Endocrine Abstracts

Background: Resistance to thyroid hormone (TH) alpha (RTHα), caused by heterozygous mutations in THRA, is characterized by abnormal thyroid function tests and features due to tissue-specific hypothyroidism, including disproportional short stature, variable motor and cognitive defects, macrocephaly and macroglossia, constipation and anemia. Mutant receptors display defective T3 binding resulting in impaired transcriptional activity. Dominant negative inhibition of the WT r...

Background: Resistance to thyroid hormone (TH) beta (RTHβ), caused by mutations in THRB, is characterized by elevated serum (F)T4 accompanied by non-suppressed TSH concentrations. Disease features arise from variable resistance to TH action in tissues expressing Thyroid Hormone Receptor (TR) β (hypothalamus, pituitary, liver) and from thyrotoxic effects in tissues expressing TRα (heart, bone, brain). In symptomatic patients, treatment mainly involves be...

Background: Resistance to thyroid hormone alpha (RTHα), caused by mutations in the T3-receptor alpha 1 (TRα1) isoform, includes growth retardation, intellectual disability, and abnormal thyroid function tests. The current paradigm entails that disease features arise from decreased T3 action in TRα1-expressing tissues. However, also for patients that carry mutations that completely abolish T3-stimulated activity, neurological features vary strongly, ranging from ...