Manuel E. Izquierdo

and 21 more

Background:  Heterozygote carriers of potentially pathogenic variants in the cystic fibrosis transmembrane conductance regulator ( CFTR) gene have increased asthma risk. However, the frequency and impact of CFTR variation among individuals with asthma is unknown. Objective: To determine whether potentially pathogenic  CFTR variants associate with disease severity and whether individuals with two potentially pathogenic variants exist in a severe asthma-enriched cohort . Methods: We analyzed sequencing data spanning a 190.5Kb region of  CFTR in participants from the Severe Asthma Research Program (SARP1-3). Potentially pathogenic, rare  CFTR variants (frequency<0.05) were classified as CF-causing or of varying clinical consequences (VVCC) ( Regression-based models tested for association between  CFTR genotypes (0-2 potentially pathogenic variants) and severity outcomes. Results: Of 1401 participants, 9.5% (134) had one potentially pathogenic variant, occurring more frequently in non-Hispanic white (NHW, 10.1% [84 of 831]) compared to African American individuals (AA, 5.2% [22 of 426]). We found ≥2 potentially pathogenic  CFTR variants in 1.4% (19); 0.5% (4) of NHW and 2.8% (12) of AA. Potentially pathogenic  CFTR variant genotypes (≥1 or ≥2 variants) were not cumulatively associated with lung function or exacerbations. In NHW, we found three F508del compound heterozygotes with F508del and a VVCC (two 5T;TG12[c.1210-11T>G] and one Arg1070Trp) and a homozygote for the VVCC, 5T;TG12. Conclusions: We found potentially pathogenic  CFTR variants within a severe asthma-enriched cohort , including three compound heterozygote genotypes variably associated with CF in NHW individuals. These findings provide the rationale for  CFTR sequencing and phenotyping of CF-related traits in individuals with severe asthma.