CFTR and congenital bilateral aplasia of vas deferens from CFTR mutation: Cystic fibrosis transmembrane conductance regulator (CFTR) variants are responsible for cystic fibrosis (CF) and were found to play a crucial role in the development of CUAVD.6 Most CAVD patients are compound heterozygotes with different mutant alleles, and about 43% of CUAVD patients carry at least one CFTR variant according to previous reports.7 Among these genotypes/alleles, 5T, F508del, and R117H are the most common.