Focus on ionocyte development in CF and the relationship between ionocytes and CFTR-dependent chloride secretion identified a relatively high expression of ionocyte markers in the nasal epithelium with a possible proximal-distal gradient along the airways with a progressively decreasing number of ionocytes (Scudieri et al., 2020), a finding also reported by others (Okuda et al., 2021). This evidence concerns the gene CFTR and cystic fibrosis.