Graves Disease is known to be a type of autoimmune problem that will make the thyroid gland produce a lot of thyroid hormone. This means that a person may become diagnosed with hyperthyroidism. A lot of people usually realize later on that the reason why they have hyperthyroidism is because of this disease.
Still, there are some people who may have hyperthyroidism and not have Graves disease. There is no obvious cause or reason why people get this disease. Take note that those who have this condition may sometimes have different manifestations of the disease aside from hyperthyroidism. For example, some people may get goiter or exophthalmos.