The most well known cause of the syndrome are mutations of the β (beta) form (THRB gene) of the thyroid hormone receptor, of which over 100 different mutations have been documented.
Den vanligaste orsaken till tyreoideahormonresistens är mutationer i β (beta) formerna (THRB) av sköldkörtelhormonreceptorn, varav över 100 olika mutationer har dokumenterats.