A Case of Thyroxine Binding Globulin Deficiency with Hypothyroidism

ABSTRACT

A child diagnosed with congenital hypothyroidism after newborn screening and follow up thyroid function test at 1 month of life in another general hospital demonstrated euthyroid state with thyroxine(T4) supplementation until the age of 22 months of life, when he was transferred to our hospital, where he was diagnosed as thyroxine binding globulin(TBG) deficiency with low T4 and TBG. Withdrawal of T4 at age of 26 months was associated with hyperthyrotropinemic hypothyroidism. This patient is a case of TBG deficiency associated with hypothyroidism, and in rare instances, TBG deficiency may lead to hypothyroidism requiring hormone supplementation.