The locus on chromosome 2q12, which includes the IL1RL1 gene, has shown a significant replicated association with asthma (5, 7, 18, 20, 22) or asthma-relevant traits such as childhood asthma (21, 31, 32), childhood asthma with exacerbation (31), severe asthma (33, 34), asthma with hay fever (35), type 2 inflammation in asthma (36), and blood eosinophil counts (20). This evidence concerns the gene IL1RL1 and asthma.