Although no formal criteria for the biochemical diagnosis of severe IR exists, there is general consensus that the following conditions are indicators: a fasting insulin value above 20.9μU/mL and/or a peak insulin value on oral glucose tolerance testing above 209 μU/mL when diabetes is absent and a body mass index (BMI) below 30kg/m2; or an exogenous insulin requirement of above 3 U/kg per day when diabetes with absolute insulin deficiency is present in association with a BMI below 30kg/m2 [8]. This evidence concerns the gene INS and diabetes mellitus.