Propylthiouracil-induced congenital hypothyroidism upregulates vimentin phosphorylation and depletes antioxidant defenses in immature rat testis.
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Neonatal thyroid screening in a mild iodine deficiency endemic area in Iran.
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BACKGROUND: Evaluated serum thyroid-stimulating hormone (TSH), as an early index for diagnosis of neonatal hypothyroidism, indicates insufficient supply of thyroid hormones. OBJECTIVE: The aim of the study was to estimate the incidence of neonatal hypothyroidism and assessment of iodine deficiency in the eastern part of Iran. SETTINGS AND DESIGN: A cross-sectional study was conducted in a pilot screening. MATERIALS AND METHODS: The measurement of blood TSH spotted on filter paper was performed by ELISA method in 59,436 neonates. TSH value equal to 5 mU/L was considered cut off point. The diagnosis of hypothyroidism in neonates with the blood TSH higher than the cut off point was based on clinical examinations and laboratory tests (serum TSH and T4). STATISTICAL ANALYSIS: The groups were compared using chi-square and ANOVA tests. RESULTS: In our study, the recall rate and incidence of hypothyroidism were 3.6% and 2 per 1000 neonates respectively. Based on the proposal made by WHO/UNICEF/ICCIDD, the results of our study showed a mild iodine deficiency in the area. CONCLUSIONS: A comprehensive policy should be developed for control of iodine deficiency and treatment of hypothyroidism in the studied population and neighboring countries. (+info)
Thyrotropin receptor and thyroid transcription factor-1 genes variant in Chinese children with congenital hypothyroidism.
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The aim of the present study was to investigate the mutation/variant of thyrotropin receptor (TSHR) and thyroid transcription factor-1 (TTF-1) genes in Chinese children with congenital hypothyroidism (CH). Seventy-nine and forty-nine Chinese children with CH were enrolled for molecular analysis of the TSHR gene and TTF-1 gene, respectively. One hundred normal children were evaluated as control. The coding regions of TSHR and TTF-1 genes were amplified by polymerase chain reaction and sequenced. Sequencing of the TSHR gene revealed a compound heterozygous variants (Pro52Thr/Val689Gly) and a heterozygous variant (Gly245Ser) in 2 of 79 patients. In 30 patients and 33 controls the normal cytosine at position 2181 in exon 10 of TSHR gene was replaced by a guanineCresulting in the replacement of Asp (727) by Glu. In 47 patients and 50 controls, the normal thymidine at position 561 in exon 7 of TSHR gene was replaced by a cytosine. This substitution did not change the amino acid in position 187. Sequencing of the TTF-1 gene revealed no mutation or polymorphism in 49 patients and 100 controls. In conclusion, three heterozygous variants (Pro52Thr, Gly245Ser, Val689Gly) of TSHR gene were firstly detected in Chinese children with CH. There were polymorphisms in exon 10 at nucleotide 2181 (C/G) and in exon 7 at nucleotide 561 (T/C) in TSHR gene. No mutation or polymorphism was detected in the coding region of TTF-1 gene. The mutation/variant of TSHR and TTF-1 genes is relatively rare in Chinese children with CH. (+info)
Polychlorinated biphenyls (Aroclor 1254) do not uniformly produce agonist actions on thyroid hormone responses in the developing rat brain.
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Mutation of a gene for thyroid transcription factor-1 (TITF1) in a patient with clinical features of resistance to thyrotropin.
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Resistance to TSH (RTSH [MIM 275200]) is a heterogeneous condition defined by variable degree of insensitivity to biologically active TSH. While this condition is classically caused by loss-of-function mutations of the TSH receptor gene (TSHR), several patients have exhibited RTSH-like phenotype in the apparent absence of TSHR mutations, and some of them have mutations of PAX8 or GNAS1. We identified a Japanese boy with congenital hypothyroidism who suffered from recurrent lower respiratory infection during infancy and choreoathetosis at a later age. At 14 years of age, he was diagnosed as having RTSH, on the basis of compensated hypothyroidism (TSH, 30.2 mU/L; FT4, 1.2 ng/dl), disproportionate increments of thyroid hormones and TSH during a TRH test (DeltaFT3, 0.4 pg/ml; DeltaT3, 13 ng/dl; and DeltaTSH, 88.3 mU/L), and normal ultrasound thyroid image and radioactive iodine uptakes. Molecular analysis for TITF1 revealed a novel de novo heterozygous deletion/insertion mutation (c.470_479delinsGCG,) that is predicted to lose the entire homeodomain and the NK2-specific domain. We suggest that a heterozygous loss-of-function TITF1 mutation can also cause RTSH-compatible phenotype. (+info)