Type Of Congenital Hypothyroidism Research Articles

Medication Adherence of Children with Congenital Hypothyroidism in Iran: A National Cross-Sectional Study

Background: Congenital hypothyroidism is the most common preventable and treatable cause of intellectual disability in children. A key component of the surveillance system for congenital hypothyroidism is ensuring a regular treatment program for affected children. Despite nearly 20 years since the successful implementation of the newborn screening program for hypothyroidism in Iran, a comprehensive evaluation of patients' adherence to treatment has not been conducted. Objectives: The aim of this study was to investigate the adherence to treatment among patients with congenital hypothyroidism in Iran. Methods: In this national cross-sectional study conducted in 2024, the adherence to treatment of 400 children with congenital hypothyroidism born between 2019 and 2023 in Iran was examined using the Morisky Medication Adherence Scale. The patients were randomly selected from national registry data. Data were analyzed using chi-squared tests, Fisher's exact test, and logistic regression in Stata software version 16. Results: The mean and standard deviation of medication adherence was 6.35 ± 1.41. Overall, adherence was good (≥ 6) in 284 (71.0%) of the study participants. In the univariate analysis, the most significant factors influencing adherence were place of residence, higher maternal education, lower paternal education, and type of congenital hypothyroidism (CH). In the multivariate analysis, children with permanent CH had good adherence, and parental education was not statistically significant (P > 0.05). Conclusions: The results of this study showed that medication compliance in more than two-thirds of hypothyroid children diagnosed by national newborn screening is good. Given the importance of treatment in these patients, it is recommended that intervention plans be implemented, including educational programs and active follow-up of patients to increase compliance.

Genetic basis of congenital hypothyroidism: abnormalities in the TSHbeta gene, the PIT1 gene, and the NIS gene.

We have elucidated the molecular pathology of three types of congenital hypothyroidism. Thyrotropin (TSH) is the major regulator of thyroid function. In cases of isolated congenital TSH deficiency, we found that they are caused by a missense mutation in the conserved CAGYC region of the TSHbeta gene. Pit-1/GHF-1 is a pituitary specific POU-domain DNA binding factor, which transactivates the growth hormone (GH), prolactin (PRL), TSHbeta genes, and the PIT1 gene itself. In cases of combined deficiency of GH, PRL, and TSH, we found that they are caused by abnormalities in the PIT1 gene, either recessively or dominantly. Sodium dependent iodide symporter (NIS) actively transports iodide into the thyroid cells to produce thyroid hormones. In cases of iodide transport defect, we elucidated that a missense mutation in the transmembrane region of the NIS gene caused them.

Influence of treatment on the maturation of the somesthetic pathway in infants with primary congenital hypothyroidism during the first year of life.

To assess the influence of treatment on the development of the somesthetic pathway in infants with congenital hypothyroidism receiving early treatment, median nerve somatosensory evoked potentials were measured during the 1st y of life. Twenty-nine infants were studied with six to seven somatosensory evoked potential tests per infant. The cervical latency (N13) divided by arm length and the first (N19) and second (N32) cephalic latencies as well as N13-N32 latency were measured. At diagnosis, all components showed a small but significant delay, which was not related to thyroxine (T4) levels before treatment. During treatment, T4 ranged from 50 to 290 nmol/L. At 12 mo, the cervical latency divided by arm length had normalized, whereas N19 and N13-N32 were more abnormal than at diagnosis. For N19, these abnormalities were related to a slow initial rise of T4 (< or = 100 nmol/L after 1 wk of treatment) and the initial N19 values. Abnormal N13-N32 values were associated with high T4 values during treatment (> 200 nmol/L) and the type of congenital hypothyroidism (partial or total deficiency in T4 production). Induction of therapy with l-triiodothyronine rather than l-thyroxine and the occurrence of low T4 values (< 100 nmol/L) after the 4th wk of therapy had no such effect. Our data suggest that, for normal CNS development, euthyroidism should be reached as soon as possible by adequate induction therapy. Thereafter, T4 supplementation should be strictly dosed, keeping the serum T4 values within narrow limits around the mean normal for age, because overtreatment, like initial undertreatment, may lead to CNS abnormalities at the end of the first year.

Concentration of plasma thyroglobulin and urinary excretion of iodinated material in the diagnosis of thyroid disorders in congenital hypothyroidism

In this paper we describe methods for the early aetiological diagnosis of congenital hypothyroidism, using beside the classical T4, T3 and TSH plasma concentrations, four additional parameters in plasma and urine. The first one is thyroglobulin (Tg). In normal children of more than one year of age and in adults, 5-35 ng/ml plasma is found, in neonates 2-3 weeks old, this level is 10-250 ng/ml. In patients with a stimulated thyroid gland, as in primary congenital hypothyroidism, plasma Tg levels increase. High Tg values are found in iodine deficiency and in organification defects. In the absence of the thyroid gland plasma Tg is undetectable. Low to normal levels are found in cases with hypoplasia of the gland. In patients with a disturbed synthesis of Tg, resulting in Tg deficiency of the gland, plasma Tg levels vary from undetectable to normal. The PBI-T4 plasma difference, which is caused by circulating abnormal iodoproteins is the second parameter. The products of thyroidal breakdown processes of the abnormal iodoproteins are excreted in the urine and used as the third parameter. We found that the excretion of this low molecular weight iodinated material (LOMWIOM) was increased only in Tg-deficient patients. If the neonate is found to be hypothyroid, thyroid hormone substitution must be given immediately. Blood and urine sampling can be done just before or even directly after starting the therapy. The measurements extended with the determination of the total iodine excretion (fourth parameter) can be carried out within 1 week. With these additional methods it appeared to be possible to distinguish between several types of congenital hypothyroidism in neonates found by screening.