Familial thyroxine binding globulin deficiency

Abstract

A kindred with deficiency of thyroxine binding globulin is presented in which the propositus, a 42-yr-old housewife, had been treated for 3 yr with thyroxine on the finding of a low thyroxine iodine after investigation for rather vague symptoms. All subjects in the pedigree were euthyroid and transmission was X-linked. Males showed low serum thyroxine iodine and high tri-iodothyronine (T3) resin uptakes, due to near complete absence of serum thyroxine binding globulin. Female carriers were less affected. A specific test for thyroxine binding globulin revealed the diagnosis, and emphasizes that a single thyroid function test should be interpreted carefully, especially if the patient presents with vague symptoms. A kindred with deficiency of thyroxine binding globulin is presented in which the propositus, a 42-yr-old housewife, had been treated for 3 yr with thyroxine on the finding of a low thyroxine iodine after investigation for rather vague symptoms. All subjects in the pedigree were euthyroid and transmission was X-linked. Males showed low serum thyroxine iodine and high tri-iodothyronine (T3) resin uptakes, due to near complete absence of serum thyroxine binding globulin. Female carriers were less affected. A specific test for thyroxine binding globulin revealed the diagnosis, and emphasizes that a single thyroid function test should be interpreted carefully, especially if the patient presents with vague symptoms.