Which condition is characterized by an autoimmune response affecting the thyroid gland?

The condition characterized by an autoimmune response affecting the thyroid gland is indeed Hashimoto thyroiditis. This autoimmune disorder occurs when the body's immune system mistakenly attacks the thyroid gland, leading to inflammation and often resulting in hypothyroidism, where the thyroid does not produce enough hormones for the body's needs.

While Graves' disease is also an autoimmune condition involving the thyroid, it presents differently by causing hyperthyroidism, which means the thyroid produces too much hormone. This distinction is important when determining the specific characteristics of each condition.

Thyroid carcinoma, on the other hand, refers to cancer of the thyroid and is not primarily an autoimmune disorder; its mechanisms involve malignancy rather than an autoimmune attack. Cushing syndrome is a hormonal disorder caused by excess cortisol and is unrelated to thyroid function.

Thus, Hashimoto thyroiditis specifically embodies an autoimmune response leading to thyroid dysfunction.