A high risk of nasal polyposis has been found in patients homozygous for ΔF508 or other severe mutations (Figure 1), although with no clear correlation with the severity of CF.(9) This hypothesis was not confirmed, and some studies even showed improved lung function and nutritional status in CF patients with nasal polyposis.(10,11) Genetic studies have suggested that the CFTR mutation responsible for CF is in itself a predisposing factor for sinonasal disease, showing an increased prevalence of CFTR mutations in the general population with CRS.(12). The gene discussed is CFTR; the disease is cystic fibrosis.