Therefore, the heading “hypersensitivity” includes allergic hypersensitivity conditions, such as milk-induced anaphylaxis (IgE-mediated) or antiepileptic-induced Stevens-Johnson syndrome (non-IgE mediated), as well as non-allergic hypersensitivity conditions, such as angiotensin-converting enzyme inhibitor induced angioedema or cold-induced urticaria (non-immune mediated hypersensitivity). The gene discussed is IGHE; the disease is Stevens-Johnson syndrome.