Patients with the rs75541969 CG genotype (one copy of the CFTR D1152H variant) and cystic fibrosis may respond to ivacaftor treatment. FDA-approved drug labeling information and CPIC guidelines indicate use of ivacaftor in cystic fibrosis patients with at least one copy of a list of 33 CFTR genetic variants, including D1152H. Other genetic and clinical factors may also influence response to ivacaftor.