CFTR and cystic fibrosis: For example, homozygous [F508del]CFTR patients generally have a more pronounced clinical challenges compared to compound heterozygous [F508del]CFTR and non‐[F508del]CFTR patients (Cystic Fibrosis Genotype‐Phenotype Consortium, 1993; Johansen et al., 1991; McKone et al., 2003, 2006).