Related Experiment Video

Updated: Jul 4, 2026

A Method to Study the C924T Polymorphism of the Thromboxane A2 Receptor Gene
07:00

A Method to Study the C924T Polymorphism of the Thromboxane A2 Receptor Gene

Published on: April 1, 2019

Thyroid hormone receptor beta gene mutation (P453A) in a family producing resistance to thyroid hormone

T Bayraktaroglu1, J Noel, F Alagol

  • 1Department of Internal Medicine, Division of Endocrinology, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey. baytaner@yahoo.com

Experimental and Clinical Endocrinology & Diabetes : Official Journal, German Society of Endocrinology [And] German Diabetes Association
|June 19, 2008
PubMed
Abstract

Insights

Genetic testing confirmed Resistance to Thyroid Hormone (RTH) in a Turkish family. Identifying mutations in the thyroid hormone receptor beta gene (TRβ) offers a definitive RTH diagnosis.

Area of Science:

  • Endocrinology
  • Genetics

Background:

  • Resistance to Thyroid Hormone (RTH) is an inherited disorder affecting thyroid hormone responsiveness.
  • A Turkish family presented with symptoms suggestive of RTH.

Observation:

  • Clinical presentations varied between mother and son.
  • The mother experienced symptoms like palpitations and nervousness, leading to a misdiagnosis.
  • The son exhibited attention deficit hyperactivity disorder and encopresis.

Findings:

  • Both individuals had elevated serum iodothyronine and non-suppressed thyrotropin.
  • Genetic analysis revealed a P453A mutation in the thyroid hormone receptor beta gene (TRβ).

Implications:

  • Mutational analysis of the TRβ gene provides definitive RTH diagnosis.
  • This genetic approach may obviate the need for extensive pituitary function testing.

Related Concept Videos

Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase01:11

Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
Synthesis and Regulation of Thyroid Hormones01:20

Synthesis and Regulation of Thyroid Hormones

Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Hyperthyroidism II: Pathophysiology01:27

Hyperthyroidism II: Pathophysiology

Hyperthyroidism is a hypermetabolic state caused by elevated levels of thyroid hormones, triiodothyronine (T3) and thyroxine (T4). It results from dysregulation at the thyroid, pituitary, or immune system level and affects multiple organ systems.PathophysiologyThe most common cause of hyperthyroidism is Graves’ disease, an autoimmune disorder in which antibodies, specifically thyroid-stimulating antibodies (TSAb), a subtype of TSH receptor antibodies (TRAb), bind to and activate TSH receptors...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu01:29

Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu

Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes01:28

Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes

Cytochrome P450 (CYP450) enzymes are a superfamily of heme-containing monooxygenases that play a pivotal role in Phase I drug metabolism by catalyzing oxidation and reduction reactions.These enzymes transform lipophilic xenobiotics into more hydrophilic metabolites, facilitating subsequent Phase II conjugation and eventual excretion. The CYP450 family is classified into families (e.g., CYP1–CYP3) and subfamilies (e.g., CYP2A, CYP2C), based on amino acid sequence homology.CYP450 isoenzymes,...
Graves' Disease I: Introduction01:28

Graves' Disease I: Introduction

Graves' disease is an autoimmune disorder that causes hyperthyroidism, or overactivity of the thyroid gland. It results from autoantibodies called thyroid-stimulating immunoglobulins (TSIs), which bind to thyroid-stimulating hormone (TSH) receptors, leading to overstimulation of hormone production and a hypermetabolic state.EtiologyAlthough considered idiopathic, Graves’ disease has well-established contributing factors. There is a strong genetic component, with increased prevalence in...