A type 2 inflammation is evident in more than 50% of those with a formal asthma diagnosis [90] and is typically characterized by activation of proinflammatory cytokines including interleukins (IL)-4, − 5, and − 13, manifesting as the type 2 endotype with raised levels of immunoglobulin E (IgE), eosinophils, and fractional exhaled nitric oxide (FeNO), and dysfunction of epithelial or epidermal barriers [91]. The gene discussed is IL4; the disease is asthma.