Endocrine Abstracts

It has been known for a long time that both hypo- and hyperthyroidism are associated with an increased risk of morbidity and mortality. In recent years, it has also become clear that minor variations in thyroid function, including subclinical dysfunction and even variation in thyroid function within the reference range, can have important effects on clinical endpoints, such as bone mineral density, depression, metabolic syndrome, and cardiovascular mortality. Serum thyroid parameters show substantial interindividual variability, whereas the intraindividual variability lies within a narrow range. This suggests that every individual has a unique hypothalamus-pituitary-thyroid axis setpoint that is mainly determined by genetic factors, and this heritability has been estimated to be 40–60%. In recent years, advances in genetic research have contributed to unraveling part of these genetic factors. In my presentation I will discuss the identification of important new genes contributing to the overall variation in TSH and FT4 levels, as well as the relevance of the optimal thyroid function set-point in specific examples such as aging and pregnancy.