[Thyroid hormone receptors and the disorders]

Thyroid hormone is essential for normal development and several metabolic pathways. Its action is mediated through its nuclear receptors (thyroid hormone receptors: TRs), which regulate gene transcriptions in a ligand-dependent manner. The abnormality of TR functions is linked with several disorders including resistance to thyroid hormone (RTH), malignancy and euthyroid sick syndrome. For example, mutant TRs were identified to cause RTH and a certain malignancy. The functionally impaired TRs might be related with euthyroid sick syndrome. The analyses of these TRs will elucidate the molecular mechanism or basis for the disorders, and may provide a new insight to find the way of diagnosis and treatment.