The Italian screening program for primary congenital hypothyroidism: actions to improve screening, diagnosis, follow-up, and surveillance

Congenital hypothyroidism after newborn screening program reorganization in the Apulia region

Background

Congenital hypothyroidism (CH) is the most frequent congenital endocrine disorder. The purpose of the present study was to evaluate the incidence and etiological classification of CH in Apulia in a three-year period according to the reorganization of the regional screening program in a single central laboratory, as well as to analyze the growth characteristics and the associated risk factors of the CH newborns diagnosed during the study period.

Methods

Data derived from the reorganization of the newborn screening program for CH in a single central laboratory that collects dried blood spot (DBS) from 27 Maternity Hospitals are analyzed over a three-year period. Birth weight and length, daily dose of L-T4 at specific key points (3, 6, 12 and 18 months, 2, 2.5 and 3 years) were also obtained from medical records of the CH newborns during the study period and calculated as standard deviation score (SDS).

Results

The screening program diagnosed 90 newborns with confirmed CH (incidence 1:990; recall rate: 3.6%). In detail, 75.6% newborns had an eutopic thyroid, and 24.4% had thyroid dysgenesis; 33 out of the 90 newborns (36.6%) had one or more risk factors. Among these, the multiple pregnancies are the most important because they tripled the risk of CH. At diagnosis, TSH levels were different between patients with dysgenesis and those with an eutopic thyroid (p = 0.005). Treatment was started at a mean of 18.5 ± 12.8 days of life. The mean starting dose of levothyroxine (L-T4) was 11.38 ± 2.46 μg/kg/day.

Conclusions

The results of these study show an increase of CH cases in newborns with an eutopic thyroid compared to the traditional classification. The centralization of the screening program allows a closer cooperation between laboratory and clinical centers and facilitates the implementation of appropriate diagnostic evaluations and timely initiation of treatment, with positive effects on the management of the condition.

Different combinations of monoclonal antibodies and polyclonal antibodies in the design of neonatal hypothyroidism diagnostic kit

Neonatal hypothyroidism is a deficiency of thyroid hormones at birth that can cause lifelong mental and physical disorders in humans. Lack of timely detection could lead to irreversible damage by neonatal hypothyroidism. However, it could be managed quickly and efficiently via timely diagnosis. The screening programs rely on immunoassays to diagnose neonatal hypothyroidism in most countries. This method is time-consuming, needs laboratory equipment, and should be performed by trained and skilled technicians. Given these circumstances, the ELISA method is not a preferable method for the diagnosing of neonatal hypothyroidism. However, it can be used as a confirmatory method in infants with suspected and unknown neonatal hypothyroidism. In the present study, the homemade SR95-1, SR95-2, and SR95-3 anti-β-TSH polyclonal and the commercially available monoclonal antibodies were used to detect β-TSH in a rapid assay kit design hypothyroidism screening. To design the kit, the different combinations of the antibodies were used to establish a sandwich immune-chromatography method. The designed rapid neonatal hypothyroidism tests were used to measure neonatal β-TSH in 100 dry blood samples. This study showed that the best antibody pair in terms of sensitivity is the SR95-1 antibody as capture antibody and the SR95-2 as a conjugated antibody. Using 100 clinical samples, the designed assay was shown to have 94% sensitivity, 83% specificity, and 94% accuracy. The results showed that polyclonal antibodies (SR95-1 as capture) and SR95-2 (as detector) antibodies can detect the reference range of β-TSH in dried blood samples and can be used in the screening of neonatal hypothyroidism.

An Overview on Different L-Thyroxine (l-T4) Formulations and Factors Potentially Influencing the Treatment of Congenital Hypothyroidism During the First 3 Years of Life

Congenital hypothyroidism (CH) is a relatively frequent congenital endocrine disorder, caused by defective production of thyroid hormones (THs) at birth. Because THs are essential for the development of normal neuronal networks, CH is also a common preventable cause of irreversible intellectual disability (ID) in children. Prolonged hypothyroidism, particularly during the THs-dependent processes of brain development in the first years of life, due to delays in diagnosis, inadequate timing and dosing of levothyroxine (l-thyroxine or l-T₄), the non-compliance of families, incorrect follow-up and the interference of foods, drugs and medications affecting the absorption of l-T₄, may be responsible for more severe ID. In this review we evaluate the main factors influencing levels of THs and the absorption of l-T₄ in order to provide a practical guide, based on the existing literature, to allow optimal follow-up for these patients.

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-European Reference Network (ERN) initiative was launched that 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 CH. The evidence-based guidelines were graded with the Grading of Recommendations, Assessment, Development and Evaluation 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. Harmonization of diagnostics, treatment, and follow-up will optimize 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 condition.

A Detailed Analysis of the Factors Influencing Neonatal TSH: Results From a 6-Year Congenital Hypothyroidism Screening Program

Background: Neonatal thyrotropin (TSH) on dried blood spot (DBS), the most common screening strategy for primary congenital hypothyroidism (CH), is influenced by numerous factors that may hinder a true CH diagnosis. A second test can thus be performed to clarify the initial findings, although its application varies among screening programs. Objectives: The aim of this study was to evaluate the effect of maternal and neonatal factors on neonatal TSH levels and offer practical screening recommendations. Methods: We retrospectively analyzed screening data of 62,132 neonates born in Abruzzo, an Italian region considered mildly iodine deficient, between 2011 and 2016. We then performed a multiple linear regression to model the relationship between TSH (the dependent variable) and 13 independent variables extracted from blood collection cards. Results: Most neonates (53,551 of 62,132, 86%) had normal TSH and no clinical indications for a second screening. A minority (1,423, 2.3%) had elevated TSH in the initial DBS, which was confirmed in 97 cases (7%) on a second screen. The remaining neonates (6,594, 10.6%) had a normal initial TSH but underwent a second test in accordance with screening protocols, and were found to have delayed TSH elevation in 23 cases (0.4%). Those 120 newborns (97 + 23), considered highly suspicious for primary CH, were referred to a pediatrician for confirmatory testing and excluded from subsequent analysis of factors influencing TSH levels. Sex (β regression coefficient, β = 1.11 female to male, 95% CI 1.09, 1.12) and age at collection (β = 0.78 day 5 to days 2-3, 95% CI 0.74, 0.83) affected neonatal TSH, suggesting the utility of specific nomograms. In addition, prematurity (β = 0.85 term to preterm, 95% CI 0.80, 0.91), dopamine use (β = 0.71, 95% CI 0.62, 0.81), and birth weight (β = 1.40 normal vs. very low, 95% CI 1.05, 1.89) strongly influenced neonatal TSH. Conclusions: Neonatal TSH is influenced by several factors supporting the delineation of local sex- and age-adjusted TSH cutoffs, and the universal adoption of a second TSH test in neonates at risk of missed primary CH diagnosis.

Transoral thyroidectomy: advantages and limitations

In this opinion paper of the Journal of Endocrinological Investigation, leading experts in the field report on their current clinical experience with a novel approach for thyroid gland surgery, namely, "transoral thyroidectomy" (TOT). This feasible and novel surgical procedure does not require visible incisions and is, therefore, a truly scarless surgery. Patients meeting the following criteria can be considered as candidates for TOT: (a) an ultrasonographically (US) estimated thyroid diameter ≤10 cm; (b) US-estimated gland volume ≤45 mL; (c) nodule size ≤50 mm; (d) presence of a benign tumor such as a thyroid cyst or a single- or multi-nodular goiter; (e) Bethesda 3 and/or 4 category and (f) papillary microcarcinoma without the evidence of metastasis. The procedure is conducted via a three-port technique at the oral vestibule using a 10-mm port for the 30° endoscope and two additional 5-mm ports for the dissecting and coagulating instruments. TOT is performed using conventional endoscopic instruments and is probably the best scarless approach to the thyroid because of the short distance between the thyroid and the incisions placed intra-orally that do not result in any cutaneous scar and upon following the surgical planes. Experts in TOT organized a working group of general, endocrine, head and neck ENT surgeons and endocrinologist to develop the standards for practicing this emerging technique.

Screening of HHEX Mutations in Chinese Children with Thyroid Dysgenesis

OBJECTIVE

Congenital hypothyroidism (CH) is a frequent neonatal endocrine disease with an incidence of about 1:2500 worldwide. Although thyroid dysgenesis (TD) is the most frequent cause of CH cases, its pathogenesis remains unclear. The aim of this study was to screen the hematopoietically-expressedhomeobox gene (HHEX) mutations in Chinese children with TD.

METHODS

Genomic deoxyribonucleic acid was extracted from peripheral blood leukocytes in 234 TD patients from Shandong Province. Mutations in all exons and nearby introns of HHEX were analyzed by direct sequencing after polymerase chain reaction amplification.

RESULTS

Sequencing analysis of HHEX indicated that no causative mutations were present in the coding regionof the TD patients. However, a genetic variant (IVS2+ 127 G/T, 10.26%) was observed in the intron 2 in HHEX.

CONCLUSION

Our results indicate that the frequency of HHEX mutation is very low and may not be the main causative factor in Chinese TD patients. However, these results need to be replicated using larger datasets collected from different populations.

Final height in Italian patients with congenital hypothyroidism detected by neonatal screening: a 20-year observational study

BACKGROUND

Linear growth and final height are reported as normal in congenital hypothyroid patients in the neonatal screening era.

METHODS

We evaluated the final height in 215 patients with congenital hypothyroidism to assess if it improved over the last 2 decades.

RESULTS

Final height (-0.1 ± 1.0 SDS) was higher than target height (-0.8 ± 1.0 SDS, p < 0.001) and not different among the 4 quartiles for birthdate. It was correlated with target height (r(2) = 0.564, p < 0.001) and height at puberty onset (r(2) = 0.685, p < 0.001), but not with age at diagnosis or the starting LT4/kg/day dose. The curve fitting analysis showed that the age at diagnosis progressively decreased during the 20-year study period, while the target height and the starting LT4/kg/day increased. Final height was not affected by the birthdate, the age at diagnosis, the starting LT4 dose.

CONCLUSIONS

The final height is higher than the target height, but despite the improvement in the screening and the treatment, it did not improve over the last 20 years. These findings are in keeping with the described secular trend and suggest that earlier diagnosis and replacement therapy do not significantly modify final height in these patients.

Heterogeneous phenotype in children affected by non-autoimmune hypothyroidism: an update

BACKGROUND

In the last decades, a higher incidence of congenital hypothyroidism (CH) has been recorded in Italy (1:1940) and worldwide, mainly due to the shift to lower screening TSH cutoffs. Although CH can also be caused by dysgenetic defects, most CH cases have recently been found to be more frequently associated with functional defects of an in situ thyroid gland. Although the clinical phenotype is milder with high prevalence of transient forms, some cases eventually prove to be permanent.

RESULTS

Possible explanations of the raised incidence of CH are ethnic modifications of the screened population and the increasing incidence of preterm birth and multiple pregnancies. These findings are important in terms of public health and standardization of screening programmes for special at-risk categories such as preterms, acutely ill term neonates, low birth weight and very low birth weight infants, and newborns with specific drug exposure. Other environmental factors have contributed to the increased incidence of hypothyroidism, including thyroid disrupting chemicals, iodine supply (excess/deficiency), and drugs interfering with thyroid function. Finally, an increased prevalence of hypothyroidism has been documented in obese children and patients with syndromic forms (Williams, Down, Turner, pseudohypoparathyroidism). The clinical and molecular phenotype of patients with CH will be better defined thanks to novel genetic approach based on the systematic analysis of a panel of genes (TSHR, DUOX2, DUOXA, TPO, PDS, TG, NKX2.1, JAG1, GLIS3, FOXE1, PAX-8).

CONCLUSIONS

This review summarizes significant advances in the epidemiology and aetiology of non-autoimmune hypothyroidism, with a focus on thyroid dysfunction in preterm infants.

The molecular causes of thyroid dysgenesis: a systematic review

BACKGROUND

Congenital hypothyroidism (CH) is a frequent disease occurring with an incidence of about 1/2500 newborns/year. In 80-85% of the cases CH is caused by alterations in thyroid morphogenesis, generally indicated by the term "thyroid dysgenesis" (TD). TD is generally a sporadic disease, but in about 5% of the cases a genetic origin has been demonstrated. In these cases, mutations in genes playing a role during thyroid morphogenesis (NKX2-1, PAX8, FOXE1, NKX2-5, TSHR) have been reported.

AIM

This work reviews the main steps of thyroid morphogenesis and all the genetic alterations associated with TD and published in the literature.