As early as 2006, Hizawa et al. found five single nucleotide polymorphisms (SNPs) in IL-17F and found that rs763780 {His-to-Arg substitution at amino acid 161 (H161R)} in the third exon of the IL-17F gene influenced the susceptibility to asthma and chronic obstructive pulmonary disease (COPD) in the Japanese population (4, 5). Here, IL17F is linked to asthma.