Six common variants were significantly associated with hypersensitivity pneumonitis, with MUC5B rs35705950 showing the strongest association with both hypersensitivity pneumonitis as a whole [odds ratio (OR); 2.11, P = 1.74 × 10−6] and fibrotic hypersensitivity pneumonitis (OR; 2.32, P = 2.61 × 10−6). This evidence concerns the gene MUC5B and hypersensitivity pneumonitis.