Except for the functional analysis of the IL1RL1 SNP rs6543116 associated with asthma and atopic dermatitis [36, 53], there has been no functional analysis of the disease-associated variants in IL1RL1; functional characterization of genetically-associated variants is necessary to determine the causal pathways leading to expression and/or function changes in the proteins. Here, IL1RL1 is linked to asthma.