Experimental Factor Ontology id EFO_0920039 (CFTR dysfunction bronchiectasis) is a bronchiectasis endotype characterized by cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction that does not meet full diagnostic criteria for cystic fibrosis, typically presenting with elevated sweat chloride concentration (intermediate range 30-59 mmol/L), mucociliary clearance defects, and susceptibility to nontuberculous mycobacterial pulmonary infection. Patients may carry heterozygous CFTR mutations or have reduced CFTR function without detectable mutations, and may be candidates for CFTR modulator therapy. Also known as: CFTR-predominant bronchiectasis, CFTR-related bronchiectasis, cystic fibrosis transmembrane conductance regulator dysfunction bronchiectasis.