In a study using 30 patients with type 2 diabetes and known cardiovascular disease, glucose monitoring in conjunction with electrocardiograms showed patients taking insulin and/or sulfonylurea had a high incidence of severe (< 3.1 mmol/L) but asymptomatic hypoglycemia whereas patients taking metformin and/or dipeptidyl peptidase-4 inhibitors did not and patients with severe hypoglycemia had more ventricular arrhythmias (Stahn et al., 2014). The gene discussed is DPP4; the disease is Hypoglycemia.