Keywords: adult onset CF; CF sinusitis; CFTR genotyping; CFTR-related disorder; chronic rhinosinusitis EN adult onset CF CF sinusitis CFTR genotyping CFTR-related disorder chronic rhinosinusitis 1135 1137 3 06/30/21 20210701 NES 210701 HISTORY AND CLINICAL FEATURES A 66-year-old female with an 8-year history of worsening chronic rhinosinusitis (CRS) and three prior sinus surgeries presented to the rhinology clinic in 2017 with persistent purulent drainage, sinus pressure, congestion, and olfactory dysfunction. Adult onset CF, CF sinusitis, CFTR genotyping, CFTR-related disorder, chronic rhinosinusitis Highlights CFTR dysfunction in the upper airway Adult-onset CF sinusitis CFTR-related disorder clinical improvement with CF therapy DISCUSSION Diagnosis and clinical course A diagnosis of CFTR-related disorder was made with the patient's sinopulmonary manifestations, intermediate sweat chloride levels, and CFTR testing. [Extracted from the article]