The wide fluctuations of glucose are due not only to the insulin deficiency, which has been considered to be one of the leading causes of glycemic volatility [1], [2], but also may be at least partly due to abnormal glucagon secretion [3]; namely, a deficient glucagon response to hypoglycemia [4] and an inappropriately high glucagon response to hyperglycemia [5]. This evidence concerns the gene GCG and Hyperglycemia.