Cognitive profiles of patients with early detected and treated congenital hypothyroidism

Neuropsychological Alterations in Patients with Congenital Hypothyroidism Treated with Levothyroxine: Linked Factors and Thyroid Hormone Hyposensitivity

Eighty-five percent of the studies of patients with congenital hypothyroidism (CH) treated with Levothyroxine (L-T₄) report neuropsychological sequelae throughout life. In neonates and infants, there is a deficit in sensorimotor skills (impaired balance). In preschool and elementary school children and adolescents, there are alterations in intellectual quotient (low scores), language (delayed phonological acquisition), memory (visual, verbal, visuospatial, visuoconstructive, autobiographical, and semantic), sensorimotor skills (impaired fine and gross motor control), and visuoconstructive–visuospatial domain (low scores in spatial location, block design, and object assembly). These neuropsychological domains are also affected in young adults, except for language (adequate verbal fluency) and visuoconstructive–visuospatial domain (no data). The onset and severity of neuropsychological sequelae in patients with treated CH depend on several factors: extrinsic, related to L-T₄ treatment and social aspects, and intrinsic, such as severity and etiology of CH, as well as structural and physiological changes in the brain. In this review, we hypothesized that thyroid hormone hyposensitivity (THH) could also contribute to neuropsychological alterations by reducing the effectiveness of L-T₄ treatment in the brain. Thus, further research could approach the THH hypothesis at basic and clinical levels to implement new endocrinological and neuropsychological therapies for CH patients.

Neonatal thyrotropin levels and auditory neural maturation in full-term newborns

Objective

This study aimed to look for a possible relationship between thyrotropin (TSH) values from neonatal bloodspot screening testing and newborn lower auditory pathway myelinization evaluated using the brainstem evoked response audiometry (ABR) test.

Methods

Sixty-two healthy full-term newborns without perinatal problems were enrolled in the study. TSH results were collected from neonatal bloodspot screening data and were below the test cut-off level (15μUI/mL). The TSH test was performed between three and seven days, and the ABR test was performed in the first 28 days of life. The newborns were divided into two groups: Group 1 (n = 35), TSH between 0 and 5μUI/mL, and group 2 (n = 27), TSH between 5 and 15μUI/mL. Data are presented as mean ± SD, median, or percentage, depending on the variable.

Results

Wave latency and interpeak interval values for Groups 1 and 2 were as follows: Wave I: 1.8 ± 0.1 and 1.7 ± 0.1; Wave III: 4.4 ± 0.1 and 4.4 ± 0.1; Wave V: 6.9 ± 0.1 and 6.9 ± 0.1; interval I–III: 2.6 ± 0.1 and 2.6 ± 0.1; interval I–V: 5.1 ± 0.1 and 5.1 ± 0.1; interval III–V: 2.4 ± 0.1 and 2.4 ± 0.1. There were no significant differences in ABR parameters between groups 1 and 2 (p > 0.05). Multiple regression analysis showed a slight significant negative correlation between TSH and wave I values (standardized β = −0.267; p = 0.036), without observing any relationship with the other ABR waves recorded.

Conclusions

This study investigated the relationship of TSH and auditory myelinization evaluated by ABR. It did not show a significant change in lower auditory pathway myelinization according to TSH levels in newborns with TSH screening levels lower than 15 μUI/mL.

Cognitive and Motor Outcome in Patients with Early-Detected Central Congenital Hypothyroidism Compared with Siblings

CONTEXT

Early treatment of primary congenital hypothyroidism (CH) prevents irreversible brain damage. Contrary to primary CH, outcome studies on central CH are scarce. Most patients with central CH have multiple pituitary hormone deficiencies (MPHD); these patients are also at risk for neonatal hypoglycemia.

OBJECTIVE

To assess cognitive and motor outcome in patients with early-treated central CH detected by the Dutch neonatal screening.

METHODS

In this cross-sectional study, primary outcome full-scale intelligence quotient (FSIQ) was measured in patients with MPHD and patients with isolated central CH born between January 1, 1995, and January 1, 2015, with siblings as controls. Secondary outcomes were intelligence test subscales and motor function. Linear mixed models were used to compare both patient groups and siblings, followed by post hoc tests in case of significant differences.

RESULTS

Eighty-seven patients (52 MPHD; 35 isolated central CH) and 52 siblings were included. Estimated marginal means for FSIQ were 90.7 (95% CI 86.4-95.0) in patients with MPHD and 98.2 (95% CI 93.0-103.5) in patients with isolated central CH. While patients with MPHD scored lower FSIQs than siblings (mean difference -7.9 points, 95% CI -13.4 to -2.5; P = .002), patients with isolated central CH did not. Processing speed was lower in both patient groups than in siblings (mean differences -10.5 and -10.3 points). Motor difficulties occurred significantly more often in patients (33%) versus siblings (5%; P = .004).

CONCLUSION

In early-treated central CH, FSIQ is comparable with siblings in patients with isolated central CH, while patients with MPHD have a significantly lower FSIQ. This may be explained by disease-specific consequences of MPHD, such as neonatal hypoglycemia and more severe hypothyroidism.

A Success Story: Review of the Implementation and Achievements of the National Newborn Screening Program for Congenital Hypothyroidism in Iran

CONTEXT

Today, newborn screening for congenital hypothyroidism (CH) as one of the significant achievements in preventive medicine is integrated into the health systems of many countries worldwide. The national newborn screening for early identification of CH disorder in Iran was established in 2004. The purpose of this study was to review the national newborn screening for CH and its achievements in Iran.

EVIDENCE ACQUISITION

In this study, we reviewed the structures, processes, main indicators, and achievements during the 15 years of implementing the national neonatal screening program for the diagnosis and treatment of CH in Iran.

RESULTS

Primary TSH measurement with backup thyroxine (T4) determination in infants with high TSH levels was used as the screening strategy in Iran. The coverage of this screening program was higher than 98%. By the end of 2017, 1,501,624 neonates were screened, among which 40,773 were diagnosed with CH and treated based on the national guidelines. The average incidence rate of CH during these years was approximately 2.6:1,000 live births.

CONCLUSIONS

The performance of the newborn screening program for congenital hypothyroidism in Iran is favorable, with over a 95% coverage rate. Due to the high recall rate and incidence rate of CH, it is essential to monitor the screening program in the country and also to conduct further studies to determine the main risk factors for the high recall rate and incidence of this congenital error.

MicroRNA-1236-3p/translationally controlled tumor protein (TPT1) axis participates in congenital hypothyroidism progression by regulating neuronal apoptosis

Congenital hypothyroidism (CH) is an endocrine disease caused by congenital thyroid hormone (TH) deficiency. MicroRNAs (miRNAs or miRs) have been reported to inhibit the progression of congenital hypothyroidism. However, the expression and role of miR-1236-3p in CH remains unclear. To address this, 12 day old Sprague-Dawley rats were divided into five groups: Control; Congenital hypothyroidism (CH), miR-1236-3p inhibitor control (inhibitor control); miR-1236-3p inhibitor (inhibitor); and miR-1236-3p inhibitor + translationally-controlled tumor protein 1 (TPT1)-small interfering (si)RNA (inhibitor + siRNA). Propylthiouracil (50 mg/day) was injected intraperitoneally into pregnant rats to generate pups with CH. The levels of miR-1236-3p and TPT1 were detected via reverse transcription-quantitative PCR and western blot analysis. Bioinformatics analysis was performed to predict the targets of miR-1236-3p, which was confirmed using dual luciferase reporter assay. Flow cytometry and MTT assay were used to measure neuronal cell apoptosis and cell viability, whereas western blotting was applied to detect the expression of Pim-3, p-Bad (Ser112), Bad and Bcl-xL, proteins associated with apoptosis. The results revealed that miR-1236-3p expression was significantly upregulated, whilst TPT1 expression was significantly downregulated in the hippocampus tissues of CH rats compared with the control group. TPT1 was confirmed as a target of miR-1236-3p. MiR-1236-3p inhibitor prevented hippocampal neuron apoptosis induced by CH induction, which was reversed by TPT1-siRNA transfection. In addition, following miR-1236-3p inhibitor transfection, neuronal cell apoptosis significantly reduced compared with the control group, which was accompanied by significantly increased expressions of Pim-3, p-Bad (Ser112) and Bcl-xL expression. These effects were reversed by TPT1-siRNA co-transfection. These results indicated that inhibition of miR-1236-3p expression inhibited neuron apoptosis in vivo and in vitro by targeting TPT1, serving a protective role in CH.

Two siblings with congenital central hypothyroidism caused by a novel mutation in the IGSF1 gene

Genetic defects in the immunoglobulin superfamily member 1(IGSF1) protein are the cause of congenital central hypothyroidism (C-CH). Here we report two Japanese siblings with C-CH due to a novel IGSF1 mutation. The youngest brother showed a failure to thrive, hypothermia, and neonatal icterus six days after birth. Further endocrine evaluations led to the diagnosis of C-CH. In addition, PRL deficiency was later detected. In contrast, the elder brother did not show symptoms of severe hypothyroidism during the neonatal period, but he had been followed up by doctors due to psychomotor developmental delays since the age of 1 yr. At the age of 3 yr, he had low thyroxine and PRL levels and was also diagnosed with C-CH. Because of the C-CH and PRL deficiency, an IGSF1 deficiency was suspected. Sequence analysis of the IGSF1 gene identified a novel hemizygous mutation of p.Trp1173GlyfsTer8 (NM_001170961.1:c.3517del) in both siblings. In conclusion, the phenotypic severity of C-CH is different, even in siblings. Importantly, an IGSF1 deficiency may result in severe hypothyroidism during the neonatal period.