Mutations in the gene encoding DOCK8 account for the majority of patients with AR-HIES2, referred to as DOCK8 deficiency, characterized by eosinophilia, elevated immunoglobulin E (IgE) levels, recurrent infections, atopic dermatitis (AD), allergies, autoimmunity and malignancy (2, 3). The gene discussed is DOCK8; the disease is hyperinsulinemic hypoglycemia, familial, 4.