In summary, the CFTR−/− rat exhibits many features of the CF phenotype found in human subjects and CF animal models (summarized in Table 2), including defects in airway mucus production (Figure 4), tracheal development (Table 1), airway surface and periciliary fluid depth (Figure 6), nasal mucus (Figure 4), dentition (Figure 8), and involution of the vas deferens (Figure 7). The gene discussed is CFTR; the disease is cystic fibrosis.