Autoimmune thyroiditis is an autoimmune disease of the thyroid gland. It occurs when the body's immune system mistakenly targets the thyroid gland by attacking its own tissues. Autoimmune thyroiditis causes the thyroid gland to become inflamed and damaged, causing it to lose function. While hyperthyroidism initially occurs due to rapid depletion of thyroid stores, hypothyroidism occurs over time. As with other autoimmune diseases, the risk of autoimmune thyroiditis is associated with genes such as IL-17 and TNFA, which play a role in the inflammatory pathway. In addition, genes involved in the methylation cycle and liver detoxification in relation to environmental factors may also play a role in the pathogenesis of autoimmune thyroiditis.