What is the hallmark immune system disorder associated with hyperthyroidism?

The hallmark immune system disorder associated with hyperthyroidism is Graves' Disease. This condition is characterized by the production of antibodies that stimulate the thyroid gland, leading to excessive thyroid hormone production, also known as hyperthyroidism. The autoantibodies, specifically thyroid-stimulating immunoglobulins, bind to the thyroid receptors, mimicking the action of thyroid-stimulating hormone (TSH) and causing the gland to become overactive.

In contrast, Hashimoto's Thyroiditis, another autoimmune thyroid disorder, typically leads to hypothyroidism rather than hyperthyroidism. Cushing's Syndrome is related to excessive cortisol levels, which affects metabolism and immune function, but is not directly linked with thyroid function. Aldosteronism involves an imbalance in aldosterone levels affecting sodium and potassium balance and does not pertain to thyroid hormone regulation.