Thyroid Hormone Resistance P453A Mutation.
Thyroid hormone resistance is a disease characterized by reduced sensitivity to thyroid hormone in cell membrane, altered metabolism and nuclear receptor. The clinic signs of thyroid hormone resistance are goiter, sinus tachycardia, attention deficit hyperactivity disorder; the laboratory signs are high level of free T4 and normal level of TSH.
A 10-year-old girl was admitted to our clinic with complaints of palpitation and nervousness. Her weight and height were 27 kg (3-10p) and 132.8 cm (3-10p), respectively. On physical examination, heart rate was 84 beats/min, blood pressure was 90/60 mmHg, and her thyroid was stage 1. Her thyroid function tests were as follows: total [T.sub.3] 2.4 ng/mL (0.9-2.3), free T3 6.17 pg/mL (1.7-3.7), total [T.sub.4] 12.9 [micro]g/dL (5.9-12.9), free [T.sub.4] 2.33 ng/dL (0.7-1.48), TSH 3.29 [micro]IU/mL, thyroglobulin 15.2 ng/mL (0.2-70), and negative antibodies of thyroglobulin and thyroperoxidase. In the genetic analysis of the patient suspected of having thyroid hormone resistance, the P453A c.1357C > G mutation was detected to be heterozygous on the exon 10 of the THRB gene. Beta-blocker therapy was initiated in the patient who was still complaining of palpitations and tachycardia.
Among THRB gene mutations, 453 mutation is the most common one. In our case, the receptor affinity of [T.sub.3] was reduced to 17% as a result of alanine substitution of proline amino acid due to guanine transversion instead of cytosine in codon 453 at exon 10. This mutation has been reported in six patients in the literature and it is noteworthy that four of the patients are of Turkish origin.
Aylin Kilinc Ugurlu, Esra Doger, Emine Demet Akbas, Aysun Bideci, Orhun Camurdan, Peyami Cinaz
Gazi University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
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|Author:||Ugurlu, Aylin Kilinc; Doger, Esra; Akbas, Emine Demet; Bideci, Aysun; Camurdan, Orhun; Cinaz, Peyami|
|Publication:||Journal of Clinical Research in Pediatric Endocrinology|
|Article Type:||Case study|
|Date:||Jun 1, 2017|
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