Autoimmune thyroiditis

Nature

Autoimmune thyroiditis, also known as Hashimoto's disease and chronic lymphocytic thyroiditis, is a chronic disease occurring in the thyroid, the butterfly-shaped endocrine gland in the anterior neck. This disease occurs when the body interprets components of the thyroid glands as threats, therefore producing special antibodies that target the thyroid's cells or proteins, thereby destroying it. It most commonly presents as hypothyroidism with or without a goiter. It is the most common cause of hypothyroidism in iodine-sufficient areas of the world.

Source: Wikipedia

Type 
(G) Very specific problems