Coming back to our index patient, she fulfilled the necessary criteria to diagnose a glucagonoma [42]: in fact, we demonstrated the presence of increased levels of blood glucagon in a patient with glucose intolerance (Online Resource 5), we found the tumor mass with direct visualization at both diagnostic (Online Resource 6 and Online Resource 7) and nuclear medicine imaging (Online Resource 8) and we finally obtained a histological confirmation (Online Resource 9). The gene discussed is GCG; the disease is Glucose intolerance.