CFTR mutations and genotypic patterns among cystic fibrosis patients with allergic bronchopulmonary aspergillosis: analysis from a tertiary care center in Saudi Arabia.

INTRODUCTION: Cystic fibrosis (CF) is a multisystem disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Allergic bronchopulmonary aspergillosis (ABPA) is a recognized complication in CF, with genetic variability potentially influencing susceptibility. This study aims to assess the distribution of CFTR genotype classes in CF patients with ABPA and explore their association with disease severity and baseline pulmonary function. METHODS: A retrospective cross-sectional study was conducted over a 10-year period, including patients <18 years with genetically confirmed CF and concomitant ABPA. CFTR mutation data were analyzed, and comparative analyses were performed across CFTR genotype classes. RESULTS: Twenty-two patients were included, with a median age of 13.75 years at the time of ABPA diagnosis. CFTR mutations identified were predominantly classified as Class I (72.7%), followed by Class II (22.7%), with a single patient harboring a Class V mutation. Patients with Class II/V mutations showed lower growth indices and baseline pulmonary function compared to Class I, without statistical significance (p > 0.05). Chest CT findings were comparable between the groups, with bronchiectasis and bronchial wall thickening representing the most common radiological abnormalities. CONCLUSION: CFTR genotype may influence clinical phenotype in CF patients with ABPA, with trends toward poorer growth and lung function in more severe mutation classes, although larger studies are needed to confirm these associations.