Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) were introduced for type 2 diabetes therapy nearly 10 years ago, among them short-acting compounds on the basis of the GLP-1-like peptide exendin-4 (exenatide and lixisenatide) and a long-acting GLP-1 RA based on the human GLP-1 sequence (liraglutide). This evidence concerns the gene GCG and type 2 diabetes mellitus.