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. This evidence concerns the gene GH1 and Laron syndrome.