Hypoglycemia in the range of ∼2.5–3.5 mmol/L typically fails to trigger a clinically meaningful increase in plasma glucagon levels (systemic values fail to rise above ∼60 pg/mL when the expected increase is >100 pg/mL) within months of T1D diagnosis (Siafarikas et al., 2012), thereby shifting the counterregulatory burden to sympathoadrenal (epinephrine) and other autonomic mechanisms (Cryer, 2005). Here, GCG is linked to type 1 diabetes mellitus.