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Narayanan Kandasamy, Laura Fugazzola, Mark Evans, Krishna Chatterjee and Fiona Karet

Introduction

Pendred syndrome, a combination of sensorineural deafness, impaired organification of iodide in the thyroid and goitre, results from biallelic defects in pendrin (encoded by SLC26A4), which transports chloride and iodide in the inner ear and thyroid respectively. Recently, pendrin has also been identified in the kidneys, where it is found in the apical plasma membrane of non-α-type intercalated cells of the cortical collecting duct. Here, it functions as a chloride–bicarbonate exchanger, capable of secreting bicarbonate into the urine. Despite this function, patients with Pendred syndrome have not been reported to develop any significant acid–base disturbances, except a single previous reported case of metabolic alkalosis in the context of Pendred syndrome in a child started on a diuretic.

Case report

We describe a 46-year-old female with sensorineural deafness and hypothyroidism, who presented with severe hypokalaemic metabolic alkalosis during inter-current illnesses on two occasions, and who was found to be homozygous for a loss-of-function mutation (V138F) in SLC26A4. Her acid–base status and electrolytes were unremarkable when she was well.

Conclusion

This case illustrates that, although pendrin is not usually required to maintain acid–base homeostasis under ambient condition, loss of renal bicarbonate excretion by pendrin during a metabolic alkalotic challenge may contribute to life-threatening acid–base disturbances in patients with Pendred syndrome.

Free access

Andrea Busnelli, Guia Vannucchi, Alessio Paffoni, Sonia Faulisi, Laura Fugazzola, Luigi Fedele and Edgardo Somigliana

Objective

About one out of two women with primary hypothyroidism has to increase the dosage of exogenous levothyroxine (l-T4) during pregnancy. Considering the detrimental impact of IVF on thyroid function, it has been claimed but not demonstrated that l-T4 dose adjustment may be more significant in hypothyroid women who become pregnant after IVF.

Design

Retrospective cohort study.

Methods

Hypothyroid-treated women who achieved a live birth through IVF were reviewed. Women could be included if thyroid function was well compensated with l-T4 before the IVF cycle (i.e., serum TSH <2.5 mIU/l and serum free T4 within the normal range). Serum TSH and dose adjustment were evaluated at five time points during pregnancy. The trimester ranges for serum TSH considered as reference to adjust l-T4 therapy were 0.1–2.5 mIU/l for the first trimester, 0.2–3.0 mIU/l for the second trimester, and 0.3–3.0 mIU/l for the third trimester.

Results

Thirty-eight women were selected. During the whole pregnancy 32 women (84%; 95% CI: 72–96%) required an increase in the dose of l-T4. In most cases (n=28), this occured within the first 5–7 weeks of gestation (74%, 95% CI: 58–85%). At 5–7 weeks of gestation, the median (interquartile range) increase of l-T4 dose for the whole cohort was 26% (0–50%). At 30–32 weeks, it was 33% (14–68%). In order to identify predictive factors of dose adjustment, we compared women who did (n=28) and did not (n=10) adjust l-T4 dosage at 5–7 weeks' gestation. Significant differences emerged for thyroid autoimmunity prevalence and for the distribution of hypothyroidism aetiology.

Conclusions

The vast majority of hypothyroid-treated women who achieve pregnancy through IVF need an increase in the l-T4 dose during gestation. This requirement tends to occur very early during gestation.

Free access

Guia Vannucchi, Michela Perrino, Stefania Rossi, Carla Colombo, Leonardo Vicentini, Davide Dazzi, Paolo Beck-Peccoz and Laura Fugazzola

Objective

Pregnancy represents a favorable condition for the development of thyroid nodules, likely due to the secretion of hormones with stimulatory activity. In particular, differentiated thyroid cancer (DTC) represents the second most frequent tumor among those diagnosed during pregnancy. However, few and discordant data are available about the impact of pregnancy on tumor outcome.

Methods

A total of 123 women with DTC were divided into three groups according to the timing of tumor diagnosis (group 1, at least 1 year after the delivery; group 2, during pregnancy or in the first year after delivery; and group 3, before pregnancy or nulliparity) and evaluated according to the international guidelines. Furthermore, immunohistochemical studies of estrogen receptor α (ERα) were performed in 38 papillary thyroid cancer tissues from the three groups.

Results

Thyroid cancer diagnosed during pregnancy was associated with a poorer prognosis compared to tumors developed in nongravidic periods (P<0.0001). Accordingly, at the stepwise logistic regression analysis, the diagnosis of DTC during pregnancy or in the first year post partum was the most significant indicator of persistent disease (P=0.001). Interestingly, ERα expression significantly differed among tumors of the three groups, being detected in 31% of group 1, in 87.5% of group 2, and in 0% of group 3 (P=0.01).

Conclusions

Present data indicate that pregnancy has a negative impact on the outcome of thyroid cancer. The presence of ERα in the majority of tumors diagnosed during pregnancy indicates that the poorer outcome of these cases could be related to the estrogen-mediated growth stimulus.

Free access

Laura Fugazzola, Valentina Cirello, Silvia Dossena, Simona Rodighiero, Marina Muzza, Pierangela Castorina, Faustina Lalatta, Umberto Ambrosetti, Paolo Beck-Peccoz, Guido Bottà and Markus Paulmichl

Objective: Pendred syndrome (PS) is characterized by the association of sensorineural hearing loss (SNHL) and a partial iodide organification defect at the thyroid level. It is caused by mutations in the SLC26A4 gene. The encoded transmembrane protein, called pendrin, has been found to be able to transport chloride and other anions.

Design: The aim of the present study was to characterize a family with PS, which shows a strong intrafamilial phenotypic variability, including kidney atrophy in one member. The age of disease-onset was significantly different in all three affected siblings, ranging from 2 to 21 years for thyroid alterations and from 1.5 to 11 years for SNHL.

Methods: Clinical and genetic studies were carried out in affected siblings. The functional activity of the novel duplication found was studied by a fluorimetric method in a human renal cell line (HEK293 Phoenix) in which the protein was overexpressed.

Results: All three siblings were found to be compound heterozygotes for the missense mutation (1226G>A, R409H) and for a novel 11 bp duplication (1561_1571CTTGGAATGGC, S523fsX548). The latter mutation creates a frame shift leading to the loss of the entire carboxy-terminus domain. Functional studies of this mutant demonstrated impaired transport of chloride and iodide when expressed in HEK 293 Phoenix cells, when compared with wild type pendrin.

Conclusions: A novel 11 bp duplication was found in a family with Pendred syndrome, showing a high intrafamilial phenotypic variability. An impaired transmembrane anionic transport of the mutated SLC26A4 protein was demonstrated in functional studies using a heterologous cell system.

Free access

Valentina Cirello, Roberta Rizzo, Milena Crippa, Irene Campi, Daria Bortolotti, Silvia Bolzani, Carla Colombo, Guia Vannucchi, Maria Antonia Maffini, Federica de Liso, Stefano Ferrero, Palma Finelli and Laura Fugazzola

Objective

The physiological persistence of fetal cells in the circulation and tissue of a previously pregnant woman is called fetal cell microchimerism (FCM). It has been hypothesized to play a role in systemic autoimmune disease; however, only limited data are available regarding its role in autoimmune thyroid disease (AITD).

Design

Circulating FCM was analyzed in a large series of previously pregnant women with Graves' disease (GD), Hashimoto's thyroiditis (HT), or no disease (healthy controls (HCs)). To exclude the possible bias related to placental factors, the polymorphic pattern of human leukocyte antigen-G (HLA-G) gene, which is known to be involved in the tolerance of fetal cells by the maternal immune system, was investigated.

Methods

FCM was evaluated by PCR in the peripheral blood, and the Y chromosome was identified by fluorescence in situ hybridization in some GD tissues. HLA-G polymorphism typing was assessed by real-time PCR.

Results

FCM was significantly more frequent in HC (63.6%) than in GD (33.3%) or HT (27.8%) women (P=0.0004 and P=0.001 respectively). A quantitative analysis confirmed that circulating male DNA was more abundant in HC than it was in GD or HT. Microchimeric cells were documented in vessels and in thyroid follicles. In neither GD/HT patients nor HC women was the HLA-G typing different between FCM-positive and FCM-negative cases.

Conclusion

The higher prevalence of FCM in HC as compared to GD and HT patients suggests that it plays a possible protective role in autoimmune thyroid disorders. Placental factors have been excluded as determinants of the differences found. The vascular and tissue localization of microchimeric cells further highlights the ability of those cells to migrate to damaged tissues.

Free access

Guia Vannucchi, Simone De Leo, Michela Perrino, Stefania Rossi, Delfina Tosi, Valentina Cirello, Carla Colombo, Gaetano Bulfamante, Leonardo Vicentini and Laura Fugazzola

Background

Thyroid cancer is highly prevalent in women during the fertile age, which suggests a possible impact of hormonal and reproductive factors.

Methods

We studied the expression of estrogen receptor α (ERα or ESR1) and progesterone receptor (PR or PGR) in 182 female and male patients with papillary thyroid cancer and correlated it to clinical and molecular features.

Results

ERα and PR expression was found in 66.5 and 75.8% of patients respectively and was significantly correlated with larger tumor size and with a non-incidental diagnosis. Moreover, a trend toward a higher prevalence of local metastases was observed in ER- and PR-expressing tumors, which possibly indicates a more aggressive behavior. Interestingly, the occurrence of the ‘receptor conversion’ phenomenon, which has already been reported to have a negative prognostic effect in breast cancer, was demonstrated for the first time in thyroid tumors. Indeed, almost all of the ERα-positive primary tumors analyzed had ERα-negative metastatic lymph nodes. At the genetic analyses, BRAF V600E mutation was detected in 23.2% of the tumors and had a higher prevalence in larger tumors and in those with a stronger ERα or PR staining.

Conclusions

The whole of the findings reported in the present study argue for an association between ERα and PR sex hormone receptor expression and a more aggressive presentation. Although no impact on outcome was found, the evaluation of ERα and PR receptor expression could add insights into the biological behavior of tumors and could modify the follow-up, particularly in fertile women affected with persistent disease.

Restricted access

Irene Campi, Giovanni B Perego, Antonella Ravogli, Antonella Groppelli, Gianfranco Parati, Luca Persani and Laura Fugazzola

Objectives

Amiodarone-induced thyrotoxicosis (AIT) affects up to 3% of treated patients. Type 2 AIT (AIT2) is a destructive thyroiditis and is usually treated with medium-high oral doses of prednisone. As AIT may worsen the underlying heart disease, a rapid control of thyroid function is desirable. We aimed to determine whether a combined intravenous methylprednisolone (IVMP) pulses therapy associated to prednisone in the interpulse period can represent an efficient and safe alternative to urgent total thyroidectomy in patients with AIT2 not responsive to prednisone alone.

Design and methods

Patients presenting with a severe AIT2 studied in a tertiary referral Center from August 2018 to April 2019. We included four patients requiring a rapid improvement of thyroid function for their underlying cardiac disorders. The baseline doses of oral prednisone (range: 5–12.5 mg/day) and IVMP (range: 250–500 twice a week) were determined according to the severity of the thyrotoxicosis and were titrated based on clinical response.

Results

Combined treatment was effective in all patients in the prompt restoration of euthyroidism and no major adverse events were reported during the follow-up. In all cases, FT4 and FT3 levels normalized at 3–5 weeks of treatment. A permanent hypothyroidism was observed in one patient, 3 months after the discontinuation of treatment.

Conclusions

We report for the first time that the combined intravenous and oral steroid therapy is effective in patients with AIT2. The treatment is well tolerated and leads to a rapid improvement of thyroid function, avoiding urgent total thyroidectomy and favoring a quick functional recovery and rehabilitation of cardiac patients.

Free access

Marina Muzza, Daniela Cordella, Johny Bombled, Brigitte Bressac-de Paillerets, Fabiana Guizzardi, Zelia Francis, Paolo Beck-Peccoz, Martin Schlumberger, Luca Persani and Laura Fugazzola

Context

Most germline-activating mutations of the RET proto-oncogene associated with inherited medullary thyroid cancer (MTC) are localized in exons 10, 11 and 13–15. Four novel RET variants, located in the extracellular domain (p.A510V, p.E511K and p.C531R) coded by exon 8 and in the intracellular juxtamembrane region (p.K666N) coded by exon 11, were identified on the leukocyte DNA from apparently sporadic cases.

Methods

Plasmids carrying Ret9-wild-type (Ret9-WT), Ret9-C634R and all Ret9 variants were transfected, and the phosphorylation levels of RET and ERK were evaluated by western blot analyses. The transforming potentials were assessed by the focus formation assay.

Results

The p.A510V, p.E511K and p.C531R variants were found to generate RET and ERK phosphorylation levels and to have a transforming activity higher than that of Ret9-WT variant, but lower than that of Ret9-C634R variant. Differently, the p.K666N variant, located immediately downstream of the transmembrane domain, and involving a conserved residue, displayed high kinase and transforming activities. Computational analysis predicted non-conservative alterations in the mutant proteins consistent with putative modifications of the receptor conformation.

Conclusions

The molecular analyses revealed an oncogenic potential for all the novel germline RET variants. Therefore, the prevalence of exon 8 genomic variations with an oncogenic potential may be higher than previously thought, and the analysis of this exon should be considered after the exclusion of mutations in the classical hotspots. In addition, on the basis of these functional data, it is advisable to extend the genetic screening to all the first-degree relatives of the MTC patients, and to perform a strict follow-up of familial carriers.

Free access

Silvia Dossena, Antonella Maccagni, Valeria Vezzoli, Claudia Bazzini, Maria Lisa Garavaglia, Giuliano Meyer, Johannes Fürst, Markus Ritter, Laura Fugazzola, Luca Persani, Patrick Zorowka, Carlo Storelli, Paolo Beck-Peccoz, Guido Bottà and Markus Paulmichl

Objective: The SLC26A4 protein (pendrin) seems to be involved in the exchange of chloride with other anions, therefore being responsible for iodide organification in the thyroid gland and the conditioning of the endolymphatic fluid in the inner ear. Malfunction of SLC26A4 leads to Pendred syndrome, characterized by mild thyroid dysfunction often associated with goiter and/or prelingual deafness. The precise function of the SLC26A4 protein, however, is still elusive. An open question is still whether the SLC26A4-induced ion exchange mechanism is electrogenic or electroneutral. Recently, it has been shown that human pendrin expressed in monkey cells leads to chloride currents.

Methods: We overexpressed the human SLC26A4 isoform in HEK293 Phoenix cells and measured cationic and anionic currents by the patch-clamp technique in whole cell configuration.

Results: Here we show that human pendrin expressed in human cells does not lead to the activation of chloride currents, but, in contrast, leads to an increase of cationic currents.

Conclusion: Our experiments suggest that the SLC26A4-induced chloride transport is electroneutral when expressed in human cellular systems.

Free access

Cristina Romei, Stefano Mariotti, Laura Fugazzola, Augusto Taccaliti, Furio Pacini, Giuseppe Opocher, Caterina Mian, Maurizio Castellano, Ettore degli Uberti, Isabella Ceccherini, Nadia Cremonini, Ettore Seregni, Fabio Orlandi, Piero Ferolla, Efisio Puxeddu, Francesco Giorgino, Annamaria Colao, Paola Loli, Fabio Bondi, Barbara Cosci, Valeria Bottici, Antonello Cappai, Giovanni Pinna, Luca Persani, Verga Uberta, Marco Boscaro, Maria Grazia Castagna, Carlo Cappelli, Maria Chiara Zatelli, Antongiulio Faggiano, Giuseppe Francia, Maria Luisa Brandi, Alberto Falchetti, Aldo Pinchera, Rossella Elisei and The ItaMEN network

The journal and the authors apologise for an error in the name of one of the authors (appears as Verga Uberta) of this article published in the European Journal of Endocrinology Vol 163 301–308. The correct name of the author should be Uberta Verga and not as published.