The clinical consequences of primary hypothyroidism include cardiovascular morbidity, increased mortality, and poor quality of life; therefore guidelines endorsed by several Scientific Societies ...recommend measuring circulating thyroid-stimulating hormone (TSH) in patients at risk. The assessment of serum TSH levels is also deemed to be the most robust and accurate biomarker during the management of replacement therapy in patients with a previous diagnosis of primary hypothyroidism. In line with a reflex TSH laboratory strategy, free thyroxine is measured only if the TSH falls outside specific cutoffs, in order to streamline investigations and save unjustified costs. This serum TSH-based approach to both diagnosis and monitoring has been widely accepted by several national and local health services; nevertheless, false-negative or -positive testing may occur, leading to inappropriate management or treatment. This review aims to describe several infrequent causes of increased circulating TSH, including analytical interferences, resistance to TSH, consumptive hypothyroidism, and refractoriness to levothyroxine replacement treatment. We propose a clinical flowchart to aid correct recognition of these various conditions, which represent important potential pitfalls in the diagnosis and treatment of primary hypothyroidism.
Purpose
To report the incidence of 4–12% of differentiated thyroid cancer (DTC) and up to 50% of benign thyroid nodular disease and to describe nodular thyroid disease in a multicentre pediatric ...population with PTEN mutations. Methods: Retrospective data of pediatric patients with PTEN mutations collected from tertiary Departments of Pediatric Endocrinology of Turin, Milan and Genua, Italy, in the period 2010–2020.
Results
Seventeen children with PTEN mutations were recruited in the study. Thyroid involvement was present in 12/17 (70.6%) subjects, showing a multinodular struma in 6/17 (35.3%), nodules with benign ultrasound features in 5/17 (29.4%) and a follicular adenoma in 1/17 (6%). No correlation was found between thyroid disease and gender, puberty, vascular manifestations, delayed development, or brain MRI abnormalities, while multiple lipomas were associated with thyroid disease (
p
= 0.03), as was macrocephaly. Standard Deviation (SD) score head circumference was 4.35 ± 1.35 cm in subjects with thyroid disease, 3 ± 0.43 cm (
p
= 0.02) in the group without thyroid disease. Thyroid involvement was present in all subjects with mutations in exon 6 (4/4) and exon 8 (3/3) of the PTEN gene (
p
= 0.02).
Conclusion
In the presented cohort, benign thyroid disorders were prevalent, with no evidence of DTC. A correlation was found between thyroid lesions and head circumference and the occurrence of multiple lipomas. Future studies in larger cohorts should assess whether risk stratification is needed when recommending surveillance strategies in children or young adolescents with PTEN hamartoma syndrome.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Newborn screening program for congenital hypothyroidism (CH) adopting rescreening in at-risk neonates.
To estimate the concordance rate for CH in twin pairs discordant at the first screening; to ...verify whether long-term follow-up of healthy cotwins belonging to CH discordant pairs may be useful to diagnose thyroid hypofunction during development; to evaluate the importance of genetic and environmental influences on liability to permanent and transient CH.
Forty-seven screening discordant twin pairs were investigated. Proband was defined as the twin in the pair with a positive test at the first screening and a confirmed diagnosis of CH.
Seven screening discordant twin pairs became concordant for CH within the first month of life (pairwise concordance of 14.9%) because seven screening negative cotwins showed high TSH values when retested. During long-term follow-up (range, 3 to 21 years), hypothyroidism was diagnosed in two monozygotic screening negative cotwins at the age of 9 months and 12 years, respectively. Furthermore, the twin analysis showed that 95% of liability to transient CH was explained by genetic factors and 5% by environmental (unshared) factors, whereas 64% of phenotypic variance of permanent CH was explained by common environmental factors (shared during the fetal life) and 36% by unshared environmental factors.
This study showed that the introduction of rescreening permits the diagnosis of CH in a greater number of twins. It also showed the importance of long-term follow-up in both twins in the pair, and the role of nongenetic factors in the etiology of permanent CH.
Objective To evaluate clinical and biochemical features of 115 children (98 female, mean age 11.3 ± 3.5 years) with Graves disease to identify possible determinants of remission. Study design We ...defined as positive outcome the improvement of clinical features and restoration of euthyroidism or induction of hypothyroidism after antithyroid drug (ATD) therapy and as negative outcome hyperthyroidism persistent over 2 years of ATD therapy or relapsed after ATD withdrawal. Results Thirty-eight children (33%) had remission after 2 years of ATD therapy. The absence of goiter at diagnosis was correlated with a better outcome. Median thyroid-stimulating hormone receptor antibody (TRAb) values at diagnosis were significantly lower in patients with a positive outcome ( P = .031). We found a significant relationship between the time required for TRAb normalization and the patient outcome; TRAb normalization within 1 year from time of Graves disease diagnosis was significantly more common among patients with a positive outcome ( P < .0001), and the mean time for TRAb normalization was significantly shorter in patients with a positive outcome (1.3 ± 0.8 years) compared with that observed in patients with a negative outcome (2.5 ± 2.7 years, P = .026). Conclusions Although no clinical variable investigated is constantly associated with a definite outcome, the absence of goiter at the diagnosis may be associated with a better outcome. The most relevant predictor of Graves disease outcome was serum level; TRAb at time of Graves disease diagnosis less than 2.5 times the upper reference limit, TRAb normalization during ATD, and TRAb normalization timing each may predict positive outcomes. These results may have a role in the empiric clinical management of pediatric patients with Graves disease.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Objective To determine the evolution of congenital hypothyroidism in preterms and the clinical features of permanent forms. Study design We retrospectively evaluated 24 preterm children detected by ...newborn screening for congenital hypothyroidism: first screening with blood-thyroid stimulating hormone cutoff ≥10 mU/L and second screening with blood-thyroid stimulating hormone cutoff ≥5 mU/L. After the age of 2 years, patients with eutopic thyroid had diagnostic reevaluations, including thyroid function testing and thyroid ultrasonography after L-thyroxine therapy withdrawal. Results The first screening identified 21.7% of patients with thyroid stimulating hormone elevation, and the second screening identified 73.9% of patients. One patient (4.4%) was identified with a third screening test; 21 patients had an eutopic thyroid and 3 patients a thyroid dysgenesis. At reevaluation, 5 patients (23.8%) showed permanent hypothyroidism (serum-thyroid stimulating hormone s-TSH >10 mU/L) resulting in the need to reintroduce therapy, 5 patients (23.8%) showed persistent hyperthyrotropinemia (s-TSH 5-10 mU/L), and 11 infants (52.4%) transient hypothyroidism (s-TSH <5 mU/L). The main clinical features of patients affected by permanent hypothyroidism were 1 case of assisted reproduction, 2 twins, 2 small for gestational age, 1 maternal thyroiditis, and 2 patients with malformations/syndromes. Conclusions Premature birth is a significant risk for congenital hypothyroidism with eutopic thyroid. In preterm infants, the evolution of congenital hypothyroidism remains difficult to predict. Our data emphasizes the high incidence of transient hypothyroidism in preterm infants, and the importance of diagnostic reevaluation to determine the definitive diagnosis.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Context:
The pathogenesis of congenital hypothyroidism (CH) is still largely unexplained. We previously reported that perturbations of the Notch pathway and knockdown of the ligand jagged1 cause a ...hypothyroid phenotype in the zebrafish. Heterozygous JAG1 variants are known to account for Alagille syndrome type 1 (ALGS1), a rare multisystemic developmental disorder characterized by variable expressivity and penetrance.
Objective:
Verify the involvement of JAG1 variants in the pathogenesis of congenital thyroid defects and the frequency of unexplained hypothyroidism in a series of ALGS1 patients.
Design, Settings, and Patients:
A total of 21 young ALGS1 and 100 CH unrelated patients were recruited in academic and public hospitals. The JAG1 variants were studied in vitro and in the zebrafish.
Results:
We report a previously unknown nonautoimmune hypothyroidism in 6/21 ALGS1 patients, 2 of them with thyroid hypoplasia. We found 2 JAG1 variants in the heterozygous state in 4/100 CH cases (3 with thyroid dysgenesis, 2 with cardiac malformations). Five out 7 JAG1 variants are new. Different bioassays demonstrate that the identified variants exhibit a variable loss of function. In zebrafish, the knock-down of jag1a/b expression causes a primary thyroid defect, and rescue experiments of the hypothyroid phenotype with wild-type or variant JAG1 transcripts support a role for JAG1 variations in the pathogenesis of the hypothyroid phenotype seen in CH and ALGS1 patients.
Conclusions:
clinical and experimental data indicate that ALGS1 patients have an increased risk of nonautoimmune hypothyroidism, and that variations in JAG1 gene can contribute to the pathogenesis of variable congenital thyroid defects, including CH.
We report the case of a paediatric female patient affected by Bannayan-Riley-Ruvalcaba syndrome (BRRS) and congenital hypothyroidism (CH) with homozygous mutation of the TPO gene. She underwent total ...thyroidectomy at the age of seven years because of the development of a multinodular goiter. BRRS patients present an increased risk of benign and malignant thyroid disease since childhood because of inactivating mutation of PTEN, an onco-suppressor gene. Instead, homozygous mutations in the TPO gene can be associated with severe forms of hypothyroidism with goiter; previous studies have described cases of follicular and papillary thyroid cancer in CH patients with TPO mutation despite a perfectly controlled thyroid function with Levothyroxine therapy. To our knowledge, this is the first case that describes the possible synergic role of coexisting mutation of both TPO and PTEN in the development of multinodular goiter underlining the importance of a tailored surveillance program in these patients, especially during childhood.
Context: Dual oxidase 2 (DUOX2) is the catalytic core of the H2O2 generator crucial for the iodination of thyroglobulin in thyroid hormone synthesis. DUOX2 deficiency produces congenital ...hypothyroidism (CH) in humans and mice. We recently cloned a novel gene, the product of which (dual oxidase maturation factor 2; DUOXA2) is required to express DUOX2 enzymatic activity.
Objective: Our objective was to identify DUOXA2 mutations as a novel cause of CH due to dyshormonogenesis.
Patients: Subjects included 11 CH patients with partial iodine organification defect but negative for other known genetic causes of partial iodine organification defect.
Results: One Chinese patient born to nonconsanguineous parents was homozygous for a nonsense mutation (p.Y246X), producing a truncated DUOXA2 protein lacking transmembrane helix 5 and the C-terminal cytoplasmic domain. The mutant protein was inactive in reconstituting DUOX2 in vitro. Pedigree analysis demonstrated recessive inheritance, because heterozygous carriers had normal thyroid function including negative results in neonatal TSH screening. One heterozygous carrier of Y246X was identified in unrelated Chinese controls (n = 92) but not in Caucasian or Japanese controls, indicating that homozygosity for Y246X could be a frequent cause of CH in Chinese. Functional studies suggest that the DUOXA2 paralog (DUOXA1) can partially compensate DUOXA2 deficiency, consistent with the proband having a milder CH phenotype than patients with biallelic DUOX2 nonsense mutations.
Conclusions: We report the first mutation in DUOXA2, identified in a patient with CH and dyshormonogenic goiter. Results of our studies provide evidence for the critical role of DUOXA2 in thyroid hormonogenesis. Biallelic DUOXA2 mutations are a novel genetic event in permanent CH.
PDF
