Two signals are known to be associated with asthma and COPD/lung function, including the HLA-DQB1 locus (the first signal identified as associated with both asthma and COPD), and a signal at C5orf56, encoding IRF1-AS1, on chromosome 5, near a cytokine gene cluster. Here, HLA-DQB1 is linked to chronic obstructive pulmonary disease.