Familial elevation of serum thyroxine binding globulin in an Icelandic family.

A kindred of four generations with inherited elevation of serum thyroxine binding globulin (TBG) is reported. To our knowledge this is the twelfth kindred reported with this disorder. Of the 35 family members studied, 10 females and 5 males had elevated serum TBG. The patients were clinically euthyroid. The pedigree data was consistent with an X-chromosome linked mode of inheritance.