Genetic Influences on Thyroid Function Tests

In this review we will discuss the possible effects of polymorphic variation in the genes important for thyroid hormone synthesis, metabolism, and action, on the interindividual variation in thyroid functions tests. The genes involved are summarized in the following outline of thyroid hormone production and action, but their role is discussed in detail in other sections (Chaps. 1 and 4). In addition to these genes, we will also briefly discuss the possible contribution of genetic variation in the thyroid-specific transcription factors which are known to be important for thyroid development and regulation: TTF1, TTF2, and Pax8.