CFTR and cystic fibrosis: In a therapeutic study of CF, researchers used PDOs derived from patients with the G542X genotype and found that ELX-02 targeting of the G542X cystic fibrosis transmembrane conductance regulator (CFTR) nonsense allele restored CFTR function in HIOs (Crawford et al., 2021), supporting the clinical evaluation of ELX-02 as a through-putting agent for the treatment of CF caused by mutations in the G542X allele.