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OBJECTIVE: To study school achievement in grade 9 of compulsory school in children with congenital hypothyroidism (CH), both those detected by the national screening program and those with a normal screening result and thus diagnosed later. STUDY DESIGN: Nationwide study of children in the Swedish Medical Birth Register (n = 1 547 927) from 1982 through 1997, linked to the neonatal screening CH cohort and the National School Register. Dried blood spot (DBS) samples are collected from all newborn infants, according to the neonatal screening program. Thyroid-stimulating hormone was used for CH screening. CH was defined as either having an abnormal screening result (DBS+) and treatment with levothyroxine (LT4+) or having a normal screening result but a CH diagnosis in the National Patient Register and treatment with LT4 (DBS-/ICD+/LT4+). Regression models were used to study school performance, which as measured as grade point sum and national test results. Sibling analysis also was performed to account for unmeasured familial factors. RESULTS: There were 448 children who were DBS+/LT4+ and 475 children who were DBS-/ICD+/LT4+. Children with CH had lower grade point sum, adjusted ß = - 6.34 (95% CI -11.7 to -1.01) and adjusted ß = -10.3 (95% CI -15.5 to -5.20) for those with abnormal (DBS+/LT4+) and normal screening (DBS-/ICD+/LT4+) results, respectively. CH also was associated with lower result on the national tests, especially in mathematics. These associations remained in the sibling analyses. CONCLUSIONS: Youth with CH had slightly lower school achievements compared with those without CH and compared with their siblings. CH children with a normal screening result, and thus diagnosed later, presented the lowest results on grade point sum and national tests.

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A higher incidence of primary congenital hypothyroidism (CH) has been related to increased sensitivity in neonatal screening tests. The benefit of treatment in mild cases remains a topic of debate. We evaluated the impact of reducing the blood-spot TSH cut-off (b-TSH) from 10 (Group 2) to 6 mIU/L (Group 1) in a public neonatal screening program. During the study period, 40% of 123 newborns with CH (n = 162,729; incidence = 1:1323) had b-TSH between 6 and 10 mIU/L. Group 1 patients had fewer clinical signs (p = 0.02), lower serum TSH (p < 0.01), and higher free T4 (p < 0.01) compared to those in Group 2 at diagnosis. Reducing the b-TSH cut-off from 10 to 6 mIU/L increased screening sensitivity, allowing a third of diagnoses, mainly mild cases, not being missed. However, when evaluating the performances of b-TSH cut-offs (6, 7, 8, 9, and 10 mIU/L), the lower values were associated with low positive predictive values (PPVs) and unacceptable increased recall rates (0.57%) for a public health care program. A proposed strategy is to adopt a higher b-TSH cut-off in the first sample and a lower one in the subsequent samples from the same child, which yields a greater number of diagnoses with an acceptable PPV.

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Background and Objectives: Congenital thyroid dyshormonogenesis is caused by alterations in the synthesis of thyroid hormones in a newborn. Additionally, 10 to 20% of these cases are hereditary, caused by defects in proteins involved in hormonal synthesis. One of the most common causes is mutations in the thyroid peroxidase (TPO) enzyme gene, an autosomal recessive disease. We aimed to detect mutations of the TPO gene in 12 Chilean patients with congenital hypothyroidism due to dyshormonogenesis (CHD) and to characterize these patients clinically and molecularly. Materials and Methods: Twelve patients under 20 years of age with CHD, controlled at San Juan de Dios Hospital in Santiago, Chile, were selected according to the inclusion criteria: elevated neonatal TSH, persistent hypothyroidism, and thyroid normotopic by imaging study. Those with deafness, Down syndrome, and central or transient congenital hypothyroidism were excluded. Blood samples were taken for DNA extraction, and the 17 exons and exon-intron junctions of the TPO gene were amplified by PCR. The PCR products were sequenced by Sanger. Results: Two possibly pathogenic mutations of the TPO gene were detected: c.2242G>A (p.Val748Met) and c.1103C>T (p.Pro368Leu). These mutations were detected in 2 of 12 patients (16.6%): 1 was compound heterozygous c.1103C>T/c.2242G>A, and the other was heterozygous for c.2242G>A. In the diagnostic confirmation test, both patients presented diffuse hyper-uptake goiter on thyroid scintigraphy and high TSH in venous blood (>190 uIU/mL). Conclusions: The frequency of patients with possibly pathogenic mutations in TPO with CHD was 16.6%. Its study would allow for genetic counseling to be offered to the families of affected patients.

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Introduction. The first neonatal screening program in Colombia ­ PREGEN ­ was set up in the medical private sector of Bogotá in 1988. We report the results from recent years that, given the scarcity of similar information in our country, may help estimate the frequency of the evaluated neonatal disorders and which ones should be included in the neonatal screening programs in our country. Objective. To describe the results of PREGEN´s newborn screening program between 2006 and 2019. Materials and methods. We analyzed databases and other informative documents preserved in PREGEN from the 2006-2019 period. Results. One in every 164 newborns screened in our program had an abnormal hemoglobin variant, and one in every 194 carried some hemoglobin S variant. Glucose-6- phosphate dehydrogenase deficiency and congenital hypothyroidism are next as the more common disorders. Conclusions. Abnormal hemoglobin causes the most frequent monogenic disorder in the world. Glucose-6-phosphate dehydrogenase deficiency is the most common enzymopathy affecting nearly 400 million individuals worldwide. Since both disorders are more common in people of African descent and confer some resistance to malaria, we believe that screening for both disorders may be more relevant in the areas with African ancestry in our country.

Introducción. En Colombia, el primer programa de tamizaje neonatal, PREGEN, inició labores en el sector privado de Bogotá en 1988. En este artículo se presentan los resultados obtenidos en los últimos años, que, dada la carencia de estos estudios en el país, pueden servir para evaluar la frecuencia de aparición de los trastornos congénitos evaluados y estimar cuáles de ellos deben ser objeto de tamizaje neonatal a nivel nacional. Objetivos. Reportar los resultados del programa de tamizaje PREGEN entre el 2006 y el 2019. Materiales y métodos. Para este análisis se examinaron las bases de datos y otros documentos informativos de PREGEN para el periodo 2006-2019. Resultados. Uno de cada 164 recién nacidos tamizados en el programa PREGEN en Bogotá presentó una variante anormal de la hemoglobina y uno de cada 194 es portador de hemoglobina S. Los siguientes dos trastornos más frecuentes encontrados fueron la deficiencia de la enzima glucosa-6-fosfato deshidrogenasa (frecuencia 1:2.231) y el hipotiroidismo congénito (frecuencia 1:3.915). Conclusiones. Las hemoglobinopatías mostraron ser uno de los desórdenes monogénicos más comunes, seguidos por la deficiencia de glucosa-6-fosfato deshidrogenasa y el hipotiroidismo congénito. Se calcula que cerca de 400 millones de personas en el mundo están afectadas por la deficiencia de glucosa-6-fosfato deshidrogenasa, por lo cual es la enzimopatía más común en el mundo. Como ambos desórdenes son más frecuentes en poblaciones de origen africano y confieren algún grado de resistencia a la malaria, es de prever que su tamizaje debe ser de mayor importancia en las zonas con ancestros africanos en Colombia.

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OBJECTIVE: To determine among infants born very preterm (VPT) or with very low birth weight (VLBW) the incidence of alterations in thyroid function and associated comorbidities; the incidence of atypical congenital hypothyroidism (CH) requiring thyroxine therapy; and reference ranges for rescreening at 1 month of age. STUDY DESIGN: A retrospective review of infants born VPT or with VLBW and admitted to UC Irvine Medical Center between January 1, 2012, and December 31, 2020. Repeat thyroid screening was obtained at 1 month of life (+10 days). Infants with thyroid-stimulating hormone (TSH) >5 µIU/mL or free thyroxine <0.8 ng/dL underwent follow-up testing and endocrinology consultation. Initial newborn screening (NBS) and repeat thyroid screening data were collected via chart review. Demographic data and short-term outcomes were abstracted from the California Perinatal Quality Care Collaborative database. RESULTS: In total, 430 patients were included; 64 of 429 patients (14.9%) had TSH >5 µIU/mL and 20 of 421 patients (4.8%) had free thyroxine <0.8 ng/dL. Logistic regression analysis identified small for gestational age (P = .044), patent ductus arteriosus (P = .013), and late-onset sepsis (P = .026) as risk factors associated with delayed TSH rise. Atypical CH requiring treatment through neonatal intensive care unit discharge was diagnosed in 6 patients (incidence of 1.4%); none were identified by NBS. The 90th percentile TSH for infants with extremely low birth weight (<1000 g) was 7.2 µIU/mL, and the 95th percentile for those with birth weight of 1000-1500 g was 6.1 µIU/mL; using these cutoff values identified all infants diagnosed with atypical CH with 100% sensitivity and 90%-95% specificity. CONCLUSIONS: Abnormal thyroid function is common in infants born preterm. Those infants, including some with atypical CH, are missed by NBS. We recommend repeat thyroid screening with TSH at 1 month of age in infants born VPT or infants with VLBW to identify CH that may require therapy.

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CONTEXT: Subtle cognitive impairments have been described in children with congenital hypothyroidism (CH) detected by neonatal screening (NS), even with early and adequate treatment. Patients with CH may present with brain cortical thickness (CT) abnormalities, which may be associated with neurocognitive impairments. OBJECTIVE: This work aimed to evaluate the CT in adolescents with CH detected by the NS Program (Paraná, Brazil), and to correlate possible abnormalities with cognitive level and variables of neurocognitive prognosis. METHODS: A review was conducted of medical records followed by psychometric evaluation of adolescents with CH. Brain magnetic resonance imaging with analysis of 33 brain areas of each hemisphere was performed in 41 patients (29 girls) and in a control group of 20 healthy adolescents. CT values were correlated with Full-scale Intelligence Quotient (FSIQ) scores, age at start of treatment, pretreatment thyroxine levels, and maternal schooling. RESULTS: No significant difference in CT between patients and controls were found. However, there was a trend toward thinning in the right lateral orbitofrontal cortex among patients and in the right postcentral gyrus cortex among controls. CT correlated significantly with FSIQ scores and with age at start of treatment in 1 area, and with hypothyroidism severity in 5 brain areas. Maternal schooling level did not correlate with CT but was significantly correlated with FSIQ. Cognitive level was within average in 44.7% of patients (13.2% had intellectual deficiency). CONCLUSION: There was a trend toward morphometric alterations in the cerebral cortex of adolescents with CH compared with healthy controls. The correlations between CT and variables of neurocognitive prognosis emphasize the influence of hypothyroidism on cortical development. Socioeconomic status exerts a limiting factor on cognitive outcome.

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OBJECTIVES: Congenital hypothyroidism (CH) is a decrease in thyroid hormone function in newborns, being one of the leading causes of neurological deficits and long-term metabolic complications. This study aims to determine the prevalence and characteristics of CH cases in Bogotá, Colombia, between 2015 and 2021, as notified through the mandatory report to the Public Health Surveillance System (PHSS). METHODS: A retrospective cross-sectional study was conducted. All live births (LB) with a weight ≥500 g, diagnosed with CH with or without goiter (ICD-10 codes E030 and E031, respectively) in Bogotá during 2015-2021 were analyzed. RESULTS: For a total of 201 cases, the prevalence rate was 3.29 cases per 10,000 LB. 92.54 % were classified as isolated cases of CH, 4.48 % syndromic, and 2.98 % polymalformated. A total of 16.92 % was small for gestational age. The mean gestational age was 37.38 weeks (SD 2.76), 26.87 % were preterm births. Among the mothers, 8.96 % suffered from pregnancy-related or chronic diseases, the most common being hypertensive disorders of pregnancy and pre-existant hypothyroidism (without clarity concerning etiology). A total of 66.67 % of cases did not receive treatment after diagnosis. Treatment was established by an average age of 27 days after birth (SD 36.02) and 17 days after case notification to the PHSS (SD 36.13). CONCLUSIONS: Observed prevalence is similar to the rate reported by health authorities in Colombia but inferior to reports from high-income countries, highlighting the importance of improvements in the Colombian LB's screening program. Time to diagnosis and treatment was observed to be prolonged, suggesting that new pathways are required for timely CH treatment.

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Objective: To determine the incidence of congenital hypothyroidism (CH) over a 10-year period at the Reference Service in Neonatal Screening of the state of Rio Grande do Sul (RSNS-RS). Subjects and methods: Historical cohort study including all newborns screened for CH by the RSNS-RS from January 2008 until December 2017. Data of all newborns with neonatal TSH (neoTSH; heel prick test) values ≥ 9 mIU/L were collected. According to neoTSH values, the newborns were allocated into two groups: Group 1 (G1), comprising newborns with neoTSH ≥ 9 mIU/L and serum TSH (sTSH) < 10 mIU/L, and Group 2 (G2), comprising those with neoTSH ≥ 9 mIU/L and sTSH ≥ 10 mIU/L. Results: Of 1,043,565 newborns screened, 829 (0.08%) had neoTSH values ≥ 9 mIU/L. Of these, 284 (39.3%) had sTSH values < 10 mIU/L and were allocated to the G1 group, while 439 (60.7%) had sTSH ≥ 10 mIU/L and were allocated to the G2 group, and 106 (12.7%) were considered missing data. The overall incidence of CH was 42.1 per 100,000 newborns screened (95% confidence interval [CI] 38.5-45.7/100,000) or 1:2377 screened newborns. The sensibility and specificity of neoTSH ≥ 9 mIU/L were 97% and 11%; of neoTSH 12.6 mUI/L, 73% and 85% respectively. Conclusion: In this population, the incidence of permanent and transitory CH was 1:2377 screened newborns. The neoTSH cutoff value adopted during the study period showed excellent sensibility, which matters for a screening test.

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Congenital hypothyroidism (CH) due to thyroglobulin (TG) variants causes very low serum TG levels with normal or enlarged thyroid glands, depending on the severity of the defect, and with autosomal recessive inheritance. The purpose of this study was to functionally characterize p.Cys1281Tyr variant in the TG gene in order to increase our knowledge of the molecular mechanisms associated with CH. In order to find evidence that support the hypothesis that the p.Cys1281Tyr variant would affect the TG folding were performed amino acid prediction, 3D modeling and transient expression analysis in HEK293T cells. 18 of the 21″in silico" algorithms predict a deleterious effect of the p.Cys1281Tyr variant. The full-length 3D model p.Cys1281Tyr TG showed disulfide bond cleavage between the cysteines at positions 1249 and 1281 and rearrangement of the TG structure, while transient expression analysis indicated that p.Cys1281Tyr causes retention of the protein inside the cell. Consequently, these results show that this pathogenic variant makes it impossible for TG to fulfill its function in the biosynthesis process of thyroid hormones, causing CH. In conclusion, our results confirm the pathophysiological importance of misfolding of TG as a consequence of p.Cys1281Tyr variant located in the hinge module/flap region of TG.

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OBJECTIVES: To describe the neurocognitive profile of 458 children with congenital hypothyroidism detected by neonatal screening, followed under the same treatment protocol over 25 years. To correlate estimated full-scale IQ (FSIQ) scores with age at the start of treatment, disease severity, and maternal education. METHODS: Observational, analytical, retrospective, and longitudinal cohort study, that evaluated children detected between 1991 and 2014, who underwent at least one psychometric assessment (WPPSI- R and/or WISC-III). Estimated FSIQ scores are described and correlated with prognosis determinants. RESULTS: Median T4 at diagnosis was 2.8 µg/dL (0.0-16.5), the median age at the start of treatment was 18.5 days (3-309). Maternal education (n = 445): 2.7% of illiteracy, 59.8% with basic education. Estimated FSIQ scores were 88.0 (±11.8) in WPPSI-R (age 5.6 ± 0.5 years) and 84.1 (±13.0) in WISC-III (age 9.1 ± 1.4 years). The intellectual deficit was identified in 11.6%. Correlation between age at the start of treatment and estimated FSIQ was found only in the WPPSI-R test (p = 0.02). Initial T4 and maternal education significantly correlated with estimated FSIQ scores in both tests, with the latter being the most important determining factor. CONCLUSIONS: In this large cohort of mainly low socioeconomic status children, most children achieved normal cognitive levels; however, a significant percentage presented with below-average estimated FSIQ scores and intellectual deficits. Maternal education was the main determining factor in cognitive level followed by hypothyroidism severity.

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Objective: Congenital hypothyroidism (CH) can be permanent (PCH) or transient (TCH). While the importance of thyroxine in myelination of the brain is undisputed, the benefits to neurodevelopmental outcomes of TCH treatment are controversial. Our objectives were to determine predictive factors for PCH and verify its prevalence changes over time. Subjects and methods: A total of 165 children were evaluated at 3 years of age to verify the diagnosis of PCH. 130 were submitted to a two-step cluster analysis, with the aim of grouping them into homogeneous clusters. The mean incidence of PCH and TCH was calculated from 2004 to 2010 and 2011 to 2015. Results: Sixty-six children were diagnosed with PCH, and 99 were diagnosed with TCH. Eighty-one percent of PCH children and all TCH children with thyroid imaging had glands in situ. Eighty children (61.5%) were in Cluster 1, 8 children (6.2%) were in Cluster 2 and 42 children (32.3%) were in Cluster 3. No children had PCH in Cluster 1, while 87.5% of children in Cluster 2 and all children in Cluster 3 had PCH. The most important predictor for PCH was the initial serum TSH, which was marginally higher in importance than the blood spot TSH, followed by the initial serum free T4. The mean incidence of PCH (odds ratio: 1.95, 95% CI 1.36 to 2.95, p < 0.0001) and TCH (odds ratio 1.33, 95%, CI 1.02 to 1.77, p = 0,038) increased over time. Conclusion: The most important PCH predictors are the initial serum TSH and the blood spot TSH. The mean incidence of both PCH and TCH in our series increased.

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Thyroglobulin (TG), the predominant glycoprotein of the thyroid gland, functions as matrix protein in thyroid hormonegenesis. TG deficiency results in thyroid dyshormonogenesis. These variants produce a heterogeneous spectrum of congenital goitre, with an autosomal recessive mode of inheritance. The purpose of this study was to identify and functionally characterize new variants in the TG gene in order to increase the understanding of the molecular mechanisms responsible for thyroid dyshormonogenesis. A total of four patients from two non-consanguineous families with marked alteration of TG synthesis were studied. The two families were previously analysed in our laboratory, only one deleterious allele, in each one, was detected after sequencing the TG gene (c.2359 C > T [p.Arg787*], c.5560 G > T [p.Glu1854*]). These findings were confirmed in the present studies by Next-Generation Sequencing. The single nucleotide coding variants of the TG gene were then analyzed to predict the possible variant causing the disease. The p.Pro2232Leu (c.6695 C > T), identified in both families, showing a low frequency population in gnomAD v2.1.1 database and protein homology, amino acid prediction, and 3D modeling analysis predict a potential pathogenic effect of this variant. We also transiently express p.Pro2232Leu in a full-length rat TG cDNA clone and confirmed that this point variant was sufficient to cause intracellular retention of mutant TG in HEK293T cells. Consequently, each family carried a compound heterozygous for p.Arg787*/p.Pro2232Leu or p.Glu1854*/p.Pro2232Leu variants. In conclusion, our results confirm the pathophysiological importance of altered TG folding as a consequence of missense variants located in the ChEL domain of TG.

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ABSTRACT Objectives: Congenital hypothyroidism (CH) can be permanent (PCH) or transient (TCH). While the importance of thyroxine in myelination of the brain is undisputed, the benefits to neurodevelopmental outcomes of TCH treatment are controversial. Our objectives were to determine predictive factors for PCH and verify its prevalence changes over time. Subjects and methods: A total of 165 children were evaluated at 3 years of age to verify the diagnosis of PCH. 130 were submitted to a two-step cluster analysis, with the aim of grouping them into homogeneous clusters. The mean incidence of PCH and TCH was calculated from 2004 to 2010 and 2011 to 2015. Results: Sixty-six children were diagnosed with PCH, and 99 were diagnosed with TCH. Eighty-one percent of PCH children and all TCH children with thyroid imaging had glands in situ. Eighty children (61.5%) were in Cluster 1, 8 children (6.2%) were in Cluster 2 and 42 children (32.3%) were in Cluster 3. No children had PCH in Cluster 1, while 87.5% of children in Cluster 2 and all children in Cluster 3 had PCH. The most important predictor for PCH was the initial serum TSH, which was marginally higher in importance than the blood spot TSH, followed by the initial serum free T4. The mean incidence of PCH (odds ratio: 1.95, 95% CI 1.36 to 2.95, p < 0.0001) and TCH (odds ratio 1.33, 95%, CI 1.02 to 1.77, p = 0,038) increased over time. Conclusions: The most important PCH predictors are the initial serum TSH and the blood spot TSH. The mean incidence of both PCH and TCH in our series increased.

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ABSTRACT Objective: To determine the incidence of congenital hypothyroidism (CH) over a 10-year period at the Reference Service in Neonatal Screening of the state of Rio Grande do Sul (RSNS-RS). Subjects and methods: Historical cohort study including all newborns screened for CH by the RSNS-RS from January 2008 until December 2017. Data of all newborns with neonatal TSH (neoTSH; heel prick test) values ≥ 9 mIU/L were collected. According to neoTSH values, the newborns were allocated into two groups: Group 1 (G1), comprising newborns with neoTSH ≥ 9 mIU/L and serum TSH (sTSH) < 10 mIU/L, and Group 2 (G2), comprising those with neoTSH ≥ 9 mIU/L and sTSH ≥ 10 mIU/L. Results: Of 1,043,565 newborns screened, 829 (0.08%) had neoTSH values ≥ 9 mIU/L. Of these, 284 (39.3%) had sTSH values < 10 mIU/L and were allocated to the G1 group, while 439 (60.7%) had sTSH ≥ 10 mIU/L and were allocated to the G2 group, and 106 (12.7%) were considered missing data. The overall incidence of CH was 42.1 per 100,000 newborns screened (95% confidence interval [CI] 38.5-45.7/100,000) or 1:2377 screened newborns. The sensibility and specificity of neoTSH ≥ 9 mIU/L were 97% and 11%; of neoTSH 12.6 mUI/L, 73% and 85% respectively. Conclusion: In this population, the incidence of permanent and transitory CH was 1:2377 screened newborns. The neoTSH cutoff value adopted during the study period showed excellent sensibility, which matters for a screening test.

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Abstract Objectives: To describe the neurocognitive profile of 458 children with congenital hypothyroidism detected by neonatal screening, followed under the same treatment protocol over 25 years. To correlate estimated full-scale IQ (FSIQ) scores with age at the start of treatment, disease severity, and maternal education. Methods: Observational, analytical, retrospective, and longitudinal cohort study, that evaluated children detected between 1991 and 2014, who underwent at least one psychometric assessment (WPPSI- R and/or WISC-III). Estimated FSIQ scores are described and correlated with prognosis determinants. Results: Median T4 at diagnosis was 2.8 µg/dL (0.0-16.5), the median age at the start of treatment was 18.5 days (3-309). Maternal education (n = 445): 2.7% of illiteracy, 59.8% with basic education. Estimated FSIQ scores were 88.0 (±11.8) in WPPSI-R (age 5.6 ± 0.5 years) and 84.1 (±13.0) in WISC-III (age 9.1 ± 1.4 years). The intellectual deficit was identified in 11.6%. Correlation between age at the start of treatment and estimated FSIQ was found only in the WPPSI-R test (p = 0.02). Initial T4 and maternal education significantly correlated with estimated FSIQ scores in both tests, with the latter being the most important determining factor. Conclusions: In this large cohort of mainly low socioeconomic status children, most children achieved normal cognitive levels; however, a significant percentage presented with below-average estimated FSIQ scores and intellectual deficits. Maternal education was the main determining factor in cognitive level followed by hypothyroidism severity.

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Abstract Introduction Perinatal hypothyroidism has a negative repercussion on the development and maturation of auditory system function. However, its long-term effect on auditory function remains unsettled. Objective To evaluate the effect of prenatal hypothyroidism on the auditory function of adult offspring in rats. Methods Pregnant Wistar rats were given the antithyroid drug methimazole (0.02%-1-methylimidazole-2-thiol- MMI) in drinking water, ad libitum, from gestational day (GD) 9 to postnatal day 15 (PND15). Anesthetized offspring from MMI-treated dams (OMTD) and control rats were evaluated by tympanometry, distortion product otoacoustic emission (DPOAE), and auditory brainstem response (ABR) at PNDs 30, 60, 90, and 120. Results Our data demonstrated no middle ear dysfunction, with the OMTD compliance lower than that of the control group. The DPOAE revealed the absence of outer hair cells function, and the ABR showed normal integrity of neural auditory pathways up to brainstem level in the central nervous system. Furthermore, in the OMTD group, hearing loss was characterized by a higher electrophysiological threshold. Conclusion Our data suggest that perinatal hypothyroidism leads to irreversible damage to cochlear function in offspring.

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Introduction Perinatal hypothyroidism has a negative repercussion on the development and maturation of auditory system function. However, its long-term effect on auditory function remains unsettled. Objective To evaluate the effect of prenatal hypothyroidism on the auditory function of adult offspring in rats. Methods Pregnant Wistar rats were given the antithyroid drug methimazole (0.02% -1-methylimidazole-2-thiol- MMI) in drinking water, ad libitum, from gestational day (GD) 9 to postnatal day 15 (PND15). Anesthetized offspring from MMI-treated dams (OMTD) and control rats were evaluated by tympanometry, distortion product otoacoustic emission (DPOAE), and auditory brainstem response (ABR) at PNDs 30, 60, 90, and 120. Results Our data demonstrated no middle ear dysfunction, with the OMTD compliance lower than that of the control group. The DPOAE revealed the absence of outer hair cells function, and the ABR showed normal integrity of neural auditory pathways up to brainstem level in the central nervous system. Furthermore, in the OMTD group, hearing loss was characterized by a higher electrophysiological threshold. Conclusion Our data suggest that perinatal hypothyroidism leads to irreversible damage to cochlear function in offspring.

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Congenital iodide transport defect is an uncommon autosomal recessive disorder caused by loss-of-function variants in the sodium iodide symporter (NIS)-coding SLC5A5 gene and leading to dyshormonogenic congenital hypothyroidism. Here, we conducted a targeted next-generation sequencing assessment of congenital hypothyroidism-causative genes in a cohort of nine unrelated pediatric patients suspected of having a congenital iodide transport defect based on the absence of 99mTc-pertechnetate accumulation in a eutopic thyroid gland. Although, unexpectedly, we could not detect pathogenic SLC5A5 gene variants, we identified two novel compound heterozygous TG gene variants (p.Q29* and c.177-2A>C), three novel heterozygous TG gene variants (p.F1542Vfs*20, p.Y2563C, and p.S523P), and a novel heterozygous DUOX2 gene variant (p.E1496Dfs*51). Splicing minigene reporter-based in vitro assays revealed that the variant c.177-2A>C affected normal TG pre-mRNA splicing, leading to the frameshift variant p.T59Sfs*17. The frameshift TG variants p.T59Sfs*17 and p.F1542Vfs*20, but not the DUOX2 variant p.E1496Dfs*51, were predicted to undergo nonsense-mediated decay. Moreover, functional in vitro expression assays revealed that the variant p.Y2563C reduced the secretion of the TG protein. Our investigation revealed unexpected findings regarding the genetics of congenital iodide transport defects, supporting the existence of yet to be discovered mechanisms involved in thyroid hormonogenesis.

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Helicobacter pylori (H. pylori) infection leads to a systemic low-grade inflammatory state and has been associated causally with a diverse spectrum of extra-gastric disorders. Among them, the infection has been involved in the pathogenesis of autoimmune thyroid disease (ATD), but only one study had evaluated children. Therefore, a cross-sectional study was conducted in a cohort of 142 children and adolescents, randomly assessed among those followed up for thyroid diseases in a university pediatric endocrinology service: 106 with congenital hypothyroidism (CH) and 36 with ATD. All children were asymptomatic, under strict control on levothyroxine replacement, and reported no other diseases or use of drugs. Helicobacter pylori status was evaluated by the 13C-Urea Breath Test (13C-UBT). Antithyroid antibodies (ATPO, antiTg, and TRAb) and serum thyroid hormones (TSH, free T4, and T3) were assessed by standard assays. Data were analyzed in logistic models by the SPSS statistical software package, and a p-value ≤ 0.05 was considered statistically significant. The prevalence of H. pylori infection was 19.44% in children with ATD. Neither the gender nor the serum levels of thyroid hormones and antithyroid antibodies were associated with the H. pylori-positive status. Thirty-seven (34.90%) children with CH were infected with H. pylori. The mean T3 serum level (3.59 ± 0.84) was significantly lower (p = 0.001) in the infected children than in those free from the infection (3.95 ± 0.89), association that remained after adjustment for the other variables in the multivariate analysis. Because no difference was observed in the levels of TSH and T4, the results indicate that the infection may lead to impairment in the thyroid hormonal balance, but not in the hypothalamic-pituitary-thyroid axis function. In as much as H. pylori infection is highly widespread and the prevalence of CH is also not negligible, additional studies are required to confirm our results and to identify the involved mechanisms.

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Introduction: Congenital hypothyroidism is the leading cause of preventable cognitive disability in the world. Therefore, screening programs have been developed in order to reduce the neurological sequelae associated with this pathology. Objective: To describe the demographic characteristics, the treatment, and the follow-up of patients diagnosed with congenital hypothyroidism in the screening program at the San Ignacio University Hospital in Bogotá, Colombia. Materials and methods: We conducted an observational cross-sectional study. The study population was patients diagnosed with congenital hypothyroidism at the Hospital between 2001 and 2017. Results: Fourteen of the 19 patients diagnosed with congenital hypothyroidism in the hospital screening program were contacted. All of the patients had schooling, most of them had adequate weight and height, and two had short stature. In most of them, the etiological diagnosis was thyroid hypoplasia, and all began the treatment and follow-up in an adequate way. The most frequent alteration in the neuropsychological tests was in the memory domain and the level of maternal education could be related to an abnormal result in the domain of language. Conclusion: In our study, alterations in the memory tests were the most prevalent; however, due to the design and type of study, more research is required to establish associations. A low frequency of abnormal growth and puberty was found.

Introducción. El hipotiroidismo congénito es la principal causa de discapacidad cognitiva prevenible en el mundo. Para detectarlo se han desarrollado programas de tamización, con el fin de disminuir las secuelas neurológicas asociadas. El seguimiento y las evaluaciones a mediano y largo plazo de estos pacientes son fundamentales. Objetivo. Describir las características demográficas, el tratamiento y el seguimiento de los pacientes con diagnóstico de hipotiroidismo congénito en el marco del programa de tamización del Hospital Universitario de San Ignacio en Bogotá, Colombia. Materiales y métodos. Se hizo un estudio observacional de corte transversal. La población de estudio fueron los pacientes con diagnóstico de hipotiroidismo congénito en el Hospital Universitario San Ignacio entre el 2001 y el 2017. Resultados. Se contactó a 14 de los 19 pacientes con diagnóstico de hipotiroidismo congénito en el programa de tamizaje del Hospital. Los 14 niños estaban escolarizados, y la mayoría tenía el peso y la talla adecuados, aunque hubo talla baja en dos de ellos. El diagnóstico etiológico más frecuente fue hipoplasia tiroidea. Todos empezaron su tratamiento y el seguimiento oportunamente. La alteración más frecuente en las pruebas neuropsicológicas se registró en la memoria. El nivel de educación materno podría estar relacionado con el resultado anormal en el dominio del lenguaje. Conclusión. En el presente estudio, las alteraciones en las pruebas de memoria fueron las más prevalentes; sin embargo, dado el diseño y el tipo de estudio, se requieren más investigaciones que permitan establecer asociaciones. El crecimiento y el desarrollo puberal presentaron una frecuencia baja de alteraciones.

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