Additionally to the traditional markers, homeostasis model assessment insulin resistance index [20] (HOMA-IR; as a marker of insulin resistance), insulinogenic index (II) as a reasonable surrogate and valid marker of insulin sensitivity disturbances and beta cell function in type 2 diabetes and other cardiometabolic diseases [21], glycated hemoglobin [22] (HbA1c; as a marker for long-term glycemic control) and glucagon-like peptide-1 [23,24] (GLP-1; as a marker of insulin secretion glucose-induced), are assessed. The gene discussed is GCG; the disease is type 2 diabetes mellitus.