Methods: In the child with the organification defect, TPO, DUOX2, and DUOXA2 genes were analyzed. The functional activity of the DUOX2 mutants was studied after expression in eukaryotic cells., Results: No TPO or DUOXA2 gene mutations were identified. Direct sequencing of the DUOX2 gene revealed a compound heterozygous genotype for S911L and C1052Y substitutions. S911L and C1052Y caused a partial defect in H(2)O(2) production after transient expression in HeLa cells., Conclusions: We performed a genetic analysis in one child with CH and a eutopic thyroid gland. Two new mutations in DUOX2 gene responsible for the partial deficit in the organification process were identified.

Context: Mutations in TSH receptor (TSHR) are notoriously associated with congenital hypothyroidism as well as with non-autoimmune subclinical hypothyroidism, a mild form of TSH resistance that is not as well characterized by diagnostic procedures., Objective: The genetic analysis of the TSHR gene was performed to determine the prevalence of TSHR gene mutations in non-autoimmune subclinical hypothyroidism during the pediatric age. The new mutations were studied for genotypic-phenotypic correlation., Patients: Thirty-eight children (ages 0.5-18.0 yr) affected by non-autoimmune subclinical hypothyroidism diagnosed in our center (follow-up from 1 to 11.5 yr) and normal at neonatal screening were enrolled in the genetic study. In 11 cases, the relatives were included in the genetic analysis., Results: Eleven different mutations of the TSHR gene were identified in 11 of the 38 patients. Two are new: the nonsense mutation C31X and the missense mutation P68S, which shows a decrease in TSH binding capacity but not in biological activity. In all cases the carrier parent was identified., Conclusions: To date, this study demonstrates the highest prevalence (29%) of TSHR gene mutations in children and adolescents with non-autoimmune subclinical hypothyroidism not selected by neonatal screening. Functional studies show that some mutations cause a slight inactivation of the TSHR. This reveals a possible limit of the in vitro study or of the knowledge of mechanisms involving TSHR, or that other candidate genes must be considered.

Thyroid hormones have profound effects on mood and behavior, but the molecular basis of thyroid hormone action in the adult brain is relatively unknown. In particular, few thyroid hormone-dependent genes have been identified in the adult brain despite extensive work carried out on the developing brain. In this work we performed global analysis of gene expression in the adult rat striatum in search for genomic changes taking place after administration of T(3) to hypothyroid rats. The hormone was administered in two different schedules: 1) a single, large dose of 25 microg per 100 g body weight (SD) or 2) 1.5 microg per 100 g body weight once daily for 5 d (RD). Twenty-four hours after the single or last of multiple doses, gene expression in the striatum was analyzed using Codelink microarrays. SD caused up-regulation of 149 genes and down-regulation of 88 genes. RD caused up-regulation of 18 genes and down-regulation of one gene. The results were confirmed by hybridization to Affymetrix microarrays and by TaqMan PCR. Among the genes identified are genes involved in circadian regulation and the regulation of signaling pathways in the striatum. These results suggest that thyroid hormone is involved in regulation of striatal physiology at multiple control points. In addition, they may explain the beneficial effects of large doses of thyroid hormone in bipolar disorders.

Objective: Thyroid-associated ophthalmopathy (TAO) is a chronic autoimmune disorder characterized by an increased volume of adipose/connective tissue in the human orbit., Design: The aim of this study was to investigate the thyrotropin receptor (TSHr) expression in orbital fibroblasts from TAO patients undergoing adipocytic differentiation., Methods: Retro-ocular tissue and skin were obtained from five patients undergoing orbital decompression surgery for TAO and placed in culture. Proliferating fibroblasts were subjected to adipocytic differentiation for 10 days. Total RNA was isolated from fibroblasts and was reverse transcribed. TSHr mRNA levels were determined by real-time PCR. cAMP was determined by radioimmunoassay (RIA) after fibroblast incubation with the substances to test., Results: Orbital differentiated fibroblasts became rounded and acquired lipid droplets. The amount of TSHr mRNA in these fibroblasts was higher than fibroblasts not subjected to adipocytic differentiation. Immunocytochemical analysis showed TSHr protein in differentiated orbital fibroblasts. Differentiated orbital fibroblasts stimulated with bovine (b) TSH showed a cAMP production greater than that in paired undifferentiated cultures. A specific thyroid-inhibiting antibody (TBAb) inhibited cAMP production after bTSH challenge, and a thyroid-stimulating antibody (TSAb) stimulated cAMP production in differentiated fibroblasts., Conclusions: We suggest that orbital fibroblasts subjected to adipocytic differentiation increase TSHr expression that responds specifically to bTSH and TSAb stimulation, and to TBAb inhibition.

Subclinical hypothyroidism of chronic autoimmune thyroiditis must be distinguished from the rare condition of thyroid resistance to TSH in which variable degrees of congenital insensitivity of the thyroid to a biologically active TSH molecule are present. We studied 42 subjects with slight to moderate elevations of circulating TSH and normal free thyroid hormone levels in whom the diagnosis of autoimmune thyroid disease had been excluded using the best of the currently available laboratory and instrumental techniques. In three families (A, B, and C), which included 8 of the 42 cases, other members besides the propositus were found to have isolated hyperthyrotropinemia. The entire coding regions of the TSH receptor (TSHr) gene were sequenced, and TSHr mutations were found in five subjects from families A and B. No mutations were identified in the two members of family C, in one member of family A, and in the 34 remaining cases of isolated hyperthyrotropinemia. A previously described P162A mutation was found in the proband (homozygous state), the son, and the mother of family A (both in the heterozygous state). A new inactivating heterozygous mutation was found in the proband and the mother of family B and consisted of the substitution of a leucine in place of a highly conserved proline at position 252 (L252P) in the extracellular portion of the TSHr. After transfection in COS-7 cells, the mutant L252P displayed a low expression at the cell surface and a reduced response to bovine TSH in terms of cAMP production. A structural defect of the mutant TSHr protein was probably responsible for the poor routing of the receptor to the cell membrane. In conclusion, in two of three families, but in none of 34 sporadic cases of isolated hyperthyrotropinemia, inactivating mutations of the TSHr were identified. The question of whether the latter cases represent subtle forms of autoimmune thyroiditis or might bear as yet unidentified genetic defects remains a matter of future studies.

Objective: TSH receptor (TSHr) mediates the activating action of TSH on the thyroid gland resulting in the growth and proliferation of thyrocytes and thyroid hormone production. TSHr is a major autoantigen in Graves' disease (GD) and is the target for TSHr antibodies. In GD, thyroid-stimulating antibodies (TSAb) are competitive agonists of TSH. In atrophic thyroiditis (AT), thyroid-stimulating blocking antibodies (TSHBAb) are TSH antagonists. The TSHr together with the LH receptor (LHr) and FSH receptor (FSHr) are G-protein-coupled receptors with considerable amino acid homologies in the extracellular domain. We studied the cross-reactivity of the antibodies measured in sera from patients with GD or AT on the LHr and FSHr function., Methods: We tested the activity of TSAb and TSHBAb in cell lines expressing the LHr and the FSHr. To this purpose a pSVL-FSHr construct was transfected in CHO cells and one clone was used., Results: Twenty-eight sera from patients with GD and four from patients with AT, known to contain TSHr antibodies measured with a radioreceptor assay, were selected. TSAb and TSHBAb activities were measured in CHO cells expressing the TSHr (CHO-TSHr). TSAb and TSHBAb were then tested with the cell lines expressing the LHr and the FSHr for their ability to elicit cAMP accumulation or inhibit FSH/LH-induced cAMP production. None of the TSAb identified was able to stimulate cAMP increase in CHO-LHr or CHO-FSHr. Similarly, none of the TSHBAb was able to block the cAMP response induced by FSH or LH in the respective cell lines., Conclusions: Our results confirm the notion of the organ-specific nature of the TSHr antibodies.

Objective: The TSH receptor (TSHr) expressed on thyroid follicular cells is the autoantigen involved in the pathogenesis of Graves' hyperthyroidism. Whether this receptor is expressed in extrathyroidal tissues, and whether it participates directly in the pathogenesis of thyroid-associated ophthalmopathy (TAO) is unclear., Design: The aim of the present study was to measure TSHr mRNA in retro-orbital tissues, retro-orbital adipose tissue, extraocular muscle, and skin from patients with TAO and in several tissues from patients not affected by thyroid diseases using RT-PCR and real-time PCR., Methods: Total RNA was isolated from tissue specimens, reverse transcribed, and amplified using specific primers for the extracellular portion and a part of a 1.3 kbp variant form of the TSHr gene. Determination of TSHr mRNA levels using real-time PCR was also performed by the TaqMan system; to normalize for differences in the amount of total RNA added to the reaction, amplification of beta-actin gene was performed as an endogenous control., Results: A single-round RT-PCR amplification using specific primers for the extracellular portion of the TSHr gene demonstrated an amplification product of 1.2 kbp in the thyroid, but not in all other tissues. A second-round RT-PCR amplification using the same primers and starting from the previous amplification product demonstrated a band of the size expected for the TSHr gene in all tissue specimens analyzed irrespective of their origin. Similar results were obtained using primers specific for a part of the variant form of 1.3 kbp of the TSHr gene. The amount of TSHr mRNA measured by real-time PCR with the TaqMan probe and expressed as TSHr/beta-actin ratio was similar in the tissues from TAO patients with respect to the tissues from subjects not affected by thyroid diseases., Conclusions: We measured TSHr mRNA in tissues from patients with TAO using the very sensitive and quantitative method of real-time PCR. The level of transcription was similar to that measured in extraorbital tissues from patients who were not affected by thyroid diseases. These data suggest an illegitimate TSHr mRNA transcription in all the tissues examined apart from thyroid.

Nodular thyroid disease is the most common endocrine disorder. Nonfunctioning thyroid nodules are identified by their low radioiodide uptake compared with the normal extranodular tissue, which, at thyroid scintiscan, produces the typical picture of a cold thyroid nodule. Previous in vitro studies demonstrated that the majority of nonfunctioning thyroid nodules have a specific defect in iodide transport that accounts for their failure to accumulate radioactive iodide in vivo. A defect in the expression or structure of the sodium iodide symporter (NIS) gene has been hypothesized as a possible cause of the impaired iodide trapping in nonfunctioning thyroid nodules. We studied 22 patients who were submitted to surgery for a solitary nonfunctioning thyroid nodule that originated in an otherwise normal gland. Thyroid scintigraphy was performed at 1, 2, 3, 4, 6, and 24 h after the oral administration of a tracer dose of 131I (iodine). All patients showed absence of 131I uptake in the nodule, with normal uptake in the extranodular tissue and in the contralateral thyroid lobe. Eight patients with toxic adenomas who underwent lobectomy were also included in the study. We first studied the expression of human NIS (hNIS) protein by immunohistochemistry in paraffin-embedded tissue sections using a specific anti-hNIS monoclonal antibody. Subsequently, we searched for somatic mutations of hNIS gene in nonfunctioning thyroid nodules. The level of hNIS expression was determined in both the nodules and the normal tissue from the same thyroid gland. In all functioning thyroid nodules (toxic adenomas), a high expression of hNIS protein was detected with respect to normal surrounding tissue. Similar to the normal thyroid tissue, follicular cells of toxic thyroid adenomas showed an exclusive expression of hNIS protein at the cell membrane. Fifty-four percent of benign nonfunctioning thyroid nodules overexpressed hNIS protein compared with the normal surrounding tissue, but in these nodules the hNIS protein failed to target the cell membrane, being mostly localized inside the cytoplasm. hNIS protein was not detected by immunohistochemistry in 46% of nonfunctioning nodules, whereas it was expressed in the surrounding unaffected thyroid tissue. Direct sequencing of the hNIS gene in all of the nonfunctioning nodules did not reveal major genetic alterations. A silent polymorphism (GCC/GCG codon 544, exon 13) was found in one nodule. In conclusion, the results obtained in this study show that two mechanisms contribute to the reduced radioiodide uptake typical of benign nonfunctioning thyroid nodules: 1) reduced expression of the hNIS protein, and 2) defective targeting of hNIS to the cell membrane.