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Two Novel Mutations in the Thyroid Hormone Receptor β in Patients with Resistance to Thyroid Hormone (RTH β):
A M Esquiaveto-Aun1,2,3, D E Zantut-Wittmann4, R J Petroli2
1Department of Pediatrics, Faculty of Medical Sciences (FCM), University of Campinas (UNICAMP), Campinas, Brazil.
Abstract:
The syndrome of resistance to thyroid hormone (RTH β) is an inherited disorder characterized by variable tissue hyposensitivity to 3,5,30-L-triiodothyronine (T(3)), with persistent elevation of free-circulating T(3) (FT(3)) and free thyroxine (FT(4)) levels in association with nonsuppressed serum thyrotropin (TSH). Clinical presentation is variable and the molecular analysis of THRB gene provides a short cut diagnosis. Here, we describe 2 cases in which RTH β was suspected on the basis of laboratory findings. The diagnosis was confirmed by direct THRB sequencing that revealed 2 novel mutations: the heterozygous p.Ala317Ser in subject 1 and the heterozygous p.Arg438Pro in subject 2. Both mutations were shown to be deleterious by SIFT, PolyPhen, and Align GV-GD predictive methods.
Insights
This study identifies two novel mutations in the THRB gene causing resistance to thyroid hormone beta (RTH β), a genetic disorder affecting thyroid hormone sensitivity. These findings aid in diagnosing RTH β through molecular analysis.
Area of Science:
- Endocrinology
- Genetics
- Molecular Biology
Background:
- Resistance to thyroid hormone beta (RTH β) is an inherited condition with variable tissue insensitivity to thyroid hormones.
- It is characterized by elevated free thyroid hormone levels (FT3 and FT4) and non-suppressed TSH.
- Molecular analysis of the THRB gene is crucial for diagnosis.
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