Impact of high- versus low-risk genotype on sinonasal radiographic disease in cystic fibrosis

Objective: Understanding of how specific mutations impact the cystic fibrosis transmembrane conductance regulator (CFTR) protein has given rise to the classification of CF patients into low-risk and high-risk genotypes. Few prior studies have investigated differences in sinonasal disease between low-risk and high-risk CF genotypes. This multi-institutional review aimed to evaluate radiographic sinus disease severity based on genotype. Methods: A review was conducted on adult patients with CF evaluated between 2005 to 2017 at three academic institutions. Data including age, gender, CFTR mutation, and presence of a maxillofacial/sinus computed tomography scan was collected. A modified Lund-Mackay score (MLMS) was assigned to each scan, and the presence of sinus aplasia or hypoplasia was determined. Patients were further grouped depending on genotype into low- or high-risk for comparison. Results: A total of 126 patients were included with 99 patients in the high-risk and 21 in the low-risk groups. The high-risk group had significantly higher MLMS than the low-risk group (mean 13.88 vs. 8.06, P < 0.0001, 95% CI −8.196 to −3.462) The rate of frontal (P < 0.01), maxillary (P = 0.04), and sphenoid (P < 0.001) hypoplasia/aplasia was significantly higher in high-risk patients compared to low-risk. Conclusion: This is one of the largest studies to date evaluating the impact of CF genotype on paranasal sinus development and disease. Genotype appears to impact sinonasal disease severity and also potentially paranasal sinus cavity development to a degree, although the exact mechanism is unknown. Level of Evidence: 4 Laryngoscope, 129:788–793, 2019.