Resistance to thyroid hormone in the absence of mutations in the thyroid hormone receptor genes

Most people with resistance to thyroid hormone have mutant thyroid hormone receptors that interfere with the function of the normal receptor and produce a dominant mode of inheritance. Conversely, thyroid hormone receptor β gene deletion is inherited as a recessive trait. In about 10% of cases, resistance to thyroid hormone manifests in the absence of thyroid hormone receptor gene abnormalities. The clinical manifestations and laboratory abnormalities found in these individuals are not significantly different than those found in patients with thyroid hormone receptor β defects. We propose that the defect must be elsewhere in the pathway of thyroid hormone action.