Insulin Autoimmune Syndrome (Hirata Disease)- Severe Hypoglycemic Episodes in Graves Hyperthyroidism Patient Treated with Methimazole

: Insulin Autoimmune Syndrome (IAS) or Hirata disease is characterized by severe hypoglycemic episodes, a high level of immunoreactive insulin, and a high titer of insulin autoantibody in a person who has never received exogenous insulin. It is noted that IAS has a strong genetic predisposition and the majority of the IAS cases were reported from Japan where it is the third leading cause of hypoglycemia. It is also known that some drugs with sulfhydryl groups in their chemical structures can induce the formation of insulin autoantibodies in predisposed individuals, and Graves patient who possesses Bw62- Cw4-DR4 carrying DRB1-0406 maybe at risk of developing IAS when methimazole is administered. We present such a case which is very rare in our Caucasian population, who developed Hirata disease probably the first case in our Indian population.