Abstract
A 44 year old male was admitted to our hospital because of a bone fracture. Labora-tory examination upon admission revealed a high serum cholesterol level and this was examined in detail. Although he had no goiter, physical examination revealed slight edema on his face, mounding phenomenon at Biceps and diminished Achilles tendon reflex. Laboratory examination also showed low concentrations of serum T3, T4 and free T4, and high concentration of TSH. Since elevated T3RSU was observed in this patient, serum TBG concentration was measured, but it was not detectable. High serum CPK level and decreased creatinine clearance without proteinuria were also discovered. As no other diseases which might cause low TBG concentration were recognized and a low concentra-tion of TBG was also ascertaind in one of his daughters, this case was diagnosed as familial TBG deficiency associated with hypothyroidism.
Familial deficiency of TBG has frequently been reported in cases of hyperthyroidism. On the contrary, case reports of hypothyroidism are few up to the present. It might be only due to the fact that the ratio of free T4 is increased in TBG deficiency, and this in-crease resulted in subclinical manifestation of symptoms of hypothyroidism. Therefore, careful examination in patients with hypothyroidism, paticularly in those who have slight or no symptoms of hypothyroidism, might detect much more cases with TBG deficiency in the future. The pathogenesis of renal insufficiency in this patient remains uncertain.
