The IgE-mediated activation of MCs is an effective target for attenuating the symptoms of allergic diseases because current antiallergic drugs, including the anti-IgE humanized antibody (Ab) [4], antagonists of leukotriene receptors [5], and histamine receptors [6], inhibit events related to the IgE-mediated activation of MCs. The gene discussed is IGHE; the disease is allergic disease.