Search

Introduction: Congenital hypothyroidism (CH) is the most common preventable cause of mental retardation, and the two important causes of CH are thyroid dysgenesis and dyshormonogenesis. Thyroid imaging is an integral part of identifying the specific aetiology of CH. We aimed to study the aetiological profile of CH and compare the imaging findings of ultrasonography (USG) and nuclear scintigraphy. Methods: It is a prospective, cross-sectional study conducted over 3 years. The clinical, USG, and technetium-99 m (99 mTc) scintigraphy reports of CH children were analysed. Results: Sixty-two CH children were included in the study with an equal male-to-female ratio (1.1:1). There was a significant association between parental consanguinity and CH observed in 35.5% of cases (P = 0.006). In USG neck, 44 (71%) had normal and/or enlarged thyroid glands at the eutopic location, 16 (27.4%) cases had an absent gland, and ectopic as well as hypoplastic unilateral gland was observed in one (1.6%) each. Among 35 children, who underwent scintigraphy, 12 (34.3%) had absent uptake, 4 (11.4%) had ectopic uptake, and 1 (2.8%) child had unilateral normal uptake. The remaining 18 (51.5%) children, whose scintigraphy showed normal or avid uptakes, were diagnosed with dyshormonogenesis. Three cases were diagnosed as apparent athyreosis. Conclusion: Dyshormonogeneis is the more commonly observed etiology of CH as compared to thyroid agenesis in the present study. A combined imaging approach with scintigraphy and USG is needed to delineate the specific etiology of CH. We need long-term Indian data to know the paradigm shift in the etiological pattern of CH as compared to Western studies.

Introduction: Congenital hypothyroidism (CH) is the most common preventable cause of mental retardation, and the two important causes of CH are thyroid dysgenesis and dyshormonogenesis. Thyroid imaging is an integral part of identifying the specific aetiology of CH. We aimed to study the aetiological profile of CH and compare the imaging findings of ultrasonography (USG) and nuclear scintigraphy. Methods: It is a prospective, cross-sectional study conducted over 3 years. The clinical, USG, and technetium-99 m (99 mTc) scintigraphy reports of CH children were analysed. Results: Sixty-two CH children were included in the study with an equal male-to-female ratio (1.1:1). There was a significant association between parental consanguinity and CH observed in 35.5% of cases (P = 0.006). In USG neck, 44 (71%) had normal and/or enlarged thyroid glands at the eutopic location, 16 (27.4%) cases had an absent gland, and ectopic as well as hypoplastic unilateral gland was observed in one (1.6%) each. Among 35 children, who underwent scintigraphy, 12 (34.3%) had absent uptake, 4 (11.4%) had ectopic uptake, and 1 (2.8%) child had unilateral normal uptake. The remaining 18 (51.5%) children, whose scintigraphy showed normal or avid uptakes, were diagnosed with dyshormonogenesis. Three cases were diagnosed as apparent athyreosis. Conclusion: Dyshormonogeneis is the more commonly observed etiology of CH as compared to thyroid agenesis in the present study. A combined imaging approach with scintigraphy and USG is needed to delineate the specific etiology of CH. We need long-term Indian data to know the paradigm shift in the etiological pattern of CH as compared to Western studies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.

Abstract Background Primary congenital hypothyroidism (CH) is a rare endocrine disorder in cats with a largely unknown genetic cause. Objectives Describe the clinical presentation of CH in 11 affected cats and identify the causal genetic variant. Animals Eleven CH‐cats from 10 unrelated families, 11 CH‐free family members, 21 unrelated CH‐free cats, and 155 unrelated nondiagnosed cats from different breeds. Methods Case control study of CH‐cats and their siblings (2019‐2021). Diagnosis was based on low to low‐normal serum thyroxine (T4) concentrations, high thyroid‐stimulating hormone (TSH) concentrations and clinical signs compatible with CH. We identified the causal variant using Sanger sequencing, genotyping via PCR‐RFLP and variant interpretation using ACMG/AMP guidelines. Results All CH‐cats (5 weeks‐8 years) had disproportionate dwarfism. A goiter was not palpable in all. Thyroid scintigraphy with radiopertechnetate showed abnormally high uptake by thyroid glands, whereas scintigraphy with radioiodine showed abnormally low uptake, compatible with a defect in iodine organification by thyroid peroxidase (TPO). All cases were homozygous for TPO variant XM_006930524.4:c.430G>A(p.(Gly144Arg)), while none of the CH‐free cats were. All sampled parents were heterozygous for this recessive variant. This variant was found in 15 cat breeds with an estimated allele frequency of 9%. Conclusions and Clinical Importance Disproportionate dwarfism, abnormally high TSH and abnormally low to low‐normal T4 concentrations are diagnostic for CH in cats. All cases had dyshormonogenesis demonstrated by thyroid scintigraphy. This novel TPO missense variant (not described in humans) causes CH in cats and awareness of it can assist in diagnosis and breeding.

ABSTRACT Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder and one of the most common preventable causes of intellectual disability in the world. CH may be due to developmental or functional thyroid defects (primary or peripheral CH) or be hypothalamic‐pituitary in origin (central CH). In most cases, primary CH is caused by a developmental malformation of the gland (thyroid dysgenesis, TD) or by a defect in thyroid hormones synthesis (dyshormonogenesis, DH). TD represents about 65% of CH and a genetic cause is currently identified in fewer than 5% of patients. The remaining 35% are cases of DH and are explained with certainty at the molecular level in more than 50% of cases. The etiology of CH is mostly unknown and may include contributions from individual and environmental factors. In recent years, the detailed phenotypic description of patients, high‐throughput sequencing technologies, and the use of animal models have made it possible to discover new genes involved in the development or function of the thyroid gland. This paper reviews all the genetic causes of CH. The modes by which CH is transmitted will also be discussed, including a new oligogenic model. CH is no longer simply a dominant disease for cases of CH due to TD and recessive for cases of CH due to DH, but a far more complex disorder.

Aim:Congenital hypothyroidism (CH) is one of the most common endocrinological problems in the neonatal period. CH, which occurs in 1:3,000-4,000 births, is a preventable cause of mental retardation. In the literature, the most common cause of CH is dysgenesis of the thyroid gland, followed by thyroid dyshormonogenesis. We aimed to determine the prevalence of permanent (P-CH) and transient (T-CH) CH in cases followed up with a diagnosis of CH and to identify a prediction method for persistency.Materials and Methods:We retrospectively analyzed the medical records of 105 children with CH. TSH levels in a screening program, TSH and fT4 levels of the first venous sample, 10-15th day of treatment, monthly in the first 6 months, 2-3 monthly until 18th months, and 6-monthly until 3 years of age were recorded. L-T4 doses (per microgram per body weight) in each visit were also recorded.Results:From the 105 children (58 males, 47 females) enrolled in this study, 38 (36.2 %) were referred from the National Newborn Screening Program. Treatment was discontinued during the 3rd year follow-up period in 44 (41.9 %) of the cases with normal thyroid gland morphology. L-thyroxine (L-T4) therapy was discontinued at a median age of 1.9+-1.08 years.TSH levels at the time of diagnosis were higher in the P-CH group, but this difference was not statistically significant (p=0.165). At the sixth month, first and second years of follow-up, L-T4 doses were significantly higher in the P-CH than in the T-CH group (p

Background and aims: Although the significance of primary congenital hypothyroidism (CH) is supported by an increasing amount of evidence, the clinical and genetic characteristics of this condition are still poorly understood. This study aimed to explore the underlying genetic etiologies in a cohort of primary CH patients. Subjects and Methods: The clinical data of 33 patients with primary CH were collected and analyzed via a cross-sectional study. Genetic analysis was performed by high-throughput sequencing and Sanger verification, and the pathogenicity of the novel missense variants was predicted using a variety of comprehensive bioinformatic tools. Results: Among the 33 patients, 22 (22/33, 66.7%) harbored pathogenic variants in the causative genes of thyroid dysgenesis or dyshormonogenesis, with DUOX2 (15/33, 45.5%) topping the list, followed by TG, TPO, DUOXA2 and PAX8. Four novel genetic variants were detected, including a pathogenic frameshift and three likely pathogenic missense variants. Positive neonatal screening for TSH, neonatal jaundice and abnormal thyroid morphology were the main positive findings among all cases. Although 31 of the total 33 CH patients exhibited normal anthropometric and social performance, the other 2 had poor prognosis in this study. Conclusions: This study reported 33 new CH patients bearing four novel genetic variants, which enriched the variant spectrum of CH genes. In this cohort, genetic factors causing thyroid dyshormonogenesis were the main etiologies of CH development. Most patients exhibited a favorable prognosis; however, systematic management remains a challenge in achieving improved clinical outcomes for CH patients. [ABSTRACT FROM AUTHOR]

Background: Primary congenital hypothyroidism (CH) is a rare endocrine disorder in cats with a largely unknown genetic cause. Objectives: Describe the clinical presentation of CH in 11 affected cats and identify the causal genetic variant. Animals: Eleven CH‐cats from 10 unrelated families, 11 CH‐free family members, 21 unrelated CH‐free cats, and 155 unrelated nondiagnosed cats from different breeds. Methods: Case control study of CH‐cats and their siblings (2019‐2021). Diagnosis was based on low to low‐normal serum thyroxine (T4) concentrations, high thyroid‐stimulating hormone (TSH) concentrations and clinical signs compatible with CH. We identified the causal variant using Sanger sequencing, genotyping via PCR‐RFLP and variant interpretation using ACMG/AMP guidelines. Results: All CH‐cats (5 weeks‐8 years) had disproportionate dwarfism. A goiter was not palpable in all. Thyroid scintigraphy with radiopertechnetate showed abnormally high uptake by thyroid glands, whereas scintigraphy with radioiodine showed abnormally low uptake, compatible with a defect in iodine organification by thyroid peroxidase (TPO). All cases were homozygous for TPO variant XM_006930524.4:c.430G>A(p.(Gly144Arg)), while none of the CH‐free cats were. All sampled parents were heterozygous for this recessive variant. This variant was found in 15 cat breeds with an estimated allele frequency of 9%. Conclusions and Clinical Importance: Disproportionate dwarfism, abnormally high TSH and abnormally low to low‐normal T4 concentrations are diagnostic for CH in cats. All cases had dyshormonogenesis demonstrated by thyroid scintigraphy. This novel TPO missense variant (not described in humans) causes CH in cats and awareness of it can assist in diagnosis and breeding. [ABSTRACT FROM AUTHOR]

Thyroglobulin gene abnormalities cause thyroid dyshormonogenesis. A 6-yr-old boy of consanguineous parents presented with a large goiter and mild hypothyroidism (thyroid-stimulating hormone [TSH] 7.2 μIU/mL, free T3 [FT3] 3.4 pg/mL, free T4 [FT4] 0.6 ng/dL). Despite levothyroxine (LT4) administration and normal TSH levels, the goiter progressed slowly and increased rapidly in size at the onset of puberty. Thyroid scintigraphy revealed a remarkably high 123I uptake of 75.2%, with a serum thyroglobulin level of 13 ng/ml, which was disproportionately low for the goiter size. DNA sequencing revealed a novel homozygous missense variant, c.434G>A [p.Gly145Glu], in the thyroglobulin gene. Goiter growth was suppressed by increasing the LT4 dose. Thyroidectomy was performed at 17-yr-of-age. Thyroglobulin analysis of the thyroid tissue detected mutant thyroglobulin present in the endoplasmic reticulum, demonstrating that thyroglobulin transport from the endoplasmic reticulum to the Golgi apparatus was impaired by the Gly145Glu variant. During the clinical course, an elevated FT3/FT4 ratio was observed along with thyroid enlargement. A high FT3/FT4 ratio and goiter seemed to be compensatory responses to impaired hormone synthesis. Thyroglobulin defects with goiter should be treated with LT4, even if TSH levels are normal. [ABSTRACT FROM AUTHOR]

Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder and one of the most common preventable causes of intellectual disability in the world. CH may be due to developmental or functional thyroid defects (primary or peripheral CH) or be hypothalamic‐pituitary in origin (central CH). In most cases, primary CH is caused by a developmental malformation of the gland (thyroid dysgenesis, TD) or by a defect in thyroid hormones synthesis (dyshormonogenesis, DH). TD represents about 65% of CH and a genetic cause is currently identified in fewer than 5% of patients. The remaining 35% are cases of DH and are explained with certainty at the molecular level in more than 50% of cases. The etiology of CH is mostly unknown and may include contributions from individual and environmental factors. In recent years, the detailed phenotypic description of patients, high‐throughput sequencing technologies, and the use of animal models have made it possible to discover new genes involved in the development or function of the thyroid gland. This paper reviews all the genetic causes of CH. The modes by which CH is transmitted will also be discussed, including a new oligogenic model. CH is no longer simply a dominant disease for cases of CH due to TD and recessive for cases of CH due to DH, but a far more complex disorder. [ABSTRACT FROM AUTHOR]

Aim: Congenital hypothyroidism (CH) is one of the most common endocrinological problems in the neonatal period. CH, which occurs in 1:3,000-4,000 births, is a preventable cause of mental retardation. In the literature, the most common cause of CH is dysgenesis of the thyroid gland, followed by thyroid dyshormonogenesis. We aimed to determine the prevalence of permanent (P-CH) and transient (T-CH) CH in cases followed up with a diagnosis of CH and to identify a prediction method for persistency. Materials and Methods: We retrospectively analyzed the medical records of 105 children with CH. TSH levels in a screening program, TSH and fT4 levels of the first venous sample, 10-15th day of treatment, monthly in the first 6 months, 2-3 monthly until 18th months, and 6-monthly until 3 years of age were recorded. L-T4 doses (per microgram per body weight) in each visit were also recorded. Results: From the 105 children (58 males, 47 females) enrolled in this study, 38 (36.2 %) were referred from the National Newborn Screening Program. Treatment was discontinued during the 3rd year follow-up period in 44 (41.9 %) of the cases with normal thyroid gland morphology. L-thyroxine (L-T4) therapy was discontinued at a median age of 1.9+-1.08 years. TSH levels at the time of diagnosis were higher in the P-CH group, but this difference was not statistically significant (p=0.165). At the sixth month, first and second years of follow-up, L-T4 doses were significantly higher in the P-CH than in the T-CH group (p<0.001, p<0.001, p<0.001 respectively). TSH levels were also higher in the P-CH group than in the T-CH group (p=0.123, p=0.038, p=0.049 respectively). Consistent with these results, measured fT4 levels were found to be lower in the P-CH group compared to the T-CH group (p=0.431, p=0.361, p=0.028 respectively). Conclusion: L-T4 doses at 6, 12 and 24 months may predict transient hypothyroidism in patients with normal thyroid gland morphology before 36 months. [ABSTRACT FROM AUTHOR]

Abstract Indications and administration of intra‐amniotic infusions of L‐thyroxine in the context of non‐immune fetal hypothyroidism with goiter lack of standardization. Systematic follow‐up of clinical features related to thyroid hormonal homeostasis may be useful to evaluate their efficiency and develop standardized management guidelines.

Indications and administration of intra‐amniotic infusions of L‐thyroxine in the context of non‐immune fetal hypothyroidism with goiter lack of standardization. Systematic follow‐up of clinical features related to thyroid hormonal homeostasis may be useful to evaluate their efficiency and develop standardized management guidelines. [ABSTRACT FROM AUTHOR]

The prevalence of congenital hypothyroidism is high in India at 5.7 per 10,000 infants and an incidence rate of 1 in 244 in Kerala state. Neonatal mass screening programs have been largely successful in early diagnosis of congenital hypothyroidism. Both, very young and advanced maternal age are considered at risk for adverse pregnancy outcomes which in turn may be a factor for development of congenital hypothyroidism in neonates. The studies related to the role of maternal age as a risk factor for development of congenital hypothyroidism are minimal. Not much studies are available which analyse the association of adequately treated maternal hypothyroidism on the neonatal thyroid dysgenesis and other causes of neonatal congenital hypothyroidism. The study collected data about the age and thyroid status of 120 mothers of neonates in which n=60 cases were Mothers of the neonates with congenital hypothyroidism (TSH > 15.2 µIU/mL) and n=60 controls mothers of euthyroid healthy neonates (TSH ≤ 15.2 µIU/mL). Data collected regarding the maternal thyroid status was evaluated in the antenatal period during first trimester and neonatal thyroid status was evaluated at birth from cord blood. All the mothers included in the study with hypothyroidism (both cases and controls) were either already on treatment or were treated appropriately during pregnancy. The mean maternal age in cases (n=60) was 34.8± 5.7 years while that in control (n=60) was 25.43± 4.3 years. There is a high statistically significant (p<0.0001) increase in maternal age in cases compared to controls. The odds of being ≥35 years were higher in mothers of neonates with congenital hypothyroidism as compared to mothers of normal children with Odds ratio of 5.06; and highly significant P value 0.0001. The odds of mothers of neonates with congenital hypothyroidism having hypothyroidism, compared mothers of euthyroid neonates having hypothyroidism is not statistically significant with Odds ratio of 3.14; with P value 0.06. The risks of acquiring congenital hypothyroidism in neonates increase with advanced maternal age. Neonatal TSH levels are dynamic and are affected by several factors including maternal hypothyroidism. Pre-conceptional consultation and evaluation of thyroid status as well as first trimester universal screening and adequate treatment of maternal hypothyroidism may play an effective role in decreasing the incidence of neonatal congenital hypothyroidism, especially in high risk pregnancies due to advanced maternal age. [ABSTRACT FROM AUTHOR]

ObjectiveTo elucidate the molecular cause in a well-characterized cohort of patients with Congenital Hypothyroidism (CH) and Dyshormonogenesis (DH) by using targeted next-generation sequencing (TNGS).Study designWe studied 19 well-characterized patients diagnosed with CH and DH by targeted NGS including genes involved in thyroid hormone production. The pathogenicity of novel mutations was assessed based on in silico prediction tool results, functional studies when possible, variant location in important protein domains, and a review of the recent literature.ResultsTNGS with variant prioritization and detailed assessment identified likely disease-causing mutations in 10 patients (53%). Monogenic defects most often involved TG, followed by DUOXA2, DUOX2, and NIS and were usually homozygous or compound heterozygous. Our review shows the importance of the detailed phenotypic description of patients and accurate analysis of variants to provide a molecular diagnosis.ConclusionsIn a clinically well-characterized cohort, TNGS had a diagnostic yield of 53%, in accordance with previous studies using a similar strategy. TG mutations were the most common genetic defect. TNGS identified gene mutations causing DH, thereby providing a rapid and cost-effective genetic diagnosis in patients with CH due to DH.

Neonatal screening in Macedonia detects congenital hypothyroidism (CH) with an incidence of 1 in 1,585, and more than 50% of cases exhibit a normally located gland-in-situ (GIS). Monogenic mutations causing dyshormonogenesis may underlie GIS CH; additionally, a small proportion of thyroid hypoplasia has a monogenic cause, such as TSHR and PAX8 defects. The genetic architecture of Macedonian CH cases has not previously been studied. We recruited screening-detected, non-syndromic GIS CH or thyroid hypoplasia cases (n = 40) exhibiting a spectrum of biochemical thyroid dysfunction ranging from severe permanent to mild transient CH and including 11 familial cases. Cases were born at term, with birth weight >3,000 g, and thyroid morphologies included goiter (n = 11), thyroid hypoplasia (n = 6), and apparently normal-sized thyroid. A comprehensive, phenotype-driven, Sanger sequencing approach was used to identify genetic mutations underlying CH, by sequentially screening known dyshormonogenesis-associated genes and TSHR in GIS cases and TSHR and PAX8 in cases with thyroid hypoplasia. Potentially pathogenic variants were identified in 14 cases, of which four were definitively causative; we also detected digenic variants in three cases. Seventeen variants (nine novel) were identified in TPO (n = 4), TG (n = 3), TSHR (n = 4), DUOX2 (n = 4), and PAX8 (n = 2). No mutations were detected in DUOXA2, NIS, IYD, and SLC26A7. The relatively low mutation frequency suggests that factors other than recognized monogenic causes (oligogenic variants, environmental factors, or novel genes) may contribute to GIS CH in this region. Future non–hypothesis-driven, next-generation sequencing studies are required to confirm these findings.

Thyroid dyshormonogenesis is characterized by impairment in one of the several stages of thyroid hormone synthesis and accounts for 10%–15% of congenital hypothyroidism (CH). Seven genes are known to be associated with thyroid dyshormonogenesis: SLC5A5 (NIS), SCL26A4 (PDS), TG, TPO, DUOX2, DUOXA2, and IYD (DHEAL1). Depending on the underlying mechanism, CH can be permanent or transient. Inheritance is usually autosomal recessive, but there are also cases of autosomal dominant inheritance. In this review, we describe the molecular basis, clinical presentation, and genetic diagnosis of CH due to thyroid dyshormonogenesis, with an emphasis on the benefits of targeted exome sequencing as an updated diagnostic approach.

Objective: To elucidate the molecular cause in a well-characterized cohort of patients with Congenital Hypothyroidism (CH) and Dyshormonogenesis (DH) by using targeted next-generation sequencing (TNGS). Study design: We studied 19 well-characterized patients diagnosed with CH and DH by targeted NGS including genes involved in thyroid hormone production. The pathogenicity of novel mutations was assessed based on in silico prediction tool results, functional studies when possible, variant location in important protein domains, and a review of the recent literature. Results: TNGS with variant prioritization and detailed assessment identified likely disease-causing mutations in 10 patients (53%). Monogenic defects most often involved TG , followed by DUOXA2 , DUOX2 , and NIS and were usually homozygous or compound heterozygous. Our review shows the importance of the detailed phenotypic description of patients and accurate analysis of variants to provide a molecular diagnosis. Conclusions: In a clinically well-characterized cohort, TNGS had a diagnostic yield of 53%, in accordance with previous studies using a similar strategy. TG mutations were the most common genetic defect. TNGS identified gene mutations causing DH, thereby providing a rapid and cost-effective genetic diagnosis in patients with CH due to DH. [ABSTRACT FROM AUTHOR]

Objective: Congenital hypothyroidism (CH) is a common cause of preventable severe neurocognitive impairment in children. Previously conducted studies describing the natural history of CH in Saudi Arabia were either of shorter duration or a limited number of patients. In this study, we aim to assess our experience in the clinical course and therapeutic outcome of CH in two large tertiary centers in Saudi Arabia. Methods: This is a retrospective chart review of patients <18 years of age diagnosed with CH at King Abdulaziz Medical City in Jeddah and Riyadh, Saudi Arabia, between 2000 and 2018. Data were collected from the patients’ medical records, including epidemiological, clinical, laboratory, and radiological features as well as a long-term outcome of CH. Statistical analysis was carried out using the JMP statistical software. This study was approved by the Institutional Review Board (IRB) at King Abdullah International Medical Research Center (KAIMRC). Results: Out of the 71 cases, 53.5% were female, and 80.3% of these cases were diagnosed in the 1st week of life. The estimated incidence of CH is 1:2470 in the two study centers. Ectopic thyroid (43%, n = 25/58), dyshormonogenesis (34.5%, n = 20/58), and thyroid agenesis and hypoplasia (22.4%, n = 13/58). Learning difficulty was significantly associated with delayed treatment onset (P = 0.044) and lower compliance with treatment (P = 0.001). Conclusion: In our study, the incidence of dyshormonogenesis in CH is higher than international rates (34.5% vs. 20%), possibly because of consanguinity. Effective neonatal screening program facilitates early diagnosis that leads to prompt management of CH and avoidance of long-term outcome of neurocognitive impairment. [ABSTRACT FROM AUTHOR]

Fetal goitrous hypothyroidism is a rare condition associated with important obstetrical, neonatal complications, and neurodevelopmental impairments. Prenatal treatment remains controversial, and the risk to benefit ratio must be accurately assessed and considered for individualized management. The objective of this review was to evaluate the feasibility, safety, and effectiveness of the conservative in utero treatment of fetal goitrous hypothyroidism. In total, 25 reports that met our inclusion criteria were selected and the management of 38 cases was analyzed. Prenatal diagnosis consisted mainly of ultrasonographic findings. Fetal thyroid status was assessed by cordocentesis. Prenatal treatment varied widely in terms of levothyroxine (LT4) route of administration, dosage, number of injections, and frequency. Although different regimens and routes of administration were proposed, they seem to have similar results regarding fetal goiter reduction and thyroid status at birth. At birth, most babies had hypothyroidism, but the long-term follow-up indicated a normal psycho-neuromotor development. Our data confirm the feasibility of conservative treatment with LT4 for fetal goitrous hypothyroidism. Further studies are needed to determine the optimal management of this disorder. [ABSTRACT FROM AUTHOR]

Neonatal screening in Macedonia detects congenital hypothyroidism (CH) with an incidence of 1 in 1,585, and more than 50% of cases exhibit a normally located gland- in-situ (GIS). Monogenic mutations causing dyshormonogenesis may underlie GIS CH; additionally, a small proportion of thyroid hypoplasia has a monogenic cause, such as TSHR and PAX8 defects. The genetic architecture of Macedonian CH cases has not previously been studied. We recruited screening-detected, non-syndromic GIS CH or thyroid hypoplasia cases (n = 40) exhibiting a spectrum of biochemical thyroid dysfunction ranging from severe permanent to mild transient CH and including 11 familial cases. Cases were born at term, with birth weight >3,000 g , and thyroid morphologies included goiter (n = 11), thyroid hypoplasia (n = 6), and apparently normal-sized thyroid. A comprehensive, phenotype-driven, Sanger sequencing approach was used to identify genetic mutations underlying CH, by sequentially screening known dyshormonogenesis-associated genes and TSHR in GIS cases and TSHR and PAX8 in cases with thyroid hypoplasia. Potentially pathogenic variants were identified in 14 cases, of which four were definitively causative; we also detected digenic variants in three cases. Seventeen variants (nine novel) were identified in TPO (n = 4), TG (n = 3), TSHR (n = 4), DUOX2 (n = 4), and PAX8 (n = 2). No mutations were detected in DUOXA2, NIS, IYD , and SLC26A7. The relatively low mutation frequency suggests that factors other than recognized monogenic causes (oligogenic variants, environmental factors, or novel genes) may contribute to GIS CH in this region. Future non–hypothesis-driven, next-generation sequencing studies are required to confirm these findings. [ABSTRACT FROM AUTHOR]

Congenital hypothyroidism (CH) occurs due to thyroid dysgenesis, thyroid ectopy, and dyshormonogenesis. A proportion of CH is transient which might be due to iodine deficiency/excess or maternal antibody-mediated. Certain forms of dyshormonogenetic defects may cause transient hypothyroidism. Here is a report of a neonate with overt clinical and biochemical hypothyroidism, who on evaluation was found to have dyshormonogenesis with a homozygous mutation in dual oxidase 2 (DUOX2) gene. During infancy, she became euthyroid. Severe in utero deficiency of thyroid hormone, very short duration of hypothyroidism and first-reported mutation of the DUOX2 gene in the Indian subcontinent were interesting features in this infant. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives To describe the findings of thyroid ultrasonography (T-US), its contribution to diagnose congenital hypothyroidism (CH) and the best time to perform it. Subjects and methods Forty-four patients with CH were invited to undergo T-US and 41 accepted. Age ranged from 2 months to 45 years; 23 patients were females. All were treated with L-thyroxine; 16 had previously undergone scintigraphy and 30 had previous T-US, which were compared to current ones. Results At the current T-US, the thyroid gland was not visualized in its normal topography in 10 patients (24.5%); 31 T-US showed topic thyroid, 17 with normal or increased volume due to probable dyshormonogenesis, 13 cases of hypoplasia and one case of left-lobe hemiagenesis. One patient had decreased volume due to central hypothyroidism. Scintigraphy scans performed 3-4 years earlier showed 100% agreement with current results. Comparisons with previous T-US showed concordant results regarding thyroid location, but a decrease in current volume was observed in eight due to the use of L-thyroxine, calling the diagnosis of hypoplasia into question. Conclusions The role of T-US goes beyond complementing scintigraphy results. It allows inferring the etiology of CH, but it must be performed in the first months of life. An accurate diagnosis of CH will be attained with molecular study and the T-US can guide this early assessment, without therapy withdrawal.

Congenital hypothyroidism (CH) is the one of the most common preventable cause of mental retardation. In the majority of patients, CH is caused by an abnormal development of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis. The clinical features of congenital hypothyroidism are so subtle that many newborn infants remain undiagnosed at birth and delayed diagnosis leads to the most severe outcome of CH, mental retardation, emphasizing the importance of neonatal screening. Dried capillary blood is used for screening and it is taken from heel prick optimally between 2 and 5 days of age. Blood spot TSH or thyroxine (T4) or both are being used for CH screening in different programs around the world. Neonates with abnormal thyroid screening tests should be recalled immediately for examination and a venipuncture blood sample should be drawn for confirmatory serum testing. Confirmatory serum should be tested for TSH and free T4, or total T4. Serum TSH and T4 undergo dynamic changes in the first weeks of life; it is important to compare serum results with age-normal reference ranges. Treatment should be started promptly and infant should be rendered euthyroid as early as possible, as there is an inverse relationship between intelligence quotient (IQ) and the age at diagnosis. Levothyroxine (l-thyroxine) is the treatment of choice and American academy of pediatrics and European society of pediatric endocrinology recommend 10-15μgm/kg/day as initial dose. The immediate goal of therapy is to normalize T4 within 2 weeks and TSH within one month. The overall goal of treatment is to ensure growth and neurodevelopmental outcomes as close as possible to their genetic potential.

Background: Considering the high prevalence of congenital hypothyroidism (CH) in Isfahan and its different etiologies in comparison with other countries, the high rate of parental consanguinity, and the role of NIS gene in permanent CH due to dyshormonogenesis, the aim of this study was to investigate the G395R mutation of the NIS gene in patients with permanent CH due to dyshormonogenesis Methods: In this case-control study, patients diagnosed with permanent CH due to dyshormonogenesis during CH screening program were selected. Venous blood sample was obtained to determine the G395R mutations of NIS gene using polymerase chain reaction (PCR) sequencing method. Results: In this study, 35 CH patients with permanent CH due to dyshormonogenesis and 35 neonates with normal screening results as a control group were studied. We did not find any changes of the mentioned mutation of NIS gene in the patients′ group. Conclusion: Considering the findings of the current study, it seems that further studies with larger sample size and with consideration of other gene mutations such as pendrin and thyroglobulin are needed for more accurate conclusion.

BACKGROUND AND OBJECTIVE: Congenital hypothyroidism is a neonatal disorder that late diagnosis and treatment of it can be resulted to mental retardation and irreversible brain damage. Neonatal goiter is a rare condition that can be associated with hypothyroidism or hyperthyroidism. The aim of this report is early diagnosis and treatment. CASE: In this article we report two female twins that had goiter and prenatal diagnosis by ultrasonography had been documented for them. At third days of life patients with diagnosis of congenital hypothyroidism treated with Levothyroxin. Now they are 10 months old and developmentally normal. Size of goiter has been reduced and thyroid function tests are acceptable.CONCLUSION: Results of this report revealed that in conditions that prenatal management of fetal goiter is not available brain damage in patients can be prevented by early etiologic diagnosis of neonatal goiter and early treatment of dyshormonogenesis.

Congenial hypothyroidism (CH) is the most common congenital endocrine disease and is treatable when recognized early enough. We investigated the genetic variants in 12 children diagnosed with CH by newborn screening in Huangshi area central China. Twelve genes commonly involved in CH development were studied. Genomic DNA from peripheral blood was used to amplify all exons of the selected genes, and the constructed sequencing libraries were subjected to next generation high throughput DNA sequencing (NGS). Analysis of the sequencing results identified rare genetic variants in 11 of the 12 patients (91.7%), and two novel rare variants were found in DUOX2 gene and two in TPO gene. Mutations in DUOX2 gene were identified in 10 patients (83.3%), and all these patients were found to carry bi-allelic, tri-allelic mutations or compound mutations with other genes. Recurrent DUOX2 mutations include K530X, R683L, R1110Q, and L1343F. Truncating, splicing, and proven deleterious DUOX2 missense mutations were detected in 50% of the patients. Mutations in TG gene were identified in four patients, and mutations in TPO , THSR , SLC26A4 genes were identified, one in each patient, respectively. The high prevalence of DUOX2 mutations in this cohort of children with CH appears striking and surprising. The clinical implications were discussed. [ABSTRACT FROM AUTHOR]

Introduction: Thyroid hormone is critical for normal brain development in the early postnatal months. Biochemical diagnosis must be made soon after birth and effective treatment must be initiated promptly to prevent irreversible brain damage. Early diagnosis and adequate treatment from the first weeks of life result in normal linear growth and development. This study was conducted to find out the clinical features suggestive of congenital hypothyroidism and also its causation. Materials and Methods: This was a hospital based retrospective study of 40 congenital hypothyroid children conducted at endocrine unit of Kanti Children’s hospital from 2067 to 2072. All congenital hypothyroid children were reviewed in detail and frequency of signs/symptoms was calculated and also the possible causes were established using ultrasonography and scintigraphy. Results: Out of 40 congenital hypothyroid children 55% were male and 45% were female with M: F ratio of 1.23:1.Common age of presentation of congenital hypothyroidism was 6 to 12 months. The most frequent symptoms were decreased activity/ lethargy (78.9%) followed by stunted height (68.4%) and hypotonia (65.8%).Technetium thyroid scan was performed in 19 cases among which thyroid agenesis was the most common cause of congenital hypothyroidism (42.1%) followed by dyshormonogenesis (31.6%) and ectopic thyroid (26.3%). Conclusion: Early diagnosis of congenital hypothyroidism is possible in some children based on clinical features followed by biomedical investigation soon after birth. [ABSTRACT FROM AUTHOR]

Dyshormonogenesis is an uncommon cause of congenital hypothyroidism. The most common abnormality is absent or insufficient thyroid peroxidase enzyme. Maternal intake of antithyroid drug can also lead to elevated thyroid stimulating hormone (TSH) in a neonate, albeit the scenario is temporary. We report one such interesting case where a clinically euthyroid neonate borne to a mother on antithyroid drug presents on 12 th day of life with reports of elevated TSH and increased tracer uptake in 99mTc thyroid scan. Disproportionately high TSH in comparison to low maternal antithyroid drug dosage and further elevation of TSH after stopping mother′s antithyroid drugs ruled out maternal antithyroid drug-induced congenital hypothyroidism in the baby. Early institution of therapy in these patients can prevent mental retardation and other features of hypothyroidism.

Introduction: Congenital hypothyroidism is the most common congenital endocrine disorder worldwide. Approximately 80 to 85% of cases are caused by defects in thyroid development (dysgenesis), the remaining 15 to 20% are due to errors of thyroid hormone biosynthesis (dyshormonogenesis). Congenital hypothyroidism is also the most common preventable cause of mental retardation. Its neurological defects can only be reversible if diagnosed and treated early. Its incidence rate is 1 out of 3000/4000 live births worldwide However, this incidence rate is higher in developing countries such as Sudan (1 of 1400/2200 newborn infants) in which its population is characterized by consanguinity (25-70%). The present study aimed to assess the demographic and clinical pattern of congenital hypothyroidism (dyshormonogenesis) in Sudan. Material and Methods: A total of 54 patients referred to Gaffar Ibn Auf Children Hospital presented with clinical features suggesting congenital hypothyroidism (dyshormonogenesis) were enrolled in this study. Demographic and clinical data was obtained by a predesigned questionnare. Data were analyzed using SPSS 13 software. Descriptive statistics (frequencies and percentages) were obtained for categorical variables. Results: Most patients enrolled in this study (85.7%) are descendants of consanguineous marriages. There were 11 reported families, comprising 74.3% of cases, with more than one affected member, of those family members, 68.6 % were in fact siblings. Patients from consanguineous marriage had a 96.6% positive family history. The majority of patients (97.1%) developed complications. According to the tribal origin, the vast majority of patients (65.7%) were from Afro-Asiatic tribes, whereas 34.3% were from Nilo-Saharan tribes. There was a large variation in the geographical distribution of patients. Biochemical analysis and ultrasound findings were concordant with the clinical presentation of patients. Conclusion: 1) Early diagnosis and treatment are crucial to prevent both cognitive and motor detrimental effects of the disease. 2) Consanguineous marriages are a major risk factor in patients with congenital hypothyroidism. 3)There is a wide range of tribal variation of both Afro-Asian (65.7%) and Nilo-Saharan (34.3%) tribes. 4) Poor education and unawareness of the disease were major factors in late diagnosis, treatment and further complications. [ABSTRACT FROM AUTHOR]

Rare diseases are usually defined as entities affecting less than 1 person per 2,000. About 7,000 different rare entities are distinguished and, among them, rare diseases of the thyroid gland. Although not frequent, they can be found in the everyday practice of endocrinologists and should be considered in differential diagnosis. Rare non-neoplastic thyroid diseases will be discussed. Congenital hypothyroidism's frequency is relatively high and its early treatment is of vital importance for neonatal psychomotor development; CH is caused primarily by thyroid dysgenesis (85%) or dyshormonogenesis (10-15%), although secondary defects - hypothalamic and pituitary - can also be found; up to 40% of cases diagnosed on neonatal screening are transient. Inherited abnormalities of thyroid hormone binding proteins (TBG, TBP and albumin) include alterations in their concentration or affinity for iodothyronines, this leads to laboratory test abnormalities, although usually with normal free hormones and clinical euthyroidism. Thyroid hormone resistance is most commonly found in THRB gene mutations and more rarely in THRA mutations; in some cases both genes are unchanged (non-TR RTH). Recently the term 'reduced sensitivity to thyroid hormones' was introduced, which encompass not only iodothyronine receptor defects but also their defective transmembrane transport or metabolism. Rare causes of hyperthyroidism are: activating mutations in TSHR or GNAS genes, pituitary adenomas, differentiated thyroid cancer or gestational trophoblastic disease; congenital hyperthyroidism cases are also seen, although less frequently than CH. Like other organs and tissues, the thyroid can be affected by different inflammatory and infectious processes, including tuberculosis and sarcoidosis. In most of the rare thyroid diseases genetic factors play a key role, many of them can be classified as monogenic disorders. Although there are still some limitations, progress has been made in our understanding of rare thyroid diseases etiopathogenesis, and, thanks to these studies, also in our understanding of how normal thyroid gland functions. [ABSTRACT FROM AUTHOR]

Congenital hypothyroidism (CH) is the one of the most common preventable cause of mental retardation. In the majority of patients, CH is caused by an abnormal development of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis. The clinical features of congenital hypothyroidism are so subtle that many newborn infants remain undiagnosed at birth and delayed diagnosis leads to the most severe outcome of CH, mental retardation, emphasizing the importance of neonatal screening. Dried capillary blood is used for screening and it is taken from heel prick optimally between 2 and 5 days of age. Blood spot TSH or thyroxine (T4) or both are being used for CH screening in different programs around the world. Neonates with abnormal thyroid screening tests should be recalled immediately for examination and a venipuncture blood sample should be drawn for confirmatory serum testing. Confirmatory serum should be tested for TSH and free T4, or total T4. Serum TSH and T4 undergo dynamic changes in the first weeks of life; it is important to compare serum results with age-normal reference ranges. Treatment should be started promptly and infant should be rendered euthyroid as early as possible, as there is an inverse relationship between intelligence quotient (IQ) and the age at diagnosis. Levothyroxine (l-thyroxine) is the treatment of choice and American academy of pediatrics and European society of pediatric endocrinology recommend 10-15µgm/kg/day as initial dose. The immediate goal of therapy is to normalize T4 within 2 weeks and TSH within one month. The overall goal of treatment is to ensure growth and neurodevelopmental outcomes as close as possible to their genetic potential. [ABSTRACT FROM AUTHOR]

Background: Congenital hypothyroidism (CH) due to the thyroid dyshormonogenesis is more prevalent in Iran in comparison to other countries. Sodium iodide symporter (NIS) is one of the plasma membrane glycoproteins that is located on the basolateral side of thyroid follicular cells and mediates active I− trapping into these cells. Playing a prominent role in thyroid hormone synthesis, NIS gene mutations can be a cause of permanent CH with the etiology of dyshormonogenesis. The aim of this study was to investigate the occurrence of T354P mutation of the NIS gene, in a group of children affected with permanent CH in Isfahan. Materials and Methods: Thirty-five patients with the etiology of dyshormonogenesis, and 35 healthy children, collected between 2002 and 2011 in Isfahan Endocrine and Metabolism Research Center, were examined for T354P mutation of the NIS gene by direct polymerase chain reaction-sequencing method. Results: No T354P mutation was detected in any of the studied children. Conclusions: More subjects with confirmed iodide transport defects should be screened for detecting the frequency of different reported NIS gene mutations in our population.

Background: Considering the high prevalence of congenital hypothyroidism (CH) in Isfahan and its different etiologies in comparison with other countries, the high rate of parental consanguinity, and the role of NIS gene in permanent CH due to dyshormonogenesis, the aim of this study was to investigate the G395R mutation of the NIS gene in patients with permanent CH due to dyshormonogenesis Methods: In this case-control study, patients diagnosed with permanent CH due to dyshormonogenesis during CH screening program were selected. Venous blood sample was obtained to determine the G395R mutations of NIS gene using polymerase chain reaction (PCR) sequencing method. Results: In this study, 35 CH patients with permanent CH due to dyshormonogenesis and 35 neonates with normal screening results as a control group were studied. We did not find any changes of the mentioned mutation of NIS gene in the patients' group. Conclusion: Considering the findings of the current study, it seems that further studies with larger sample size and with consideration of other gene mutations such as pendrin and thyroglobulin are needed for more accurate conclusion. [ABSTRACT FROM AUTHOR]

Objective: To determine the prevalence of congenital hypothyroidism (CH), permanent and transient CH. Methods: From November 2006 to September 2007, 63031 newborns were screened by measuring serum TSH obtained by heel prick. The neonates who had a TSH≥5mU/L were recalled for measurement of serum T4, thyroid stimulating hormone (TSH) and TSH receptor blocking antibodies (TRBAb) in venous samples. In 43 primarily diagnosed as cases of CH, treatment was discontinued at age 2-3 years for 4 weeks and T4 and TSH were measured again. Permanent or transient CH was determined from the results of these tests and radiologic evaluation. Findings: The incidence of congenital hypothyroidism was found to be 1:1465 with a female to male ratio of 1.19:1. The most common clinical findings were prolonged jaundice (73%), large anterior fontanel (56%) and wide posterior fontanel (55%). In 43 patients with CH, prevalence of permanent and transient form of the disorder was 53.6% and 46.4% respectively. Permanent CH was associated with higher initial TSH level than transient hypothyroidism (P<0.001). The most common etiology of permanent CH was dyshormonogenesis (57%). TRBAb was found in 6.8% of the total 43 cases. Conclusion: Congenital hypothyroidism in Iran may have different etiologies. Due to higher rate of transient CH than other similar researches, it is reasonable to follow these patients for a longer period to rule out the possibility of permanent hypothyroidism. _H [ABSTRACT FROM AUTHOR]

The endocrinological disorders constitute an important percentage of the pediatric consultations. The most frequently endocrinopathy is congenital hypothyroidism, which is considered a public health problem. Newborn screening is mandatory in Mexico. The advances in the molecular field have allowed differentiating among the alterations caused by this disease with especial relevance in the organogenesis and homonogenesis. In this review, the main molecular alterations are analyzed, describing their relationship with thyroid cellular differentiation, hormonal synthesis, central origin hypothyroidism and peripheral tissues target. The study of the molecular abnormalities open new possibilities as to the precise knowledge of the physiopathological and molecular processes. A better and earlier diagnosis and management of this pathology may arise, which in turn will prevent the severe sequelae that congenital hypothyroidism causes. [ABSTRACT FROM AUTHOR]

Background: Considering the higher prevalence of congenital hypothyroidism (CH) in Iran and the importance of determination of the etiology of CH for assessing appropriate treatment strategies, understanding the pathogenesis of CH and the implications of its inheritance and prognosis, the aim of this study was to determine the etiology of CH 7 years after initiation of the program in Isfahan province. Materials and Methods: In this cross-sectional study, children with a primary diagnosis of CH studied. They clinically examined and their medical files were reviewed by a Pediatric Endocrinologist. Considering screening and follow-up lab data and radiologic findings the etiology of CH was determined. Screening properties of different etiologies of CH was compared. Results: In this study, 437 patients with permanent CH (PCH) were studied. Etiology of PCH in 316 (72.3%) and 121 (27.7%) of cases was thyroid dyshormonogenesis and thyroid dysgenesis, respectively. Prevalence of agenesis, ectopia, hypoplasia and hemiagenesis in thyroid dysgenetic patients was 13.3%, 6.4%, 4.3% and 3.7% respectively. Mean of thyroid stimulating hormone in screening, recall and after discontinuing treatment at 3 years of age was significantly lower in dyshormonogenetic CH patients than dysgenetic ones(P < 0.01). Conclusion: Seven years of our experiences in CH screening program indicated that the etiology of CH in Isfahan, with a higher rate of CH, with a predominance of thyroid dyshormonogenesis is different from most of the studies world-wide and similar to other reports from Iran. The findings of the current study provide us baseline information for determination of CH pathogenesis in this region.