MUC5AC and sinusitis: A total of 21 mucin genes have now been identified in humans, and a total of 8 mucins have been detected in chronic sinusitis (CRS) tissues, including 6 secreted mucins (MUC2, MUC5AC, MUC5B, MUC6, MUC7, and MUC8) and two membrane‐bound mucins (MUC1 and MUC4).3