Clinical trials as well as real world observational studies consistently demonstrated larger effects of CFTR modulator therapy on CFTR function in children compared to adolescents and adults with CF (Middleton et al., 2019; Heijerman et al., 2019; Goralski et al., 2023; McNamara et al., 2019; Stahl et al., 2024b; Graeber et al., 2018; Berges et al., 2023; Boyle et al., 2014; Stahl et al., 2023; Nichols et al., 2022; Mall et al., 2022). Here, CFTR is linked to cystic fibrosis.