Although these results are to be considered with caution given the small sample size–despite the sufficient power (β=0.20, Power=0.8; Supplementary Table 6)—which demands for a definitive validation using a larger new cohort of CF patients, the present findings confirm the existence of a sex dimorphism at IL9 and IL9R loci, as already reported in several respiratory-related human phenotypes36, 37. Here, IL9R is linked to cystic fibrosis.