Considering that children affected with microcephaly present an increase in serum levels of Th2 cytokines such as IL-13, IL-4, and IL-5 [6], which are associated with allergic conditions such as asthma, atopic dermatitis, and food allergies, we decided to administer an allergy profile questionnaire answered by the legal guardian of the patient to evaluate this condition. The gene discussed is IL4; the disease is microcephaly.