A principal função da glândula tireoide é a produção dos hormônios T3 e T4, que promovem a regulação do consumo energético no organismo. O hipotireoidismo congênito (HC) é um distúrbio metabólico sistêmico, onde a produção de T3 e T4 no período neonatal é insuficiente. O HC por disormonogênese é uma doença causada por erros inatos na síntese de T3 e T4, com herança autossômica recessiva. Já foram descritas mutações nos genes NIS, SLC26A4, DUOX2, DUOXA2, TPO, TG e DEHAL-1. O defeito na organificação do iodeto (DOI) é o mais comum na disormonogênese, sendo a falha mais frequente na TPO, seguida pelas proteínas DUOX2 e DUOXA2. A TPO é responsável pela oxidação do iodeto, pela iodação da tireoglobulina e pelo acoplamento das tirosinas iodinizadas. Já foram descritas 70 mutações ao longo de todo o gene TPO. Por ser uma heme peroxidase, a TPO requer H2O2 para sua função. O principal núcleo catalítico gerador de H2O2 na tireoide é o complexo DUOX2/DUOXA2. Foram descritas 25 mutações no gene DUOX2 e uma única mutação no gene DUOXA2. Em estudo anterior, avaliamos pacientes com HC após os 3 anos de idade para estabelecimento do diagnóstico etiológico, através de dosagem de TG sérica, ultrassonografia, captação e mapeamento da tireoide com 131I. Sete pacientes apresentaram DOI. Nestes pacientes avaliamos o gene TPO e identificamos diversos SNPs já descritos na literatura. Um paciente apresentou a mutação p.Q660E em heterozigose, outro paciente o SNP p.R584Q em homozigose, e um terceiro paciente as alterações p.Q660E e p.584Q em heterozigose composta. Os objetivos deste estudo foram pesquisar mutações dos genes DUOX2 e DUOXA2 nos pacientes com DOI e realizar o estudo funcional da alteração p.R584Q na TPO. Para o estudo molecular, extraímos o DNA de leucócitos periféricos dos pacientes e seus familiares, seguido de amplificação por PCR, e sequenciamento automático, e os resultados comparados com as sequencias normais de cada gene (GenBank). Na análise funcional da alteração p.R584Q na TPO, células HeLa foram transfectadas com plasmídios pcDNA contendo o gene da TPO normal e alterado, e a atividade das proteínas produzidas pelas células foi avaliada pelo sistema AmplexRed. Análises in silico foram realizadas com os programas de bioanálise PolyPhen, MutationTaster, SIFT e PSIPRED. Ao final do estudo molecular, no gene DUOX2, identificamos 20 SNPs previamente descritos, incluindo o SNP funcional p.H678R (rs57659670), presente em heterozigose em 3 pacientes. Também identificamos a nova substituição p.A1087V em heterozigose em um paciente. De acordo com dados dos programas de bioanálise, a alteração p.A1087V é prejudicial e o SNP p.H678R é tolerável. No gene DUOXA2 identificamos 5 polimorfismos previamente descritos e nenhuma mutação. No estudo funcional, verificamos uma diminuição significativa da atividade da TPO portadora da alteração p.R584Q em comparação à proteína normal (5% de atividade residual; p=0,0193). De acordo com os dados dos programas de bioanálise, a alteração p.R584Q é prejudicial. Três pacientes não apresentaram alterações nas regiões estudadas dos genes TPO, DUOX2 e DUOXA2. As revisões dos dados clínicos e laboratoriais sugerem a presença de outras proteínas alteradas, como TG, Pendrina ou receptor do TSH. Um paciente apresentou a nova alteração p.A1087V na DUOX2 em heterozigose e nenhuma outra alteração nas regiões estudadas dos genes avaliados. Cogitamos a presença de alterações em regiões não avaliadas ou ainda a expressão monoalélica de DUOX2. O SNP funcional p.H678R na DUOX2 foi identificado em três pacientes com alterações na TPO: um com a alteração p.R584Q em homozigose, outro com a p.R584Q e a mutação p.Q660E em heterozigose composta. Estes dois pacientes apresentam os dois alelos da TPO alterados, justificando o DOI. O terceiro caso apresentou apenas a mutação p.Q660E em heterozigose, podendo apresentar alterações em regiões não avaliadas ou ainda a expressão monoalélica da TPO. Concluímos que definimos o diagnóstico molecular de 4 dos nossos pacientes, que apresentaram importantes alterações nos genes avaliados, e ressaltamos que a alteração p.R584Q na TPO provoca perda da atividade, causando DOI / The main role of the thyroid gland is to produce T3 and T4, which promote the regulation of body energy intake. Congenital hypothyroidism (CH) is a systemic metabolic disorder where T3 and T4 production during neonatal period is insufficient. CH due to dyshormonogenesis is a disease caused by inborn errors in T3 and T4 synthesis, with autosomal recessive inheritance. Mutations in NIS, SLC26A4, DUOX2, DUOXA2, TPO, TG and DEHAL-1 genes have been described. The iodide organification defect (IOD) is the most common cause of dyshormonogenesis, being the TPO defect the most frequent, followed by defects in DUOX2 and DUOXA2 proteins. TPO is responsible for iodide oxidation, tyrosine iodination and its coupling. Seventy mutations have been described throughout the gene. As a heme peroxidase, TPO requires H2O2 to its regular function. The main catalytic core for H2O2 generation in thyroid is the DUOX2/DUOXA2 complex. Twenty five mutations have been described in DUOX2 gene and only one mutation in DUOXA2 gene. In our previous study, we evaluated patients with CH after 3 years of age to establish their etiologic diagnosis, by combining serum TG, thyroid ultrasound, and radioiodide uptake with 131I. Seven patients were diagnosed with IOD. In these patients, we evaluated TPO gene and identified several already described SNPs. One patient had the p.Q660E mutation in heterozygous state, another patient had the SNP p.R584Q in homozygous state and a third one had p.Q660E and p.584Q in compound heterozygous state. The aims of this study were to search for mutations in DUOX2 and DUOXA2 genes in patients with IOD and perform a functional study of TPO p.R584Q change. For the molecular study, DNA was extracted from peripheral blood leukocytes of each patient and parents, followed by PCR, and automatic sequence, and the results were compared with normal sequences of each gene (GenBank). For functional analysis of TPO p.R584Q, HeLa cells were transfected with pcDNA plasmids containing normal and altered TPO gene and the protein activity was assessed by AmplexRed system. In silico analyzes were performed with the bioanalysis programs: PolyPhen, MutationTaster, SIFT and PSIPRED. At the end of the molecular study, in DUOX2 gene we identified 20 previously described SNPs, including the functional p.H678R SNP (rs57659670), present in heterozygous state in 3 patients. We also identified the new p.A1087V change in heterozygous state in one patient. According to bioassay programs datas, p.A1087V change is damage and p.H678R SNP is tolerable. In DUOXA2 gene we identified five previously described polymorphisms and no mutation. In TPO functional study, we observed a significant activity decrease of TPO p.R584Q compared to normal TPO (5% of activity; p=0.0193). According to bioassay programs datas, p.R584Q is damaging. Three patients showed no changes in TPO, DUOX2 and DUOXA2 genes studied regions. A review of clinical and laboratory data suggested the presence of other altered proteins, such as TG, Pendrin or TSH receptor. One patient had the new DUOX2 p.A1087V alteration in heterozygous state and no other changes in the studied regions of evaluated genes, suggesting that there could be changes in other nonevaluated regions or the monoallelic expression of DUOX2. The functional DUOX2 p.H678R SNP was identified in three patients with changes in TPO: one with p.R584Q change in homozygous state and another one with p.R584Q and p.Q660E in compound heterozygous state. These cases have the two alleles of TPO changed, justifying their IOD. A third case showed only the TPO p.Q660E mutation in heterozygous state. We speculate that the patient may present changes in regions nonevaluated or the monoallelic expression of TPO. We conclude that we defined the molecular diagnosis of four patients, that showed significant changes in evaluated genes, and that TPO p.R584Q change is functionally harmful, causing IOD

Introdução: O hipotireoidismo congênito é a causa mais frequente de retardo mental evitável, cuja prevalência é de 1/3000 crianças nascidas vivas. Pode ser causado por disgenesia tireoideana (80% dos casos) ou por defeitos de síntese hormonal (20% restantes). As disormonogêneses tem sido associadas a mutações nos genes da tireoperoxidase (TPO), tireoglobulina, dual oxidase 2, pendrina, desalogenase e do simportador sódio/iodo. A tireoperoxidase (TPO) é uma glicoproteína de 105 KDa, localizada na membrana apical do tireócito, responsável pela organificação do iodeto. Até o momento 54 mutações, associadas ao hipotireoidismo congênito foram identificadas no gene TPO. Objetivos: Este estudo visou rastrear mutações no gene TPO em pacientes com hipotireoidismo congênito, com defeito total ou parcial de incorporação de iodeto, e associar o defeito genético com o fenótipo do paciente. Casuística e Métodos: Foram estudados 34 pacientes com hipotireoidismo congênito, 13 com DIIT (descarga de iodeto >50%) e 21 com DIIP (descarga de iodeto entre 25 e 50%) por possível defeito no gene TPO. Os métodos empregados foram: extração do DNA genômico de sangue periférico, amplificação por PCR do promotor e dos 17 exons do gene TPO e dos 33 exons do gene DUOX2 , eletroforese em gel de gradiente denaturante (DGGE) e seqüenciamento. Resultados: Foram identificadas 8 novas alterações de seqüências que levam a troca de aminoácidos: Leu68Ile, Gly319Glu, Ala426Gly, Arg584Gln, Val618Met, Pro883Leu, Ala909Thr, A909fsX49; e 4 já descritas na literatura: 396fsX76, Gln660Gly, Arg665Trp, Cys838Ser. Dois pacientes com DTII apresentaram mutações em homozigose, e dois pacientes (um com DTII e um com DPII) eram portadores de alterações em heterozigose composta. Seis pacientes eram portadores de um único alelo da TPO afetado (três com DPII e três com DTII). Foram identificados também 33 polimorfismos (10 novos). Apenas polimorfismos foram identifiados no gene DUOX2. Conclusão: Foi verificada alta freqüência de mutações monoalélicas em pacientes com DIIT e DIIP. Em ambos os grupos as mutações se localizaram ao longo de todo o gene, tanto no domínio extracelular como no intracelular da proteína. Somente duas mutações foram identificadas em mais de um paciente, mostrando a heterogeneidade genotípica da doença nesta população / I ntroduction: Congenital Hypothyroidism affects 1/3000 birth, is caused by thyroid gland dysgenesis (80%) or inborn errors of the thyroid hormone biosynthesis (20%). Genetics defects of the genes for thyroid peroxidase, (TPO), thyroglobulin, sodium/iodine simporter, dual oxidase 2, and pendrine have been associated to dyshormonogenesis. TPO is a glycoprotein of 105 KDa situated in the apical membrane of the thyroid cell, responsible for iodide organification. At least 54 mutations have been identified in patients with dyshormonogenesis. Objectives: The aim of the study was to identify TPO gene mutations in patients with congenital hypothyroidism with total (DIIT) and partial (DIIP) iodide organification defects and to associate the genetic defect with the phenotype of the patient. Patients and Methods: Thirty four patients with congenital hypothyroidism, 13 with DIIT (iodide discharge >50%) and 21 patients with DIIP (iodide discharge between 25- 50%) due to possible TPO gene defect. Extraction of genomic DNA from peripheral blood, PCR amplification of the promoter, 17 exons of TPO gene and of the 33 exons of DUOX2 gene, denaturant gradient gel electrophoreses (DGGE) and sequencement were performed. Results: Eight new sequence alterations were identified: Leu68Ile, Gly319Glu, Ala426Gly, Arg584Gln, Val618Met, Pro883Leu, Ala909Thr, A909fsX49; and four previously described mutations: 396fsX76, Gln660Gly, Arg665Trp, Cys838Ser. Homozygous mutations were identified in two patients with DTII. Ttwo patients (one with DTII and one with DPII) were carrying compound heterozygous mutations. TPO monoallelic mutations were identified in six patients (3 with DPII and 3 with DTII). Thirty three polymorphisms had also been identified (10 news). Conclusion: High frequency of TPO monoallelic mutations was detected in patients with DIIT and DIIP. In both groups of patients the mutations were located all throughout the gene, in the extracellular as well as in the intracellular domain. Only two mutations have been identified in more than one patient, indicating the genotypic heterogeneity of the illness in this population

Estudamos 32 crianças com HC devido à agenesia ou ectopia tireoideana para mutações no PAX8 e 30 crianças com hipoplasia da tireóide para mutações no rTSH. Todos os exons de ambos os genes foram amplificados a partir do DNA genômico, seguido por seqüenciamento direto. Encontramos, em dois pacientes com ectopia, duas alterações no gene PAX8, uma no promotor, e outra no exon um. Os outros indivíduos estudados apresentaram as seqüências codificáveis dos genes PAX8 e rTSH normais. Em relação ao caráter funcional e ensaios de luciferase verificamos que no promotor a resposta transcricional diminuiu significativamente na presença de TSH, por um mecanismo dependente de cAMP / We studied 32 children with hypothyrodism (CH) from thyroid agenesis or ectopia for PAX8 mutations, and 30 children with thyroid hypoplasia for rTSH mutations. All exons of both genes were amplified from the genomic DNA, then sequenced directly. We found two alterations in the PAX8 gene in two patients, one in the promoter and the other in exon one. The other children had normal sequences in both PAX8 and rTSH genes. In relation to functional character and luciferase assays, we verified that transcriptional response was significantly reduced in the presence of TSH by a cAMP dependant mechanism

La maladie d’Alzheimer (MA) est une maladie multifactorielle et à ce jour aucune cause des formes sporadiques de la maladie, qui représente plus de 99% des cas, n’a été mise en évidence. Des données émergentes de la littérature suggèrent l’existence d’un lien entre les dysfonctionnements thyroïdiens et la MA. Dans ce contexte, l’objectif de cette étude était de préciser l’implication de l’hypothyroïdie dans les processus neuropathologiques de la MA. En utilisant un modèle de rats rendus hypothyroïdiens par un traitement au propylthiouracile (PTU), nous avons montré que l’hypothyroïdie favorise la mise en place de lésions caractéristiques de la MA dans l’hippocampe, structure du cerveau précocement altérée dans la maladie et qui joue un rôle crucial dans les processus de mémoire. Une étude d’IRM in vivo a révélé une diminution progressive du volume cérébral des rats hypothyroïdiens. Dans l’hippocampe, l’hypothyroïdie s’accompagne d’une augmentation de la production de peptides amyloïdes, d’une hyperphosphorylation de la protéine Tau et d’une augmentation de la libération de plusieurs cytokines pro-Inflammatoires. Ces lésions, caractéristiques de la MA, sont associées à des troubles de la mémoire spatiale à court et long terme et à une altération de deux voies de signalisation connues pour jouer un rôle important dans les processus de plasticité synaptique et de mémoire : la voie calcique et la voie ERK-MAPK. Afin d’évaluer le potentiel de restauration de ces lésions, une partie des rats hypothyroïdiens a reçu des injections intra-Péritonéales de triiodothyronine (T3), forme active des hormones thyroïdiennes. Nos résultats montrent que l’administration de T3 permet de restaurer les déficits de mémoire spatiale à court terme, mais pas à long terme. En outre, ce même traitement permet de restaurer les niveaux de cytokines pro-Inflammatoires, de peptides amyloïdes ainsi que les voies « calcique » et « ERK-MAPK ». Ces données renforcent l’existence d’un lien entre l’hypothyroïdie et la MA : elles suggèrent que l’hypothyroïdie pourrait représenter un facteur important pouvant impacter le risque de développer des formes sporadiques de la MA. / Alzheimer’s disease (AD) is a multifactorial disease and to date no single cause for the sporadic forms, which accounts for over 99% of the cases, has been established. Converging evidence suggests a possible link between thyroid dysfunctions and AD. The aim of the present study was to explore the possibility that adult hypothyroidism represents an etiopathogenic mechanism of AD. In this context, using a hypothyroid rat model induced by propylthiouracil (PTU) treatment, we report that hypothyroidism is associated with several AD-Associated hallmarks in the hippocampus, a brain structure affected in early stages of AD and which plays a crucial role in memory processes. In vivo MRI revealed a progressive decrease in cerebral volume of hypothyroid-Rats. In the hippocampus, hypothyroidism resulted in Tau hyperphosphorylation, increased levels of amyloid peptide and of several pro-Inflammatory cytokines. These AD-Related pathological hallmarks were associated with impaired short- and long-Term spatial memory and alteration of hippocampal signalling pathways important for synaptic plasticity and memory, including calcium and ERK-MAPK pathways. To test the potential reversion of PTU-Induced lesions, we injected hypothyroid rats with triiodothyronine (T3), the active form of thyroid hormone. Our results show that intraperitoneal injections of T3 restored spatial short-Term, but not long-Term memory in hypothyroid-Treated rat. Furthermore, levels of pro-Inflammatory cytokines, amyloid peptide and of proteins involved in calcium and ERK-MAPK signalling were restored. These data strengthen the link between hypothyroidism and AD, supporting the idea that hypothyroidism may represent an important factor impacting the risk for developing sporadic forms of AD.

Deficiencies of selenium (Se) and iodine (I) are widespread in livestock all over Europe. They have an impact on the animals health. Since the clinical signs of the deficiencies are rarely pathognomic, auxiliary exams, based on blood and milk samples are needed for the confirmation of the diagnosis. To evaluate the Se and I status, the plasmatic Se content, the erythrocytic glutathione peroxydase activity (GPX), and the inorganic plasmatic I (IIP) content are measured routinely. Other analyses, like e.g. the dosage of tri-iodothyronine (T3) or thyrotropine (bTSH) can be used. Once the deficiency is diagnosed, it can be corrected by several methods. The first aim of the study was to evaluate the zinc, copper, Se, and I status of Wallonian dairy and beef herds and to correlate their trace element status to their health. The trace element status of the herds with pathologies was less good than that of healthy herds. Further, more herds with pathologies had deficiencies when compared to healthy ones. Dairy herds had a better trace element status than beef herds. Se and I deficiencies are among the most important ones and have the most severe sequels. Therefore, the subsequent parts of the study focussed on these two trace elements. The second aim was the establishment of a technique for the dosage of bTSH and of reference values in healthy cattle. Reference ranges for bTSH and for thyroxine (T4) have been determined in healthy adult cows and in healthy calves. Thereafter, the next aim was to compare the concentration of bTSH in newborn calves with goitre to those obtained in healthy calves, in order to validate a diagnostic test for this pathology. The bTSH allowed the discrimination of the two groups and to approve the diagnosis of hypothyroidism in some of the calves. The threshold value of bTSH for the diagnosis of hypothyroidism in the newborn calf has been fixed at 35 µU/ml. The fourth aim was to compare the I (IIP) and Se (plasmatic Se, GPX) status as well as the thyroid status (bTSH, T4, T3, rT3) in dried pregnant cows and their calves and in non-pregnant cows, that received normal diet and a diet enriched in Se and I. In those receiving a Se and I enriched diet, the T4 and the bTSH decreased while the IIP, the T3, and the GPX activity increased. In the group that received a diet with normal Se and I contents, only the GPX activity increased. At birth, calves from mothers receiving the Se and I enriched diet, had a higher IPP content and GPX activity, and a lower bTSH concentration than calves from the other group. The last aim was to compare the effects of two different forms of Se (sodium selenite versus seleno-methionine) and two different doses of Se (0.1 versus 0.5 ppm) on the health and the Se status of Se deficient Belgian Blue cows and their calves. The first two groups of cows received a ration with 0.1 and 0.5 ppm, respectively, of Se in the form of sodium selenite (Na-Se 0.1 and Na-Se 0.5), while the third group received 0.5 ppm of Se in the form of seleno-methionine (Y-Se 0.5). The Se content of plasma, colostrum, and milk was higher in the cows of group Y-Se 0.5 when compared to the two other groups. The Se content of the plasma was higher in calves from group Y-Se 0.5 when compared to the two other groups. The daily weight gain of the Y-Se 0.5 group was higher than those of the group Na-Se 0.1. The incidence of diarrhoea among calves in group Na-Se 0.1 was higher than in group Y-Se 0.5. In conclusion, trace elements deficiencies are common in Wallonia and often they are multiple. They play a major role in the aetiology of multifactorial diseases diagnosed in the cattle herds. Deficiencies in Se and in I are most commonly implicated in clinical problems. The diagnosis of these deficiencies is determined by blood analyses. Therefore, the tests need to be differentiated according to their capacity to test the nutritional or the thyroid status. A simultaneous supplementation with I and Se, as well as the form of the supplemented Se, may modify the interpretation of the nutritional and the thyroid status. Better reproduction performances and a better health have been observed in herds with a normal trace element status. Furthermore, the advantage of the supplementation with Se in the form of seleno-methionine has been demonstrated in comparison to sodium selenite in deficient Belgian Blue cattle. This study opened numerous perspectives. The measurement of bTSH should be implemented in laboratories in order to offer it as a routine analysis to the practitioning veterinarian, who could use this tool in the framework of many diseases other than goitre. From a fundamental point of view, the dosage of deiodinases would allow the understanding of the regulation and of the synthesis of the thyroid hormones in bovines, and identifying the role of Se and I in this process. Finally, following the discoveries concerning the seleno-methionine, the effect of organic forms of other trace elements in bovine supplementation should be investigated. / Les carences en sélénium (Se) et en iode (I) sont répandues en Europe chez le bétail et ont des répercussions sur leur santé. Les signes cliniques de carence sont rarement pathognomoniques, ce qui nécessite le recours à des examens de sang ou de lait afin de confirmer le diagnostic. Pour évaluer le statut en Se et en I des bovins, le dosage du Se plasmatique, de lactivité de la glutathion peroxydase érythrocytaire (GPX) et de lI inorganique plasmatique (IIP) est réalisé en routine. Lévaluation du statut thyroïdien se fait principalement via la détermination de la thyroxine (T4) dans le plasma. Dautres analyses sont utilisables à cette fin, telles que la tri-iodothyronine (T3) ou la thyrotropine (bTSH). Une fois le diagnostic de carence posé, la carence peut être corrigée de diverses façons. Le 1er objectif de ce travail a été dévaluer les statuts en zinc, cuivre, Se et I dans les exploitations bovines laitières et viandeuses en Wallonie et de mettre en corrélation ces statuts avec létat de santé des troupeaux étudiés. Le statut en oligo-éléments (O-E) dans les troupeaux avec pathologies était moins bon que celui des troupeaux sains. De même, davantage de troupeaux avec pathologies étaient carencés par rapport aux troupeaux sains. Les troupeaux laitiers bénéficiaient de meilleurs statuts par rapport aux troupeaux viandeux. Les carences en Se et en I sont parmi les plus importantes et les plus lourdes de conséquences. La suite du travail sest donc focalisé sur ces 2 oligo-éléments. Le 2ème objectif a consisté à mettre au point un dosage de la bTSH et à établir des valeurs de référence chez des bovins adultes en bonne santé. Un intervalle de référence pour la bTSH et la T4 a été établi pour des vaches adultes saines et des veaux nouveau-nés sains. En corollaire, lobjectif suivant a été de comparer la concentration en bTSH trouvée chez des veaux nouveau-nés atteints dun goitre avec celle obtenue chez des veaux nouveau-nés en bonne santé, afin de valider un test diagnostique pour cette pathologie. La bTSH a permis de discriminer ces 2 groupes de veaux et détablir le diagnostic dhypothyroïdie chez certains veaux goitreux. Une valeur seuil de bTSH pour poser le diagnostic dhypothyroïdie chez des veaux nouveau-nés a été établie à 35 µU/ml. Le 4ème objectif a été de comparer les statuts en I (IIP) et Se (Se plasmatique, GPX) mais également le statut thyroïdien (bTSH, T4, T3, rT3) de vaches taries gestantes ou non et, le cas échéant, de leur veau, qui ont reçu une ration normalement pourvue ou enrichie en I et Se. Chez les vaches recevant une ration enrichie en Se et I, la T4 et la bTSH ont diminué alors que lIIP, la T3 et lactivité de la GPX ont augmenté. Dans le groupe recevant une ration normalement pourvue en Se et I, seule lactivité de la GPX a augmenté. A la naissance, les veaux provenant des mères ayant reçu une ration enrichie en Se et I avaient une concentration en IIP et une activité de la GPX supérieures et une concentration en bTSH inférieure par rapport aux veaux de lautre groupe. Le dernier objectif a été de comparer les effets sur la santé et le statut en Se de vaches BBB carencées et de leur veau de deux formes (sélénite de soude versus séléno-méthionine) et de deux doses différentes de Se (0,1 versus 0,5 ppm). Les deux premiers groupes de vaches ont reçu une ration avec respectivement 0,1 et 0,5 ppm de Se sous forme de sélénite de soude (Na-Se 0,1 et Na-Se 0,5), alors que le troisième groupe de vaches a reçu 0,5 ppm de Se sous forme de séléno-méthionine (Y-Se 0,5). Les concentrations en Se dans le plasma, le colostrum et le lait étaient plus élevées chez les vaches du groupe Y-Se 0,5 par rapport aux 2 autres groupes. La concentration en Se plasmatique était plus importante chez les veaux du groupe Y-Se 0,5 par rapport à celles des autres groupes. Le gain quotidien moyen des veaux du groupe Y-Se 0,5 était plus important par rapport à celui du groupe Na-Se 0,1. La prévalence de diarrhée des veaux du groupe Na-Se 0,1 était plus élevée par rapport à celle du groupe Y-Se 0,5. En conclusion, les carences en oligo-éléments sont fréquentes en Wallonie et souvent multiples. Elles interviennent de manière importante dans létiologie des troubles multifactoriels constatés dans les exploitations bovines. Les carences en Se et en I sont celles qui occasionnent le plus de répercussions cliniques. Le diagnostic de ces carences en particulier repose sur lutilisation de dosages sanguins. Il faut y distinguer ceux qui mesurent le statut nutritionnel en I et Se de ceux qui évaluent plutôt le statut thyroïdien. Une supplémentation simultanée en I et en Se peut modifier linterprétation des statuts nutritionnel et thyroïdien, de même que la forme sous laquelle le Se est apporté aux bovins. De meilleures performances zootechniques et une meilleure santé sont constatées dans les troupeaux supplémentés en O-E qui jouissent de statuts corrects. De plus, de ce point de vue, la supériorité de la supplémentation en Se sous forme de séléno-méthionine a été démontrée par rapport au sélénite de soude chez des bovins BBB carencés. De nombreuses perspectives se dégagent de ce travail. Le dosage de la bTSH est à implémenter dans des laboratoires en vue den faire une analyse de routine à disposition des vétérinaires praticiens qui pourraient ainsi utiliser cet outil dans le cadre de nombreuses autres pathologies que le goitre congénital. Dun point de vue plus fondamental, le dosage des désiodases permettrait daffiner la compréhension de la régulation de la synthèse des hormones thyroïdiennes chez le bovin, en précisant les rôles respectifs de lI et du Se à ce propos. Enfin, à linstar des découvertes concernant la séléno-méthionine, lintérêt annoncé des formes organiques des autres O-E chez les ruminants devrait être investigué plus avant.

A naturally occurring disease involving hyperplasia of the thyroid gland and a consistent pattern of musculoskeletal deformities of newborn foals in western Canada was first described in 1981. This disease was an important cause of foal mortality and, therefore, reproductive loss throughout western Canada during the 1990s and has since been recognized in western Ontario and the northwestern United States. A series of investigations were conducted to describe, characterize, and attempt to determine the pathogenesis and cause of this syndrome. Affected foals were typically born after a long gestation (x = 360 days, range = 340 to 400 days), were diagnosed as hypothyroid based on a poor response to the administration of thyroid-stimulating hormone, and had various musculoskeletal lesions of which mandibular prognathism, flexural deformities and rupture of tendons of the limbs, and incomplete ossification of the carpal and tarsal bones were present most commonly. In spite of the normal to long gestation, foals had signs of immaturity, were usually weak and unable to stand, became septic, and died or were euthanatised. Similar histories, clinical findings, and lesions were present in surgically created hypothyroid foals that were thyroidectomized in utero at about 210 days gestation. These findings supported the conclusion that foals which naturally developed these lesions were also hypothyroid in utero and that all the lesions present in affected foals were the result of the hypothyroidism and not of an underlying concurrent disease process. A case-control study was conducted to identify risk factors for naturally occurring congenital hypothyroidism. Information from congenitally hypothyroid foals concerning foal and dam signalment, farm environment, and dam management was compared with that from normal foals. Pregnant mares fed greenfeed, not supplemented with mineral, that left their "home farm" during gestation, or grazed irrigated pasture, had a 13.1 (<i>P</i>=0.0068), 5.6 (<i>P</i>=0.0472), 4.3 (<i>P</i>=0.0076) and approximately 15.3 (<i>P</i>=0.0245) times greater odds, respectively, of producing a congenitally hypothyroid foal than mares not exposed to these factors. Greenfeed often contains high levels of nitrate (NO₃^-) which is known to impair thyroid gland function. In light of this, forage samples from participating farms were analysed for nitrate levels. The odds of one or more congenitally hypothyroid foal being born on a farm feeding forage with at least a trace of nitrate was 8.0 times greater (<i>P</i>=0.0873) than the odds of the disease occurring a farm that fed forage free of nitrate. Further, the odds of a mare producing an affected foal when fed forage containing at least a trace of nitrate was 5.9 times greater (<i>P</i>=0.0007) than a mare fed nitrate-free forage.This study suggests that congenital hypothyroidism in foals may result from diets containing nitrate or low in iodine being fed to pregnant mares. These results need to be confirmed through further field investigations and controlled experiments. However, if they are accurate, there is cause for concern that other livestock raised in areas where congenitally hypothyroid foals occur may be exposed to the same dietary risk factors and may suffer similar disease.

Infertility is defined as not being able to conceive after 1 year of regular intercourse without use of contraception. Unexplained infertility is a diagnosis given to couples where the reason to infertility cannot be clarified even after the routine examination. Undefined infertility is a common and growing problem because most people are not aware of the fact that fertility decreases after the age of 35. Hyper- and hypothyroidism has been known to affect the menstrual cycle as well as increased risk of miscarriage. However, the specific effect of thyroid hormones on infertility has not yet been clarified. This study aims to compare the gene expression of two thyroid hormone receptors DIO2 and MOT8 in human endometrium and fallopian tube tissue from two phases of the menstruation cycle, follicular phase and lutheal phase. The methods used were RT-qPCR and immunohistochemistry, which showed a statistically significant difference in the expression of DIO2 and MOT8 between fallopian tube tissue and endometrium, but not between follicular and lutheal phase. However, MOT8 seemed to have a tendency to be down-regulated in the follicular phase but the results need to be validated with different endogenous controls and larger study groups.

Objectives: The introduction of neonatal screening programs (NSP) led to an increased in detection of congenital hypothyroidism (CH). This increase may be due to ethnic composition (predominance of Iberian and Asian people), environmental factors (temperature and iodine intake) and inclusion of cases of transient CH and hyperthyrotropinemia, defined by moderate elevation of TSH with normal T4. The main objectives of this study were to evaluate, in children with altered neonatal screening tests in the NSP in the Northeastern Brazilian Sergipe state, the evolution for permanent or temporary condition and to evaluate the mean incidence of permanent CH, hyperthyrotropinemia and transient TSH elevation. Subjects and methods: Review of medical records of children with altered neonatal and confirmatory TSH from 2004 to 2010 (levels more than 5.2 &#956;U/ml and 4.2 &#956;U/ml, respectively), followed at the Clinic of Pediatric Endocrinology of the University Hospital of the Federal University of Sergipe. From the confirmatory serum TSH values, children were classified as initial CH: serum TSH > 10.0 &#956;U/ml; or suspect CH: serum TSH > 4.2 &#956;U/ml and &#8804; 10.0 &#956;U/ml. According to follow-up parameters, the final diagnosis included three categories. Permanent CH: Serum TSH > 10.0 &#956;U/ml, independent of T4 levels or current use of thyroxine; or without l-thyroxine use serum TSH level between 4.2 &#956;U/ml and 10.0 &#956;U/ml, but with low free T4 or total T4. Hyperthyrotropinemia: children without l-thyroxine use with serum TSH level between 4.2 &#956;U/ml and 10.0 &#956;U/ml with normal free T4 and total T4. Transient TSH elevation: Initial CH or suspect CH children which normalized in the follow up without l-thyroxine treatment (serum TSH &#8804; 4.2 &#956;U/ml, free T4 &#8805; 0.79 ng/dl and total T4 &#8805; 7.2 &#956;g/dl). The mean incidence of permanent CH, hyperthyrotropinemia and transient TSH elevation in the period was calculated by dividing the number of children with each category for the total number of children screened. Results: The initial diagnosis included 37 cases of initial CH (18.1%) and 167 suspect CH (81.9%). The final diagnosis included 46 cases of permanent CH (22.5%); 56 hyperthyrotropinemia (27.5%) and 102 transient TSH elevation (50.0%). Out of the 37 cases of initial CH, it was found 23 (62.2%) of permanent CH; 9 (24.3%) of hyperthyrotropinemia; and 5 (13.5%) of transient TSH elevation. Out of the 167 suspects, it was found 23 (13.8%) of permanent CH, 47 (28.1%) of hyperthyrotropinemia and 97 (58.1%) of transient TSH elevation. We found a mean incidence of 1:4166 of permanent CH, 1:3448 of hyperthyrotropinemia and 1:1887 of transient TSH elevation. 86.5% of children with an initial diagnosis of CH and 41.9% of suspicions have permanent condition (CH or hyperthyrotropinemia). Conclusions: The follow-up of children with initial diagnosis and suspicion is necessary to characterize the permanence or not of the disorder, since the prediction of the evolution of children with initial CH or suspect is difficult. / Objetivos: A introdução dos programas de triagem neonatal (PTN) propiciou o aumento na detecção do hipotireoidismo congênito (HC). Este aumento pode estar ligado à composição étnica (predomínio em ibéricos e asiáticos), fatores ambientais (temperatura e ingestão de iodo) e inclusão de casos de HC transitório e da hipertirotropinemia, definida pela elevação moderada do TSH com T4 normal. Os objetivos principais deste estudo foram avaliar em crianças com teste de triagem neonatal alterado no PTN em Sergipe, no nordeste do Brasil, a evolução para condição permanente ou transitória e avaliar a incidência média do HC permanente, da hipertirotropinemia e da elevação transitória do TSH. Sujeitos e métodos: Foi realizada revisão dos prontuários das crianças convocadas no período de 2004 a 2010, com TSH neonatal e confirmatório alterados (maior que 5,2 &#956;U/ml e 4,2 &#956;U/ml, respectivamente), acompanhados no Ambulatório de Endocrinologia Pediátrica do Hospital Universitário da Universidade Federal de Sergipe. A partir dos valores do TSH sérico confirmatório, as crianças foram classificadas como HC inicial: TSH sérico > 10,0 &#956;U/ml; ou suspeito HC: TSH sérico > 4,2 &#956;U/ml e &#8804; 10,0 &#956;U/ml. De acordo com parâmetros do seguimento, o diagnóstico final incluiu três categorias. HC permanente: TSH sérico > 10,0 &#956;U/ml, independente de valores de T4 ou do uso de l-tiroxina; ou sem l-tiroxina com TSH sérico entre 4,2 &#956;U/ml e 10,0 &#956;U/ml, mas com T4 livre ou T4 total baixos; Hipertirotropinemia: Criança sem l-tiroxina, com TSH sérico entre 4,2 &#956;U/ml e 10,0 &#956;U/ml, com T4 livre e T4 total normais; Elevação transitória do TSH: Criança HC inicial ou suspeito HC que normalizou no seguimento, sem a l-tiroxina (TSH sérico &#8804; 4,2 &#956;U/ml, T4 livre &#8805; 0,79 ng/dl e T4 total &#8805; 7,2 &#956;g/dl). A incidência média do HC permanente, da hipertirotropinemia e da elevação transitória do TSH no período foi calculada dividindo-se o número de crianças com cada uma das três condições pelo número total de crianças triadas. Resultados: No diagnóstico inicial tivemos 37 casos de HC inicial (18,1%) e 167 suspeitos HC (81,9%). No diagnóstico final tivemos 46 casos de HC permanente (22,5%); 56 de hipertirotropinemia (27,5%) e 102 de elevação transitória do TSH (50,0%). Dos 37 casos HC inicial encontramos 23 (62,2%) de HC permanente; 9 (24,3%) de hipertirotropinemia; e 5 (13,5%) de elevação transitória do TSH. Dos 167 suspeitos encontramos 23 (13,8%) de HC permanente, 47 (28,1%) de hipertirotropinemia e 97 (58,1%) de elevação transitória do TSH. Encontramos uma incidência média de 1:4166 de HC permanente, 1:3448 de hipertirotropinemia e 1:1887 de elevação transitória do TSH. 86,5 % das crianças com diagnóstico inicial de HC e 41,9 % das suspeitas apresentam condição permanente (HC ou hipertirotropinemia). Conclusões: O seguimento das crianças seja com o diagnóstico inicial de HC ou de suspeição é necessário para caracterizar a permanência ou transitoriedade do distúrbio, haja vista que a predição da evolução destas crianças é difícil.

Introdução: O hipotireoidismo congênito é a causa mais frequente de retardo mental evitável, cuja prevalência é de 1/3000 crianças nascidas vivas. Pode ser causado por disgenesia tireoideana (80% dos casos) ou por defeitos de síntese hormonal (20% restantes). As disormonogêneses tem sido associadas a mutações nos genes da tireoperoxidase (TPO), tireoglobulina, dual oxidase 2, pendrina, desalogenase e do simportador sódio/iodo. A tireoperoxidase (TPO) é uma glicoproteína de 105 KDa, localizada na membrana apical do tireócito, responsável pela organificação do iodeto. Até o momento 54 mutações, associadas ao hipotireoidismo congênito foram identificadas no gene TPO. Objetivos: Este estudo visou rastrear mutações no gene TPO em pacientes com hipotireoidismo congênito, com defeito total ou parcial de incorporação de iodeto, e associar o defeito genético com o fenótipo do paciente. Casuística e Métodos: Foram estudados 34 pacientes com hipotireoidismo congênito, 13 com DIIT (descarga de iodeto >50%) e 21 com DIIP (descarga de iodeto entre 25 e 50%) por possível defeito no gene TPO. Os métodos empregados foram: extração do DNA genômico de sangue periférico, amplificação por PCR do promotor e dos 17 exons do gene TPO e dos 33 exons do gene DUOX2 , eletroforese em gel de gradiente denaturante (DGGE) e seqüenciamento. Resultados: Foram identificadas 8 novas alterações de seqüências que levam a troca de aminoácidos: Leu68Ile, Gly319Glu, Ala426Gly, Arg584Gln, Val618Met, Pro883Leu, Ala909Thr, A909fsX49; e 4 já descritas na literatura: 396fsX76, Gln660Gly, Arg665Trp, Cys838Ser. Dois pacientes com DTII apresentaram mutações em homozigose, e dois pacientes (um com DTII e um com DPII) eram portadores de alterações em heterozigose composta. Seis pacientes eram portadores de um único alelo da TPO afetado (três com DPII e três com DTII). Foram identificados também 33 polimorfismos (10 novos). Apenas polimorfismos foram identifiados no gene DUOX2. Conclusão: Foi verificada alta freqüência de mutações monoalélicas em pacientes com DIIT e DIIP. Em ambos os grupos as mutações se localizaram ao longo de todo o gene, tanto no domínio extracelular como no intracelular da proteína. Somente duas mutações foram identificadas em mais de um paciente, mostrando a heterogeneidade genotípica da doença nesta população / I ntroduction: Congenital Hypothyroidism affects 1/3000 birth, is caused by thyroid gland dysgenesis (80%) or inborn errors of the thyroid hormone biosynthesis (20%). Genetics defects of the genes for thyroid peroxidase, (TPO), thyroglobulin, sodium/iodine simporter, dual oxidase 2, and pendrine have been associated to dyshormonogenesis. TPO is a glycoprotein of 105 KDa situated in the apical membrane of the thyroid cell, responsible for iodide organification. At least 54 mutations have been identified in patients with dyshormonogenesis. Objectives: The aim of the study was to identify TPO gene mutations in patients with congenital hypothyroidism with total (DIIT) and partial (DIIP) iodide organification defects and to associate the genetic defect with the phenotype of the patient. Patients and Methods: Thirty four patients with congenital hypothyroidism, 13 with DIIT (iodide discharge >50%) and 21 patients with DIIP (iodide discharge between 25- 50%) due to possible TPO gene defect. Extraction of genomic DNA from peripheral blood, PCR amplification of the promoter, 17 exons of TPO gene and of the 33 exons of DUOX2 gene, denaturant gradient gel electrophoreses (DGGE) and sequencement were performed. Results: Eight new sequence alterations were identified: Leu68Ile, Gly319Glu, Ala426Gly, Arg584Gln, Val618Met, Pro883Leu, Ala909Thr, A909fsX49; and four previously described mutations: 396fsX76, Gln660Gly, Arg665Trp, Cys838Ser. Homozygous mutations were identified in two patients with DTII. Ttwo patients (one with DTII and one with DPII) were carrying compound heterozygous mutations. TPO monoallelic mutations were identified in six patients (3 with DPII and 3 with DTII). Thirty three polymorphisms had also been identified (10 news). Conclusion: High frequency of TPO monoallelic mutations was detected in patients with DIIT and DIIP. In both groups of patients the mutations were located all throughout the gene, in the extracellular as well as in the intracellular domain. Only two mutations have been identified in more than one patient, indicating the genotypic heterogeneity of the illness in this population

Estudamos 32 crianças com HC devido à agenesia ou ectopia tireoideana para mutações no PAX8 e 30 crianças com hipoplasia da tireóide para mutações no rTSH. Todos os exons de ambos os genes foram amplificados a partir do DNA genômico, seguido por seqüenciamento direto. Encontramos, em dois pacientes com ectopia, duas alterações no gene PAX8, uma no promotor, e outra no exon um. Os outros indivíduos estudados apresentaram as seqüências codificáveis dos genes PAX8 e rTSH normais. Em relação ao caráter funcional e ensaios de luciferase verificamos que no promotor a resposta transcricional diminuiu significativamente na presença de TSH, por um mecanismo dependente de cAMP / We studied 32 children with hypothyrodism (CH) from thyroid agenesis or ectopia for PAX8 mutations, and 30 children with thyroid hypoplasia for rTSH mutations. All exons of both genes were amplified from the genomic DNA, then sequenced directly. We found two alterations in the PAX8 gene in two patients, one in the promoter and the other in exon one. The other children had normal sequences in both PAX8 and rTSH genes. In relation to functional character and luciferase assays, we verified that transcriptional response was significantly reduced in the presence of TSH by a cAMP dependant mechanism