Studies have shown that mucin is the major component of airway mucus in patients with CRS, which affects the rheological properties of mucus [16], leading to a series of pathophysiological changes, including submucosal gland hyperplasia, the increased numbers and excessive secretion of airway goblet cells, and mucin hypersecretion, particularly MUC5AC and MUC5B [17]. The gene discussed is MUC5AC; the disease is congenital rubella syndrome.