Thyroid Hormone Generalized Resistance

Abstract

The syndromes of thyroid hormone resistance may affect overall or only some tissues. The generalized resistance is an inherited disease which involves a familial eumetabolic or hypometabolic goiter, increased free thyroid hormones with normal or elevated plasma TSH levels; children may present mental retardation, deafness, short stature and delayed bone age. The disease is frequently misdiagnosed. In vivo and in vitro tests may be used to assess the diagnosis. The defect of increment of sex hormone-binding globulin after administration of T₃ may be useful in the demonstration of the disease. Therapy uses high T₄ or T₃ doses in hypometabolic patients. The generalized thyroid hormone resistance could be linked to abnormalities at the T₃ receptor and c-erb A gene level, as a consequence of different point mutations or deletions involving the hormone-binding domain.