IAS is seldom considered in patients presenting with hypoglycemia due to its rarity among most ethnicities, although it is the third leading cause of hypoglycemia in Japan.[3,7] IAS is characterized by spontaneous hypoglycemia accompanied by hyperinsulinism and elevated insulin autoantibody tilters.[1] IAS has been associated with autoimmune syndromes, including rheumatoid arthritis, polymyositis, systemic sclerosis, ankylosing spondylitis, and especially Graves’ disease.[9]Although uncommon clinically, IAS can lead to prolonged hypoglycemia and life-threatening consequences in some cases. The gene discussed is INS; the disease is hyperinsulinism.