Umbilical cord blood TSH levels in term neonates: a screening tool for congenital hypothyroidism.
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This study was conducted to find normative values for thyroid stimulating hormone (TSH) in 1200 cord blood samples of term babies whose mothers were not on any thyroid medications. TSH was estimated within 24 hrs by enzyme immunoassay. A full thyroid profile, viz, T3, T4, TSH, fT3 and fT4 was done at 7-10 days of age in all babies with cord TSH >20 mIU/L. The mean, median and standard deviation for the TSH values for the cohort were 6.13 mIU/L, 5.8 mIU/L and 4.523 respectively. 22 babies with TSH values >20 mIU/L were given repeat tests. Hypothyroidism was confirmed in two of these babies. We conclude that a cut off value of TSH >20 mIU/L is adequate for neonatal thyroid screening in Indian settings. (+info)
Further studies on episodic occurrence of congenital dysgenetic hypothyroidism in Osaka, Japan.
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A total of 1,228,551 newborn babies, who were almost all of babies born in Osaka for 14 years (168 months), were screened for congenital primary hypothyroidism by an identical mass-screening program using the thyrotropin method, and 429 patients with hypothyroidism due to thyroid dysgenesis (dysgenetic hypothyroidism) were found. The occurrence of the patients in every month was not random but episodic and the incidence was higher in the late autumn (from October to December). These observations support a hypothesis that some environmental factors may cause this disorder overtime and the possibility of relation with intrauterine viral infection was discussed. (+info)
Two novel mutations in the thyroid peroxidase gene with goitrous hypothyroidism.
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We encountered a Japanese patient with goitrous hypothyroidism due to iodide organification defect in the thyroid gland. Sequence analysis identified two novel mutations (E378K in exon 8 and a heterozygous 10 base deletion of the intron 15-exon 16 boundary) in the thyroid peroxidase (TPO) gene. As individuals with goitrous hypothyroidism caused by TPO gene mutation develop thyroid cancer, regular and careful follow-up for such patients must be done. (+info)
Three mutations (p.Q36H, p.G418fsX482, and g.IVS19-2A>C) in the dual oxidase 2 gene responsible for congenital goiter and iodide organification defect.
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BACKGROUND: Iodide organification defects are associated with mutations in the dual oxidase 2 (DUOX2) gene and are characterized by a positive perchlorate discharge test. These mutations produce a congenital goitrous hypothyroidism, usually transmitted in an autosomal recessive mode. METHODS: We studied the complete coding sequence of the human DUOX2 gene by single-strand conformational polymorphism (SSCP) analysis of DNA from 17 unrelated patients with iodide organification defects. Samples showing an aberrant pattern were directly sequenced. All mutations were validated by SSCP analysis. Finally, the effect of a splicing mutation was studied by construction of minigenes. RESULTS: Genomic DNA sequencing revealed 3 novel mutations [c.108G>C (p.Q36H), c.1253delG (p.G418fsX482), and g.IVS19-2A>C] and 1 previously reported mutation [c.2895-2898delGTTC (p.S965fsX994)] in 2 families with 1 (family 1) and 2 (family 2) affected members. This implies the inheritance of 2 compound heterozygous mutations, p.Q36H and p.S965fsX994 in family 1 and p.G418fsX482 and g.IVS19-2A>C in family 2. The c.1253delG mutation was associated with a c.1254C>A transversion. In vitro transcription analysis showed that exon 20 is skipped entirely when the g.IVS19-2A>C mutation is present. The wild-type glutamine residue at position 36 is strictly conserved. CONCLUSIONS: Two previously unknown compound heterozygous mutations in the DUOX2 gene, p.Q36H/p.S965fsX994 and p.G418fsX482/g.IVS19-2A>C, are responsible for iodide organification defects in 2 unrelated families. Identification of the molecular basis of this disorder might be helpful for understanding the pathophysiology of this congenital hypothyroidism. (+info)
Risk factors for congenital hypothyroidism: results of a population case-control study (1997-2003).
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OBJECTIVE: To identify risk factors for permanent and transient congenital hypothyroidism (CH). DESIGN: A population-based case-control study was carried out by using the network created in Italy for the National Register of Infants with CH. METHODS: Four controls were enrolled for each new CH infant; 173 cases and 690 controls were enrolled in 4 years. In order to distinguish among risk factors for permanent and transient CH, diagnosis was re-evaluated 3 years after enrollment when there was a suspicion of transient CH being present. Familial, maternal, neonatal and environmental influences were investigated. RESULTS: An increased risk for permanent CH was detected in twins by a multivariate analysis (odds ratio (OR) = 12.2, 95% confidence interval (CI): 2.4-62.3). A statistically significant association with additional birth defects, female gender and gestational age >40 weeks was also confirmed. Although not significant, an increased risk of CH was observed among infants with a family history of thyroid diseases among parents (OR = 1.9, 95% CI: 0.7-5.2). Maternal diabetes was also found to be slightly associated with permanent CH (OR = 15.7, 95% CI: 0.9-523) in infants who were large for gestational age. With regard to transient CH, intrauterine growth retardation and preterm delivery were independent risk factors for this form of CH. CONCLUSION: This study showed that many risk factors contribute to the aetiology of CH. In particular, our results suggested a multifactorial origin of CH in which genetic and environmental factors play a role in the development of the disease. (+info)
Role of scintigraphy in congenital thyroid anomalies.
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Thyroid scintigraphy using Tc-99m pertechnetate is a frequently performed procedure in routine nuclear medicine practice. The indications for thyroid scintigraphy are investigation of hyperthyroidism, nodularity of the gland, cause of thyroid stimulating hormone elevation and localization of an ectopic thyroid gland. In the pediatric population, the most common request is for the evaluation of neonatal hypothyroidism. This imaging procedure is helpful in the identification of the underlying cause as well as in making a differential diagnosis. Early diagnosis is essential for appropriate therapy planning in this age group, and thyroid scintigraphy provides important diagnostic data. This article is written to review the scintigraphic findings in various congenital thyroid anomalies and to underline its use in the differential diagnosis. (+info)
Thyroid dyshormonogenesis.
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Dyshormonogenesis is an uncommon cause of congenital hypothyroidism. The most common abnormality is absent or insufficient thyroid peroxidase enzyme. Perchlorate discharge test can be used to diagnose thyroid peroxidase deficiency. We report three siblings with hypothyroidism due to thyroid dyshormonogenesis. Early institution of therapy in these patients can prevent mental retardation and other features of hypothyroidism. (+info)
Improvement in screening performance and diagnosis of congenital hypothyroidism in Scotland 1979-2003.
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AIM: To assess the Scottish newborn screening programme for congenital hypothyroidism from 1994 to 2003 (period 2) for performance and compare with an initial audit covering 1979 to 1993 (period 1). DESIGN: Performance data-age at blood spot sampling, notification by screening laboratory, start of treatment, and the prevalence of late testing, notification or treatment-were compared, together with the incidence of congenital hypothyroidism. RESULTS: Comparing data for period 2 with period 1, the mean annual incidence of true congenital hypothyroidism was 1:3655 live births v 1:4363. Median age for Guthrie sampling (all referrals) was 6 v 7 days (p<0.0001). Late sampling (>10 days) had fallen from 10.7% to 7%. For infants requiring repeat sampling before notification, the median (range) interval between initial and final repeat samples was 11 (1 to 52) compared with 14 (3 to 73) days. Median age at notification for true congenital hypothyroidism was 10 v 12 days (p <0.0001). Late notification (>15 days) was justifiable (mild TSH elevation) in 10 of 13 patients in period 2. Median age at start of treatment for true congenital hypothyroidism had improved to 11 days from 13.5 days. For true congenital hypothyroidism, late treatment (>16 days) occurred in 7% of patients compared with 19% (p<0.0001). CONCLUSIONS: There has been an improvement in performance measures for the congenital hypothyroidism screening programme in Scotland. However, late sampling, occurring primarily in inpatients and which is never justified, remains a problem, while the interval between initial and recall sampling is a further source of delay. (+info)