Graves’ disease is an autoimmune disease (i.e., when the body reacts to its own tissues as though they were foreign substances). Graves’ disease is a type of autoimmune problem that causes the thyroid gland to produce too much thyroid hormone, which is called hyperthyroidism. This is called an overactive thyroid or hyperthyroidism.

With Graves' disease, the immune system makes antibodies that act like TSH, causing the thyroid to make more thyroid hormone than your body needs. It is closely related to Hashimoto's disease, another autoimmune disease affecting the thyroid. The underlying cause of Graves disease is not known, but there is genetic susceptibility to the disease, and smoking is a risk factor, especially for Graves ophthalmopathy. Thyroid eye disease is an inflammatory condition, which affects the orbital contents including the extraocular muscles and orbital fat.

Graves disease occurs in women four to six times as often as in men. It most often affects young to middle-aged adults but can occur at all ages. Another characteristic of the disease is spontaneous remission of hyperthyroidism, which occurs in 30 to 40 percent of patients.