CFTR and cystic fibrosis: Abnormal bioelectric phenotype was discovered to be corrected in cystic fibrosis caused by variants of the cystic fibrosis transmembrane conductance regulator gene (CFTR) by administering replication-deficient, recombinant adenovirus vector containing a normal copy of the CFTR cDNA (AdCFTR) in a clinical trial (Hay et al., 1995).