Thyroglobulin is a protein from which thyroid hormones are subsequently formed.Normally, it is found only in the gland and does not go beyond the organ. For unknown reasons, a person may have a malfunction in the immune system, and autoantibodies appear (components of an aggressively tuned immunity against their own organs) that "attack" thyroglobulin (see "Thyroglobulin"). Inflammation of the gland develops – thyroiditis. This leads to a decrease in the level of thyroid gland hormones – T3, T4, that is, hypothyroidism develops.

Thyroiditis can develop gradually, then the following symptoms will occur: fatigue, weight gain, memory impairment, swellings may occur. The person becomes tearful, resentful. If the number of antibodies is very large, then thyroiditis develops acutely: the structure of the thyroid gland is destroyed, and thyroid hormones enter the blood in huge quantities. In this case, the clinical picture will correspond to hyperthyroidism: there is trembling of the limbs, increased body temperature, weight loss with increased appetite, increased heart rate.