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Background/aims: Thyroid disease is a common comorbidity in individuals with Down syndrome (DS), but historical studies have multiple limitations. We assessed thyroid abnormalities in a large cohort of children with DS., Methods: Retrospective records review from a single institution. Calculated prevalence of common thyroid abnormalities and associations with common comorbidities., Results: Among 508 patients, 120 (24%) had a thyroid-related diagnosis, the majority having elevated thyrotropin treated with levothyroxine. A Kaplan-Meier estimate projects that 50% have thyroid disorder by adulthood, with 20% of hypothyroidism diagnosed before the age of 6 months. When tested, approximately 50% had positive antithyroid antibodies, though this rate was 100% in overt hypothyroidism. There was no association between congenital or acquired hypothyroidism and common comorbidities., Conclusion: Thyroid disease in DS is more common and occurs earlier than in the general population, and is often transient. Thyroid disease is unrelated to gender, obesity, or other comorbidities. Apart from overt hypothyroidism, much of hypothyroidism in DS appears unrelated to autoimmunity; we recommend checking of antithyroid antibodies only in select cases. An additional screen for thyroid disease between the newborn screen and the 6-month well-child visit will detect early cases of hypothyroidism who passed their newborn screen.
., (© 2017 S. Karger AG, Basel.)

Background: During gestation, the primordial thymus migrates from the pharynx to the anterior mediastinum, thus thymic tissue can remain at any point along this path. Intrathyroidal thymic remnants are rare, and their sonographic patterns have only recently been described. This retrospective study presents the sonographic appearance of ectopic intrathyroidal thymus and emphasizes the role of sonography in order to avoid misdiagnosis., Methods: The population consisted of 42 children, 3.5-14 years old, who had a thyroid sonogram performed due to a positive family history or symptoms indicative of thyroid disease, and ectopic intrathyroidal thymus was recognized., Results: In all patients, the same pattern was revealed: a fusiform intrathyroidal lesion, with no mass effect, homogeneously hypoechoic, with diffuse bright internal echoes. The similarity to the characteristic sonographic pattern of the normal mediastinal thymus was crucial for the diagnosis of ectopic intrathyroidal thymic tissue. In 8 cases, a normal elongated thymus was found connected to the thyroid with an accessory lobe embedded in the lower thyroid pole. The above sonographic appearances mimicked a thyroid nodule., Conclusions: Awareness of the sonographic patterns of the ectopic intrathyroidal thymus is mandatory to avoid misdiagnosis. In most cases, further investigation is unnecessary, but sonographic follow-up should be recommended., (© 2016 S. Karger AG, Basel.)

Down syndrome is characterized by a high prevalence of thyroid dysfunction during childhood. In this paper, we review the different kinds of thyroid dysfunction that occur excluding those of autoimmune origin: congenital hypothyroidism (elevated plasma TSH with low plasma T4 occurring at birth usually detected by neonatal screening), subclinical hypothyroidism (elevated plasma TSH with plasma T4 in the normal range, which can be congenital or acquired) and acquired primary hypothyroidism (elevated plasma TSH and low plasma T4 occurring after birth). These dysfunctions, while not due to autoimmunity, are of thyroidal origin. However, the mechanisms leading to these different thyroidal abnormalities have not been clearly defined; in particular, it is difficult to determine whether the different types of dysfunction have a common cause, or if the causes are distinct. Treatment is prescribed according to the type of thyroidal abnormality., (© 2015 S. Karger AG, Basel.)

Background: Dyshormonogenetic goiter refers to familial goiters owing to an inherited defect in the metabolism of thyroid hormones., Methods: 19 patients with clinical and biochemically proven hypothyroidism (low T3, FT4 and high TSH) were recruited for the study. All patients were subjected to (i) ultrasound of the neck to rule out thyroid dysgenesis and (ii) technetium-99m radionuclide thyroid scintigraphy and a perchlorate discharge test (PDT). Extrathyroidal malformations were identified by clinical ultrasound (USG) examination of the abdomen and pelvis and by echocardiography., Results: Out of 19 patients with elevated thyroid uptakes on technetium-99m thyroid scintigraphy, 12 (63%) had a positive PDT and 7 patients (37%) had a negative PDT. All patients were subjected to abdominopelvic USG and echocardiography. Out of 12 patients with a positive PDT, 5 (42%) had associated extrathyroid malformations, 2 had urogenital malformations, and cardiac abnormalities on echocardiography were present in 2 patients (17%). One patient (8%) had features of dysmorphism in the form of a high-arched palate, low-set ears and microcephaly., Conclusion: Congenital hypothyroidism due to dyshormogenesis is associated with a high prevalence of extrathyroidal malformations and needs to be managed as early as possible to ensure normal neurocognitive development of the children affected., (© 2014 S. Karger AG, Basel.)

Background: Chromosome 22q11.2 microduplications are extremely rarely detected; in comparison, the deletion of same region, known as the DiGeorge/velocardiofacial syndrome, occurs more frequently. Thyroid anomalies commonly occur in patients with 22q11.2 deletion syndrome, however few reports of thyroid anomalies associated with 22q11.2 microduplication have been published thus far., Case Report: We present a case of a male infant who was prenatally diagnosed with 22q11.2 microduplication and was found to have congenital hypothyroidism due to thyroid hemiagenesis after birth. Moreover, the baby had bilateral hearing impairment, bilateral cryptorchidism, and a rotated penis. At the age of 2 years, the infant was euthyroid with levothyroxine replacement, but he showed significant developmental delay., Conclusions: To our knowledge, this is the first case of congenital hypothyroidism with thyroid hemiagenesis in a patient showing 22q11.2 microduplication. Thyroid dysgenesis could be an additional clinical feature shared by the 22q11.2 microduplication and deletion syndrome, suggesting that the duplication and deletion of a gene may result in a common phenotype. Thyroid dysgenesis should be considered in the evaluation and management of patients with this genomic disorder., (Copyright © 2013 S. Karger AG, Basel.)

Background/aims: To describe a case of left thyroid dysgenesis, accompanied by ipsilateral double parathyroid adenomas in a setting of primary hyperparathyroidism, and to review the pertinent literature on the diagnosis of these rare clinical scenarios., Methods: Review of the English literature with addition of a case report., Results: Preoperative evaluation included both sestamibi and ultrasound evaluation of the neck. Fine-needle aspiration biopsies of what was thought to be two concerning thyroid nodules revealed potential double intrathyroidal parathyroid adenomas. Video-assisted exploration verified double parathyroid adenomas and revealed concomitant left thyroid lobe dysgenesis. Intact parathyroid hormone level returned to normal and a greater than 50% drop from baseline was achieved intraoperatively with subsequent long-term cure., Conclusions: Thyroid dysgenesis is a rare, poorly understood and potentially confusing variety of developmental anomalies, which can be associated with thyroid as well as parathyroid disease. Clinical diagnosis is highly dependent upon the clinician maintaining an index of suspicion for these anomalies, thorough physical examination and careful review of available imaging modalities, especially while investigating thyroid and parathyroid disorders.

Background: Congenital hypothyroidism (CH) is caused by thyroid dysgenesis and dyshormonogenesis. Evidence suggests the presence of genetic factors in both types of pathogenesis. We investigated whether an increased incidence of thyroid abnormalities could be shown by ultrasonography among first-degree relatives of children with CH., Material and Methods: In this case-control study the presence of both developmental and non-developmental thyroid abnormalities was studied among first-degree relatives of CH patients and healthy children. Assessments included neck ultrasonography and thyroid function tests. The data obtained from parents, siblings and children were compared in the case and control groups., Results: In the case group, 92 patients, 172 parents and 57 siblings, and in the control group, 82 healthy children, 160 parents and 39 siblings were studied. Thyroid developmental abnormalities were more prevalent among parents (3.5 vs. 0%, p = 0.03) and siblings (10.5 vs. 0, p = 0.01) of CH patients than the control group. Non-developmental abnormalities were not significantly different between the case and control groups (17 vs. 13%, p = 0.3)., Conclusion: Thyroid developmental abnormalities were more prevalent among parents and siblings of CH patients than the control group, confirming the familial component of this entity., (Copyright 2008 S. Karger AG, Basel.)

In the Williams-Beuren syndrome (WBS), disorders of the thyroid function and morphology have been reported and programs of thyroid screening and surveillance are recommended. However, the frequency of biochemical thyroid assessment, particularly in the first year of life, is being debated. In this report we describe an infant with WBS and congenital hypothyroidism, due to an important thyroid hypoplasia. The patient, a 1-month-old female, negative at primary neonatal thyroid screening, was referred to our hospital for dyspnea. Thyroid function tests showed a raised TSH (42 mIU/l; normal range 0.5-4 mIU/l) with a low FT(4) concentration (10.21 pmol/l; normal range: 10.29-24.45 pmol/l). Ultrasound examination of the neck showed a significant thyroid hypoplasia, whereas (99m)Tc-pertechnetate thyroid scintigraphy evidenced a thyroid gland in normal position, with reduced shape and overall weak fixation. Therefore, treatment with L-thyroxinewas started. Thyroid hypoplasia is a frequent characteristic of WBS and abnormalities of thyroid function are common in patients with this feature. Therefore, the possibility of congenital hypothyroidism should always be taken into consideration too and, even if congenital hypothyroidism neonatal screening is negative, thyroid (morphology and function) evaluation should be regularly assessed when the diagnosis is made and, thereafter, every year in the first years of life., (Copyright 2008 S. Karger AG, Basel.)

Aims: To evaluate therapy and dose adjustments in patients with congenital hypothyroidism (CH), longitudinally followed up until 16 years old, according to aetiology, Beclard's nuclei presence, and thyroxine (T4) level at diagnosis., Methods: L-T4/kg/day and dose change ratio (CR) were assessed in 74 CH patients., Results: The dose was statistically larger in athyreosis than in dyshormonogenesis (1-10 and beyond 14 years) and in ectopy (2, 15, 16 years). The ectopic children required statistically larger L-T4/kg than the dyshormonogenetic ones (3-7 years). The L-T4/kg/day was increased, not statistically, in patients or with T4 <30 nmol/l or without Beclard's nuclei at diagnosis. The CR progressively dropped after the 6th month at each attendance, without any difference in terms of aetiology, T4 level at diagnosis, or Beclard's nuclei. The total CR was greater (significantly) in patients without Beclard's nuclei, and (not significantly) in those with T4 <30 nmol/l at diagnosis or with agenesia., Conclusion: The L-T4 dose in CH is highly affected by the aetiology. The CR is higher in patients with delayed bone maturation at diagnosis. We suggest that these latter patients need blood tests more frequently to obtain a proper titration of the therapy., (Copyright 2007 S. Karger AG, Basel.)

We report the observation of an unusual case of Graves' disease associated with thyroid hemiagenesis. A 41-year-old woman who presented with symptoms and clinical signs of hyperthyroidism was discovered to have thyroid hemiagenesia of the left lobe. Thyroid ultrasound scan showed enlargement of the right lobe with a single nodule, and absence of the left lobe; isotope scan showed homogeneous uptake in the single lobe and nodule. Ophthalmopathy, which was absent at presentation, developed after two years; after a further 2 years the patient developed decompensated hypothyroidism requiring thyroxine replacement. This is the first case of Graves' disease in thyroid hemiagenesis evolved to hypothyroidism, and a rare case of thyroid ophthalmopathy accompanying this condition., (Copyright 2005 S. Karger AG, Basel.)

Thyroid dysgenesis (TD) is the most prevalent form of congenital hypothyroidism. Ttf-1, Ttf-2, Pax8 and the Tshr are expressed at early stages of thyroid development and are implicated in thyroid ontogeny. Mutations in these genes have been found in some cases of TD. The prevalence of familial forms of TD is significantly higher than expected if the disease was only sporadic, allowing to postulate a genetic basis of the disease. Linkage analysis and mutational screening of the four above-mentioned genes in familial forms of TD showed their exclusion as contributors to the disease in some families, implicating genetic heterogeneity and involving other genetic mechanisms. Strategies to uncover new genes involved in TD are therefore needed. We underscore differences in the temporal expression patterns during the human thyroid development with those in animal models. Further, the extrathyroid expression of these genes during human development enables to define the gene-specific malformations that may be present in patients bearing mutations. The data gathered on molecular thyroid development enable precise genetic counselling of affected families. By increasing our knowledge of thyroid development, we hope to uncover new perspectives of genetic screening and eventually of early in utero treatment., (2004 S. Karger AG, Basel.)

Congenital hypothyroidism is the most prevalent endocrine disorder in the newborn and affects 1 in 3000-4000 newborns. Screening for congenital hypothyroidism is a major achievement of paediatrics because early diagnosis and treatment have resulted in normal development in nearly all cases. The cause of congenital hypothyroidism in the majority of newborns is unknown. However, in some patients the molecular basis of their congenital hypothyroidism has recently been clarified. In patients with congenital hypothyroidism and a normally developed thyroid gland, the autosomal recessive inheritance of loss-of-function mutations of genes encoding for the thyroid peroxidase gene, the sodium-iodide symporter gene and the pendrin gene have been identified. The autosomal recessive inheritance of loss-of-function mutations of the thyroid stimulating hormone (TSH) receptor as well as the dominant inheritance of mutations encoding for transcription factors have been identified in patients with defective thyroid development. Furthermore, it has become evident that in some patients with persistent mental retardation and neurological symptoms, defects of the transcription factor NKX2.1, which is expressed in the thyroid gland as well as in the CNS during embryonic development, cause both defective thyroid and CNS development resulting in persistent neurological and mental defects despite early diagnosis and treatment. Central hypothyroidism is a rare disease with an estimated frequency of not more than 1 in 50000 newborns. Central hypothyroidism can be due to recessive inheritance of loss-of-function mutations of the TSH-beta gene and to developmental defects of the hypothalamus or pituitary. In contrast to the previous assumption that isolated TSH deficiency will not lead to impaired mental development, identification of the molecular defects in central hypothyroidism has clearly demonstrated that some of these patients will have impaired mental development. Clarification of the molecular defects of thyroid development will help to explain the differences in outcome in patients with congenital hypothyroidism and to develop new diagnostic and therapeutic strategies to ensure adequate counselling and care for these patients., (Copyright 2003 S. Karger AG, Basel)

The subject is a 44-year-old female with thyroid hemiagenesis, who initially presented with hyperthyroidism. Thyroid peroxide antibody and thyroglobulin antibody levels were high. The scintiscan study and sonographic findings were compatible with thyroid hemiagenesis with accompanying Graves' disease. In reviewing her family history, her daughter was found to have thyroid agenesis, and other thyroid disorders were found in 2 female family members., (Copyright 2003 S. Karger AG, Basel)

Objective: To study the growth, puberty and compliance of 66 hypothyroid children and to determine prognostic factors for adult height., Patients: 66 children were included (12 boys, 54 girls). Aetiologies were 43 ectopic glands, 14 thyroid agenesis, 9 dyshormonogenesis., Results: In girls the mean adult height was 164.7 +/- 6.5 cm for a target height (TH) of 162.8 +/- 5.4 cm. In boys the mean adult height was 178.2 +/- 6.4 cm for a TH of 175.7 +/- 4.7 cm. Puberty development was normal. Children who exceeded their TH had an earlier start of treatment versus children who failed to reach their TH: 24.8 +/- 13.5 vs. 42.0 +/- 47.3 days, p = 0.004. Delayed normalisation of TSH is a risk factor for bad compliance. Adequate correlations between treatment variables appeared only in children who exceeded their TH., Conclusions: TH, day of start of treatment and compliance with treatment are the main prognostic factors for adult height. Early detection of bad compliance is possible., (Copyright 2002 S. Karger AG, Basel)

A group of infants, affected by congenital hypothyroidism diagnosed through the neonatal screening program, was investigated with echocardiography to detect the presence of pericardial effusion. We studied the relationship between the effusion and the etiology of hypothyroidism, established through thyroid scintiscanning. Our data show a high prevalence of effusion in hypothyroid patients, without other clinical signs of cardiac involvement as well as a relationship between the etiology of hypothyroidism and the presence of effusion. This seems to be much more frequent in those forms which can imply a more severe hormonal defect, particularly during fetal life (agenesis/dyshormonogenesis). Furthermore, the high prevalence of pericardial effusion suggests to start the L-T4 replacement therapy with lower dosages as commonly advised, in order to avoid a cardiac involvement.