In relation to asthma, the causal SNP was -131 C→G (rs4950928) in the core promoter region of CHI3L1. Recently, the -247C/T promoter polymorphism (rs10399805) of CHI3L1 was found to associate with serum YKL-40 levels and the risk of atopy in children [7]. This evidence concerns the gene CHI3L1 and asthma.