The IL4 and IL13 genes are located in one cluster of chromosome5q31.1 and encode cytokines that play a key role inthe asthma pathogenesis, namely, IL-4 and IL-13 promoteairway eosinophilia, mucus hyperproduction, bronchial hyperreactivity,and IgE synthesis (Zhang et al., 2015). The gene discussed is IL4; the disease is asthma.