Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines Update-An ENDO-European Reference Network Initiative Endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology

Background An ENDO-ERN initiative was launched which was endorsed by the European Society for Pediatric Endocrinology and the European Society for Endocrinology with 22 participants from the ENDO-ERN and the two societies. The aim was to update the practice guidelines for the diagnosis and management of congenital hypothyroidism (CH). A systematic literature search was conducted to identify key articles on neonatal screening, diagnosis and management of primary and central congenital hypothyroidism. The evidence-based guidelines were graded with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion. Summary The recommendations include the various neonatal screening approaches for CH as well as the etiology (also genetics), diagnostics, treatment and prognosis of both primary and central CH. When CH is diagnosed, the expert panel recommends the immediate start of correctly dosed levothyroxine treatment and frequent follow-up including laboratory testing to keep thyroid hormone levels in their target ranges, timely assessment of the need to continue treatment, attention for neurodevelopment and neurosensory functions and, if necessary, consulting other health professionals, and education of the child and family about CH. Harmonisation of diagnostics, treatment and follow-up will optimise patient outcomes. Lastly, all individuals with CH are entitled to a well-planned transition of care from pediatrics to adult medicine. Conclusions This consensus guidelines update should be used to further optimize detection, diagnosis, treatment and follow-up of children with all forms of CH in the light of the most recent evidence. It should be helpful in convincing health authorities of the benefits of neonatal screening for CH. Further epidemiological and experimental studies are needed to understand the increased incidence of this conditio

Disease characteristics of MCT8 deficiency : an international, retrospective, multicentre cohort study

Background Disordered thyroid hormone transport, due to mutations in the SLC16A2 gene encoding monocarboxylate transporter 8 (MCT8), is characterised by intellectual and motor disability resulting from cerebral hypothyroidism and chronic peripheral thyrotoxicosis. We sought to systematically assess the phenotypic characteristics and natural history of patients with MCT8 deficiency. Methods We did an international, multicentre, cohort study, analysing retrospective data from Jan 1, 2003, to Dec 31, 2019, from patients with MCT8 deficiency followed up in 47 hospitals in 22 countries globally. The key inclusion criterion was genetically confirmed MCT8 deficiency. There were no exclusion criteria. Our primary objective was to analyse the overall survival of patients with MCT8 deficiency and document causes of death. We also compared survival between patients who did or did not attain full head control by age 1·5 years and between patients who were or were not underweight by age 1–3 years (defined as a bodyweight-for-age Z score <–2 SDs or <5th percentile according to WHO definition). Other objectives were to assess neurocognitive function and outcomes, and clinical parameters including anthropometric characteristics, biochemical markers, and neuroimaging findings. Findings Between Oct 14, 2014, and Jan 17, 2020, we enrolled 151 patients with 73 different MCT8 (SLC16A2) mutations. Median age at diagnosis was 24·0 months (IQR 12·0-60·0, range 0·0-744·0). 32 (21%) of 151 patients died; the main causes of mortality in these patients were pulmonary infection (six [19%]) and sudden death (six [19%]). Median overall survival was 35·0 years (95% CI 8·3–61·7). Individuals who did not attain head control by age 1·5 years had an increased risk of death compared with patients who did attain head control (hazard ratio [HR] 3·46, 95% CI 1·76–8·34; log-rank test p=0·0041). Patients who were underweight during age 1–3 years had an increased risk for death compared with patients who were of normal bodyweight at this age (HR 4·71, 95% CI 1·26–17·58, p=0·021). The few motor and cognitive abilities of patients did not improve with age, as evidenced by the absence of significant correlations between biological age and scores on the Gross Motor Function Measure-88 and Bayley Scales of Infant Development III. Tri-iodothyronine concentrations were above the age-specific upper limit in 96 (95%) of 101 patients and free thyroxine concentrations were below the age-specific lower limit in 94 (89%) of 106 patients. 59 (71%) of 83 patients were underweight. 25 (53%) of 47 patients had elevated systolic blood pressure above the 90th percentile, 34 (76%) of 45 patients had premature atrial contractions, and 20 (31%) of 64 had resting tachycardia. The most consistent MRI finding was a global delay in myelination, which occurred in 13 (100%) of 13 patients. Interpretation Our description of characteristics of MCT8 deficiency in a large patient cohort reveals poor survival with a high prevalence of treatable underlying risk factors, and provides knowledge that might inform clinical management and future evaluation of therapies

Eur J Endocrinol

Background: Among patients with congenital hypothyroidism, 35% have dyshormonogenesis (DH) with thyroid gland in situ with or without goiter. The majority of DH cases are due to mutations in genes involved in thyroid hormone production as TG, TPO, SLC5A5/NIS, SLC26A4/PDS, IYD/DEHAL1, DUOX2, and DUOXA2, and are usually inherited on an autosomal recessive basis. Most previously reported cases of fetal hypothyroidism and goiter were related to TG or TPO mutations and recently DUOXA2. Patient: In a male patient with antenatal goiter treated with intraamniotic levothyroxine injections, whose long-term follow-up is described in detail, two novel NIS mutations were detected. Mutations of NIS were located in exon 1 (c.52G>A, p.G18R) and exon 13 (c.1546C>T, p.R516X), each mutation was inherited from parents, who are healthy carriers. The p.G18R mutation affecting the first transmembrane domain of the protein can be responsible for deficient iodide uptake. However, the second is a nonsense mutation leading probably to mRNA degradation. In addition, the patient has undergone a thyroidectomy and we have studied the thyroid tissue. The thyroid histology showed heterogeneity with large follicles, epithelial hyperplasia and many areas of fibrosis. Immunohistochemistry with NIS specific antibody showed NIS staining at the basolateral plasma membrane of the thyrocytes. Conclusions: We report the first case of fetal goitrous hypothyroidism due to two novel NIS mutations with access to thyroid tissue of the patient, specific histology studies and long-term follow-up. This case expands our knowledge and provides further insights on molecular causes of fetal goiter in humans