Our aim is to replicate the analyses of the PIAMA birth cohort in the ALSPAC birth cohort. We hypothesise that the association of the IL1RL1 pathway with asthma, the number of eosinophils and the wheezing phenotypes can be replicated in the ALSPAC birth cohort. Therefore, we would like to study the association of SNPs of the IR1RL1 pathway (genes IL33, IL1RL1, IL1RAcP, MYD88, TIRAP, IRAK1, IRAK4 and TRAF6) with a doctor diagnosis of asthma in childhood, with the number of eosinophils in childhood with wheezing phenotypes in childhood in the ALSPAC birth cohort. Furthermore, we would like to study 10 selected interactions of SNPs in the IL1RL1 pathway and the presence of a doctor diagnosis of asthma in childhood.