Etiological evaluation of primary congenital hypothyroidism cases

Outcomes of newborns screened for congenital hypothyroidism in Turkey - a single center experience

OBJECTIVES

It was aimed to investigate the outcomes of babies referred to a tertiary health center in Turkey for evaluation primary congenital hypothyroidism (CH) through newborn screening.

METHODS

The hospital files of 328 newborns who were referred for CH from newborn screening between June 2013 and June 2020 were retrospectively reviewed. The newborns were evaluated with their clinical characteristics at admission, as well as their follow-up data and final diagnoses.

RESULTS

Sixteen (4.9 %) newborns were diagnosed with transient neonatal hyperthyrotropinemia after follow-up. Treatment was initiated in 166 (50.6 %) of the cases with a diagnosis of CH. The median age at initiation of treatment was 17 days (5-69). Treatment was initiated in 88.3 % of the cases in the first month of the life. After at least 3 years of follow-up, 30/120 (20.0 %) of the cases were diagnosed with permanent CH and 11/30 (36.7 %) of them were diagnosed with thyroid dysgenesis. All of the cases who used >37.5 µg per day levothyroxine at the age of 1 or 2 years were diagnosed with permanent CH during their follow-up. For the prediction of transient CH, the sensitivity and specificity of levothyroxine doses of ≤25 µg per day at 1 year of age were calculated as 96.2 and 46.2 %, and for 2 years of age, the sensitivity and specificity were calculated as 97.8 and 65.2 %.

CONCLUSIONS

In this cohort, 10 % of all referrals result in permanent CH. Thyroid imaging with ultrasonography and levothyroxine dose during follow-up can be guiding in predicting permanent CH.

High frequency of transient congenital hypothyroidism among infants referred for suspected congenital hypothyroidism from the Turkish National screening program: thyroxine dose may guide the prediction of transients

PURPOSE

We aimed to determine the frequency of transient congenital hypothyroidism (TCH) in 17 participating centers in Türkiye, evaluate the etiological distribution in permanent congenital hypothyroidism (PCH) cases, and investigate the role of laboratory and clinical findings in predicting TCH.

METHODS

This retrospective observational multicenter study included patients from 17 pediatric endocrinology centers identified by "National Newborn Screening Program" (NNSP) who were born in 2015 and followed for 6 years. Demographic, clinical, and laboratory information of the cases were compiled through the database http://cedd.saglik-network.org (CEDD-NET).

RESULTS

Of the 239 cases initially treated for CH, 128 (53.6%) were determined as transient in whom a trial of levothyroxine (LT4) withdrawal was performed at a median age of 36 (34-38) months. Among the patients with PCH (n = 111), thyroid dysgenesis was diagnosed in 39.6% (n = 44). The predictive factors for TCH were: LT4 dose at the withdrawal of treatment, and initial newborn blood screening (NBS)-TSH level. Based on the receiver operating characteristic (ROC) curve analysis to predict optimal cut-offs for TCH predictors, LT4 dose < 2.0 µg/kg/day at treatment discontinuation was predictive for TCH and was associated with 94.5% specificity and 55.7% sensitivity, with an area under the curve (AUC) of 0.802. The initial NBS-TSH level value < 45 µIU/mL was predictive for TCH with 93.1% specificity and 45.5% sensitivity, with an AUC of 0.641. In patients with eutopic thyroid gland only LT4 dose < 1.1 µg/kg/day at withdrawal time was predictive for TCH with 84.7% sensitivity and 40.4% specificity, with an AUC of 0.750.

CONCLUSION

According to our national follow-up data, the frequency of TCH was 53.6%. We determined the LT4 dose < 2.0 µg/kg/day at discontinuation of treatment and the initial NBS-TSH level < 45 µIU/mL as the best cut-off limits to predict TCH.

Guidelines for Newborn Screening of Congenital Hypothyroidism (2021 Revision)

Purpose of developing the guidelines: Newborn screening (NBS) for congenital hypothyroidism (CH) was started in 1979 in Japan, and early diagnosis and treatment improved the intelligence prognosis of CH patients. The incidence of CH was once about one in 5,000-8,000 births, but has been increased with diagnosis of subclinical CH. The disease requires continuous treatment and specialized medical facilities should conduct differential diagnosis and treatment in patients who are positive by NBS to avoid unnecessary treatment. The Guidelines for Mass Screening of Congenital Hypothyroidism (1998 version) were developed by the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology in 1998. Subsequently, the guidelines were revised in 2014. Here, we have added minor revisions to the 2014 version to include the most recent findings. Target disease/conditions: Primary congenital hypothyroidism. Users of the Guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, physicians referring pediatric practitioners, general physicians, laboratory technicians in charge of mass screening, and patients.

Etiological, clinical, and laboratory evaluation of congenital hypothyroidism and determination of levothyroxine (LT4) dose at treatment interruption in differentiating permanent vs. transient patients

BACKGROUND

Congenital hypothyroidism (CH) is the most common cause of preventable but irreversible mental retardation in children, although the risk has been widely abolished by national neonatal screening programs. The aim of this study was to determine, (a) the cause of CH, (b) the etiological cause of persistent CH and (c) to investigate the role of laboratory and clinical data in predicting persistent and transient CH.

METHODS

Patients diagnosed with CH, who started L-thyroxine treatment and were followed up for at least three years were included. Patient data were reviewed retrospectively. Serum thyroid hormones were measured four weeks after discontinuation of therapy at age three or earlier. Cases with a thyroid-stimulating hormone (TSH) value of >10 mIU/mL were accepted as permanent hypothyroidism, while cases with normal TSH values for six months after cessation were accepted as transient hypothyroidism.

RESULTS

There were 232 treated cases, of whom 108 (46.6%) were female, and 169 (72.8%) were eventually diagnosed with transient CH. The best cut-off point for predicting permanent status was determined as LT4 cut-off dose ≥1.45 mcg/kg/day. The median (range) duration of L-thyroxine treatment in transient hypothyroid cases was 24 (range: 6-36) months, and treatment was discontinued before the age of three years in 64%.

DISCUSSION

There were 232 treated cases, of whom 108 (46.6%) were female, and 169 (72.8%) were eventually diagnosed with transient CH. The best cut-off point for predicting permanent status was determined as LT4 cut-off dose ≥1.45 mcg/kg/day. The median (range) duration of L-thyroxine treatment in transient hypothyroid cases was 24 (range: 6-36) months, and treatment was discontinued before the age of three years in 64%.

Evaluation of permanent and transient congenital hypothyroidism in cases referred from National Neonatal Screening Program

AIM

The incidence of congenital hypothyroidism (CH) has increased world-wide. Lowering cut-off in screening programs has led to an increase in the rate of transient CH. We aimed to evaluate the rates of permanent and transient CH in cases referred from the screening program and to investigate the clinical and laboratory factors which predict transient CH.

METHODS

In 109 cases referred from the neonatal screening program to our hospital, from September 2015 to April 2018, 52 primarily diagnosed CH cases were prospectively evaluated. Regularly followed up, 44 CH cases were included in the study at the end of 3 years.

RESULTS

38.2 ± 1.31 weeks (w) and mean birthweight 3021.3 ± 389.6 gram (g) in the transient CH group; both were significantly lower compared to permanent CH cases with 39.06 ± 1.33 w and 3375.3 ± 425.3 g (P = 0.025, P = 0.007) respectively. Transient CH rate was found to be 50% (all hypoplastic) in the dysgenesis group and 73.3% in groups with normal and hyperplasic thyroid gland. While fT₄ , thyroid-stimulating hormone, and thyroglobulin levels at diagnosis do not predict transient/permanent CH, levothyroxine (LT-4) dosage was significantly lower in the transient CH group in all years. The optimal cut-off value with highest sensitivity and specificity for LT-4 dosage as a predictive marker to differentiate transient CH from permanent CH was 2.27 μg/kg/day (P = 0.004; sensitivity: 71%, specificity: 83%) at 1st year, 1.85 μg /kg/day (P = 0.013; sensitivity: 66%, specificity: 72%) at 2nd year and 1.69 μg /kg/day at 3rd year (P < 0.0001; sensitivity: 90%, specificity: 83%).

CONCLUSION

Transient CH is more frequent than expected. Our results suggest that LT-4 requirement may be a good marker for predicting transient CH, while thyroid hormone levels at the time of diagnosis do not significantly predict permanent and transient CH. Therefore, infants with CH requiring LT-4 doses <2.27 μg/kg/day at 1st year, <1.85 μg /kg/day at 2nd year may be re-evaluated earlier to discriminate transient CH rather than at 3 years of age.

Modeling Human Thyroid Development by Fetal Tissue-Derived Organoid Culture

Euthyroidism is of profound importance for lifetime health. However, the early diagnosis or therapeutics of thyroid developmental defects has not been established, mainly due to limited understanding of human thyroid development and a lack of recapitulating research model. Herein, the authors elaborate the cell atlas and potential regulatory signaling of the evolution of heterogeneous thyrocyte population from 12 to 16 gestational weeks. Moreover, they establish a long-term culture of human fetal thyroid organoids (hFTOs) system, which retains the fetal thyroid lineages and molecular signatures, as well as the ability to generate functional human thyroid follicles post mice renal transplantation. Notably, cAMP signaling activation in hFTOs by forskolin boosts the maturation of follicle and thus thyroid hormone T4 secretion, which recapitulates the key developmental events of fetal thyroid. Employing this ex vivo system, it is found that enhanced chromatin accessibility at thyroid maturation genes (such as TPO and TG) loci permits the transcription for hormone production. This study provides the cell atlas of and an organoid model for human thyroid development, which will facilitate thyroid research and prospective medicine.

Cases Referred from the Turkish National Screening Program: Frequency of Congenital Hypothyroidism and Etiological Distribution

OBJECTIVE

The aim of this study was to evaluate cases referred from the congenital hypothyroidism (CH) newborn screening program.

METHODS

Infants referred to Pediatric Endocrinology between 30.09.2015 - 01.04.2018 because of suspected CH identified by National Neonatal Screening Program were prospectively evaluated.

RESULTS

Of the 109 newborns referred to our clinic, 60 (55%) were diagnosed with elevated neonatal thyroid stimulating hormone (TSH). The diagnosis of elevated neonatal TSH was made in 52 (47.7%) and eight (7.3%) infants at initial evaluation and after follow up, respectively of all referrals with 86.7% (52/60) diagnosed at initial visit. The median first and second heel prick times were 1.8 (0-7) and 8.72 (4-30) days. The median age at starting treatment of the infants diagnosed as a result of initial evaluation was 22.13 (7-53) days. Clinical findings associated with CH were present in 19 (36%) of patients. Etiology in patients diagnosed with elevated neonatal TSH on admission was: agenesis in one (2.08%); ectopia in one (2.08%); hypoplasia in 14 (29.16%); normal gland in situ 16 (33.3%); and hyperplasia in 16 (33.3%). The median time to normalization of TSH and free thyroxine concentrations after treatment initiation was 11.02 (4-30) and 9.03 (3-30) days, respectively.

CONCLUSION

The rate of diagnosis in the first month was found to be 87%. The etiological incidence of both dysgenesis and dyshormonogenesis was equal at 33.3%. The majority of cases with normal thyroid gland will be diagnosed with transient hypothyroidism but some of them may be diagnosed with thyroid dyshormonogenesis so the rate of dyshormonogenesis will increase later after final diagnosis.