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.

EFFECTS OF THE GONADOTROPIN-RELEASING HORMONE AGONIST THERAPY ON GROWTH AND BODY MASS INDEX IN GIRLS WITH IDIOPATHIC CENTRAL PRECOCIOUS PUBERTY.

Objective: We aimed to examine the auxological findings of girls diagnosed with idiopathic central precocious puberty (CPP) at the end of the GnRHa treatment and to investigate the effect of related factors on the height gain of those patients. Design: Single-center, descriptive, cross-sectional retrospective study. Method: A total of 43 patients who were diagnosed with idiopathic CPP and treated with GnRHa between 2012 - 2021 were included in to the study. Results: A decline in height standard deviation score (SDS) from 1.20 ± 0.14 to 1.02 ± 0.06 during the therapy was observed (P<0.001). The bone age/chronological age ratio was decreased and predictive adult height was increased at the end of the therapy (P<0.001; P=0.001). Both the rates of being overweight and obesity were increased (38.6% to 50% and 9% to 15.9%) when the treatment onset compared to the end of therapy. At the end of the treatment, the mean body mass index (BMI) SDS of the overweight patients was still higher compared to the normal-weight group (P<0.001). Conclusion: We observed a positive effect of GnRHa therapy on height potential. An increase in BMI during the therapy has been also demonstrated especially in subjects who were overweight before treatment.