To date more than 2,000 mutations in the CFTR gene are known, with the F508del mutation NM_000492.3(CFTR):c.1521_1523del (p.Phe508del) being the most common, affecting about 70% of CF patients (De Boeck, 2020; Rodrigues et al., 2008). The gene discussed is CFTR; the disease is cystic fibrosis.