CFTR and cystic fibrosis: Based on these findings and the observation that CFTR−/− and CFTRΔF508/ΔF508 pigs develop lung disease, we hypothesized that CF pigs would spontaneously develop sinus disease.24, 25 Five of nine CF pigs followed longitudinally developed sinus disease confirmed by sinus CT findings, gross disease on necropsy, and/or positive microbiology (Fig. 6).