The study reported that CF patients with biallelic deletion of ACE were associated with earlier clinical symptoms and a higher risk of lung deterioration than patients with ACE biallelic or monoallelic insertion polymorphisms.39 The effect of ACE polymorphisms and ACE2 downregulation exhibited in patients with CF may be attributed to the variability of the COVID-19 course in those patients.40 This evidence concerns the gene ACE2 and COVID-19.