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Thyroid hormone transporters and resistance
1Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands. t.j.visser@erasmusmc.nl
Endocrine Development
|February 9, 2013
Summary
Thyroid hormone (TH) transport into cells requires specific transporters like monocarboxylate transporter 8 (MCT8). MCT8 defects cause Allan-Herndon-Dudley syndrome (AHDS), a severe neurodevelopmental disorder.
Area of Science:
- Endocrinology
- Neuroscience
- Molecular Biology
Background:
- Cellular uptake is crucial for thyroid hormone (TH) action.
- TH transport across cell membranes is protein-mediated, not passive diffusion.
- Monocarboxylate transporter 8 (MCT8) is a key TH transporter, encoded on the X chromosome.
Purpose of the Study:
- To highlight the critical role of MCT8 in cellular TH transport.
- To explain the genetic basis and clinical manifestations of MCT8 defects.
- To define Allan-Herndon-Dudley syndrome (AHDS) as a TH transport defect.
Main Methods:
- Literature review on TH transport mechanisms.
- Analysis of genetic data related to MCT8 mutations.
- Clinical case studies of patients with AHDS.
Main Results:
- MCT8 is essential for TH entry into various tissues, particularly the brain.
- Mutations in the MCT8 gene cause severe psychomotor retardation in males (AHDS).
- AHDS is characterized by abnormal serum TH levels and impaired neurological development.
Conclusions:
- MCT8 is indispensable for normal brain development and TH homeostasis.
- Defective MCT8 function leads to a specific form of thyroid hormone resistance.
- Understanding MCT8 transport is vital for diagnosing and potentially treating AHDS.
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