High-resolution melt curve analysis: An approach for variant detection in the TPO gene of congenital hypothyroid patients in Bangladesh.

TPO (Thyroid Peroxidase) is known to be one of the major genes involved in congenital hypothyroid patients with thyroid dyshormonogenesis. The present study aims to validate high-resolution melting (HRM) curve analysis as a substitute method for Sanger sequencing, focusing on the frequently observed non-synonymous mutations c.1117G>T, c.1193G>C, and c.2173A>C in the TPO gene in patients from Bangladesh. We enrolled 36 confirmed cases of congenital hypothyroid patients with dyshormonogenesis to establish the HRM method. Blood specimens were collected, and DNA was extracted followed by PCR and Sanger sequencing. Among the 36 specimens, 20 were pre-sequenced, and variants were characterized through Sanger sequencing. Following pre-sequencing, the 20 pre-sequenced specimens underwent real-time PCR-HRM curve analysis to determine the proper HRM condition for separating the three variations from the wild-type state into heterozygous and homozygous states. Furthermore, 16 unknown specimens were subjected to HRM analysis to validate the method. This method demonstrated a sensitivity and specificity of 100 percent in accurately discerning wild-type alleles from both homozygous and heterozygous states of c.1117G>T (23/36; 63.8%), c.1193G>C (30/36; 83.3%), and c.2173A>C (23/36; 63.8%) variants frequently encountered among 36 Bangladeshi patients. The HRM data was found to be similar to the sequencing result, thus confirming the validity of the HRM approach for TPO gene variant detection. In conclusion, HRM-based molecular technique targeting variants c.1117G>T, c.1193G>C, and c.2173A>C could be used as a high throughput, rapid, reliable, and cost-effective screening approach for the detection of all common mutations in TPO gene in Bangladeshi patients with dyshormonogenesis.

Newborn screening in Colombia: The experience of a private program in Bogotá / Tamizaje neonatal en Colombia: la experiencia de un programa privado en Bogotá.

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.

TSHR Variant Screening and Phenotype Analysis in 367 Chinese Patients With Congenital Hypothyroidism.

Background: Genetic defects in the human thyroid-stimulating hormone (TSH) receptor (TSHR) gene can cause congenital hypothyroidism (CH). However, the biological functions and comprehensive genotype-phenotype relationships for most TSHR variants associated with CH remain unexplored. We aimed to identify TSHR variants in Chinese patients with CH, analyze the functions of the variants, and explore the relationships between TSHR genotypes and clinical phenotypes. Methods: In total, 367 patients with CH were recruited for TSHR variant screening using whole-exome sequencing. The effects of the variants were evaluated by in-silico programs such as SIFT and polyphen2. Furthermore, these variants were transfected into 293T cells to detect their Gs/cyclic AMP and Gq/11 signaling activity. Results: Among the 367 patients with CH, 17 TSHR variants, including three novel variants, were identified in 45 patients, and 18 patients carried biallelic TSHR variants. In vitro experiments showed that 10 variants were associated with Gs/cyclic AMP and Gq/11 signaling pathway impairment to varying degrees. Patients with TSHR biallelic variants had lower serum TSH levels and higher free triiodothyronine and thyroxine levels at diagnosis than those with DUOX2 biallelic variants. Conclusions: We found a high frequency of TSHR variants in Chinese patients with CH (12.3%), and 4.9% of cases were caused by TSHR biallelic variants. Ten variants were identified as loss-of-function variants. The data suggest that the clinical phenotype of CH patients caused by TSHR biallelic variants is relatively mild. Our study expands the TSHR variant spectrum and provides further evidence for the elucidation of the genetic etiology of CH.

A literature review on the redundancy of additional thyroid function tests in neonates of mothers with hypothyroidism.

AIM: Newborn thyroid screening tests are carried out during the first days after birth in many parts of the world. The aim of this review was to assess whether additional thyroid function tests of neonates born to mothers with hypothyroidism are necessary to diagnose newborns with congenital hypothyroidism (CH) missed by the usual screening test. METHODS: A search in PubMed and Google Scholar databases was conducted for pertinent studies, using relevant keywords. All studies that were published in any language from 1 January 2000 to 30 June 2023 were included. Observational cohort studies were included in the analysis, while case reports and studies not referring to neonates were excluded. RESULTS: Thirteen studies were identified comprising more than 4400 infants with CH. Studies with the larger study populations recommended against additional testing in healthy infants of hypothyroid mothers. Similar were the results of some smaller retrospective studies. Few studies identified in total 16 infants with CH that were missed on neonatal screening without, though, a definite causative link between the mother's and the infant's thyroid dysfunction. CONCLUSION: Based on available data, additional thyroid function tests seem redundant in identifying undiagnosed cases of CH. Larger studies are needed to reach a definite conclusion.

Hoffmann's syndrome in subclinical hypothyroidism.

Hypothyroidism is an endocrine disorder which occurs due to a deficiency of thyroid hormones. Hoffmann's syndrome is a rare complication of hypothyroidism - presenting as hypothyroid myopathy. We describe the case of a 20-year-old lactating female, known to have hypothyroidism (diagnosed during her pregnancy and having discontinued treatment following delivery), presenting with complaints of pain, swelling of bilateral calf muscles with cramps in bilateral lower limbs. Symptoms of muscle pseudohypertrophy with muscle stiffness are relatively rare in subclinical hypothyroidism and it is important to identify and diagnose this rare condition, and initiate appropriate treatment.

Evaluation of patients diagnosed with congenital hypothyroidism by newborn screening between 2011-2019 in Diyarbakir, Turkey.

This study aimed to determine the incidence of congenital hypothyroidism in Turkey's Diyarbakir Province and assess the development and growth conditions of people with congenital hypothyroidism. Patients born between 2011-2019 and diagnosed with congenital hypothyroidism within the scope of the newborn screening program were included. The medical records of these patients were retrospectively reviewed. The length and weight for age, weight for length, and body mass index standard deviation scores were calculated. We investigated the treatment status of the patients, whether their relatives had a similar disorder, and the presence of consanguinity between parents. Blood samples were collected from 380,592 newborns. As a result of further tests, 498 newborns were diagnosed with congenital hypothyroidism (incidence: 1/764). Demographic and anthropometric data of 241 patients were analyzed. The patients comprised 46.9% (n = 113) females and 53.1% (n = 128) males. It was determined that 44.4% of the individuals had transient congenital hypothyroidism and 53.6% had permanent congenital hypothyroidism. The parents of 29.8% of the individuals diagnosed with transient congenital hypothyroidism and 44.2% of the individuals diagnosed with permanent congenital hypothyroidism were consanguineous (P = .02). According to the latest anthropometric assessment, 6.8% of individuals diagnosed with congenital hypothyroidism had a weight z-score below -2 SD and 16.9% had a length z-score below -2 SD. The incidence of congenital hypothyroidism was higher in our region. The ratio of consanguinity between parents was higher in patients diagnosed with permanent congenital hypothyroidism than in those diagnosed with transient congenital hypothyroidism. According to the most recent follow-up, weight and age were found to be similar in patients with transient and permanent congenital hypothyroidism.

Results of neonatal screening for congenital hypothyroidism and hyperphenylalaninemia in Zhejiang province from 1999 to 2022. / 浙江省1200ä¸‡ä¾‹æ–°ç”Ÿå„¿å ˆå¤©æ€§ç”²çŠ¶è ºåŠŸèƒ½å‡é€€ç—‡ã€é«˜è‹¯ä¸™æ°¨é ¸è¡€ç—‡ç­›æŸ¥ç»“æžœåˆ†æž.

OBJECTIVES: To analyze the results of neonatal screening for congenital hypothyroidism (CH) and hyperphenylalaninemia (HPA) in Zhejiang province from 1999 to 2022. METHODS: A total of 11 922 318 newborns were screened from September 1999 and December 2022 in Zhejiang province. The blood thyroid stimulating hormone (TSH) levels were measured by a fluorescence method and blood phenylalanine (Phe) levels were measured by fluorescence method or tandem mass spectrometry. TSH≥9 µIU/mL was considered positive for CH, while Phe>120 µmol/L and/or Phe/Tyr ratio>2.0 were considered positive for HPA. The positive newborns in screening were recalled, and the gene variations were detected by high-throughput sequencing and MassARRAY tests. RESULTS: The overall neonatal screening rate during 1999-2022 was 89.41% (11 922 318/13 333 929) and the screening rate was increased from 6.46% in 1999 to 100.0% in 2022. A total of 8924 cases of CH were diagnosed among screened newborns with an incidence rate of 1/1336. A total of 563 cases of HPA were diagnosed, including 508 cases of classic phenylketonuria (cPKU) and 55 cases of tetrahydrobiopterin deficiency (BH4D), with an incidence rate of 1/21 176. Ninety-seven out of 8924 cases of CH underwent genetic analysis. Gene mutations were detected in 9 CH related genes, the highest frequency mutations were found in DUOX2 gene (69.0%) with c.3329G>A (p.R1110Q) (18.2%) and c.1588A>T (p.K530X) (17.3%) as the hotspot mutations. There were 81 PAH gene variants detected in a total of 250 cases of cPKU, and c728G>A (p.R243Q) (24.4%), c.721C>T (p.R241C) (15.0%) were the hotspot mutations. Meanwhile 7 novel variants in PAH gene were detected: c.107C>A (p.S36*), c.137G>T (p.G46V), c.148A>G(p.K50E), c.285C>T (p.I95I), c.843-10delTTCC, exon4-7del and c.1066-2A>G. There were 12 PTS gene variants detected in 36 cases of BH4D, and c.259C>T (p.P87S) (31.9%) was the hotspot mutation. CONCLUSIONS: The incident of CH has increased from 1999 to 2022 in Zhejiang province, and it is higher than that of national and global levels; while the incidence of HPA is similar to the national average. DUOX2 gene variation is the most common in CH patients; c.728G>A (p.R243Q) is the hotspot mutation in cPKU patients, while c.259C>T (p.P87S) is the hotspot mutation in BH4D patients.

Rare case of central congenital hypothyroidism due to a TSHß mutation presenting with macro-orchidism.

A male infant was brought to our paediatric endocrine unit with typical clinical features of congenital hypothyroidism (CH) and striking macro-orchidism. On evaluation, free T3, free T4 and thyroid stimulating hormone (TSH) were found to be low, suggestive of congenital CH. Cortisol was within reference range and prolactin was mildly elevated. No suspicious lesions were encountered on neurosonography. On commencing treatment with thyroxine, clinical features of hypothyroidism showed dramatic improvement with regression of testicular enlargement. Genetic analysis revealed deletion of the TSHß gene.Our case highlights a rare presentation of central CH with macro-orchidism in a genetically proven deletion of TSHß gene. Macro-orchidism has been widely reported in IGSF-1 mutations leading to central CH; however, central CH and macro-orchidism have not been reported in association with TSHß deletions.

[A case of congenital hypothyroidism and Turner syndrome.] / Un caso di ipotiroidismo congenito e sindrome di Turner.

When properly treated, congenital hypothyroidism (CH) allows normal growth. We describe the case of a girl followed-up for CH diagnosed upon newborn screening, with good adherence to L-T4 therapy, who had an impaired linear growth starting from 4 years of age. Diagnostic work-up allowed exclusion of inflammatory diseases and/or malabsorption and led to the diagnosis of Turner syndrome (TS). Recombinant GH (rGH) therapy was undertaken with satisfactory growth recovery. At the age of 8, a condition of autoimmune thyroiditis was detected, due to an increased risk in the context of her syndrome. Except for small adjustments in the dose of L-T4, hypothyroidism remained well-controlled even after starting rGH therapy.

Homozygous Mutations in Thyroid Peroxidase (TPO) in Hypothyroidism with Intellectual Disability, Developmental Delay, and Hearing and Ocular Anomalies in Two Families: Severe Manifestation of Untreated TPO-deficiency Poses a Diagnostic Dilemma.

Intellectual disability (ID) involves compromised intellectual, learning and cognitive skills, and behavioral capabilities with reduced psychomotor skills. One of the preventable causes of ID is congenital hypothyroidism (CH), which may be due to biallelic mutations in thyroid peroxidase (TPO). In low- and middle-income countries with no newborn screening programs, CH poses a great risk of ID and long-term morbidity. We report two large Pakistani families with a total of 16 patients afflicted with CH. Detailed clinical and behavioral assessments, SNP-based homozygosity mapping, linkage analysis, and exome sequencing were performed. Initially, affected individuals were referred as suffering ID (in 11 of 16 patients) and developmental delay (in 14). Secondary/associated features were verbal apraxia (in 13), goiter (in 12), short stature (in 11), limb hypotonia (in 14), no pubertal onset (five of 10 of age ≥14 years), high myopia (in eight), muscle cramps (in six), and in some, variable microcephaly and enuresis/encopresis, fits, chronic fatigue, and other behavioral symptoms, which are not characteristics of CH. Molecular genetic analyses led to the discovery of homozygous variants in TPO: novel missense variant c.719A>G (p.Asp240Gly) in family 1 and rare c.2315A>G (p.Tyr772Cys) in family 2. In low-resource countries where neonatal screening programs do not include a CH test, the burden of neurodevelopmental disorders is likely to be increased due to untreated CH. Secondly, in the background of the high prevalence of recessive disorders due to high parental consanguinity, the severe manifestation of TPO-deficiency mimics a wide range of neurological and other presentations posing a diagnostic dilemma.

Two Cases of Congenital Hypothyroidism Revealing Thyroid Agenesis.

Congenital hypothyroidism (CH) may have major detrimental effects on growth and neurological development, but early intervention leads to excellent outcomes. CH is classified as transient or permanent, primary or secondary, with primary CH being the most common neonatal endocrine disorder. Most patients with CH do not present any typical signs and symptoms of hypothyroidism shortly after birth, partly due to transplacental maternal thyroid hormone transfer and residual neonatal thyroid function. This paper reports on two CH cases. During the initial Neonatal Intensive Care Unit (NICU) admission phase, CH was not suspected due to nonspecific signs. The distinct characteristics of our cases are as follows: both infants were admitted to the NICU for respiratory distress syndrome, requiring invasive mechanical ventilation, and both were born to diabetic mothers. Following extubation, they both showed similar neurological issues, including reduced muscle tone and feeding difficulties. Initially, those symptoms were attributed to delayed clearance of analgesic and sedative medication. However, symptoms progressively worsened over time. Subsequent tests revealed both meeting CH diagnostic criteria: an unusual ultrasound indicating thyroid agenesis and abnormal hormone levels. Guided by the pediatric endocrinology team, prompt hormonal treatment was started with improvements in neurocognitive function and feeding. Usually, CH screening involves blood samples from healthy newborns at 2-3 days of life. Abnormal results require confirmation, prompting treatment within two weeks. Certain NICU-admitted infants face higher diagnosis delays, as seen in those two cases where CH screening was postponed. Thus, for all neonates with persistent pathologies unresponsive to standard etiological treatment, conducting a comprehensive anamnestic evaluation of the medical history, along with maternal preconceptional and prenatal nutrition, is recommended.

Optimizing the Dutch newborn screening for congenital hypothyroidism by incorporating amino acids and acylcarnitines in a machine learning-based model.

Objective: Congenital hypothyroidism (CH) is an inborn thyroid hormone (TH) deficiency mostly caused by thyroidal (primary CH) or hypothalamic/pituitary (central CH) disturbances. Most CH newborn screening (NBS) programs are thyroid-stimulating-hormone (TSH) based, thereby only detecting primary CH. The Dutch NBS is based on measuring total thyroxine (T4) from dried blood spots, aiming to detect primary and central CH at the cost of more false-positive referrals (FPRs) (positive predictive value (PPV) of 21% in 2007-2017). An artificial PPV of 26% was yielded when using a machine learning-based model on the adjusted dataset described based on the Dutch CH NBS. Recently, amino acids (AAs) and acylcarnitines (ACs) have been shown to be associated with TH concentration. We therefore aimed to investigate whether AAs and ACs measured during NBS can contribute to better performance of the CH screening in the Netherlands by using a revised machine learning-based model. Methods: Dutch NBS data between 2007 and 2017 (CH screening results, AAs and ACs) from 1079 FPRs, 515 newborns with primary (431) and central CH (84) and data from 1842 healthy controls were used. A random forest model including these data was developed. Results: The random forest model with an artificial sensitivity of 100% yielded a PPV of 48% and AUROC of 0.99. Besides T4 and TSH, tyrosine, and succinylacetone were the main parameters contributing to the model's performance. Conclusions: The PPV improved significantly (26-48%) by adding several AAs and ACs to our machine learning-based model, suggesting that adding these parameters benefits the current algorithm.

[Cognitive performance of preschoolers with Congenital Hypothyroidism enrolled in a follow-up program]. / Desempeño cognitivo en preescolares con Hipotiroidismo Congénito incorporados en un programa de seguimiento.

The age at treatment initiation is decisive for limiting the neurological sequelae of Congenital Hypothyroidism (CH). Incorporating children into follow-up programs could be very helpful. OBJECTIVE: To evaluate the cognitive performance of preschool children with CH incorporated into a follow- up program. PATIENTS AND METHOD: Prospective study of 93 patients with a confirmed diagnosis of CH. Intelligence quotient (IQ) was assessed using the Wechsler Preschool and Primary Intelligence Scale (WPPSI) at 4 and 5 years, and the WISC-R at 6 years of age. Full-Scale IQ (FSIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) scores were analyzed. RESULTS: The study sample was 80 children. The average age at starting hormonal treatment was 42 ± 18 days; treatment started early in 25 patients (24 ± 6 days) and late in 55 patients (50 ± 16 days). The mean initial dose of Levothyroxine was 13.5 ± 1.5µg/kg/day. Children with athyrosis and late initiation of treatment had lower scores on the VIQ (85 ± 14), the PIQ (89 ± 12), and the FSIQ (86 ± 13) scales at 4 years of age, in comparison with patients with early initiation of treatment. These patients scored within the cut-off point for the normal IQ classification (90-109 points). IQ comparison at 6 years of age revealed differences up to 14 points in the PIQ and 11 points in the FSIQ between children with athyrosis and early initiation of treatment, with and without regular attendance to the follow-up program. DISCUSSION: These results support the importance of early initiation of treatment and the incorporation of children in follow-up programs and early stimulation. The etiology of hypothyroidism and the age at initiation of treatment were the most significant factors that affected cognitive performance.

Screening and Management of Congenital Hypothyroidism - Guidelines by American Academy of Pediatrics, 2023.

Guidelines for screening and management of congenital hypothyroidism in neonates have been recently updated by the American Academy of Pediatrics (AAP). This article compares new AAP guideline with the Indian Society for Pediatric and Adolescent Endocrinology (ISPAE) Guidelines, 2018 and lists the changes in screening, diagnosis, and management of congenital hypothyroidism suggested in the new guidelines, along with clinical utilization in the Indian scenario.

Dynamic Screening of Thyroid Function for the Timely Diagnosis of Congenital Hypothyroidism in Very Preterm Infants: A Prospective Multicenter Cohort Study.

Background: Preterm infants presented a high prevalence of congenital hypothyroidism (CH), while the optimal screening pattern is still under debate. This study aimed at evaluating the characteristics of thyroid function by conducting weekly screening during the first month of life in very preterm infants (VPIs) to achieve timely diagnosis and treatment of CH. Methods: A prospective cohort study was carried out on VPIs born with gestational age (GA) <32 weeks (w) and admitted to the participating institutes from January 1, 2019 to December 31, 2022. Serial serum thyroid hormone levels were measured weekly within the first month after birth, and at 36 w of corrected age, or before discharge. Datasets for serial thyroid hormone levels and general information were obtained. Results: A total of 5992 VPIs were enrolled in this study, of which 456 (7.6%) [95% confidence interval (CI), 6.9-8.3%] were diagnosed with CH. The incidence of CH increased with lower GA, moving from 4.8% [CI, 3.4-6.1%] at GA 31 w to 16.9% [CI, 8.3-25.4%] at GA <26 w. Among the CH subjects, 57.7% [CI, 53.1-62.2%] were identified after the first screening and classified as delayed thyrotropin elevation (dTSH). With the decrease of GA, the proportion of dTSH also increased, moving from 38.1% [CI, 27.5-48.7%] at GA 31 w to 82.6% [CI, 65.8-99.4%] at GA <26 w. Through conducting weekly screening of thyroid function, it was remarkable that only 42.3% [CI, 37.8-46.9%] of CH subjects were diagnosed during the first screening. The cumulative rate of CH identified by rescreening performed at the second, third, and fourth week was 76.1% [CI, 72.2-80.0%], 90.6% [CI, 87.9-93.3%], and 98.9% [CI, 97.9-99.9%], respectively. Conclusion: The incidence of CH and dTSH both increase with lower GA in VPIs. Dynamic screening of thyroid function by weeks within the first month of life is crucial for the timely diagnosis and treatment of CH in VPIs, and it might effectively reduce the implications of missed diagnosis and delayed treatment. Clinical Trials Registration: ChiCTR1900025234 and ChiCTR2000037918 (Registration number).

Increased incidence of congenital hypothyroidism in China: An analysis of 119 million screened newborns.

Despite the lack of nationwide epidemiological studies, congenital hypothyroidism (CH) incidence in China has increased. We aimed to evaluate the trends of CH and the possible reasons behind them. Data from screened newborns from the Chinese Newborn Screening Information System from 2012 to 2019 was collected. We applied the Bayesian hierarchical Poisson regression model and meta-analysis to estimate incidence or proportion over the years. The estimated CH incidence increased from 4.01 per 10,000 births in 2012 to 5.77 per 10,000 births in 2019. The average annual growth rate (ARG) of CH incidence for all provinces varied from 0.59 to 20.96%. The most rapid rise in incidence was observed in cases with an initial thyroid stimulating hormone (TSH) concentration of < 10 mIU/L. The meta-analysis results showed that the proportion of permanent CH increased by 0.024% (95%CI: 0.011%, 0.037%) annually. Each 1 mIU/L decrease in TSH cutoff value was associated with a 2.96% increase in CH incidence. In the same period, the proportion of premature CH cases increased from 6.60 to 9.10%, which was much higher than the increase in preterm births. A significant relationship was not found between provincial growth rates in screening coverage and provincial baseline incidences of CH.  Conclusion: CH incidence has substantially increased in China. The slight adjustment of the TSH cutoff value and increasing preterm birth rate contribute to such a trend; however, the contribution is limited. What is Known: • An uptrend in congenital hypothyroidism (CH) incidence has been reported in many European and American countries in the last two decades; however, no studies have been conducted in China to explain the increased CH incidence. • We provide a detailed epidemiological report on the trends of CH during 2012-2019 in China, with an attempt to explore the reasons behind it. What is New: • This first-ever national-wide epidemiological report in China showed an uptrend in CH incidence with variations over regions and CH subtypes. The mild lowering of TSH cutoff values and the increasing preterm birth rate contributed to this uptrend.

Hepatomegaly and fatty liver disease secondary to central hypothyroidism in combination with macrosomia as initial presentation of IGSF1 deficiency syndrome.

PURPOSE: IGSF1 deficiency syndrome (immunoglobulin superfamily member 1) is considered the most common sex-linked cause of secondary congenital hypothyroidism and is characterized by a wide variety of other clinical and biochemical features, including hypoprolactinemia, transient and partial growth hormone deficiency, early/normal timing of testicular enlargement but delayed testosterone rise in puberty, and adult macro-orchidism. Congenital central hypothyroidism is a rare disease (1:65,000 births); the detection of which may be delayed and missed by neonatal screening programs since most neonatal screening programs are based on TSH determination in dried blood spots only. Untreated hypothyroidism may cause abnormal liver biochemistry and non-alcoholic fatty liver disease. Our aim is to report a case of secondary hypothyroidism in an infant with an uncommon initial presentation. CASE PRESENTATION (METHODS/RESULTS): A 3-month-old male baby was referred to our hospital due to elevated alpha-fetoprotein levels, hypercholesterolemia, and macrosomia. Initial investigations revealed enlarged fatty liver and central hypothyroidism. Pituitary insufficiency was biochemically excluded and a pituitary MRI showed normal findings. Upon genetic analysis, a hemizygous variant NM_001170961.1:c.2422dup, p.(His808Profs*14), in IGSF1 gene was detected, establishing the diagnosis of the IGSF1 deficiency syndrome. In our patient, no other clinical findings were identified. Treatment with levothyroxine led to the remission of liver disease. CONCLUSION: Liver disease may be the initial presentation of secondary hypothyroidism in neonates and infants. Macrosomia in patients with isolated secondary central hypothyroidism is a strong indicator of IGSF1 syndrome.