Resistance to thyrotropin (RTSH) is broadly defined as reduced sensitivity of thyroid follicle
cells to stimulation by biologically active TSH due to genetic defects. Affected individuals
have elevated serum TSH in the absence of goiter, with the severity ranging from
nongoitrous isolated hyperthyrotropinemia to severe congenital hypothyroidism with thyroid
hypoplasia. Conceptually, defects leading to RTSH impair both aspects of TSH-mediated
action, namely thyroid hormone synthesis and gland growth. These include inactivating …