Thyroid transcription factor-1.

Thyroid transcription factor-1 (TTF-1) is a recently identified member of the homeodomain transcription factor family, which plays a role in regulating genes expressed within the thyroid, lung and brain, including thyroglobulin, thyroid peroxidase, Clara cell secretory protein and the surfactant proteins. Additional studies, including gene targeting experiments, have clearly shown that expression of TTF-1 is essential for morphogenesis of the thyroid, lung and ventral forebrain, as TTF-1 knockout mice lack these organs. In the light of these studies it seems possible that mutations in TTF-1 may underlie certain abnormalities either of organogenesis of, or of cellular function within, these organ systems. A recent example of such a defect is the identification of a patient with thyroglobulin deficiency due to decreased TTF-1 expression.