Analysis of genetic variation in two human thyroxine-binding plasma proteins by immunodetection after isoelectric focusing.

An immunological method for the detection of two thyroxine-binding plasma proteins, thyroxine-binding globulin (TBG) and thyroxine-binding prealbumin (TBPA), following polyacrylamide gel isoelectric focusing is described. Both proteins show complex electrophoretic patterns, attributable to post-translational glycosylation, which are affected by unfavourable conditions of sample storage. No genetic variants of TBG or TBPA were encountered in a study of N. European individuals (n = 50). The X-linked TBG polymorphism, previously detected using a radiolabelled ligand binding technique in Pacific Islanders, was, however, demonstrable by our new immunological method in a previously untested population (n = 139) from the island of Maewo in Vanuatu.