As principal effector cells of IgE-mediated type-I and IgE-independent pseudo-allergic hypersensitivity reactions, MCs contribute to acute phenomena like food allergy and anaphylaxis, as well as to complex diseases like rhinitis, asthma, eczema, and urticaria [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21]. The gene discussed is IGHE; the disease is rhinitis.