While it was previously considered as the gold standard for the diagnosis of acromegaly, suppression of GH levels during OGTT is not specific for acromegaly, as conditions associated with an abnormal GH response to a glucose load include severe catabolic illness, malnutrition, renal or hepatic failure, uncontrolled diabetes mellitus, Laron type dwarfism. The gene discussed is GH1; the disease is diabetes mellitus.