MUC5AC is a major component of the pathological mucus gel in T2-high asthma (12), a condition associated with increased IL-13 (7, 34), and mucus plugging is a feature of both severe chronic T2-high asthma and of severe asthma exacerbations (3, 4, 35, 36). The gene discussed is MUC5AC; the disease is asthma.