Graves’ disease is an autoimmune disease. It most commonly affects the thyroid, frequently causing it to enlarge to twice its size or more, become overactive, with related symptoms such as increased heartbeat, muscle weakness, disturbed sleep, and irritability. It can also affect the eyes, causing bulging eyes. It affects other systems of the body, including the skin, heart, circulation and nervous system.
It affects up to 2% of the female population, sometimes appears after childbirth, and occurs seven to eight times more often in women than in men. Genetic factors are a major influence accounting for possibly around 80% of the risk. Smoking and exposure to second-hand smoke are associated with the eye manifestations, but not the thyroid manifestations.