Previous investigations from our laboratory identified the ultrastructural pathology and cytochemistry of macrothrombocytes (MTC) from patients with the X-linked, G208S varient of the GATA-1 mutation.A subsequent biochemical study of the MTC cytoskeletal proteins using polyacrylamide gel electrophoresis and western blot analysis revealed the MTC were deficient in the high-molecular weight, actin binding protein, talin. The present study has used immunofluorescent techniques to further characterize the talin deficiency. Results confirm that the GATA-1, G208S MTC are deficient in talin, and what little is present relocates to the undersurface of the plasma membrane following activations where it associates with adhesion plaques.