The association between the rs7216389 TT genotype and asthma exacerbation was identified in the type 2–low endo-genotype, defined by serum periostin levels less than 95 ng/mL and the presence of the rs8832 A allele on IL4RA, independent of other known risk factors such as female sex, higher BMI, and recent exacerbations. Here, POSTN is linked to asthma.