['The glucagon gene (GCG) encodes several hormones important for energy metabolism: glucagon, oxyntomodulin and glucagon-like peptide (GLP)-1 and -2. Variants in GCG may associate with type 2 diabetes, obesity and/or related metabolic traits.', 'GCG was re-sequenced as a candidate gene in 865 European individuals. Twenty-nine variants were identified. Four variants that were considered to have a likelihood for altered functionality: rs4664447, rs7581952, Ile158Val and Trp169Ter, were genotyped in 17,584 Danes.', "When examined in 5,760 treatment-naive individuals, homozygous carriers of the low frequency (minor allele frequency 2.3%) G allele of rs4664447, predicted to disrupt an essential splice enhancer binding site, had lower levels of fasting plasma glucose (mean\u2009±\u2009SD, 4.8\u2009±\u20091.2 vs 5.5\u2009±\u20090.8 mmol/l, p\u2009=\u20090.004); fasting serum insulin (22\u2009±\u200914 vs 42\u2009±\u200927 pmol/l, p\u2009=\u20090.04); glucose-stimulated serum insulin (159\u2009±\u200983 vs 290\u2009±\u2009183 pmol/l, p\u2009=\u20090.01) and adult height (165\u2009±\u200910 vs 172\u2009±\u20099 cm, p\u2009=\u20090.0009) compared with A allele carriers. During oral glucose tolerance and hyperglycaemic arginine stimulation tests, the plasma AUC for GLP-1 (730\u2009±\u200969 vs 1,334\u2009±\u2009288 pmol/l\u2009×\u2009min, p\u2009=\u20090.0002) and basal and stimulated levels of serum insulin and plasma glucagon were ∼50% decreased (p\u2009<\u20090.001) among three homozygous carriers compared with nine matched wild-type carriers. rs7581952, Ile158Val and Trp169Ter (where 'Ter' indicates 'termination') variants of GCG did not significantly associate or co-segregate with the metabolic traits examined."] Are homozygous carriers of the G allele of rs4664447 of the glucagon gene ( GCG ) characterised by decreased fasting and stimulated levels of insulin , glucagon and glucagon-like peptide ( GLP ) -1?