In patients with severe allergic phenomena (eczema, eosinophilia, food allergies) measuring IgE levels can also be helpful in identifying certain disorders, i.e., Hyper IgE syndromes such as DOCK8 deficiency, STAT3-HIES and PGM3 deficiency. The gene discussed is STAT3; the disease is hyperinsulinemic hypoglycemia, familial, 4.