Thyroid hormones are essential for carbohydrate metabolism.[8–10] Hyperthyroidism (thyroid hormone excess) may affect the secretion, action, and clearance of insulin and many aspects of carbohydrate metabolism and thus lead to hyperglycemia.[11–15] On the contrary, hypothyroidism (thyroid hormone deficiency) may also interfere with the action and metabolism of insulin and induce insulin resistance.[16–18]. This evidence concerns the gene INS and hyperthyroidism.